Vacuum reflow soldering having oven unit connected in series for each temperature section

Abstract

The present invention relates to a vacuum reflow soldering device having an oven unit connected in series for each temperature section. The vacuum reflow soldering device enables energy saving operation, reduces production costs, facilitates real-time response for ease of maintenance, minimizes the input of expensive nitrogen gas to be more economical, improves soldering quality to secure reliability of a printed circuit board product, easily changes an optimal temperature setting according to a temperature-sensitive component to easily change a design and a surface mounting component, and smoothly moves to a vacuum space for each temperature section according to the size of the printed circuit board, thereby enabling universal application regardless of the size of the printed circuit board.

Description

Vacuum reflow soldering with series-connected oven units for different temperature ranges

[0001] The present invention relates to a vacuum reflow soldering device having a series-connected oven unit for each temperature range, and more specifically, to a vacuum reflow soldering device having a series-connected oven unit for each temperature range that allows setting step-by-step temperatures for soldering through a reflow chamber composed of a plurality of vacuum compartments in series, thereby preventing unnecessary energy waste and enabling the mounting (soldering) of components on a printed circuit board without the need for gas injection to remove voids, thus improving soldering quality, and is composed of separate vacuum compartments for easy maintenance.

[0002] Generally, the reflow soldering device used in the SMT (Surface Mount Technology) process is a device used to attach a lead frame and a PCB (printed circuit board) to each other, or to attach small electronic components such as semiconductor chips or resistor chips on a PCB by undergoing a process of heating or cooling the solder paste for soldering in a production line.

[0003] Such conventional reflow soldering devices are equipped with a transfer unit, an oven, and an exhaust unit within a single-piece chamber. A PCB coated with solder paste, which is fed into the insertion unit and supplied to the transfer unit, is transported by the conveyor of the transfer unit, and the soldering process is performed by applying preheating and main heating in an oven where preheating and main heating processes take place within a single space.

[0004] Next, a lead frame or semiconductor chip is soldered onto the PCB, and subsequently, as the PCB passes through an exhaust section, the carbonized gas from the solder paste generated by the melting of the solder is recovered and discharged, and the soldering of the PCB is completed as the solder cools and solidifies.

[0005] However, these conventional reflow soldering machines have significant spatial constraints regarding installation, and because the amount or pressure of the supplied gas is not stably provided due to the influence of external devices, the gas supplied into the oven is not always supplied in a uniform state. Consequently, when soldering is performed through preheating, heating, and cooling in a single space like the above during PCB surface mounting, there was a problem in that soldering defects occurred due to voids, oxidation, and poor precise temperature control of the solder on the printed circuit board (PCB).

[0006] Here, voids are generated during the surface mounting process of a printed circuit board by immersing it in a reflow oven, due to factors such as the temperature set in the reflow and residual gases produced from molten solder during the soldering process. Since these resulting voids can impair the thermal conductivity or electrical performance of mounted components during reflow soldering, eliminating or minimizing such voids serves as a standard for improving the surface quality of printed circuit boards produced by reflow soldering.

[0007] Furthermore, oxidation in reflow devices is one of the causes of various problems in the soldering process, such as the formation of voids. Since the reduced wettability during soldering due to solder melting can weaken the solder joint, this is a critical factor that can lead to product defects. However, conventional reflow devices make it impossible to prevent oxidation because the soldering oven space itself is formed as a single unit and is exposed to the outside air.

[0008] Furthermore, it can be said that temperature control is important as a condition for improving the soldering quality of printed circuit boards. While such temperature control can improve soldering quality by preventing thermal stress on mounted components through the adjustment of heating and cooling cycles within an optimal temperature range, if temperature control is performed in a single space using a single oven, such as in conventional reflow soldering devices, the oven temperature is practically controlled based on the high-temperature range required for surface mounting. Consequently, it is difficult to expect high quality due to the influence of ambient heat sources during the cooling temperature range.

[0009] Furthermore, since such conventional reflow soldering devices consist of a single oven, they suffer from significant heat loss, and there is a problem of energy waste caused by unnecessary power consumption required to control the temperature to meet the aforementioned standards.

[0010] Furthermore, conventional reflow soldering devices utilize a reflow soldering process based on forced convection for temperature control within a single space, which results in a longer optimal temperature range for soldering. This leads to the problem of the soldering device becoming larger, causing significant limitations on installation locations and prolonged process times.

[0011] Furthermore, as previously mentioned, regarding oxidation, which is one of the factors impairing the soldering quality of printed circuit boards, conventional reflow soldering devices attempted to solve the problem by including an anti-oxidation flux in the solder or applying the flux to the wafer to prevent high-temperature oxidation of the joints of surface-mounted components. However, despite these efforts, it is difficult to completely block the inflow of oxygen to the area around the joints (soldering) of the wafer or components, resulting in product quality defects caused by poor bonding. Additionally, a nitrogen atmosphere must be maintained inside the reflow soldering device, and the amount of nitrogen exhausted into the air is very large, making it uneconomical. Moreover, as previously mentioned, the high energy consumption is unavoidable due to significant unnecessary heat loss during temperature control for soldering, leading to high power consumption.

[0012] Furthermore, there is a reality where workers are exposed to contamination of the surrounding working environment or poor working conditions caused by gas emissions and high-temperature heat sources during the soldering process, which can lead to the risk of safety accidents.

[0013] [Prior Art Literature]

[0014] [Patent Literature]

[0015] Republic of Korea Registered Patent No. 10-1881449, Registration Date: July 18, 2018.

[0016] Accordingly, the present invention was created to solve the problems described above, and aims to provide a vacuum reflow soldering device having a serially connected oven unit for each temperature section, which allows for efficient management through temperature section-by-section management by dividing the time-by-time temperature curve for reflow soldering into preheat, reflow, and cooling-down sections to establish the reflow soldering process sequence, and dividing the process sequence into multiple vacuum chambers rather than within a single space to enable efficient management. Furthermore, the minimum three sections divided into preheat, reflow, and cooling-down are further subdivided according to changes in temperature and time on the reflow soldering temperature curve to divide it into up to six sections: preheating, latent heat, temperature rise, mounting, temperature decrease, and cooling, thereby further improving the quality and precision of component mounting on a printed circuit board and the efficient management of energy.

[0017] Furthermore, the present invention aims to provide a vacuum reflow soldering device having a series-connected oven unit for temperature ranges, which enables easy real-time response during the reflow soldering process by configuring an oven unit composed of unit ovens forming vacuum chambers for each temperature range, thereby allowing easy identification of the location of malfunctions or problems occurring during the reflow soldering process from the unit ovens. It also allows for rapid replacement by stopping only the configuration at the problematic location without stopping the entire operation, and accordingly, by resetting only the temperature and vacuum state of the problematic section without having to reset the temperature and vacuum state of the unstopped section from the beginning, it minimizes delays in mounting time caused by the entire reflow soldering process and simplifies maintenance. Additionally, it enables energy-saving operation and production cost reduction through the efficient use of power consumption according to the temperature and vacuum state set for each unit oven.

[0018] Furthermore, another objective of the present invention is to provide a vacuum reflow soldering device having a serially connected oven unit for each temperature range, wherein the oven unit is configured by serially connecting unit ovens configured with vacuum chambers for each temperature range for reflow soldering, thereby allowing for individual management of energy consumption and loss for each range, resulting in cost reduction due to energy waste, and since soldering is performed in a vacuum space, there is no need to introduce expensive nitrogen gas to prevent voids and oxidation, making it more economical. Additionally, since soldering is performed in a vacuum space and contact with oxygen is limited, the occurrence of oxidation in the molten solder portion of the mounted component is limited, thereby improving soldering quality and ensuring the reliability of the printed circuit board product.

[0019] Furthermore, the present invention aims to provide a vacuum reflow soldering device having a serially connected oven unit for each temperature range, which is capable of universal application according to the size of the printed circuit board. This is achieved by forming multiple vacuum chambers and configuring them along temperature ranges required for the reflow soldering process, thereby facilitating the change of optimal temperature settings according to the type of solder used for surface mount components with different configurations based on the component material or temperature-sensitive components, and enabling easy design changes to the time-based temperature curve of reflow soldering and changes to surface mount components. Additionally, it allows for smooth movement into vacuum spaces according to the temperature range based on the size of the printed circuit board.

[0020] To achieve the above objective, the vacuum reflow soldering device having a serially connected oven unit for each temperature range according to the present invention comprises: an oven unit (OU) provided for inserting and mounting (soldering) a printed circuit board equipped with a plurality of components; a dust collection means provided to be connected to the oven unit to collect and treat harmful gases generated during the mounting process; and a main body housing provided with a control unit provided to control the soldering operation and having the oven unit and the dust collection means installed inside. In the reflow soldering device, the device comprises a time-based temperature curve for reflow soldering of a printed circuit board, wherein a printed circuit board (P) equipped with a plurality of components is initially inserted, and the flux is evaporated and removed to minimize the formation of voids through preheating that prepares for preheating for reflow soldering and raises the temperature to a latent heat temperature, and the printed circuit board is activated as all board areas and component areas of the printed circuit board are gradually heated to the same temperature. A reflow section (R) in which an activated printed circuit board (P) is introduced, the temperature is continuously raised past the melting point at which the solder of multiple components mounted on the printed circuit board begins to melt for reflow soldering to proceed, and is maintained for a certain period of time at the maximum temperature at which reflow soldering continues, and then lowered back to the melting point at which the maintenance ends to prevent the occurrence of cracks in the reflow soldering portion of the mounted components by melting the solder of the printed circuit board and stabilizing it; and a cooling down section (C) in which the printed circuit board with multiple components mounted on it is cooled to room temperature through cooling.The invention is characterized by the fact that a unit oven (100) is formed in which a vacuum chamber is formed in which the temperature and degree of vacuum state corresponding to each section of the preheat, reflow, and cooling-down sections are maintained in three stages, and an oven unit (OU) is formed in series in the order of preheat (F), reflow (R), and cooling-down (C), and a printed circuit board (P) is transferred to the vacuum chamber of each unit oven (100) in series of the oven unit (OU) for input, ambient heating, and discharge, so that components of the printed circuit board are mounted through reflow soldering.

[0021] Here, the above-mentioned preheat section (F) is divided into two stages: a preheat section (F1) in which a printed circuit board (P) equipped with multiple components is first introduced and the flux is operated through a preheating temperature in a reflow soldering temperature curve to prepare for preheating and raise the temperature to a latent heat temperature for reflow soldering, and the solvent is evaporated and removed to minimize the formation of voids; and a latent heat section (F2) in which the temperature is raised through continued preheating after reaching the latent heat temperature, and the printed circuit board is activated by gradually heating all board areas and component areas of the printed circuit board to the same temperature, thereby matching the latent heat temperature in a reflow soldering temperature curve and the vacuum state. The unit oven (100) is connected in series, and a vacuum chamber is formed in which the temperature and the degree of the vacuum state corresponding to each preheating-latent heat section is maintained, thereby forming an oven unit (OU) connected in series in the order of preheating-latent heat-reflow-cooling down.

