Conveying and heating device

Abstract

By attaching a sensor with a heat capacity corresponding to the heat capacity of a component on a circuit board to a transport chain, it becomes possible to check whether the heating conditions of the component are within a set range. [Solution] A heating device comprising one or more heating furnaces arranged in a grid, which heat an object to be heated by the heating furnaces; a transport chain for transporting substrates to the heating device; a plurality of sensing bodies attached at predetermined intervals along the longitudinal direction of the transport chain and having heated parts with different heat capacities; and a plurality of temperature sensors for measuring the temperature of the heated parts, and configured to monitor the temperature profile of the object to be heated based on the temperature data measured by the temperature sensors.

Description

TECHNICAL FIELD

[0001] The present invention relates to a conveyance heating apparatus applied to, for example, a reflow apparatus.

BACKGROUND ART

[0002] The reflow apparatus includes a reflow furnace as a heating apparatus to which a printed circuit board having surface-mount components mounted on both sides of a printed wiring board as an object to be heated is supplied by a conveyance conveyor. The reflow furnace is configured, for example, such that a plurality of heating zones each having a heating furnace and one or a plurality of cooling zones are sequentially arranged along a conveyance path extending from a carry-in port to a carry-out port.

[0003] Each of the heating zones has an upper furnace body and a lower furnace body. For example, hot air is blown from the upper furnace body of the zone toward the board, and hot air is blown from the lower furnace body toward the board, whereby the solder in the solder composition is melted, and the electrodes of the board and the electronic component are soldered together.

[0004] In the reflow apparatus, management of heating conditions during soldering is required. The heating conditions include temperature, oxygen concentration, the speed of the conveyance conveyor, and the like. In the following description, a case where the soldering temperature is managed will be described. The temperature is managed based on a temperature profile. The temperature profile is a graph plotting the soldering temperature of the printed circuit board against the lapse of time.

[0005] In the reflow apparatus, even after a new temperature profile is set, temperature profile measurement is routinely performed, for example, at the start of daily operation, and the reflow apparatus is controlled based on the measured temperature. For example, an error between a reference temperature profile and the measured temperature profile is corrected.

[0006] There are two types of methods (devices) for measuring temperature profiles. For measuring the temperature of an actual substrate, the substrate (appropriately referred to as a temperature profile measurement substrate) has thermocouples at a predetermined number of locations. A processing device (appropriately referred to as a data logger) is provided to process the outputs of the multiple thermocouples and store them as digital data. One type of temperature profile measurement device has a configuration in which one end of a thermocouple is connected to the measurement location on the temperature profile measurement substrate, and the other end of the thermocouple, which has passed through the furnace, is connected to a data logger outside the furnace.

[0007] Other types include a transmitter built into a heat-resistant case immediately after the temperature profile measurement board, which is transported together with the temperature profile measurement board. A thermocouple is connected to a connector on the transmitter, which converts the signal into a digital signal and sends it to a receiver outside the reflow machine, to which a personal computer is connected.

[0008] In the case of wired measuring instruments, several meters of thermocouples were attached to a temperature profile measuring board during temperature profile measurement, and the temperature profile measuring board was transported. After measurement, the transport conveyor was stopped and the thermocouples and temperature profile measuring board were collected from the entrance side. In the case of wireless measuring instruments, the temperature profile measuring board and the transmitting device were transported together, and after measurement, the transport conveyor was not stopped, and the temperature profile measuring board and transmitting device were collected as they flowed out from the exit side.

[0009] The reason for measuring the temperature profile immediately before production each day and periodically thereafter is to anticipate that some malfunction in the reflow machine may prevent the proper temperature profile from being achieved even when heating under pre-set conditions. It is desirable to eliminate this process (task) and automate it (continuous checking and monitoring).

[0010] For example, Patent Document 1 describes a method in which a temperature-measured object, having a unit heat capacity of 0.5 to 2 times that of a substrate to be soldered and a thickness within the range of 0.5 to 2 times, is passed through a reflow oven in the same way as a substrate to be soldered, its temperature is measured by a thermocouple attached to it, and it is guided out of the furnace through a brush or the like. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2-151366 [Overview of the project] [Problems that the invention aims to solve]

[0012] A substrate subjected to reflow typically contains multiple components with different thermal capacities. Examples of components with high thermal capacity include electrolytic capacitors and QFP (Quad Flat Package), while examples of components with low thermal capacity include chip components and microchip components. It is desirable to set the temperature profile to be optimal for both components with high and low thermal capacity.

