High-uniformity suspension type full-automatic powder spraying production line and spraying method thereof

Abstract

The invention discloses a high-uniformity suspension type full-automatic powder spraying production line and a spraying method thereof.The high-uniformity suspension type full-automatic powder spraying production line comprises a conveying line, a feeding device, a dust removal system, a powder spraying system, a curing system, a discharging device and a control center; the control center is used for controlling the overall operation of the production line, the feeding device, the dust removal system, the powder spraying system, the curing system and the discharging device are sequentially arranged in the conveying direction of the conveying line, and the conveying line sequentially penetrates through the feeding device, the dust removal system, the powder spraying system, the curing system and the discharging device to form a circulating conveying line. The problem that the thicknesses of coatings of workpieces in different rows on the suspension type powder spraying hanging tool are inconsistent is solved, the thicknesses of the workpieces above and below the hanging tool are consistent, powder waste is reduced, the spraying time is shortened, the spraying cost is reduced, and the spraying efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of powder electrostatic spraying equipment. Specifically, it relates to a high-uniformity suspended full-automatic powder electrostatic spraying production line for neodymium iron boron, and specifically relates to a powder spraying booth, a powder spraying device and a spraying method. Background Art

[0002] Powder electrostatic spraying utilizes the principle of high-voltage electrostatic corona electric field. The electrostatic needle in the spray gun is connected to a high-voltage negative electricity, and the neodymium iron boron magnet to be coated is grounded on the hanger to form a positive electrode. A strong electrostatic field is formed between the spray gun and the magnet. When the carrier gas (compressed air) sends the powder coating from the powder supply barrel to the spray gun through the powder conveying pipe, dense charges are generated around it, and the powder is charged negatively. Under the action of electrostatic force and compressed air, the powder is evenly adsorbed on the workpiece. After heating, the powder melts and pre-cures into a uniform, continuous, flat and smooth coating film.

[0003] In the prior art, by applying a thermosettable powder coating to the assembly process of an automotive motor magnet to provide a coating for the magnet. The coating is composed of a thermosettable resin matrix, and thermally expandable microspheres are embedded in the matrix. The softening temperature of the matrix is lower than the reaction temperature of the thermally expandable microspheres. Under the influence of a temperature higher than the reaction temperature of the microspheres, the volume of the microspheres increases irreversibly. When the magnet coated with this coating is heated to a temperature higher than the reaction temperature of the expandable microspheres, the resin matrix softens first, and then the microspheres expand. The softened matrix has no resistance to the expansion, and the total coating thickness of the magnet increases, filling the gap between the magnet and the rotor slot, so that the magnetic sheet is fixed in the rotor slot. Using a thermosettable powder as the coating to solve the fixation of the rotor during the motor assembly process improves the assembly efficiency and processing accuracy.

[0004] However, the rotor slot has relatively high requirements for the coating thickness consistency of the magnet. The existing full-automatic suspended powder spraying technology has certain defects and cannot effectively control the coating thickness of the magnets in different rows (when n>1) on the hanger. Usually, the coating thickness of the magnet in the top row of the hanger is thin, and the coating thickness of the magnet in the bottom row is thick, or the coating in the center of the workpiece in the first row and the last row is thin, while the coating at the corners is thick. This causes a certain proportion of the magnet coatings to be too thin to fill the rotor slot or a certain proportion of the magnet coatings to be too thick to be inserted into the cavity, and only the coating can be stripped and re-sprayed, wasting a lot of manpower and material resources.

[0005] In the prior art, by installing detectors in a spraying production line, and the signals detected by the detectors are used to be sent to a powder supply center and an electric control center, thereby controlling the powder spraying amount and powder voltage during the spraying of the spray gun. Through the cooperation of the detectors, when the spray gun runs to the top and bottom of the workpiece for spraying operations, the detectors control the powder spraying amount and powder voltage by detecting the change in the spraying speed of the spray gun, solving the problem of thick coatings on the top and bottom of a single workpiece. However, it cannot solve the problems that the magnet coating thickness of the uppermost row of multiple rows of workpieces is thin, the magnet coating thickness of the lowermost row is thick, or the center coating of the workpieces in the first row and the last row is thin and the corner coatings are thick.