[0022] Meanwhile, the reflow section (R) comprises: a temperature increase section (R1) for raising the temperature from a temperature section where the latent heat ends, corresponding to the temperature range of the mounting section of the temperature curve for reflow soldering of the printed circuit board, to a temperature section where the solder begins to melt; and a mounting section (R2) for raising the temperature from the temperature section where the solder begins to melt to a maximum temperature section of the reflow and maintaining the temperature for a certain period of time so that a number of components of the printed circuit board are mounted. The device is characterized by having a unit oven (100) formed in which a vacuum chamber is formed to maintain the temperature and vacuum state corresponding to each of the three or two stages, and the unit oven (100) is connected in series in the order of heating-heating-heating-heating-cooling-down or heating-heating-cooling-down or preheat-heating-heating-heating-cooling-down, and the unit oven (100) is connected in series in the order of heating-heating-heating-cooling-down, and the unit oven (100) is formed in which the heating section (RC1) is gradually cooled from the point where the temperature maintenance ends after the heating section is completed and the solder begins to melt to the melting point temperature where the solder begins to melt, thereby preventing cracks in the mounted part; and the heating section (RC1) can be divided into three stages or two stages, and the heating section and the mounting section (RC1) can be divided into two stages, and the unit oven (100) is formed in which the heating section and the vacuum chamber are formed to maintain the temperature and vacuum state corresponding to each of the three or two stages, and the unit oven (100) is connected in series in the order of heating-heating-heating-heating-cooling-down.

[0023] Here, the cooling down section (C) can be divided into a cooling section (C1) that rapidly cools from the temperature at which the solder begins to melt to room temperature, or a cooling down section (RC1) of the reflow section, and a unit oven (100) in which a vacuum chamber is formed to maintain the temperature and vacuum state corresponding to each section divided into the first or second stage is connected in series in the order of cooling or temperature reduction-cooling, and an oven unit (OU) is formed in the order of cooling down consisting solely of preheat-reflow-cooling or preheat-reflow (temperature increase-mounting)-temperature reduction-cooling.

[0024] Meanwhile, the unit oven (100) with an airlock function is configured to be connected in series at the front and rear ends of an oven unit (OU) line in which unit ovens are connected in series according to sections of the reflow soldering temperature curve, so as to buffer and maintain the temperature and vacuum level of each unit oven (100) of the preheat section (F) and the cooling down section (C) of the printed circuit board input side of the preheat section (F) and the printed circuit board output side of the cooling down section (C).

[0025] Here, the unit oven (100) is formed as a rectangular cuboid extending in the longitudinal direction so as to form a vacuum chamber inside, and a moving gate (113, 114) for the insertion and discharge of a printed circuit board (P) is formed on the left and right vertical surfaces (111, 112), and an openable inspection door (116) and an inspection opening (117) are formed on the upper horizontal surface (115), and a collection hole (119) connected to the dust collection means is formed on the rear vertical surface (118), and a plurality of power transmission holes (122) are formed on the front vertical surface (120) of the oven housing (110); A vacuum control means (130) provided on the left and right vertical surfaces (111, 112) on which the moving gates (113, 114) are formed to control the moving gates (113, 114) formed on the left and right vertical surfaces (111, 112) of the oven housing (110) to control the insertion and discharge of a printed circuit board into the vacuum chamber and to maintain a vacuum state inside the vacuum chamber; and a heating means (150) composed of a composite heating element (152) capable of raising the internal temperature of the vacuum chamber and controlling the solder mounting temperature, on the lower surface of the inspection door (116) forming the upper horizontal surface (115) of the vacuum chamber bottom side and the upper side of the vacuum chamber formed inside the oven housing (110); The above oven housing (110) is characterized by having a transfer drive unit (190) and a variable drive unit (180) formed on the outer side of the front vertical surface (120) of the above oven housing (110), and a variable transfer unit (160) formed on the bottom side of the vacuum chamber on the left and right sides of the heating means (150) so that the printed circuit board (P) inserted through the transfer drive unit (190) is transferred to a size corresponding to the left and right width of the insertion direction of the printed circuit board by the power of the variable drive unit (180) transmitted through the power of the power transmission hole (122), and then the printed circuit board (P) inserted through the transfer gate (113, 114) is transferred by the power of the transfer drive unit (190) in a process of insertion transfer - ambient heating - discharge transfer, so that the printed circuit board is reflow soldered according to the heat transmitted from the heating means (150) and the vacuum inside the vacuum chamber.

[0026] Meanwhile, it is preferable that a heat-reflecting shielding member (200) be formed on the upper, lower, front, rear, left, and right sides forming the vacuum chamber of the unit oven (100) to prevent internal heat loss and heat loss of heat generated from the heating means (150), enable heat conduction blockage, and prevent heat transfer to the vacuum chamber of an adjacent unit oven.

[0027] Furthermore, the vacuum control means (130) comprises: a guide bar (131) that is fixedly coupled vertically and symmetrically to the left and right sides of the front of the moving gate formed on the left and right vertical surfaces of the oven housing, and has a roller groove (132) formed on one side facing each other to guide contact and release toward the moving gates (113, 114) formed on the left and right vertical surfaces; a guide support block (133) that is symmetrically coupled to the lower side of the front of the left and right vertical surfaces of the oven housing where the moving gate is formed, and has a roll bearing formed on the upper side along an axis perpendicular to the entry direction of the moving gates (113, 114) formed on the left and right vertical surfaces (111, 112) of the oven housing, so that a printed circuit board (P) that is inserted, discharged, and transmitted while freely rotating is supported and moved; and a guide support block (133). A gasket groove (135) is formed on the rear surface facing the above-mentioned moving gates (113, 114), and guide rollers (136) are symmetrically formed on the left and right sides, fitted into the roller grooves (132) of the guide bar (131) and rolling along the roller grooves, and a gate door (134) provided as a vertical plate body to control the opening and closing and sealing force of the moving gates (113, 114) according to the position where the guide rollers (136) move along the roller grooves (132); It is characterized by being formed with a gate opening / closing means (140) formed on the upper horizontal surface of an oven housing (110) located vertically above the gate door (134), which is driven to move up and down along the roller groove (132) of a guide bar (131), and which determines the opening and closing of the moving gate (113, 114) according to the up and down movement of the gate door (134).

[0028] Here, the gate opening / closing means (140) is characterized by being formed by: an opening / closing cylinder body (142) fixedly coupled to the upper surface of one side of an inspection door (116) formed on the upper horizontal surface of an oven housing (110) located on a vertical line with the top of the gate door (134); and an opening / closing cylinder rod (144) which penetrates the lower surface of the upper horizontal surface of the oven housing (110) to which the opening / closing cylinder body (142) is fixedly coupled so as to operate up and down, and operates to move up and down in the vertical direction on a vertical line, with its lower end coupled to the upper surface of the gate door (134).

[0029] Meanwhile, the above-mentioned composite heating element (152) is installed on the bottom side of the vacuum chamber and the lower surface of the upper inspection door (116) to heat the upper and lower sides of the board of the printed circuit board transported by the variable transport means (160). It is a direct heating method like a sheath heater, which has excellent thermal efficiency, is easy to install, has excellent performance and durability with high external gravitational mechanical strength and chemical stability, and heats to directly raise the temperature inside the vacuum chamber. It is a far-infrared heater (154) that uses carbon fiber as a heating element to locally heat the solder surface and interior where components are mounted. Since it is a radiant heat method, it only gets warm when it is in a place where far-infrared rays touch, but has a lower risk of damage and a very fast heating speed compared to ceramic or halogen, and can set a clear upper temperature limit compared to other heating elements. It is a far-infrared heater (154) such as a carbon heater that emits far-infrared rays, or a heating element (153)-far-infrared heater (154). It is characterized by being configured in a composite manner so that the far-infrared heater (154) and the electric heater (153) are sequentially arranged in the order of continuous.

[0030] Here, the composite heating element (152) on either the bottom or top side of the vacuum chamber in which the composite heating element (152) is installed is provided solely as an electric heater and is configured to directly heat the board of the printed circuit board being transported by the variable transport means (160).

[0031] Furthermore, the variable transfer means (160) comprises: a fixed block (161) formed symmetrically on the front left and right sides of the bottom surface of the oven housing; a first guide support member (163) formed long in the left and right longitudinal direction and protruding toward the upper rear side so as to allow a printed circuit board (P) equipped with a plurality of parts to be inserted, heated, and discharged into the vacuum chamber formed inside the oven housing (110) through a moving gate (113, 114); a first moving chain (165) connected to a first driving sprocket (164) is provided on the left and right sides of the first guide support member (163); and a first driving sprocket (166) is provided on one of the left and right ends connected to the fixed block (161) to drive the first moving chain (165) to rotate infinitely. A variable guide section (167) is provided with a guide shaft (167a) that is horizontally extended from the rear side of each of the left and right fixed blocks (161) toward the rear vertical surface (118) where the collection hole (119) of the oven housing (110) is formed, and a guide block (168) that moves back and forth within the vacuum chamber along the guide shaft (167a); and a variable moving section (169) is formed symmetrically between the left and right variable guide sections (167), and a variable lead screw (170) is formed that extends horizontally from the rear vertical surface (118) of the oven housing (110) toward the power transmission hole (122) of the front vertical surface (120) of the oven housing (110), and a lead nut bracket (171) that is spirally coupled to move horizontally back and forth according to the rotation of the variable lead screw (170).The guide block (168) of the variable guide section (167) and the lead nut bracket (171) of the variable moving section (169) are fixedly coupled to both left and right ends, and the guide block (168) moves together on the guide shaft (167a) according to the forward and backward horizontal movement on the variable lead screw (170) of the lead nut bracket (171). A second guide support section (173) is formed extending long in the left and right longitudinal direction and protruding upwards so that a printed circuit board (P) equipped with a plurality of parts is inserted, moved, heated at air, and discharged into a vacuum chamber formed inside the oven housing (110) through the moving gates (113, 114) facing the fixed reflow conveyor (162), and the second guide support section (173) is formed to be long in the left and right longitudinal direction and protrudes upwards, and the second driving sprocket (174) is chain-coupled to the left and right of the second guide support section (173). A variable reflow conveyor (172) having a second moving chain (175) provided, and a second driving sprocket (176) coupled to one of the left and right ends coupled to the guide block (168) and the lead nut bracket (171) to drive the second moving chain (175) simultaneously with the first moving chain (165); A rotating shaft (178) that is formed as a long, rectangular shape and horizontally fitted through a power transmission hole (122) on the same axis as the first and second drive sprockets (166, 176) of the front vertical surface (120) of the oven housing (110), so that the first drive sprocket (166) of the fixed reflow conveyor (162) and the second drive sprocket (176) of the variable reflow conveyor (172) are axially coupled on the same axis so that the first drive sprocket (166) and the second drive sprocket (176) rotate simultaneously;A transfer drive unit (190) provided on the outer side along the same axis as the power transmission hole (122) on the front vertical surface (120) of the oven housing (110) along the same axis as the first and second drive sprockets (166, 176), so that the first drive sprocket (166) and the second drive sprocket (176) rotate simultaneously by the driving force of the rotation shaft so that the first movable chain (165) and the second movable chain (175) rotate along the first and second driven sprockets (164, 174) and the first and second guide support parts (163, 173), respectively; The variable drive unit (180) is formed such that it is axially coupled to the variable lead screw (170) through a power transmission hole formed on the outer side of the front vertical surface (120) of the oven housing (110) on the same axis as the variable lead screw (170), thereby transmitting power to cause the variable lead screw to rotate in forward and reverse directions, and the variable reflow conveyor (172) is configured to move along the guide shaft (167a) toward the fixed reflow conveyor (162) so that the lead nut bracket (171) moves horizontally back and forth on the variable lead screw (170) according to the forward and reverse rotation of the variable lead screw (170), thereby varying the width to correspond to the left and right width of the input direction of the printed circuit board.