[0013] However, as with the reflow apparatus described in Patent Document 1, simply measuring the temperature of a single temperature-measuring object corresponding to the production substrate does not take into account the heat capacity of the components, making it impossible to correctly determine whether the temperature profile is appropriate. Furthermore, in order to measure the temperature during actual production, it is necessary to continuously run a temperature-measuring substrate along with the main substrate, which has the disadvantage of increasing the additional configuration and workload.

[0014] Therefore, the object of the present invention is to provide a transport heating device that eliminates the need for periodic temperature profile verification and does not require the continuous flow of temperature measurement substrates within the device. [Means for solving the problem]

[0015] The present invention relates to a heating device comprising one or more heating furnaces arranged in a configuration, which heats an object to be heated by the heating furnaces, A transport chain for loading substrates into the heating device, Multiple detection bodies are attached at predetermined intervals along the longitudinal direction of the conveyor chain and have heated parts with different heat capacities, Equipped with multiple temperature sensors to measure the temperature of the heated part, This is a conveying and heating device that monitors the temperature profile of the object being heated based on temperature data measured by a temperature sensor. [Effects of the Invention]

[0016] According to at least one embodiment, since the heat capacities of multiple sensing elements are different, it is possible to estimate the temperature profiles of multiple components on the substrate, and to monitor whether the heating conditions are within a set range during production. The effects described herein are not necessarily limited, and any of the effects described in the present invention may be used. Furthermore, the effects illustrated in the following description should not be interpreted as limiting the scope of the present invention. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 is a schematic diagram showing a conventional reflow apparatus to which the present invention can be applied. [Figure 2] Figure 2 is a graph showing an example of a temperature profile during reflow. [Figure 3] Figure 3 is a graph showing specific examples of temperature profiles of components with different heat capacities. [Figure 4] Figure 4 is a front view used to explain the conveyor chain. [Figure 5] Figure 5 is a cross-sectional view illustrating the chain guide section. [Figure 6] Figure 6 is a schematic diagram used to illustrate one embodiment of the present invention. [Figure 7]FIG. 7 is a graph showing temperature changes of a sensing body with a sensor according to an embodiment of the present invention. [Figure 8] FIG. 8 is a graph of a temperature profile used for description of an embodiment of the present invention. [Figure 9] FIG. 9A, FIG. 9B, FIG. 9C, and FIG. 9D are schematic line diagrams for illustrating an example of a configuration for attaching the sensing body with a sensor to a conveyance chain. [Figure 10] FIG. 10A, FIG. 10B, FIG. 10C, and FIG. 10D are schematic line diagrams for illustrating another example of the configuration for attaching the sensing body with a sensor to the conveyance chain. [Figure 11] FIG. 11 is a schematic line diagram used for description of a modification of the embodiment of the present invention. [Figure 12] FIG. 12 is a graph of a temperature profile used for description of the modification of the embodiment of the present invention. [Figure 13] FIG. 13 is a schematic line diagram used for description of another embodiment of the present invention. [Figure 14] FIG. 14 is a graph of a temperature profile used for description of the other embodiment of the present invention. [Modes for Carrying Out the Invention]

[0018] Hereinafter, embodiments of the present invention will be described. The description will be given in the following order. <1. Example of Reflow Apparatus> <2. One Embodiment> <3. Other Embodiment> <4. Modifications> The embodiment described below is a preferred specific example of the present invention, and various technically preferable limitations are imposed thereon, but the scope of the present invention is not limited to these embodiments unless otherwise specifically stated to limit the present invention in the following description.

[0019] <1. Example of Reflow Apparatus> Figure 1 shows a schematic configuration of a conventional reflow apparatus 101 to which the present invention can be applied. The reflow apparatus 101 comprises a reflow oven 102 as a heating device, a transport chain 103 that passes a workpiece to be heated, such as a substrate W with surface-mount electronic components mounted on both sides, through the reflow oven 102, rotating bodies (idlers, sprockets, etc.) 105a, 105b, 105c, 105d that define the movement path of the transport chain 103, and an outer plate 106. Note that in Figure 1, only one of the two parallel transport chains is shown.

[0020] The reflow oven 102 heats the substrate W from above and below, and then cools it after heating. The transport chain 103 is one of two transport chains arranged parallel to the transport direction. For example, a roller chain is used as the transport chain 103. The outer plate 106 is a case that covers the entire thing.

[0021] After the substrate W is loaded into the reflow oven 102 from the loading port 107, it is transported by the transport chain 103 at a predetermined speed in the direction of the arrow (from left to right in Figure 1) and finally removed from the discharge port 108. Although not shown, a substrate loading device for loading the substrate W is provided before the loading port 107, and a substrate unloading device for sending the substrate W to the outside is located after the discharge port 108.