[0006] To solve the problem of inconsistent coating thicknesses of workpieces in different rows on a suspended powder spraying fixture, currently in the spraying industry, a method is generally adopted where the upward travel of the spray gun is greater than 100 - 200 mm of the first row of workpieces, and the downward travel is greater than 100 - 200 mm of the lowermost row of workpieces for spraying. However, this still cannot solve the problem well, and this way of extending the spraying travel will cause waste of powder, and at the same time will also extend the spraying time, affecting the spraying cost. Summary of the Invention

[0007] The present invention aims to provide a high - uniformity suspended full - automatic powder spraying production line and its spraying method, overcoming the deficiencies of the prior art and solving the problem of inconsistent coating thicknesses of workpieces in different rows on a suspended powder spraying fixture during spraying.

[0008] To achieve the above object, according to one aspect of the present invention, there is provided a high - uniformity suspended full - automatic powder spraying production line. The production line includes a conveyor line, a loading device, a dust removal system, a powder spraying system, a curing system, a unloading device, and a control center. The conveyor line is used to convey the fixtures to move on the production line. The control center is used to control the overall operation of the production line. The loading device, the dust removal system, the powder spraying system, the curing system, and the unloading device are arranged in sequence along the conveying direction of the conveyor line. The conveyor line passes through the loading device, the dust removal system, the powder spraying system, the curing system, and the unloading device in sequence to form a circulating conveyor line.

[0009] In an alternative embodiment, the powder spraying system includes:

[0010] A spray booth, which is used for performing the powder spraying process;

[0011] A recovery and filtration device, which is connected to the spray booth and is used for powder recovery and dust filtration;

[0012] Powder spraying equipment, which is used to spray powder on the workpieces passing through the spray booth;

[0013] A powder supply center, which is used to supply powder to the powder spraying equipment; and,

[0014] The electric control center is used to control the operation of the powder spraying system; among them,

[0015] The recovery and filtration device, the powder spraying equipment, the powder supply center and the electric control center are all arranged and installed in the spray booth.

[0016] In an alternative embodiment, the powder spraying equipment includes a plurality of spray guns, a fixing frame for fixing the spray guns, and a reciprocating machine for controlling the spray guns. The fixing frame is fixedly connected to the reciprocating machine, and the reciprocating machine controls the spray guns to perform reciprocating motion;

[0017] The spray guns are connected to the powder supply center, and the powder supply center controls the powder spraying amount of the spray guns;

[0018] A plurality of workpieces are arranged in an array on the hanger, and the spray guns spray electrostatic powder on each workpiece;

[0019] The reciprocating machine is electrically connected to the powder supply center and the electric control center, and the electric control center controls the moving speed, residence time and powder voltage of the spray guns.

[0020] In an alternative embodiment, the powder spraying equipment further includes a servo motor, and the servo motor controls the operation of the reciprocating machine; the electric control center further includes a PLC controller, the PLC controller controls the servo motor, and the PLC controller receives the feedback signal during the operation of the reciprocating machine, and controls the moving speed, residence time and powder voltage of the spray guns according to the feedback signal.

[0021] In an alternative embodiment, a material sensor is further arranged in the spray booth. After the material sensor senses the hanger, the reciprocating machine and the spray guns work, and the reciprocating machine controls the spray guns to spray electrostatic powder on the workpieces on the hanger according to a preset operation route and operation speed.

[0022] In an alternative embodiment, the recovery and filtration device includes a static electricity discharging device, a recovery pipeline and a return air duct. The static electricity discharging device is installed in the recovery pipeline of the recovery and filtration device, and the distance between the pipe orifice of the return air duct and the lowermost workpiece of the hanger is 35-45 cm.

[0023] In an alternative embodiment, a conductive device is further arranged on the hanger, and the conductive device is arranged above the uppermost workpiece of the hanger.

[0024] According to another aspect of the present invention, a spraying method for a high-uniformity suspended full-automatic powder spraying production line is provided. The spraying method includes:

[0025] The conveyor line transports the hangers along the production line process. When the hangers enter the spray booth through the conveyor line, the reciprocating machine of the powder spraying equipment controls the spray guns to perform reciprocating motion, and the spray guns perform reciprocating spraying on the workpieces on the hangers along the vertical direction;

[0026] When the spray gun moves reciprocally, the powder supply center and the electric control center receive electrical signals. The electric control center controls the moving speed, residence time, and powder voltage of the spray gun, and the powder supply center controls the powder spraying amount of the spray gun.

[0027] Wherein, the spray gun sprays the workpiece at a variable moving speed, the powder spraying amount of the spray gun is inversely proportional to the moving speed of the spray gun, and the powder voltage of the spray gun is inversely proportional to the moving speed of the spray gun.