[0032] Here, the first and second type sprockets (164, 174) and the first and second drive sprockets (166, 176) are each formed as belt pulleys, and the first and second moving chains (165, 175) are composed of conveyor belts usable at high temperatures, so that the printed circuit board is transferred, heated in the atmosphere, and discharged by the combination of the belt pulleys and conveyor belts within the unit oven (100) constituting the oven unit of the reflow soldering device.

[0033] The present invention establishes a reflow soldering process sequence by dividing the time-based temperature curve for reflow soldering into preheat, reflow, and cooling-down sections. By dividing the process sequence into multiple vacuum chambers rather than within a single space, efficient management is possible through temperature management by section. Furthermore, the minimum three sections divided into preheat, reflow, and cooling-down are further subdivided according to changes in temperature and time on the reflow soldering temperature curve into up to six sections: preheating, latent heat, temperature rise, mounting, temperature decrease, and cooling. This has the effect of further improving the quality and precision of component mounting on printed circuit boards and the efficient management of energy.

[0034] Furthermore, the present invention comprises an oven unit composed of unit ovens forming vacuum chambers for each temperature range. This allows for easy identification of the location of malfunctions or problems occurring during the reflow soldering process, facilitating real-time response during the reflow soldering process. Additionally, it enables rapid replacement by stopping only the configuration at the problematic location without the need to halt the entire operation. Consequently, by resetting only the temperature and vacuum conditions of the problematic section without having to reset the temperature and vacuum conditions of the unstopped sections from scratch, the delay in mounting time caused by the entire reflow soldering process is minimized and maintenance is simplified. Moreover, it offers the advantages of energy-saving operation and reduced production costs through the efficient use of power consumption based on the temperature and vacuum conditions set for each unit oven.

[0035] Furthermore, the present invention comprises an oven unit formed by serially connecting unit ovens configured with vacuum chambers for each temperature range for reflow soldering, thereby allowing for individual management of energy consumption and loss for each range, which reduces costs associated with energy waste. Additionally, since soldering is performed in a vacuum space, there is no need to introduce expensive nitrogen gas to prevent voids and oxidation, making it more economical. Moreover, as soldering proceeds in a vacuum space and contact with oxygen is limited, the occurrence of oxidation in the molten solder portion of the mounted component is restricted, thereby improving soldering quality and ensuring the reliability of the printed circuit board product. Furthermore, it is easy to change the optimal temperature setting according to the type of solder used for surface mount components with different compositions depending on the component material or temperature-sensitive components, allowing for easy design changes to the temperature curve over time for reflow soldering and changes to surface mount components. Additionally, it is possible to move smoothly to the vacuum space for each temperature range according to the size of the printed circuit board, thus providing the advantage of universal application depending on the size of the printed circuit board.

[0036] Figure 1 is a graph of the temperature curve over time of reflow soldering in a vacuum reflow soldering device having a series-connected oven unit for each temperature range according to the present invention.

[0037] FIG. 2 is an overall perspective view of a vacuum reflow soldering device having a series-connected oven unit for each temperature range according to the present invention.

[0038] FIG. 3 is a perspective view of a unit oven constituting an oven unit of a vacuum reflow soldering device having a series-connected oven unit for each temperature range according to the present invention.

[0039] FIG. 4 is an exploded perspective view of a unit oven of a vacuum reflow soldering device having a series-connected oven unit for each temperature range according to the present invention.

[0040] FIG. 5 is an exploded perspective view of a vacuum interruption means of a unit oven of a vacuum reflow soldering device having a series-connected oven unit for each temperature range according to the present invention.

[0041] FIG. 6 is a side view illustrating the opening and closing process of a vacuum interruption means of a unit oven of a vacuum reflow soldering device having a series-connected oven unit for each temperature range according to the present invention.

[0042] FIG. 7 is a perspective view of a heating means of a unit oven of a vacuum reflow soldering device having a series-connected oven unit for each temperature range according to the present invention.

[0043] FIG. 8 is a perspective view of a variable transfer means of a unit oven of a vacuum reflow soldering device having a series-connected oven unit for each temperature range according to the present invention.

[0044] FIG. 9 is a perspective view of the variable operating state of a variable reflow conveyor according to the width of a printed circuit board of a unit oven of a vacuum reflow soldering device having a serially connected oven unit for each temperature range according to the present invention.

[0045] FIG. 10 is a perspective view of a fixed, variable reflow conveyor for the forward movement of a printed circuit board of a unit oven of a vacuum reflow soldering device having a serially connected oven unit for each temperature range according to the present invention.

[0046] FIG. 11 is a side view illustrating the operation sequence of a vacuum interruption means according to the initial insertion of a printed circuit board into an oven unit of a vacuum reflow soldering device having a series-connected oven unit for each temperature range according to the present invention.

[0047] FIG. 12 is a side view illustrating the operation sequence of a vacuum interruption means that is continuously repeated after the initial insertion of a printed circuit board into the oven unit of a vacuum reflow soldering device having a serially connected oven unit according to the temperature range according to the present invention.

[0048] FIG. 13 is a side view illustrating another operation sequence of the vacuum interruption means according to the initial insertion of a printed circuit board into the oven unit of a vacuum reflow soldering device having a series-connected oven unit for each temperature range according to the present invention.

[0049] FIG. 14 is a side view illustrating another operation sequence of a vacuum interruption means that is continuously repeated after the initial insertion of a printed circuit board into the oven unit of a vacuum reflow soldering device having a serially connected oven unit according to the temperature range according to the present invention.

[0050] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in a number of different forms.

[0051] Hereinafter, technical features according to an embodiment of the vacuum reflow soldering apparatus according to the present invention will be described in detail with reference to the attached drawings.

[0052] As shown in FIG. 1, the vacuum reflow soldering device having a serially connected oven unit for each temperature range according to the present invention divides the time-based temperature curve for reflow soldering into preheat-reflow-cooling-down sections, and as shown in FIG. 2, each unit oven having a vacuum chamber operating at a temperature and vacuum state corresponding to each divided section is provided to form a single oven unit through serial connection, thereby enabling efficient management of temperature and vacuum state by dividing multiple vacuum spaces into temperature ranges for reflow soldering.

[0053] In other words, by configuring unit ovens for reflow soldering based on temperature ranges, energy consumption can be managed efficiently by utilizing temperature and vacuum levels for each unit oven, enabling energy-saving operation and production cost reduction. Furthermore, by forming vacuum spaces for each temperature range, the location of malfunctions or problems occurring during the reflow soldering process can be easily identified, facilitating real-time response during the process.

[0054] In addition, by performing reflow soldering in the vacuum space of the unit oven, mounting quality can be improved by preventing voids in the unit oven and cracks due to cooling, which are separated by temperature. Furthermore, oxidation can be prevented by limiting contact with oxygen due to the vacuum inside the chamber of the unit oven, eliminating the need for the introduction of expensive nitrogen gas, making it more economical. Additionally, the oxidation of the molten solder portion of the mounted component is limited due to the aforementioned restriction of oxygen contact, thereby improving soldering quality and ensuring the reliability of the printed circuit board product. Moreover, since it is easy to change the optimal temperature setting according to the type of solder used for surface mount components with different compositions depending on the component material or temperature-sensitive components, design changes and changes to surface mount components can be easily made.

[0055] Furthermore, as shown in FIG. 2, the reflow soldering device is configured with an oven unit (OU) provided for inserting and mounting (soldering) a printed circuit board equipped with multiple components, a dust collection means provided to be connected to the oven unit to collect and treat harmful gases generated during the mounting process, and a main body housing provided with a control unit provided to control the soldering operation and the oven unit and dust collection means installed inside, and as shown in FIG. 1, the hourly temperature curve for reflow soldering of the printed circuit board can be divided into at least three stages: a preheat section (F), a reflow section (R), and a cooling down section (C).

[0056] Here, the preheat section (F) in the reflow soldering temperature curve is a section in which a printed circuit board (P) equipped with multiple components is initially introduced, and the flux is evaporated and removed to minimize the formation of voids while the solvent is removed through preheating to prepare for reflow soldering and raise the temperature to the latent heat temperature, and the printed circuit board is activated as all board areas and component areas of the printed circuit board are gradually heated to the same temperature.

[0057] The reflow section (R), which is a continuous section following the preheat section in the reflow soldering temperature curve, is a section in which an activated printed circuit board (P) is introduced and the temperature is continuously raised until it passes the melting point at which the solder of multiple components provided on the printed circuit board begins to melt for reflow soldering to proceed, and is maintained for a certain period of time at the maximum temperature at which reflow soldering continues. At the point where the maintenance ends, the temperature is lowered back to the melting point at which the solder begins to melt, thereby stabilizing the printed circuit board to prevent cracks from forming in the reflow soldering portion of the mounted components. Here, the section where the temperature of the reflow section decreases may be included in the reflow section or cooling down section described later. That is, since the mounting of components actually proceeds up to the vicinity of the melting point where the temperature decreases, this can be considered as a reflow section.

[0058] However, if we consider only the point where the temperature drops, it can be included in the cooling-down phase, so it is a phase that can belong to both sides.

[0059] The cooling down section (C) in the reflow soldering temperature curve is a section where a printed circuit board with multiple components mounted on it is cooled to room temperature through cooling. The portion of the temperature curve that drops from the highest temperature point of the aforementioned reflow section to the melting point can be classified as either a reflow section or a cooling down section. That is, as mentioned above, it belongs to the reflow section when based on the mounting of components, and it belongs to the cooling down section when based on the drop in temperature.

[0060] Accordingly, as shown in FIG. 2, a unit oven (100) in which a vacuum chamber is formed to maintain the temperature and vacuum state corresponding to each section of the preheat-reflow-cooling-down time-by-time temperature curve of reflow soldering, divided into at least three stages as shown in FIG. 1, can be formed in series with an oven unit (OU) connected in the order of preheat-reflow-cooling-down.

[0061] Here, a printed circuit board (P) is transferred via an input, ambient heating, and discharge method to the vacuum chamber of each unit oven (100) connected in series with the oven unit (OU), thereby arranging for components of the printed circuit board to be mounted through reflow soldering. That is, each unit oven (100) can achieve high mounting quality through the temperature and vacuum level corresponding to each section.

[0062] In other words, the unit oven can be configured according to the number of temperature sections divided by reflow time on the temperature curve for reflow soldering, and the most important key point is that the configuration of unit ovens corresponding to the temperature and vacuum level of the vacuum chamber of each unit oven is connected in series and operates according to the temperature and vacuum state characteristics of each section, and that a vacuum interruption means to ensure continuity without affecting adjacent unit ovens connected to the double unit oven, and a variable transfer means capable of varying according to the width of the printed circuit board being fed, are possible.

[0063] Accordingly, we intend to explain the minimum temperature intervals of the hourly temperature curve of the reflow soldering of the present invention and the intervals of the temperature curve that can be additionally modified. Before proceeding with the explanation, the reflow soldering process is briefly described below using the hourly temperature curve for reflow soldering.

[0064] As shown in Fig. 1, the temperature curve of reflow soldering over time is the most ideal curve that enables high-quality component mounting on the printed circuit board. It involves preheating to raise the temperature within a short period of time while maintaining the temperature on the Y-axis and time on the X-axis at 25 degrees, thereby activating the printed circuit board, followed by a latent heat process with a narrow range of temperature increase over a relatively long period, and then raising the temperature and time in a nearly direct proportion to the point where the solder on the printed circuit board practically melts. After the temperature reaches the maximum temperature for reflow soldering at the melting point, the same temperature is maintained for a certain period of time to reflow solder the printed circuit board, after which the temperature is gradually lowered to the melting point to prevent soldering defects caused by cracking, followed by continuous rapid cooling.