[0022] Along the transport path from the inlet 107 to the outlet 108, the reflow oven 102 is sequentially divided into, for example, nine zones Z1 to Z9, and these zones Z1 to Z9 are arranged in line. The seven zones Z1 to Z7 on the inlet 107 side are heating zones, and the two zones Z8 and Z9 on the outlet 108 side are cooling zones. Forced cooling units (not shown) are provided in relation to the cooling zones Z8 and Z9. Note that the number of zones is just an example, and other numbers of zones may be provided. Multiple zones Z1 to Z9 control the temperature of the substrate W according to the temperature profile during reflow. Each of the heating zones Z1 to Z7 has an upper heating unit and a lower heating unit, each including a blower.

[0023] The aforementioned zones Z1 to Z9 control the temperature of the object being heated according to the temperature profile during reflow. Figure 2 shows a schematic example of a temperature profile. The horizontal axis represents time, and the vertical axis represents the surface temperature of the object being heated, such as a printed circuit board on which electronic components are mounted. The first section is the heating section R1 where the temperature rises due to heating, the next section is the preheating section R2 where the temperature remains almost constant, the next section is the reflow (main heating) section R3, and the last section is the cooling section R4.

[0024] The heating section R1 is the period during which the substrate is heated from room temperature to the preheating section R2 (e.g., 150°C to 170°C). The preheating section R2 is a period during which isothermal heating is performed to activate the flux, remove the oxide film on the surface of the electrodes and solder powder, and eliminate uneven heating of the printed circuit board. The reflow section R3 (e.g., peak temperature of 220°C to 240°C) is the period during which the solder melts and the bonding is completed. In the reflow section R3, it is necessary to raise the temperature to a level above the solder melting point. Even after passing through the preheating section R2, uneven temperature rise may exist in the reflow section R3, so heating to a level above the solder melting point is necessary. The final cooling section R4 is a period during which the printed circuit board is rapidly cooled and the solder composition is formed. In the case of lead-free solder, the temperature in the reflow section will be higher (e.g., 240°C to 260°C).

[0025] In Figure 2, curve 1 shows an example of the temperature profile for lead-free solder. An example of the temperature profile for Sn-Pb eutectic solder is shown by curve 2. Since the melting point of lead-free solder is higher than that of eutectic solder, the set temperatures in the preheating section R2 and the reflow section R3 are set higher compared to those for eutectic solder.

[0026] In the reflow apparatus shown in Figure 1, zones Z1 and Z2 are primarily responsible for controlling the temperature of the heating section R1 in Figure 2. Zones Z3, Z4, and Z5 are primarily responsible for controlling the temperature of the preheating section R2. Zones Z6 and Z7 are responsible for controlling the temperature of the reflow section R3. Zones Z8 and Z9 are responsible for controlling the temperature of the cooling section R4.

[0027] Figure 3 is a graph showing specific examples of temperature increases for components with different heat capacities on a circuit board. In Figure 3, the horizontal axis represents time (elapsed time since entering the reflow oven), and the vertical axis represents the measured temperature of the component. Graph 301 shows the temperature change of a component with a large heat capacity, and graph 302 shows the temperature change of a component with a small heat capacity.

[0028] In the heating unit R1, the heating rate gradient (°C / second) for each component is checked based on graphs 301 and 302 to see if it is within the set range. If the heating rate gradient is not within the set range, the temperature setting is changed. In addition to the temperature setting, the conveying speed and blower settings may also be adjusted.

[0029] Similarly, in the preheating section R2, it is checked whether the preheating temperature (°C) and time (seconds) have been set for each component based on graphs 301 and 302. In the reflow section R3, it is checked whether the main heating temperature (°C) and time (seconds) have been set for each component based on graphs 301 and 302. In the cooling section R4, it is checked whether the cooling gradient (°C / second) has been set for each component based on graphs 301 and 302.

[0030] Furthermore, it can be checked whether the peak temperature during the reflow period falls within the set range. It can also be checked whether the difference in peak temperatures between components with high and low heat capacity on the board falls within the set range.

[0031] On the other hand, as will be described later, the present invention involves attaching heated parts with different heat capacities to the transport chain, rather than to components on the substrate, measuring the temperature of the heated parts, and confirming and monitoring whether production is being carried out with an appropriate temperature profile based on the results. Unlike the present invention, a method can be considered in which multiple temperature sensors are attached to, for example, the rails for guiding the transport chain of a reflow apparatus to measure the temperature. However, this method has the problem that it measures the temperature of a specific part inside the furnace and cannot investigate the actual temperature conditions of the components on the substrate.