[0028] In an alternative embodiment, the moving speed of the spray gun from the uppermost workpiece of the hanging tool to the lowermost workpiece of the hanging tool is a uniformly variable motion with a gradually increasing speed; the moving speed of the spray gun from the lowermost workpiece of the hanging tool to the uppermost workpiece of the hanging tool is a uniformly variable motion with a gradually decreasing speed.

[0029] In an alternative embodiment, when the spray gun moves above the hanging tool and sprays the uppermost workpiece of the hanging tool, the residence time of the spray gun at this position is increased or the powder spraying amount of the spray gun is increased.

[0030] The above-mentioned high-uniformity suspended full-automatic powder spraying production line and its spraying method solve the problem of inconsistent coating thickness of workpieces in different rows on the suspended powder spraying hanging tool. By adjusting the powder spraying amount, moving speed, residence time of the spray gun, and the installation position of the return air duct, the thickness of the workpieces above and below the hanging tool is made consistent. At the same time, the recycled powder reduces powder waste, shortens the spraying time, reduces the spraying cost, and improves the spraying efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the production line of the present invention.

[0032] Figure 2 It is a schematic structural diagram of the powder spraying system of the present invention.

[0033] Figure 3 It is a left view of the hanging tool of the present invention.

[0034] Figure 4 It is a front view of the hanging tool of the present invention.

[0035] Figure 5 It is a schematic diagram of the control principle of the spray gun of the present invention.

[0036] Figure 6 It is a diagram of the speed change of the spray gun of the present invention in a reciprocating spraying cycle.

[0037] Figure 7 It is a diagram of the powder spraying amount change of the spray gun of the present invention in a reciprocating spraying cycle.

[0038] Figure 8This is a graph showing the change in powder spraying voltage of the spray gun of the present invention during a reciprocating spraying cycle. Detailed implementation manners

[0039] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be emphasized that the specific embodiments described herein are only for better explaining the present invention, and are partial embodiments of the present invention, rather than all embodiments, so they are not used to limit the present invention. In addition, the technical features involved in the embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0040] Embodiment modes of the present invention are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The terms "first", "second", "third", etc. (if any) in the description and claims of the present invention and in the accompanying drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that such objects can be interchanged under appropriate circumstances. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. The directional terms mentioned in the present invention, such as: up, down, left, right, front, back, inside, outside, side, etc., are only references to the directions in the accompanying drawings. The embodiment modes described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention. In addition, the present invention repeats reference numerals and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity and does not itself indicate the relationship between the various embodiment modes and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0041] As Figures 1 to 8 shown, the present invention provides a high-uniformity suspended full-automatic powder spraying production line, and this production line 100 includes a conveying line 1, a loading device 2, a dust removal system 3, a powder spraying system 4, a curing system 5, an unloading device 6 and a control center 8. Among them, the conveying line 1 is used to convey the hanging tool 7 so that it can move on the production line 100.

[0042] Preferably, the conveyor line 1 is controlled by a frequency converter to run the hanger 7 to the powder spraying system 4 at a certain speed. The control center is used to control the overall operation of the production line 100. The loading equipment 2, the dust removal system 3, the powder spraying system 4, the curing system 5, and the unloading equipment 6 are arranged in sequence according to the technological process along the conveying direction of the conveyor line 1. The conveyor line 1 passes through the loading equipment 2, the dust removal system 3, the powder spraying system 4, the curing system 5, and the unloading equipment 6 in sequence to form a circulating conveyor line.

[0043] Further, the powder spraying system 4 includes a spray booth 41, a recovery and filtration device 42, a powder spraying device 43, and a powder supply center 44. The spray booth 41 is used for the powder spraying process. The recovery and filtration device 42 is connected to the spray booth 41 and is used for powder recovery and dust filtration. The powder spraying device 43 is used to spray powder on the workpiece 71 passing through the spray booth 41. The powder supply center 44 is used to supply powder to the powder spraying device 43. The electric control center (not shown in the figure) is used to control the operation of the powder spraying system 4. The recovery and filtration device 42, the powder spraying device 43, the powder supply center 44, and the electric control center are all arranged and installed in the spray booth 41. The recovery and filtration device 42 is connected to the powder supply center 44 through a pipeline.