[0065] In the above-mentioned temperature curve of reflow soldering, the temperature range of preheating and latent heat is divided into a preheat section (F), the range from the point where latent heat ends to the melting point is divided into a reflow section (R), and the remaining portion is divided into a cooling down section (C) that cools down quickly to a temperature close to room temperature of 25 degrees.

[0066] The minimum unit section of the hourly temperature curve for such reflow soldering is configured by connecting unit ovens in series, corresponding to the sectioned parts, so that the temperature and vacuum level differ between each section according to temperature, thereby minimizing the defect rate caused by external or internal foreign substances through these differences in vacuum levels.

[0067] Accordingly, the above-mentioned preheat section (F) can be divided into two stages: a preheat section (F1) in which a printed circuit board (P) equipped with multiple components is first introduced, and the flux is operated through a preheating temperature in a reflow soldering temperature curve to prepare for reflow soldering and raise the temperature to a latent heat temperature, thereby adjusting to a vacuum state to minimize the formation of voids by evaporating the solvent; and a latent heat section (F2) in which the temperature is raised through continued preheating after reaching the latent heat temperature, and the printed circuit board is activated by gradually heating all board areas and component areas of the printed circuit board to the same temperature and adjusting to a vacuum state in a reflow soldering temperature curve. That is, it can be configured so that preheating and latent heat occur simultaneously within the preheat section (F), or it can be configured by connecting in series a unit oven (100) in which a vacuum chamber is formed to maintain the temperature and vacuum state corresponding to each preheating-latent heat section.

[0068] Accordingly, the above-mentioned preheat section (F) can be configured as a single unit oven, or unit ovens corresponding to each section divided into preheating and latent heat sections can be configured. The series-connected oven unit (OU) that can be obtained through such a preheat section (F) is formed by serially connecting unit ovens for each section through the time-dependent temperature curve of reflow soldering divided into three stages of preheat-reflow-cooling down sections, as described above, or by serially connecting oven units (OU) in the order of preheating-latent heat-reflow-cooling down.

[0069] After the unit ovens (100) individually equipped for each section are connected in series and divided into the previously mentioned preheat-reflow-cooldown or preheat-latent heat-reflow-cooldown sections, the insertion and discharge of printed circuit boards for reflow soldering can be individually set to the temperature corresponding to the section divided on the time-based temperature curve of reflow soldering by partitioning each vacuum chamber by a vacuum interruption means described later at the initial insertion section, the connection section between each unit oven, and the final discharge section, and the temperature of the vacuum chamber within each unit oven (100) can be individually set.

[0070] Accordingly, efficient temperature management is possible through vacuum compartments for each temperature level; energy is saved by configuring power consumption for each vacuum compartment; maintenance is simplified for each level due to the configuration of temperature-level vacuum compartments; energy loss is reduced due to the vacuum; it is economical as there is no need for expensive gas injection; product reliability is ensured by improving soldering quality through oxidation prevention; and it is easy to change the optimal temperature settings for surface mounting according to the material of each component.

[0071] Meanwhile, the reflow section (R) is a section where the solder on the printed circuit board melts and components are mounted by passing through the aforementioned preheat section (F), the temperature curve section divided into the preheating section (F1) and the latent heat section (F2), then passing the melting point, maintaining it at the maximum temperature section for a certain period of time, and then lowering the temperature back to the melting point. In this section, a high vacuum and temperature are maintained to prevent the occurrence of solder surface cracks during the initial cooling process after mounting is completed, thereby improving mounting quality.

[0072] The above-mentioned reflow section (R) is divided into a heating section (R1), a mounting section (R2), and a cooling section (RC1), or divided into a heating section (R1) and a mounting section (R2), and a unit oven (100) is configured to match the temperature and vacuum level for each section at different times and connected in series.

[0073] Here, the temperature increase section (R1) is a section in which the temperature is raised from the temperature section where the latent heat ends, corresponding to the temperature range of the mounting section of the temperature curve for reflow soldering of the printed circuit board, to the temperature section where the solder begins to melt; the mounting section (R2) is a section in which the temperature is raised from the temperature section where the solder begins to melt to the maximum temperature section of the reflow, and the temperature is maintained for a certain period of time so that a number of components of the printed circuit board are mounted; and the temperature decrease section (RC1) can be included in the reflow section or correspond to the cooling down section, and is a section in which the mounting is completed through the mounting section and the temperature is maintained is gradually cooled from the point where the solder begins to melt to the melting point temperature to prevent cracking of the mounted part, and can be divided into 3 stages or 2 stages of the temperature increase section and the mounting section.

[0074] In this way, a unit oven (100) having a vacuum chamber formed in which the temperature and vacuum state corresponding to each section of the reflow section (F) divided into 3 or 2 stages is maintained can be connected in series in the order of heating-heating-heating-heating-heating-heating-cooling-down or heating-heating-heating, and an oven unit (OU) having 5 or 4 stages of unit ovens (100) connected in series in the order of preheat-heating-heating-heating-heating-cooling-down or preheat-heating-heating-heating-cooling-down can be formed.

[0075] Meanwhile, the cooling down section (C) of the hourly temperature curve of reflow soldering can be divided, and multiple unit ovens according to the divided temperature curve can be configured and connected in series. Accordingly, the cooling down section (C) can be divided into a first stage consisting only of a cooling section (C1) that rapidly cools from the temperature at which the solder begins to melt to room temperature, or a second stage including a temperature reduction section (RC1) of the aforementioned reflow section. Unit ovens (100) in which a vacuum chamber is formed to maintain the temperature and vacuum state corresponding to each section divided into the first or second stage can be connected in series in the order of cooling or temperature reduction-cooling, thereby forming an oven unit (OU) connected in series in the order of preheat-reflow-cooling alone or preheat-reflow (temperature increase-mounting)-temperature reduction-cooling.

[0076] That is, the configuration of the minimum unit oven (100) that can adjust the temperature and vacuum state according to the time-dependent temperature curve of reflow soldering by configuring the unit oven (100) according to the present invention is the most basic oven unit (OU) configuration, which is a series connection of unit ovens (100) corresponding to the preheat section (F), reflow section (R), and cooling down section (C) of the unit oven (100) divided into three stages, and enables the production of high mounting quality of components of a printed circuit board through reflow soldering.

[0077] Except for the above, as described above, it can be configured as various modified embodiments. By subdividing the preheating and latent heat of the preheat section and the temperature increase, mounting, and cooling of the reflow section, or the cooling or temperature decrease and cooling of the temperature increase, mounting, and cooling down section, an oven unit (OU) can be configured according to the unit oven configuration as shown in [Table 1] below. This enables high-quality mounting of components on a printed circuit board for reflow soldering. Furthermore, as the sections are subdivided, it is easy to find errors or defects, and since only the temperature and vacuum state corresponding to each section need to be maintained, efficient temperature and vacuum management are possible, which minimizes power consumption and enables energy saving, and maintenance can be easily performed.

[0078]

[0079] Preheat triple flow cooling down preheat latent heat reflow cooling down preheat latent heat rise greenhouse chamber temperature cooling (cooling down) preheat latent heat rise greenhouse chamber temperature cooling preheat rise greenhouse chamber temperature cooling down preheat rise greenhouse chamber cooling (cooling down) preheat triple flow cooling (cooling down) preheat triple flow temperature cooling

[0080] Furthermore, a plurality of unit oven (100) vacuum chambers are configured in series, allowing for rapid movement to adjacent vacuum chambers where the temperature and vacuum level of each section are set. As the printed circuit board is transferred at a temperature and vacuum level where the temperature and vacuum level of each section are maintained constant—that is, where the continuity of the time-based temperature curve of reflow soldering is minimized—the gap between the starting and ending points of the step-by-step temperature and vacuum level for soldering is reduced, thereby minimizing unnecessary energy waste and preventing energy waste. In other words, by dividing the sections so that the gap between the minimum and maximum temperature ranges is small and the impact on reflow soldering is minimized, without the unnecessary energy consumption required to raise the temperature of each section from the preheating stage to the maximum temperature, high energy efficiency can be achieved, making energy saving possible.

[0081] In addition, by maintaining the degree of vacuum in each section, there is no need to inject gas for void removal, and by minimizing crack formation during the temperature reduction process, high mounting (soldering) quality of printed circuit board components can be achieved, thereby improving soldering quality.

[0082] Meanwhile, to buffer and maintain the temperature and vacuum level of each unit oven (100) of the preheat section (F) and the cooling down section (C) for the preheat section and the cooling down section, a unit oven (100) with an airlock function is provided to be serially connected at the front and rear ends of an oven unit (OU) line in which unit ovens are serially connected according to the sections of the reflow soldering temperature curve.

[0083] It is desirable to configure a unit oven with an airlock function to buffer the rapid changes in the temperature and vacuum state inside the vacuum chamber caused by the temperature of the outside air and the air when the gate door is opened to the outside air by the vacuum control means described later during the process of inserting and discharging printed circuit boards into the vacuum chamber of the preheat section (preheat section) and the cooling section (cooling section), which is the first printed circuit board insertion section of the preheat section and the last discharge section, so as to enable more precise temperature and vacuum state control.

[0084] In addition to the above, through an embodiment in which a unit oven with an airlock function can be configured at the beginning and end of the oven unit (OU) according to the line configuration through the serial connection of unit ovens listed in various embodiments prior to this, it is possible to configure an oven unit according to the time-dependent temperature curve of reflow soldering as a more diverse embodiment.

[0085] As such, the time-dependent temperature curve for reflow soldering can derive various embodiments, and the unit oven (100) corresponding to the temperature and vacuum state applied to the various embodiments is composed of an oven housing (110), a vacuum interruption means (130), a heating means (150), a variable transfer means (160), a heat reflection shielding member (200), and detailed components of each component, as shown in FIGS. 3 and 4.

[0086] Here, the oven housing (110) of the unit oven (100) is formed as a rectangular hexahedron or cube extending in the longitudinal direction so that a vacuum chamber is formed inside. The temperature and vacuum state of the vacuum chamber of the unit oven (100) are configured to match the temperature change and vacuum state in the most optimal temperature range by applying the corresponding section of the time-dependent temperature curve of reflow soldering as is, thereby matching the temperature change and vacuum state in that section.

[0087] A unit oven (100) of this type is configured to move from left to right in each vacuum chamber for mounting components on a printed circuit board, and a moving gate (113, 114) for inserting and discharging a printed circuit board (P) is formed on the left and right vertical surfaces (111, 112) forming the left and right sides of the vacuum chamber. Here, it is preferable that the moving gate (113, 114) be formed with a size corresponding to the maximum size of the printed circuit board for reflow soldering. This is to correspond to the maximum variable area that can be varied with respect to the insertion width of the printed circuit board by the variable driving unit (180) described later.

[0088] Furthermore, the upper horizontal surface (115) forming the vacuum chamber of the unit oven (100) is formed with an openable inspection door (116) and an inspection opening (117), the rear vertical surface (118) is formed with a collection hole (119) connected to the dust collection means, and the front vertical surface (120) is formed with a plurality of power transmission holes (122) capable of transmitting driving force so that the variable transfer means described later can be driven within the vacuum chamber without affecting the temperature inside the vacuum chamber, thereby forming an oven housing (110) having a vacuum chamber of the unit oven (100).