[0032] An example of a transport chain 103 will be described. Figure 4 shows the units that make up the transport chain 103. In Figure 4, 31 is a pin, 32a and 32b are inner link plates, 33a and 33b are outer link plates, 34 is a sleeve, and 35 is a pin-attached link plate. The pin-attached link plate 35 has substrate holding pins 37. The sleeve 34 is attached to the pin 31. The pin 31 is supported by two inner link plates 32a and 32b that are parallel to and opposite the sleeve 34, and two outer link plates 33a and 33b that are parallel to and opposite the sleeve 34.

[0033] The outer diameter of the sleeve 34 is smaller than the width of the inner link plates 32a, 32b and the outer link plates 33a, 33b. In the example in Figure 4, the widths of the inner link plates 32a, 32b and the outer link plates 33a, 33b are equal, and the width of the pinned link plate 35 is slightly larger than the widths of the inner and outer link plates. The inner link plate 32a, the outer link plate 33a and the pinned link plate 35 will be appropriately referred to as the attachment-equipped link plate section 36a, and the inner link plate 32b and the outer link plate 33b will be appropriately referred to simply as the link plate section 36b. Attachments other than pins may also be provided.

[0034] In the reflow apparatus 101 shown in Figure 1, a chain guide section 14 is provided along the transport path from the inlet 107 to the outlet 108. Figure 5 shows a cross-section of the chain guide section 14. For example, the metal rail 41 of an extruded aluminum product has a U-shaped cross-section in which an upper surface 41a, a lower surface 41b, and a side surface 41c are formed in a continuous manner. The transport chain 103 is arranged in the space between the upper surface 41a and the lower surface 41c.

[0035] A groove 42a extending in the conveying direction is formed on the inner surface of the upper surface 41a of the metal rail 41. The width of the opening extending in the longitudinal direction of the groove 42a is smaller than the width of the groove. A groove 42b extending in the conveying direction is formed on the inner surface of the lower surface 41b, which is opposite the upper surface 41a. The width of the opening extending in the longitudinal direction of the groove 42b is smaller than the width of the groove. An upper resin guide 43a, made of, for example, a heat-resistant and non-conductive resin, is inserted into the groove 42a. A lower resin guide 43b, also made of a heat-resistant and non-conductive resin, is inserted into the groove 42b.

[0036] <2. One Embodiment> An embodiment of the present invention will be described with reference to Figure 6. In one embodiment, a plurality of sensor-equipped detection bodies are attached to the transport chain 103 at predetermined intervals in the longitudinal direction. The sensor-equipped detection body is made of a metal such as stainless steel and exposed inside the furnace, and is a device in which a heat-resistant structure is integrated with a heat-resistant object to be heated whose heat capacity (or specific heat) is known in advance, a temperature sensor (e.g., a thermocouple) for measuring the temperature of the heated part, and a communication device for wirelessly transmitting the measured value of the temperature sensor.

[0037] One embodiment of the present invention involves attaching multiple sensor-equipped detection units, each having a heated section with a different heat capacity, along the longitudinal direction of a conveyor chain 103. During continuous production, the temperature rise of each of these heated sections with different heat capacities can be measured, and the temperature range, temperature gradient, etc., can be determined. Therefore, the following effects can be achieved.

[0038] By correlating the heat capacity of each heated part attached to the transport chain 103 with the heat capacity of the components on the substrate being produced, reflow conditions such as the temperature gradient and peak temperature of the components on the substrate can be estimated. Therefore, the temperature profile confirmation work that was conventionally required before the start of production each day can be omitted. Furthermore, by confirming the correlation between the temperature profile measured in advance and the temperature profile measurement results obtained by the detection element with the heat capacity difference of the present invention, the temperature profile confirmation work before the start of production can be omitted.

[0039] Furthermore, since the temperature profile can be obtained during production in this invention, it is possible to monitor whether the reflow conditions are within the set range by correlating the obtained temperature profile with a previously acquired temperature profile. Therefore, it is possible to eliminate the need to temporarily suspend production for temperature profile measurement, which contributes to the automation of the factory.

[0040] In one embodiment, for example, twelve sensor-equipped detection units Xs1 to Xs12 (in the following description, when it is not necessary to distinguish between individual sensor-equipped detection units, they will simply be referred to as sensor-equipped detection units Xsi) are attached to a transport chain 103 at approximately equal intervals along its longitudinal direction. The sensor-equipped detection units Xsi are transported by the transport chain 103 so as to pass through the reflow oven 102. Sensor-equipped detection units Xsi are attached to one of the transport chains 103 of a plurality of parallel transport chains. However, sensor-equipped detection units Xsi may be attached to multiple parallel transport chains.

[0041] Since the transport chain 103 is endless, after passing through the reflow oven 102, the transport chain 103 passes through the lower space outside the reflow oven 102 and re-enters the reflow oven 102. While passing through the lower space of the reflow oven 102, the sensor-equipped detection element Xsi attached to the transport chain 103 is cooled. Therefore, by the time it re-enters the reflow oven 102, the temperature of the sensor-equipped detection element Xsi has decreased to, for example, 25°C to 50°C. Thus, temperature profile measurements can be repeatedly performed using the sensor-equipped detection element Xsi.

[0042] The sensor-equipped detection unit Xsi uses heated parts with different heat capacities. For example, sensor-equipped detection units Xs1, Xs3, ..., Xs11, indicated by square marks, have heated parts with large heat capacities, while sensor-equipped detection units Xs2, Xs4, ..., Xs12, indicated by round marks, have heated parts with small heat capacities. As will be described later, there may be three or more types of heated parts in the sensor-equipped detection unit.

[0043] The measurement data for each sensor-equipped detection element Xsi is transmitted to a processing unit, including a data logger, located outside the reflow oven, and stored in the processing unit's memory. The measurement data is then processed for each sensor-equipped detection element with the same heat capacity, and a temperature profile for each heat capacity is obtained. The processing unit consists of digital signal processing devices such as a PLC (Programmable Logic Controller) and a PC (Personal Computer).

[0044] In other words, multiple sensor-equipped detection elements, each containing a heated part with a large heat capacity, transmit multiple measurement data at relatively low temperatures to the processing unit. The received measurement data is processed to obtain a temperature profile of the sensor-equipped detection element with a large heat capacity. Similarly, multiple sensor-equipped detection elements, each containing a heated part with a small heat capacity, transmit multiple measurement data at relatively high temperatures. The received measurement data is processed to obtain a temperature profile of the sensor-equipped detection element having a heated part with a low heat capacity. The measurement temperature data may also be transmitted to the processing unit via a wired connection. For example, the thermocouple wires of each sensor-equipped detection element Xsi may be extended to the processing unit. Alternatively, a configuration using sliding contacts may be used.

[0045] Figure 7 shows, for example, two examples of the time change in the measured temperature of sensor-equipped detection unit Xs1 (401) and sensor-equipped detection unit Xs2 (402). At time t0, sensor-equipped detection unit Xs1 enters the reflow oven 102 and is heated. At time t1, sensor-equipped detection unit Xs1 exits the reflow oven 102 and moves through the space below the oven body. At time t2, sensor-equipped detection unit Xs1 enters the reflow oven 102 again. Between time t1 and t2, sensor-equipped detection unit Xs1 is cooled. A similar temperature change occurs for sensor-equipped detection unit Xs2. Since sensor-equipped detection units Xs1 and Xs2 are mounted at different positions on the transport chain 102, there is a time difference corresponding to the positional shift, but in Figure 7, this time difference is assumed to be nonexistent.

[0046] Figure 8 shows an example of a temperature profile obtained by one embodiment. Temperature profile 501 shows the temperature profile obtained from the measurement results of sensor-equipped detection elements Xs1,...,Xs11 with large heat capacity, and temperature profile 502 shows the temperature profile obtained from the measurement results of sensor-equipped detection elements Xs1,...,Xs11 with small heat capacity.

[0047] Furthermore, the dashed temperature profile 503 represents the average temperature profile of the components on the production board, as measured in advance. As shown in the example in Figure 8, if temperature profile 503 is located between temperature profile 501 and temperature profile 502, it indicates that the reflow conditions are within the set range. If temperature profile 503 falls outside the region between temperature profiles 501 and 502, it means that the reflow conditions are outside the set range. If such deviations from the set range in reflow conditions are detected during reflow, an audible or visual alarm is triggered.

[0048] Figures 9A, 9B, 9C, and 9D show an example of the mounting structure of the sensor-equipped detection unit Xsi to the transport chain 103. The transport chain 103 will be described with reference to Figure 4, and as shown in Figure 9A, it has a configuration in which inner link plates 32a and 32b and outer link plates 33a and 33b are connected, and the pinned link plate 35 has substrate holding pins 37.

[0049] Figure 9B shows the outer link plate 51 provided at the mounting position of the sensor-equipped detection unit Xsi. The outer link plate 51 integrally has mounting legs 52 extending downward. The surface of the legs 52 is parallel to the direction of travel.