[0089] Meanwhile, when the oven housing (110) constituting the above unit oven is configured individually, each face is configured as a rectangular prism or a cube. When connected in series, it is preferable to connect unit ovens with individually configured faces, but if there are faces shared among them, it is preferable to configure them as a single face for connection. That is, when multiple unit ovens are connected in series, the left and right vertical faces where the moving gate is formed are shared as a single vertical face among the left and right vertical faces where the moving gate is formed, and it is preferable to configure the vacuum control means (130) described later, which is coupled to the vertical face where the moving gate is formed, as a single unit.

[0090] The above vacuum control means (130) is provided to minimize the variability of the temperature curve for reflow soldering within the vacuum chamber formed inside the oven housing (110) and to maintain airtightness to maintain the degree of vacuum state by controlling the moving gates (113, 114) described above. It is provided on the left and right vertical surfaces (111, 112) where the moving gates (113, 114) are formed to control the moving gates (113, 114) formed on the left and right vertical surfaces (111, 112) of the oven housing (110) in order to control the insertion and discharge of the printed circuit board into and out of the vacuum chamber and to maintain the vacuum state within the vacuum chamber.

[0091] Here, the vacuum control means (130) is composed of a guide bar (131), a guide support block (133), a gate door (134), and a gate opening / closing means (140), as shown in FIGS. 3 and 5.

[0092] The above guide bar (131) is provided to guide the gate door (134), which will be described later, to move up and down along the guide bar so as to be in contact with and released from the moving gate formed on the left and right vertical surfaces of the oven housing, thereby ensuring airtightness and release within the vacuum chamber. As previously described, it is fixedly coupled vertically and symmetrically to the left and right sides of the moving gates (113, 114) formed on the left and right vertical surfaces (111, 112) of the oven housing (110), and a roller groove (132) is formed on one side facing each other to guide contact and release toward the moving gates (113, 114) formed on the left and right vertical surfaces.

[0093] The above guide support block (133) is provided to allow a printed circuit board for component mounting to smoothly enter horizontally into a vacuum chamber formed inside an oven housing (110) through a moving gate. A roll bearing is formed so that the printed circuit board (P), which is inserted, discharged, and transmitted while freely rotating, is axially coupled to an axis perpendicular to the entry direction of the moving gates (113, 114) formed on the left and right vertical surfaces (111, 112) of the oven housing at the top and is supported and moved. It is symmetrically coupled to the lower front side of the left and right vertical surfaces of the oven housing where the moving gates are formed.

[0094] As previously described, the gate door (134) is formed such that, while the left and right sides are fitted into the roller groove (132) of the guide bar (131), the gate door (134) moves up and down along the roller groove (132) to maintain airtightness with the left and right vertical surfaces (111, 112), thereby moving closer or further apart. Typically, when moving downward to completely block the moving gate, the gate door moves along the roller groove toward the left and right vertical surfaces and makes surface contact with them. When the moving gate is to be opened, the gate door moves upward along the roller groove, releasing surface contact with the left and right vertical surfaces and becoming separated, thereby opening the vacuum chamber inside the oven housing of the unit oven. A gasket groove (135) is formed on the back surface facing the moving gate (113, 114), and guide rollers (136) are symmetrically formed on the left and right sides, fitted into the roller groove (132) of the guide bar (131) and rolling along the roller groove. A vertical plate is provided to control the opening and closing and sealing force of the moving gate (113, 114) according to the position where the guide roller (136) moves along the roller groove (132).

[0095] The above gate opening / closing means (140) generates a driving force to cause the aforementioned gate door to move up and down along a roller groove, and is formed on the upper horizontal surface of the oven housing (110) which is located vertically above the top of the gate door (134), so that the gate door (134) is driven to move up and down along the roller groove (132) of the guide bar (131), and is provided to determine the opening and closing of the moving gates (113, 114) according to the up and down movement of the gate door (134).

[0096] The above-mentioned gate opening / closing means (140) may utilize various driving means to repeatedly move the gate door up and down, but a driving method using a cylinder and a rod is easy to control simultaneously and to enable the gate door to move up and down quickly on the roller groove. This driving method using a cylinder and a rod is composed of an opening / closing cylinder body (142) and an opening / closing cylinder rod (144).

[0097] The above opening / closing cylinder body (142) is fixedly coupled to the upper surface of the inspection door (116) formed on the upper horizontal surface of the oven housing (110) which is located on a vertical line with the top of the gate door (134), and the opening / closing cylinder rod (144) is configured to operate up and down through the lower surface of the upper horizontal surface of the oven housing (110) to which the above opening / closing cylinder body (142) is fixedly coupled, and to operate up and down in the vertical direction along the vertical line, and the lower end is coupled to the upper surface of the gate door (134).

[0098] That is, as illustrated in FIG. 6, as the opening / closing cylinder rod (144) of the opening / closing cylinder body (142) moves up and down, the gate door (134) coupled to the tip of the rod moves up and down along the roller groove, and when the gate door moves downward, the roller groove is formed in a position close to the vertical surface where the moving gate is formed, so that the sealing pad coupled to the gasket groove (135) formed on the back surface of the gate door comes into surface contact and adheres to the vertical surface around the moving gate, thereby maintaining the airtightness of the vacuum chamber formed in the oven housing of the unit oven.

[0099] Conversely, when the gate door moves upward, the upper roller groove is formed at a distance from the moving gate, so as the gate door moves upward, the surface contact with the sealing pad coupled to the gasket groove is released, thereby releasing the airtightness inside the vacuum chamber.

[0100] Meanwhile, a heating means (150) is configured to control the temperature according to the time-dependent temperature range of reflow soldering within the vacuum chamber formed by the oven housing (110) of the unit oven (100) and the temperature during the vacuum state. Here, as shown in FIGS. 4 and 7, the heating means (150) is composed of a composite heating element (152) capable of raising the internal temperature of the vacuum chamber and controlling the solder mounting temperature, which is formed on the lower surface of the inspection door (116) that forms the upper horizontal plane (115) of the vacuum chamber bottom side and the upper side of the vacuum chamber formed inside the oven housing (110).

[0101] The above composite heating element (152) is provided to directly heat the upper and lower sides of a printed circuit board transported by a variable transport means (160) described later, and is configured to have excellent thermal efficiency and ease of installation, and has excellent performance and durability, such as a sheath heater that is installed on the bottom side of the vacuum chamber and the lower surface of the upper inspection door (116) and has excellent performance and durability, and is chemically stable, and is configured to directly raise the temperature inside the vacuum chamber. It is configured to use carbon fiber as a heating element to locally heat the solder surface and interior on which components are mounted, and is a radiant heat method, so it only gets warm when it is in a place where far-infrared rays are in contact, but has a lower risk of damage and a very fast heating speed compared to ceramic or halogen, and can set a clear upper temperature limit compared to other heating elements, and is configured as a far-infrared heater (154) such as a carbon heater that emits far-infrared rays. Alternatively, it is configured to be continuous by sequentially arranging the far-infrared heater (154) and the electric heater (153).

[0102] That is, the electric heater (153) of the composite heating element is designed to directly raise the temperature on the hourly temperature curve for reflow soldering, thereby facilitating the heating of the entire printed circuit board to a state of heat activation, and the far-infrared heater (154) is designed to have a fast heating speed and clearly set the upper temperature limit of the heating element. By combining these elements, it is possible to activate the entire printed circuit board and, at the same time, activate the surface of the solder for mounting. Furthermore, by emitting far-infrared rays, the temperature is raised deep inside the solder for component mounting. This suppresses the formation of voids during the initial preheating process when reflow soldering in a vacuum state, and prevents cracks from forming in the mounting area during the cooling process in the reflow process.

[0103] Meanwhile, it is preferable that the composite heating element (152) on either the bottom or top side of the vacuum chamber in which the composite heating element (152) is installed be provided only as an electric heater to directly heat the board of the printed circuit board being transported by the variable transport means (160).

[0104] However, when configured with only electric heaters, it is generally preferable to configure them on the bottom side of the vacuum chamber, as components attached to the printed circuit board are typically configured on the upper surface of the printed circuit board, and many products do not have components attached to the bottom surface. Accordingly, based on the printed circuit board with components configured on the upper surface, the bottom side of the vacuum chamber can be configured with only electric heaters that can be directly heated. In special cases, only electric heaters can be configured on the upper side, but since most components of the printed circuit board are generally configured either on the upper surface alone or on both the upper and lower surfaces, when only electric heaters are configured, they are configured on the bottom side.

[0105] Here, the heating means (150) adjusts the internal temperature of the vacuum chamber of the serially connected unit oven (100), which is set for each section of the hourly temperature curve of reflow soldering, to correspond to the optimal quality temperature curve of reflow soldering, and by continuously and rapidly performing the entire process to allow the printed circuit board to stay in the vacuum chamber with a vacuum state degree in the temperature section and to move to the next unit oven, the temperature change and vacuum change can be minimized.

[0106] Meanwhile, as shown in FIG. 4, the heat-reflective shielding member (200) is formed to prevent internal heat preservation and heat loss of heat generated from the heating means (150) in the upper, lower, front, rear, left, and right sides forming the vacuum chamber of the unit oven (100), and to block heat conduction to the oven housing of the unit oven, and to prevent heat transfer to the vacuum chamber of an adjacent unit oven. That is, the heat-reflective shielding member (200) is installed so as to prevent infrared wavelengths from being conducted to the outside, such as those emitted from a carbon heater that emits far-infrared rays from a composite heating element, thereby facilitating local heating or temperature attainment for component mounting by soldering, while preventing safety accidents caused by heat transfer from outside the unit oven.

[0107] As shown in FIGS. 4 and 8, the variable transfer means (160) is configured to be applicable by adjusting the width of the printed circuit board being inserted regardless of the size of the printed circuit board. A transfer drive unit (190) and a variable drive unit (180) are formed on the outer side of the front vertical surface (120) of the oven housing (110). After being varied to a size corresponding to the left and right width of the printed circuit board in the insertion direction by the power of the variable drive unit (180) transmitted through the power transmission hole (122), the printed circuit board (P) inserted through the moving gate (113, 114) by the power of the transfer drive unit (190) is transferred to an insertion moving-atmosphere heating-discharge transfer process, so that the printed circuit board is reflow soldered according to the heat transmitted from the heating means (150) and the vacuum inside the vacuum chamber.

[0108] Here, the variable transfer means (160) is composed of a fixed block (161), a fixed reflow conveyor (162), a variable guide (167), a variable moving part (169), a variable reflow conveyor (172), a rotating shaft (178), a transfer drive part (190), and a variable drive part (180), as shown in FIGS. 8 and 10.

[0109] The fixed block (161) described above is formed such that the fixed reflow conveyor, which will be described later, is spaced apart from the inner bottom surface of the unit oven and faces the variable reflow conveyor in parallel, and is symmetrically formed on the left and right sides in front of the bottom surface of the vacuum chamber formed inside the oven housing (110).

[0110] The above fixed reflow conveyor (162) is configured to allow one side of a printed circuit board to move for insertion, waiting, and discharge, corresponding to the width of the printed circuit board inserted through a moving gate into a vacuum chamber formed in the oven housing (110) of a unit oven (100), and both left and right ends are fixedly connected to the aforementioned fixed block (161).

[0111] And, a first guide support part (163) is formed to support and guide the chain by protruding upward and extending in the left and right longitudinal direction so that a printed circuit board (P) equipped with multiple parts is inserted, moved, heated by air, and discharged by a chain through a moving gate (113, 114), and a first moving chain (165) connected to a first driving sprocket (164) is provided on the left and right sides of the first guide support part (163), and a first driving sprocket (166) is provided on one of the left and right ends connected to a fixed block (161) to drive the first moving chain (165) to rotate infinitely.

[0112] The variable guide member (167) is provided to guide the variable reflow conveyor described later to move horizontally along the same line without left and right twisting during the process of moving horizontally back and forth based on the fixed reflow conveyor described above. A guide shaft (167a) is formed symmetrically on the left and right sides, extending horizontally from the rear side of each of the fixed blocks (161) on the left and right sides toward the rear vertical surface (118) where the collection hole (119) of the oven housing (110) is formed, and a guide block (168) that moves back and forth within the vacuum chamber along the guide shaft (167a) is provided. Here, the left and right sides of the variable reflow conveyor described later are connected to the guide block (168) that is symmetrically formed to move horizontally back and forth on the guide shaft (167a) of the variable guide member (167).

[0113] The variable moving part (169) described above is configured to transmit power equally to the left and right so that the variable reflow conveyor, which will be described later, moves horizontally back and forth relative to the fixed reflow conveyor. It is symmetrically formed on the left and right between the left and right variable guide parts (167), and a variable lead screw (170) is formed that extends horizontally from the rear vertical surface (118) of the oven housing (110) to the power transmission hole (122) on the front vertical surface (120) of the oven housing (110). It is formed by a lead nut bracket (171) that is spirally coupled to move horizontally back and forth according to the rotation of the variable lead screw (170). Here, the left and right sides of the variable reflow conveyor described later are coupled to the lead nut bracket (171) of the variable moving part (169).

[0114] The above variable reflow conveyor (172) is adjusted to correspond to the width of the printed circuit board being fed by moving back and forth relative to the fixed reflow conveyor as shown in FIG. 9, according to the width of the printed circuit board being fed. The guide block (168) of the aforementioned variable guide part (167) and the lead nut bracket (171) of the variable moving part (169) are fixedly coupled to both left and right ends, and the guide block (168) moves together on the guide shaft (167a) as it moves back and forth horizontally on the variable lead screw (170) of the lead nut bracket (171), thereby being variable to correspond to the width of the printed circuit board.

[0115] And, a second guide support part (173) is formed to support and guide a chain by protruding upward and extending in the left and right lengthwise direction so that a printed circuit board (P) equipped with a plurality of parts is inserted, heated by air, and discharged by a chain through a moving gate (113, 114) facing the fixed reflow conveyor (162) and driven simultaneously with the fixed reflow conveyor (162). A second moving chain (175) is provided on the left and right sides of the second guide support part (173) and connected to a second moving sprocket (174). A second driving sprocket (176) is connected to one of the left and right ends connected to the guide block (168) and the lead nut bracket (171) to drive the second moving chain (175) so that it is driven simultaneously with the first moving chain (165).

[0116] The above-mentioned rotating shaft (178) is configured to move a printed circuit board into a vacuum chamber, wait for a time during which the temperature and vacuum conditions inside the vacuum chamber reach a temperature and vacuum level corresponding to the reflow soldering temperature curve section for reflow soldering, and then discharge and transfer it to a unit oven in the next section. The first and second moving chains rotate simultaneously to move the printed circuit board while maintaining the left and right sides aligned. As shown in FIG. 10, one end is horizontally fitted through a power transmission hole (122) on the same axis as the first and second drive sprockets (166, 176) on the front vertical surface (120) of the oven housing (110), so that the first drive sprocket (166) of the fixed reflow conveyor (162) and the second drive sprocket (176) of the variable reflow conveyor (172) are axially coupled on the same axis. The first drive sprocket (166) and the second drive sprocket (176) are formed to be extended in a rectangular shape so that they rotate simultaneously. That is, through the simultaneous rotation of the first and second drive sprockets, the first and second moving chains rotate simultaneously, causing the printed circuit board to move horizontally with the left and right sides aligned.

[0117] The above transfer drive unit (190) is configured to generate the driving force necessary for moving a printed circuit board into, waiting for, and discharge into a unit oven (100), and is axially coupled so that the rotating shaft (178) rotates, and the first drive sprocket (166) and the second drive sprocket (176) rotate simultaneously by the driving force of the rotating shaft, and the first moving chain (165) and the second moving chain (175) rotate along the first and second driving sprockets (164, 174) and the first and second guide support parts (163, 173), respectively, so that the first and second drive sprockets (166, 176) are provided on the outer side on the same axis as the power transmission hole (122) on the front vertical surface (120) of the oven housing (110) on the same axis as the first and second drive sprockets (166, 176). The above-mentioned transfer drive unit (190) is configured to be directly coupled to the motor or to have a transmission configuration of a gear, belt pulley, or chain sprocket that transmits the rotational force of the motor.

[0118] The above variable drive unit (180) transmits driving force to rotate the aforementioned variable lead screw so that the variable reflow conveyor moves back and forth horizontally relative to the fixed reflow conveyor according to the width of the printed circuit board. It is axially coupled to the variable lead screw (170) through a power transmission hole formed on the outer side of the front vertical surface (120) of the oven housing (110) on the same axis as the variable lead screw (170) to transmit power so that the variable lead screw rotates in forward and reverse directions. Depending on the forward and reverse rotation of the variable lead screw (170), the lead nut bracket (171) moves back and forth horizontally on the variable lead screw (170) so that the variable reflow conveyor (172) moves back and forth simultaneously along the guide shaft (167a) toward the fixed reflow conveyor (162) so that the width is varied to the left and right width of the input direction of the printed circuit board. This variable drive unit (180) is also configured such that, like the moving drive unit (180), the variable lead screw is directly coupled to the motor or is configured together with a transmission configuration of a gear, belt pulley, or chain sprocket that transmits the rotational force of the motor.

[0119] Meanwhile, the first and second type sprockets (164, 174) and the first and second drive sprockets (166, 176) of the variable transfer means are each formed as belt pulleys, and the first and second moving chains (165, 175) are configured as transfer belts usable at high temperatures, so that the printed circuit board is transferred by the combination of the belt pulleys and the transfer belts within the unit oven (100) constituting the oven unit of the reflow soldering device.

[0120] As described above, when configured with a belt, there is an advantage in that flow is minimized compared to a chain during the transfer process of the printed circuit board, thereby allowing for greater improvement in reflow soldering quality.

[0121] Among the multiple embodiments classified according to the hourly temperature curve of reflow soldering of such unit ovens, we intend to examine the operational relationship through an example in which a unit oven with an airlock function is combined with a unit oven formed at the beginning and end of the minimum and maximum stages, and a minimum stage divided into three stages of preheat-reflow-cooling down, and a maximum stage of six stages of preheat-latent heat-heating-mounting-heating-cooling.

[0122] <Example 1>

[0123] After dividing the time-dependent temperature curve for reflow soldering into preheat, reflow, and cooling-down sections, unit ovens that control temperature and vacuum conditions according to each divided temperature curve are arranged in series within the sections divided into preheat, reflow, and cooling-down.

[0124] Subsequently, as illustrated in FIG. 11, the opening / closing cylinder rod (144) of the gate opening / closing means (140) of the vacuum control means (130) rises to the opening / closing cylinder body (142) to open the moving gate (113) formed on the left vertical surface (111) of the unit oven (100) of the preheat section, and the gate door (134) rises along the roller groove (132) formed on the guide bar (131), thereby releasing contact from the left vertical surface (111) and opening the moving gate (113).

[0125] Next, as the gate door (134) rises completely vertically along the roller groove (132), the moving gate (113) of the left vertical surface (111) opens, exposing the vacuum chamber of the oven housing (110) to the outside, causing the internal temperature to drop and the vacuum to weaken. In this way, the opening of the moving gate (113) causes the vacuum chamber to be exposed to the outside or changes the temperature and vacuum level of the vacuum chambers forming each space due to communication between adjacent vacuum chambers.

[0126] Therefore, it is desirable for the printed circuit board to be rapidly moved into the vacuum chamber formed inside the oven housing (110). To this end, information regarding the width of the printed circuit board is pre-set before the opening of the transfer gate, and the distance between the fixed reflow conveyor and the variable reflow conveyor is adjusted by the variable transfer means to correspond to the width of the printed circuit board. This is simultaneously applied to the variable transfer means (160) configured throughout the entire unit oven (100) connected in series according to the interval of the time-dependent temperature curve of the reflow soldering.

[0127] That is, when information regarding the width of the printed circuit board is input, the variable reflow conveyor (172) of the variable transfer means moves toward the fixed reflow conveyor (162) and the zero point is set. Subsequently, the variable drive unit (180) is driven according to the information corresponding to the width of the printed circuit board, and the variable lead screw (170) of the variable moving unit (169) rotates forward and reverse so that the lead nut bracket (171) coupled with the variable reflow conveyor (172) moves back and forth from the fixed reflow conveyor. At this time, as the lead nut bracket (171) moves by the variable lead screw, the guide block (168) moves back and forth together on the guide shaft (167a), and the spacing distance of the variable reflow conveyor relative to the fixed reflow conveyor is determined to a width corresponding to the left and right width of the printed circuit board.

[0128] Next, when the printed circuit board is fed through the left moving gate (113), the first and second moving chains (165, 175) rotate in the forward direction by the operation of the rotating shaft (178) by the transfer drive unit (190), and as the circuit board rotates in the forward direction, the left and right sides of the printed circuit board wait while positioned on the fixed reflow conveyor and the variable reflow conveyor.

[0129] Afterwards, the gate door (134) descends on the roller groove (132) through the gate opening / closing means (140) by means of the vacuum control means (130), and comes into close contact with the left vertical surface (111) around the movable gate (113), and the movable gate (113) is closed while maintaining airtightness through the sealing pad coupled to the gasket groove (135) formed on the back surface of the gate door.

[0130] In this way, as the moving gate (113) is closed while being sealed by the gate door (134), the vacuum chamber formed inside the oven housing (110) is prevented from being exposed to the outside or communicating with an adjacent vacuum chamber, and the vacuum state is maintained according to the corresponding temperature in the hourly temperature curve corresponding to the hourly temperature curve section of the reflow soldering by the composite heating element (152) of the heating means (150). At this time, both the left and right moving gates (113, 114) are kept closed while being sealed by the gate door so that the temperature and vacuum according to the hourly temperature curve section of the reflow soldering are achieved without irregular temperature changes.

[0131] Subsequently, when the final temperature section of the temperature curve for reflow soldering is reached, the gate door (134) of the vacuum control means (130) is opened by the gate opening / closing means (140) as previously mentioned to allow the printed circuit board to be discharged and moved to the unit oven of the next temperature section, and the printed circuit board is discharged and moved by the variable transfer means, and then moved to the variable transfer means side within the vacuum chamber formed inside the oven housing (110) of the unit oven (100) corresponding to the next temperature section, the reflow section. At this time, while the transfer gate of the printed circuit board input side of the preheat temperature section is closed, the transfer gate by the vacuum control means (130), which simultaneously controls the input of the printed circuit board of the reflow temperature section and the discharge of the printed circuit board of the preheat temperature section, is maintained in an open state, and the discharge movement of the printed circuit board in the preheat temperature section and the input movement of the printed circuit board in the reflow temperature section are performed.