[0050] As shown in Figure 9C, the sensor-equipped detection unit Xsi has a plate-shaped projection 53. As shown in Figure 9D, the plate-shaped projection 53 of the sensor-equipped detection unit Xsi is superimposed on the leg portion 52 and fixed with fixing means 54 such as screws or welding. Since the sensor-equipped detection unit Xsi is attached below the transport chain 103, the operation of the transport chain 103 in transporting the substrate is not obstructed. In addition, the sensor-equipped detection unit Xsi does not obstruct the circulation of hot air for heating the substrate.

[0051] Figures 10A, 10B, 10C, and 10D show other examples of mounting structures for the sensor-equipped detection unit Xsi to the transport chain 103. Figure 10B shows an outer link plate 61 provided at the mounting position of the sensor-equipped detection unit Xsi. The outer link plate 61 integrally has mounting legs 62 extending downward. The plate surface of the legs 62 is perpendicular to the direction of travel.

[0052] As shown in Figure 10C, the sensor-equipped detection unit Xsi has a plate-shaped projection 63. As shown in Figure 10D, the plate-shaped projection 63 of the sensor-equipped detection unit Xsi is superimposed on the leg portion 62 and fixed with fixing means 64 such as screws or welding. Since the sensor-equipped detection unit Xsi is mounted below the transport chain 103, the sensor-equipped detection unit Xsi does not obstruct the transport chain 103 from transporting the substrate, nor does the sensor-equipped detection unit Xsi obstruct the circulation of hot air for heating the substrate.

[0053] In the embodiment described above, a sensor-equipped detection body having a heated portion with a large heat capacity and a sensor-equipped detection body having a heated portion with a small heat capacity are attached to the transport chain 103. As shown in the following modified example, multiple sensor-equipped detection bodies, each having three or more different heat capacities, may be attached to the transport chain 103.

[0054] Figure 11 shows a modified example of one embodiment of the present invention. In the embodiment described above, a sensor-equipped detection body having a heated portion with a large heat capacity and a sensor-equipped detection body having a heated portion with a small heat capacity are attached to the transport chain 103. In the example shown in Figure 11, sensor-equipped detection bodies having heated portions with six different heat capacities are used.

[0055] The following shows the relative heat capacities of the heated parts for the six types of sensor-equipped detection devices. The inequality signs indicate the relative heat capacities.

[0056] Sensor-equipped detection units Xs22, Xs28, and Xs34 are indicated by the white circle symbol. Sensor-equipped detection units Xs24 and Xs30 are indicated by a symbol of a white circle with a diagonal line drawn inside. Sensor-equipped detection objects Xs26, Xs32 are indicated by the symbol X drawn inside a white circle. <Sensor-equipped detection units Xs21, Xs23, Xs29 are indicated by square symbols> Sensor-equipped detection objects Xs25, Xs31 are indicated by a symbol that is a square with a diagonal line drawn inside. Sensor-equipped detection objects Xs27, Xs33 are indicated by a symbol of a square with a diagonal X drawn inside.

[0057] As described above, Figure 12 shows an example of temperature profiles obtained from six types of sensor-equipped detection bodies having heated parts with different heat capacities. The correspondence between the sensor-equipped detection bodies and the temperature profiles is shown below. Temperature Profile 601: Sensor-equipped detection units Xs22, Xs28, Xs34 Temperature Profile 602: Sensor-equipped detection units Xs24, Xs30 Temperature Profile 603: Sensor-equipped detection units Xs26, Xs32 Temperature Profile 604: Sensor-equipped detectors Xs21, Xs23, Xs29 Temperature Profile 605: Sensor-equipped detection units Xs25, Xs31 Temperature Profile 606: Sensor-equipped detection units Xs27, Xs33

[0058] Furthermore, temperature profile 701, located between temperature profiles 603 and 604, represents the temperature profile of the components on the substrate being reflowed, such as the average temperature profile of multiple components. In the example in Figure 12, this indicates that the reflow conditions are within the set range. If temperature profile 701 falls outside the region between temperature profiles 601 and 606, it means that the reflow conditions are outside the set range. If such deviations from the set range are detected during reflow, an audible or visual alarm is triggered.

[0059] Table 1 shows an example of the heated portion of the sensor-equipped detection unit Xsi. This example uses stainless steel, for example, SUS304, and consists of plate-like bodies with equal length and width dimensions but varying thicknesses. The numerical values ​​for the heat capacity Q of each portion are shown.