[0132] Therefore, in the unit oven of the reflow temperature range, the opening and closing sequence of the transfer gates is carried out in the same manner as in the unit oven of the preheat temperature range; when the printed circuit board is inserted and moved, the transfer gate on the left vertical side opens, while the transfer gate on the right vertical side remains closed. Subsequently, once the printed circuit board is positioned inside the vacuum chamber of the unit oven, it waits for reflow soldering to occur according to the temperature and vacuum level of the corresponding temperature range, at which time both the left and right transfer gates remain closed.

[0133] Next, when moving the printed circuit board to the cooling-down temperature zone for discharge and insertion, the moving gate on the left vertical side of the unit oven in the reflow temperature zone is kept closed, and the moving gate on the right vertical side is opened so that discharge and insertion into the next unit oven are performed.

[0134] That is, the opening of the moving gate is controlled by a vacuum interruption means to minimize temperature changes in the internal vacuum chambers between serially connected unit ovens and to minimize changes in the vacuum state, while the interior of the vacuum chamber of each unit oven is maintained in a closed state during each temperature range for reflow soldering.

[0135] To explain this more specifically, the transfer gates (113, 114) connected in series between unit ovens (100) are opened when the gate door (134) of the vacuum control means (130) is inserted in the order of the preheat-reflow-cooldown sections of reflow soldering when the printed circuit board is first inserted. However, after the printed circuit board is positioned in the 3rd stage section, when insertion and discharge begin to occur continuously, the gate door (134) is opened simultaneously so that the printed circuit board moves one stage at a time to the vacuum chamber of the unit oven corresponding to each temperature section, and then the transfer gate is closed simultaneously again so that the temperature and vacuum state of the corresponding temperature section are adjusted and reflow soldering proceeds, or as shown in the drawing, the transfer gate is opened to transfer the printed circuit board from the unit oven (100) of the preheat temperature section to the next unit oven (100) of the reflow temperature section connected in series, and then closed again after transfer, in any one of the stepwise printed circuit board transfer formats. The operation of the vacuum control means (130) is controlled by a branch.

[0136] Meanwhile, the time-based temperature curve of reflow soldering is divided into six sections: preheating, latent heat, temperature rise, mounting, temperature reduction, and cooling. Unit ovens (100) are provided and connected in series to control the temperature and vacuum state corresponding to each section. The left and right vertical surfaces of the unit ovens (100) are connected in series, and the vertical surface is divided into a single vertical surface. The moving gates (113, 114) formed on the vertical surface also function as a left moving gate or a right moving gate.

[0137] After connecting the unit ovens divided into six sections in series, a printed circuit board is inserted, and the temperature and vacuum conditions corresponding to each temperature section are adjusted so that reflow soldering can be performed, thereby enabling component mounting on the printed circuit board.

[0138] For this purpose, the input and output of the printed circuit board into the unit oven (100) is such that it is input into the unit oven of the preheating section and then output through the unit oven of the cooling section, but the initial input of the printed circuit board is in the same as the above minimum 3-stage section, and after input, waiting, and output to each temperature section, the printed circuit board that is initially input moves to the unit oven of the cooling section through horizontal movement by opening a moving gate to input to the next unit oven, in a manner where only two temperature sections connected in series are connected.

[0139] In other words, to explain this in detail, the oven unit (OU), in which unit ovens (100) corresponding to 6 temperature ranges are connected in series, is maintained at a temperature of 25 degrees Celsius or a temperature corresponding to each temperature range and a vacuum state with the initial moving gates (113, 114) all closed. Afterwards, a printed circuit board is inserted, and the fixed reflow conveyor (162) and the variable reflow conveyor (172) are controlled by the variable transfer means (160) according to the width of the printed circuit board before insertion, as described above.

[0140] Next, the left moving gate (113) of the unit oven (100) of the preheating section located at the foremost end of the oven unit (OU) is opened by the vacuum control means (130), and the printed circuit board is introduced into the vacuum chamber of the unit oven (100) of the preheating section. Afterward, when the printed circuit board is positioned in the vacuum chamber on the variable transfer means (160), the opened left moving gate (113) of the unit oven (100) of the preheating section is closed, and the temperature and vacuum state according to the temperature curve of the preheating section are controlled by the operation of the heating means (150) and the vacuum means, and the components of the printed circuit board are preheated according to the temperature curve corresponding to the preheating section of the reflow soldering.

[0141] Next, as reflow soldering according to the temperature curve of the preheating section of the printed circuit board is completed, the moving gate on the right side of the unit oven of the preheating section and the moving gate on the left side of the unit oven of the latent heat section are opened to communicate with the vacuum chamber of the unit oven of the latent heat section connected in series with the preheating section, and the moving gate is controlled by the vacuum control means (130) according to the input movement-atmosphere heating-discharge transfer of the printed circuit board in the preheating section.

[0142] In other words, as described above, the transfer gates are sequentially opened and closed during the process of moving the printed circuit board between the unit ovens of the preheating and latent heat sections, progressing through the latent heat, temperature rise, mounting, temperature decrease, and cooling sections. When the printed circuit board is transferred to the next temperature section after all printed circuit boards have been positioned in each temperature section and reflow soldering is performed in that section, the transfer gates open simultaneously to move the board, or the board moves through a process in which the transfer gates open and close sequentially after being discharged from the unit oven of the cooling section of the reflow soldering temperature section. Through mounting according to the temperature sections of the reflow soldering, high-quality reflow soldering with void and crack prevention can be obtained.

[0143] Here, it is desirable to control the opening of the transfer gate for the insertion and discharge of the printed circuit board in the unit oven during the preheating and cooling down sections in the minimum 3-stage section and the preheating and cooling sections in the maximum 6-stage section, separately from the opening of the transfer gate in the intermediate temperature section for reflow soldering, in order to buffer temperature and vacuum changes caused by the inflow of external temperature and external air.

[0144] As described above, a unit oven (100) acting as an airlock to minimize changes in temperature and vacuum conditions within the vacuum chamber of the oven unit (OU) and to buffer against external temperature or air is formed at the leading edge and the trailing edge of the oven unit (OU) in all sections indicated in [Table 1] from a minimum of 3 stages to a maximum of 6 stages, thereby minimizing changes in temperature and vacuum conditions in the vacuum chamber of the oven unit (OU) due to the insertion and discharge of printed circuit boards.

[0145] Meanwhile, the above oven unit (OU) is configured to divide the hourly temperature curve of reflow soldering into sections and to connect in series each unit oven (100) capable of achieving a vacuum state with the temperature curve of each divided section. However, the oven housing (110) of the unit oven (100) is formed as a single configuration extending horizontally to form a single vacuum chamber, and the single vacuum chamber is partitioned into a vertical surface with a moving gate formed in the space corresponding to the section divided by the hourly temperature curve of reflow soldering. The moving gate of the partitioned vertical surface is controlled by a vacuum control means (130), and a variable transfer means (160), a heating means (150), and other detailed configurations for transmitting power are configured in each partitioned space, and the same operation as the present invention can be achieved.

[0146] Accordingly, the vacuum reflow soldering device having a serially connected oven unit for each temperature range according to the present invention enables concentrated management of temperature ranges where voids or cracks occur in the temperature curve of reflow soldering, and thus allows for easy on-site response or maintenance regarding mounting defects caused by reflow soldering, thereby enabling a reduction in overall reflow soldering production time and the achievement of high-quality reflow soldering.

[0147] Furthermore, by configuring unit ovens according to temperature ranges, rapid temperature increases or decreases are unnecessary, resulting in low power consumption and energy savings. Additionally, the buffering capabilities of temperature and vacuum allow for the rapid attainment of reflow soldering temperatures, thereby improving productivity by shortening the component mounting time on printed circuit boards.

[0148] Meanwhile, regarding the opening and closing sequence of the moving gates of the vacuum control means for transferring to each unit oven at each stage by dividing the time-dependent temperature curve of reflow soldering into sections, unlike the opening and closing of the moving gates at both ends, the opening and closing of the moving gates connected between each unit oven can be divided into a configuration in which, after the first printed circuit board is inserted into each unit oven, they are simultaneously opened and closed to be transferred between unit ovens as shown in FIGS. 11 and 12, or, as shown in FIGS. 13 and 14, the printed circuit board of each unit oven is received and sealed, after which the opening and sealing of the next unit oven are carried out sequentially.

[0149] That is, as illustrated in FIGS. 11 and 12, the type in which the opening and closing of the moving gates connected between unit ovens, in addition to the moving gates at both ends, is simultaneously opened and closed allows for rapid movement of the printed circuit board and ensures continuity, but the adjustment time for the temperature and vacuum state of each unit oven may increase. Conversely, as illustrated in FIGS. 13 and 14, if the opening and closing of the moving gates connected between unit ovens are performed individually and sequentially as the printed circuit board moves step by step, the change in the temperature and vacuum state of the unit oven is minimized, but the movement speed of the printed circuit board may decrease.

[0150] Therefore, this can be applied in combination. As previously mentioned, when unit ovens with an airlock function are connected in series, another method of opening and closing the moving gate can be applied. It is evident that various combined opening configurations of the opening and closing method of the moving gate and the movement method of the printed circuit board in such a series connection configuration fall under the scope of the present invention.

[0151]

[0152] [Explanation of Symbols]