[0060] [Table 1]

[0061] The heat capacity Q of each heated part in Table 1 corresponds to the actual soldering temperature of electronic components, as shown in the example below. Q=0.4 : Soldering temperature of 1005 chip Q=0.8 : Soldering temperature of 1608 chip capacitor Q=1.0: Soldering temperature of a plastic QFP equivalent, φ6.3mm, height 11mm aluminum electrolytic capacitor. Q=1.2: Equivalent to ceramic QFP Q=1.6: Soldering temperature of a φ10mm, 20mm high aluminum electrolytic capacitor Q=2.0: Soldering temperature of IC package BGA Q=2.3: Soldering temperature of large LSI sockets

[0062] Therefore, the heating element to be attached to the sensor-equipped detection unit Xsi is selected to correspond to the heat capacity of the components on the substrate that will actually be produced. If there is no corresponding heating element, a heating element with a similar heat capacity value is selected.

[0063] <3. Other Embodiments> Figure 13 shows a schematic configuration of another embodiment of the present invention. Similar to the embodiment shown in Figure 6 above, a sensing body having a heated portion with a small heat capacity and a heated portion with a large heat capacity are alternately attached to the transport chain 103. The sensing body in the other embodiment does not have a temperature sensor and a transmitter, and consists of a heated portion with a predetermined heat capacity. The temperature of this sensing body is measured by a fixed non-contact temperature sensor.

[0064] In other embodiments, for example, twelve detection elements X1 to X12 (in the following description, when it is not necessary to distinguish between individual detection elements, they will simply be referred to as detection elements Xi) are attached to the transport chain 103 at approximately equal intervals along its longitudinal direction. The transport chain 103 transports the detection elements Xi so that they pass through the reflow oven 102. The detection elements Xi are attached to one of a plurality of parallel transport chains 103. However, detection elements Xi may be attached to multiple parallel transport chains. The detection elements Xi are, for example, metal plate-shaped bodies and are attached to the transport chain 103 in a configuration as described with reference to Figure 9 or Figure 10.

[0065] After passing through the reflow oven 102, the transport chain 103 passes through the lower space outside the reflow oven 102 and re-enters the reflow oven 102. While passing through the lower space of the reflow oven 102, the sensing element Xi attached to the transport chain 103 is cooled. Therefore, by the time it re-enters the reflow oven 102, the temperature of the sensing element Xi has decreased to, for example, 25°C to 50°C. Thus, temperature profile measurements can be repeatedly performed using the sensing element Xi.

[0066] The heating elements of the detection body Xi are made up of different heat capacities. For example, detection bodies X1, X3, ..., X11, indicated by square marks, have heating elements with large heat capacities, while detection bodies X2, X4, ..., X12, indicated by round marks, have heating elements with small heat capacities. Note that there may be three or more different heat capacities for the heating elements of the detection body.

[0067] The temperature of the detection object Xi is measured by non-contact temperature sensors Dt1 to Dt10 (in the following description, when it is not necessary to distinguish between individual non-contact temperature sensors, they will simply be referred to as non-contact temperature sensor Dti). The non-contact temperature sensor Dti is attached to a fixed member such as a metal rail (see Figure 5) that guides the transport chain 103, and is configured to measure the temperature of the detection object Xi when it approaches and comes to a position opposite it.

[0068] In the example shown in Figure 13, four non-contact temperature sensors Dt1 to Dt4 are provided inside the reflow oven 102 at approximately equal intervals in the longitudinal direction, and six non-contact temperature sensors Dt5 to Dt10 are provided outside the oven at approximately equal intervals. Inside the oven, non-contact temperature sensors Dt1 to Dt4 are provided for the heating section R1, the preheating section R2, the reflow (main heating) section R3, and the cooling section R4, respectively. This mounting position is just an example, and other mounting positions can be adopted. For example, non-contact temperature sensors may be provided in each zone of the reflow oven 102, or non-contact temperature sensors may be provided at the inlet and outlet of the reflow oven 102, respectively. Furthermore, the non-contact temperature sensors outside the reflow oven may be omitted.

[0069] The temperature information (measurement data) measured by the non-contact temperature sensor Dti is transmitted via wireless or wired communication devices on each non-contact temperature sensor to a processing unit (such as a PC PLC) equipped with a data logger located outside the reflow oven, and stored in the processing unit's memory. The measurement data is then processed for each sensor with the same heat capacity, and a temperature profile for each heat capacity is obtained. The temperature of all sensor Xi is measured by the non-contact temperature sensor Dti, but the measurement data can be separated for each sensor based on the measured temperature. Alternatively, since the arrangement of the sensor Xi is known in advance, the measurement data can be separated for each sensor based on timing.

[0070] Multiple measurement data at relatively low temperatures are transmitted from multiple detection elements X1, X3, ..., X11, which include heated parts with large heat capacity, to the processing unit. The received measurement data is processed to obtain a temperature profile of the detection elements with large heat capacity. Similarly, multiple measurement data at relatively high measurement temperatures are transmitted from multiple detection elements X2, X4, ..., X12, which include heated parts with small heat capacity, to the processing unit. The received measurement data is processed to obtain a temperature profile of the detection elements having heated parts with low heat capacity.