[0153] OU : Oven Unit 100 : Unit Oven

[0154] 110 : Oven housing 111 : Left vertical surface

[0155] 112: Right vertical plane 113: Insertion movement gate

[0156] 114: Discharge transfer gate 115: Upper horizontal surface

[0157] 116 : Inspection door 117 : Inspection hatch

[0158] 118: Rear vertical surface 119: Collection hole

[0159] 120 : Front vertical surface 122 : Power transmission hole

[0160] 130: Vacuum interruption means 131: Guide bar

[0161] 132 : Roller groove 133 : Guide support block

[0162] 134 : Gate door 136 : Guide roller

[0163] 140: Gate opening / closing means 142: Opening / closing cylinder body

[0164] 144: Opening / closing cylinder rod 150: Heating means

[0165] 152 : Combined heating element 153 : Electric heater

[0166] 154 : Far-infrared heater 160 : Variable transfer means

[0167] 161: Fixed block 162: Fixed reflow conveyor

[0168] 163: First guide support 164: First type dynamic sprocket

[0169] 165: First moving chain 166: First driving sprocket

[0170] 167: Variable guide section 167a: Guide shaft

[0171] 168 : Guide block 169 : Variable movement part

[0172] 170 : Variable lead screw 171 : Lead nut bracket

[0173] 172: Variable reflow conveyor 173: Second guide support

[0174] 174 : Second type dynamic sprocket 175 : Second moving chain

[0175] 176: Second drive sprocket 178: Rotating shaft

[0176] 180: Variable drive unit 190: Transfer drive unit

[0177] 200 : Heat-reflective shielding member

Claims

1. A reflow soldering device formed by an oven unit (OU) provided for inserting and mounting (soldering) a printed circuit board equipped with multiple components, a dust collection means provided to be connected to the oven unit to collect and treat harmful gases generated during the mounting process, and a main body housing provided with a control unit provided to control soldering operation and having the oven unit and the dust collection means installed inside. The device comprises: a time-based temperature curve for reflow soldering of a printed circuit board, a preheat section (F) in the reflow soldering temperature curve in which the printed circuit board (P) equipped with multiple components is initially inserted, and the flux is evaporated and removed to minimize the formation of voids while preheating to prepare for reflow soldering and raise the temperature to a latent heat temperature, thereby activating the printed circuit board; and a preheat section (F) in the reflow soldering temperature curve in which the printed circuit board is activated as all board areas and component areas of the printed circuit board are gradually heated to the same temperature. A reflow section (R) in which an activated printed circuit board (P) is introduced, the temperature is continuously raised past the melting point at which the solder of multiple components provided on the printed circuit board begins to melt for reflow soldering to proceed, and is maintained for a certain period of time at the maximum temperature at which reflow soldering continues, and then lowered back to the melting point at which the maintenance ends so that the solder of the printed circuit board melts and stabilizes to prevent cracks from occurring in the reflow soldering portion of the mounted components; A unit oven (100) is formed by serially connecting oven units (OU) in the order of preheat, reflow, and cooling down, wherein the unit oven (100) is formed in three stages, including a cooling down section (C) in which a printed circuit board on which a plurality of components are mounted is cooled to room temperature through cooling, and a vacuum chamber is formed in which the temperature and degree of vacuum state corresponding to each section of preheat, reflow, and cooling down are maintained. A printed circuit board (P) is inserted, moved, heated by the atmosphere, and discharged into each vacuum chamber of the serially connected unit ovens (100) of the oven units (OU), and components of the printed circuit board are mounted through reflow soldering. The above unit oven (100) is formed as a rectangular cuboid extending in the longitudinal direction so as to form a vacuum chamber inside, and on the left and right vertical surfaces (111, 112) forming the left and right sides, a moving gate (113, 114) for the insertion and discharge of a printed circuit board (P) is formed, and on the upper horizontal surface (115), an openable inspection door (116) and an inspection opening (117) are formed, and on the rear vertical surface (118), a collection hole (119) connected to the dust collection means is formed, and on the front vertical surface (120), a plurality of power transmission holes (122) are formed, comprising an oven housing (110); A vacuum control means (130) provided on the left and right vertical surfaces (111, 112) on which the moving gates (113, 114) are formed to control the moving gates (113, 114) formed on the left and right vertical surfaces (111, 112) of the oven housing (110) to control the insertion and discharge of a printed circuit board into the vacuum chamber and to maintain a vacuum state inside the vacuum chamber; and a heating means (150) composed of a composite heating element (152) capable of raising the internal temperature of the vacuum chamber and controlling the solder mounting temperature, on the lower surface of the inspection door (116) forming the upper horizontal surface (115) of the vacuum chamber bottom side and the upper side of the vacuum chamber formed inside the oven housing (110); A vacuum reflow soldering device having a serially connected oven unit for each temperature range, characterized by being formed with a variable transfer means (160) formed on the bottom side of the vacuum chamber on the left and right of the heating means (150) so that the printed circuit board (P) inserted through the transfer means (190) is reflow soldered according to the heat transmitted from the heating means (150) and the vacuum inside the vacuum chamber, wherein the transfer drive unit (190) and the variable drive unit (180) are formed on the outer side of the front vertical surface (120) of the oven housing (110), and the printed circuit board (P) inserted through the transfer gate (113, 114) is reflow soldered according to the heat transmitted from the heating means (150) and the vacuum inside the vacuum chamber, after being changed to a size corresponding to the left and right width of the insertion direction of the printed circuit board by the power of the variable drive unit (180) transmitted through the power of the power transmission hole (122), and the printed circuit board (P) inserted through the transfer gate (113, 114) is reflow soldered according to the vacuum inside the vacuum chamber and the heat transmitted from the heating means (150).

2. A vacuum reflow soldering device having a series-connected oven unit for each temperature range, characterized in that, in the first paragraph, a heat-reflecting shielding member (200) is formed on the upper, lower, front, rear, left, and right sides forming the vacuum chamber of the unit oven (100) to prevent internal heat preservation and heat loss of heat generated from the heating means (150), enable heat conduction blockage, and prevent heat transfer to the vacuum chamber of an adjacent unit oven.

3. In claim 1, the vacuum control means (130) comprises: a guide bar (131) which is fixedly coupled vertically and symmetrically to the left and right sides of the front of the moving gate formed on the left and right vertical surfaces of the oven housing, and has a roller groove (132) formed on one side facing each other to guide contact and release toward the moving gates (113, 114) formed on the left and right vertical surfaces; and a guide support block (133) which is symmetrically coupled to the lower side of the front of the left and right vertical surfaces of the oven housing where the moving gate is formed, and has a roll bearing formed thereon so that a printed circuit board (P) that is inserted, discharged, and transmitted while freely rotating is supported and moved along an axis perpendicular to the entry direction of the moving gates (113, 114) formed on the upper side of the left and right vertical surfaces of the oven housing, and has a roll bearing formed thereon so that a printed circuit board (P) is supported and moved while being inserted, discharged, and transmitted. A gasket groove (135) is formed on the rear surface facing the above-mentioned moving gates (113, 114), and guide rollers (136) are symmetrically formed on the left and right sides, fitted into the roller grooves (132) of the guide bar (131) and rolling along the roller grooves, and a gate door (134) provided as a vertical plate body to control the opening and closing and sealing force of the moving gates (113, 114) according to the position where the guide rollers (136) move along the roller grooves (132); A vacuum reflow soldering device having a serially connected oven unit for each temperature range, characterized by being formed with a gate opening / closing means (140) formed on the upper horizontal surface of an oven housing (110) located vertically above the gate door (134), which is driven to move up and down along the roller groove (132) of a guide bar (131), and which determines the opening and closing of the moving gate (113, 114) according to the up and down movement of the gate door (134).

4. In claim 3, the gate opening / closing means (140) is characterized by being formed by: an opening / closing cylinder body (142) fixedly coupled to the upper surface of an inspection door (116) formed on the upper horizontal surface of an oven housing (110) located on a vertical line with the top of the gate door (134); and an opening / closing cylinder rod (144) which is formed by penetrating the lower surface of the upper horizontal surface of the oven housing (110) to which the opening / closing cylinder body (142) is fixedly coupled so as to operate up and down, and which operates to move up and down in the vertical direction on a vertical line, with its lower end coupled to the upper surface of the gate door (134).

5. In claim 1, the above-described composite heating element (152) is configured such that it is composed of a heat heater (153) that heats the upper and lower sides of a printed circuit board transferred by a variable transfer means (160) in a direct heating manner like a sheath heater, and a far-infrared heater (154) that uses carbon fiber as a heating element to locally heat the solder surface and interior on which components are mounted, and is sequentially arranged in the order of heat heater (153) - far-infrared heater (154) or far-infrared heater (154) - heat heater (153) to be continuous.

6. A vacuum reflow soldering device having a serially connected oven unit for each temperature range, characterized in that, in claim 5, the composite heating element (152) on either the bottom side or the top side of the vacuum chamber where the composite heating element (152) is installed is provided only as an electric heater to directly heat the board of a printed circuit board transported by a variable transport means (160).

7. In claim 1, the variable transfer means (160) comprises a fixed block (161) symmetrically formed on the left and right sides in front of the bottom surface of the vacuum chamber of the oven housing; A fixed reflow conveyor (162) having a first guide support member (163) formed long in the left and right longitudinal direction and protruding upwardly to support and guide a chain, so that a printed circuit board (P) equipped with a plurality of parts is inserted, moved, heated by air, and discharged by a chain through a moving gate (113, 114), and the left and right ends are fixedly coupled to the fixed block (161); a first moving chain (165) coupled to a first driven sprocket (164) is provided on the left and right sides of the first guide support member (163); and a first driving sprocket (166) is provided on one of the left and right ends coupled to the fixed block (161) to drive the first moving chain (165) to rotate infinitely; A variable guide section (167) is provided with a guide shaft (167a) that is horizontally extended from the rear side of each of the left and right fixed blocks (161) toward the rear vertical surface (118) where the collection hole (119) of the oven housing (110) is formed, and a guide block (168) that moves back and forth within the vacuum chamber along the guide shaft (167a); and a variable moving section (169) is formed symmetrically between the left and right variable guide sections (167), and a variable lead screw (170) is formed that extends horizontally from the rear vertical surface (118) of the oven housing (110) toward the power transmission hole (122) of the front vertical surface (120) of the oven housing (110), and a lead nut bracket (171) that is spirally coupled to move horizontally back and forth according to the rotation of the variable lead screw (170).The guide block (168) of the variable guide part (167) and the lead nut bracket (171) of the variable moving part (169) are fixedly coupled to both left and right ends, and the guide block (168) moves together on the guide shaft (167a) according to the horizontal movement back and forth on the variable lead screw (170) of the lead nut bracket (171). A second guide support part (173) is formed to support and guide the chain by protruding upward and extending in the left and right longitudinal direction so that the printed circuit board (P), equipped with a plurality of parts, is inserted and moved by a chain into the vacuum chamber formed inside the oven housing (110) through the moving gates (113, 114) facing the fixed reflow conveyor (162), and the atmospheric heating and discharge transfer are driven simultaneously with the fixed reflow conveyor (162). On the left and right of the second guide support part (173), the second driven sprocket (174) A variable reflow conveyor (172) having a second moving chain (175) connected to a chain, and a second driving sprocket (176) connected to one of the left and right ends connected to a guide block (168) and a lead nut bracket (171) to drive the second moving chain (175) simultaneously with the first moving chain (165); A rotating shaft (178) that is extended in a rectangular shape so that the first drive sprocket (166) of the fixed reflow conveyor (162) and the second drive sprocket (176) of the variable reflow conveyor (172) are axially coupled through a power transmission hole (122) on the same axis as the first and second drive sprockets (166, 176) of the front vertical surface (120) of the oven housing (110), thereby allowing the first drive sprocket (166) and the second drive sprocket (176) to rotate simultaneously;A transfer drive unit (190) provided on the outer side along the same axis as the power transmission hole (122) on the front vertical surface (120) of the oven housing (110) along the same axis as the first and second drive sprockets (166, 176), so that the first drive sprocket (166) and the second drive sprocket (176) rotate simultaneously by the driving force of the rotation shaft so that the first movable chain (165) and the second movable chain (175) rotate along the first and second driven sprockets (164, 174) and the first and second guide support parts (163, 173), respectively; A vacuum reflow soldering device having a serially connected oven unit for each temperature range, characterized by being formed by a variable drive unit (180) which is axially coupled to the variable lead screw (170) through a power transmission hole formed on the outer side of the front vertical surface (120) of the oven housing (110) on the same axis as the variable lead screw (170) to transmit power so that the variable lead screw rotates in forward and reverse directions, and a variable reflow conveyor (172) is configured to move along the guide shaft (167a) toward the fixed reflow conveyor (162) so that the lead nut bracket (171) moves horizontally back and forth on the variable lead screw (170) according to the forward and reverse rotation of the variable lead screw (170) to vary the width corresponding to the left and right width of the input direction of the printed circuit board.

8. A vacuum reflow soldering device having a serially connected oven unit for each temperature range, wherein, in claim 7, the first and second type sprockets (164, 174) and the first and second drive sprockets (166, 176) are each formed as belt pulleys, and the first and second moving chains (165, 175) are composed of a conveyor belt usable at high temperatures, so that the printed circuit board is transferred by the combination of the belt pulley and the conveyor belt within the unit oven (100) constituting the oven unit of the reflow soldering device, thereby transferring the printed circuit board by input, moving it, heating it in the atmosphere, and discharging it.

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