[0071] Figure 14 shows an example of a temperature profile obtained by another embodiment. Temperature profile 801 shows the temperature profile obtained from the measurement results of detection elements X1,...,X11 with large heat capacity, and temperature profile 802 shows the temperature profile obtained from the measurement results of detection elements X1,...,X11 with small heat capacity. Discrete measurement data is obtained inside the reflow oven 102 by non-contact temperature sensors Dt1 to Dt4. By applying interpolation processing to the discrete temperature data, a temperature profile showing a continuous temperature change is obtained.

[0072] Furthermore, the dashed temperature profile 803 represents the average temperature profile of the components on the production board, as measured in advance. As shown in the example in Figure 14, if temperature profile 803 is located between temperature profile 801 and temperature profile 802, it indicates that the reflow conditions are within the set range. If temperature profile 803 falls outside the region between temperature profiles 801 and 802, it means that the reflow conditions are outside the set range. If such deviations from the set range in reflow conditions are detected during reflow, an audible or visual alarm will be triggered.

[0073] The other embodiments of the present invention described above, like the first embodiment, can eliminate the need for temperature profile verification work, such as before the start of production, which was previously required. Furthermore, since the temperature profile can be obtained during production, it is possible to monitor whether the reflow conditions are within the set range by correlating the obtained temperature profile with a previously obtained temperature profile. Therefore, it is possible to eliminate the need for temperature profile measurement that requires temporarily stopping production.

[0074] <4. Variation> Although embodiments of the present invention have been specifically described above, the invention is not limited to the embodiments described above, and various modifications are possible based on the technical concept of the present invention. For example, the present invention is not limited to printed circuit boards, but can also be applied to reflow of flexible substrates, substrates made by bonding rigid substrates and flexible substrates, and rigid-flex substrates that combine these. Furthermore, it is not limited to reflow equipment, but can also be applied to heating equipment for curing resins, etc. In addition, the configurations, methods, processes, shapes, materials, and numerical values ​​listed in the embodiments described above are merely examples, and different configurations, methods, processes, shapes, materials, and numerical values ​​may be used as needed. Moreover, the configurations, methods, processes, shapes, materials, and numerical values ​​of the embodiments described above can be combined with each other as long as they do not deviate from the spirit of the present invention. [Explanation of symbols]

[0075] 101...Reflow apparatus, 102...Reflow oven, 103...Transport chain, W...Substrate, 14...Chain guide, 36a...Attachment link plate section, 36b...Link plate section, 37...Substrate holding pin, 41...Metal rail, 51, 61...Outer link plate, 401...Temperature profile of sensor-equipped detection body with a heated part having a large heat capacity, 402...Temperature profile of sensor-equipped detection body with a heated part having a small heat capacity, Xs1 to Xs12...Sensor-equipped detection body, X1 to X12...Detection body, Dt1 to Dt10...Non-contact temperature sensor, R1...Heating section, R2...Preheating section, R3...Reflow section, R4...Cooling section

Claims

1. A heating device comprising one or more heating furnaces arranged in a grid, which heat an object to be heated by the heating furnaces, A transport chain for loading substrates into the heating device, Multiple detection bodies are attached at predetermined intervals along the longitudinal direction of the transport chain and each has a heated portion with a different heat capacity. The system includes multiple temperature sensors for measuring the temperature of the heated portion, A conveying and heating device configured to monitor the temperature profile of the object to be heated based on the temperature data measured by the temperature sensor.

2. The transport heating apparatus according to claim 1, wherein the detection body comprises the temperature sensor and a communication device for transmitting measurement data from the temperature sensor.

3. The conveying heating device according to claim 1, wherein a non-contact temperature sensor for measuring the temperature of the heated portion of the detection body and a communication device for transmitting measurement data from the non-contact temperature sensor are attached to a fixed portion near the conveying chain.

4. The conveying and heating device according to claims 1 to 3, wherein the conveying chain is endless and is cooled after leaving the heating device and then re-entered the heating device.

5. The conveying and heating device according to claims 1 to 3, wherein the detection body is attached to the link plate of the conveying chain.

6. The conveying and heating apparatus according to claims 1 to 3, wherein the heat capacity of the heated portion is approximately equal to the heat capacity required by the object to be heated.

7. The transport heating apparatus according to claim 1 to 3, wherein the heating apparatus is a reflow oven and the object to be heated is a printed circuit board.

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