[0044] Further, the powder spraying device 43 includes a plurality of spray guns 431, a fixing frame 432 for fixing the spray guns 431, and a reciprocating machine 433 for driving the spray guns 431. The fixing frame 432 is fixedly connected to the reciprocating machine 433. The reciprocating machine 433 drives the spray guns 431 to perform reciprocating motion. Preferably, the spray guns 431 are driven to perform reciprocating up and down movement.

[0045] According to the present invention, each spray gun 431 corresponds to a fixing frame 432 and a reciprocating machine 433 respectively. Preferably, the powder spraying device 43 includes at least two spray guns 431. The spray guns 431 are connected to the powder supply center 44, and the powder supply center 44 controls the powder spraying amount of the spray guns 431.

[0046] According to the present invention, a plurality of workpieces 71 are arranged in an array on the hanger 7, and the spray guns 431 spray electrostatic powder on the workpieces 71.

[0047] Further, in order to ensure the spraying effect of the spray guns 431 on the workpieces 71, the spray guns 431 and the workpieces 71 need to maintain a certain distance. Preferably, the distance between the spray guns 431 and the workpieces 71 is 150 - 300 mm.

[0048] Preferably, the hanger 7 has a multi-row and multi-column structure, and a plurality of workpieces 71 are arranged according to the row and column structure of the hanger 4.

[0049] Among them, the reciprocating machine 433 is connected to the electric control center and the powder supply center 44 through electrical signals. The electric control center controls the running route and running speed of the reciprocating machine 433, and further controls the moving speed, residence time, and powder voltage of the spray guns 431.

[0050] Preferably, the operation of the reciprocating machine 433 is precisely controlled by a servo motor.

[0051] Furthermore, the electric control center includes an electric control system touch screen and a PLC controller. The running route and running speed of the reciprocating machine 433 can be set on the electric control system touch screen. The PLC controller controls the servo motor, thereby completing the control of the reciprocating machine 433.

[0052] When the reciprocating machine 433 starts to work, since the reciprocating machine 433 is connected to the electric control center and the powder supply center 44 through electric signals, the reciprocating machine 433 triggers electric signals to the electric control center and the powder supply center 44 while running. After the PCL controller of the electric control center and the powder supply center 44 receive the electric signals fed back by the reciprocating machine 433, the PCL controller controls the reciprocating movement and retention of the reciprocating machine 433, and then controls the movement speed, retention time and powder voltage of the spray gun 431, and the powder supply center 44 controls the powder spraying amount of the spray gun 431. In this way, the movement, retention, powder spraying, etc. of the spray gun 431 are continuously adjusted.

[0053] By spraying with the spray gun 431 , a coating is formed on the surface of the workpiece 71 , and the thickness of the coating is 50 μm-300 μm, optionally, the thickness of the coating is 100 μm-200 μm, and preferably, the thickness of the coating is 140-180 μm.

[0054] Furthermore, a material sensor is also provided in the spray room 41, and the conveyor line 1 transports the hanger into the spray room 41 at a certain speed. When the material sensor senses the hanger 7, the reciprocating machine 433 and the spray gun 431 work, and the reciprocating machine 433 controls the spray gun 431 to spray electrostatic powder onto the workpiece 71 on the hanger 7 according to a preset running route and running speed.

[0055] When the material sensor senses that the hanger 7 has entered the spray booth 41, the servo motor starts to control the reciprocating machine 433 to run, and the spray gun 431 also starts to work synchronously. The running track of the reciprocating machine 433 is pre-set using the touch screen of the electronic control system. The running track of the reciprocating machine 433 can be accurate to 0.1mm. At the same time, according to the film thickness requirements of the surface coating of the workpiece 71, the running track of the reciprocating machine 433 can be set to 8-10 sections, and the running speed of each section can be set separately on the touch screen of the electronic control system.

[0056] Furthermore, the recovery filter device 42 includes a static discharge device, a recovery pipeline and a return air duct. The static discharge device is installed in the recovery pipeline of the recovery filter device 42. The distance between the pipe opening of the return air duct and the lowest workpiece 71 of the hanger 7 is 35 to 45 cm.

[0057] Preferably, the distance H between the pipe orifice of the return air duct arranged in the spray booth 41 and the lowermost row of workpieces on the hanger 7 ranges from 20 cm to 60 cm. Further, the distance H ranges from 30 cm to 50 cm. Most preferably, the distance H ranges from 35 cm to 45 cm.

[0058] Since the recovery and filtration device 42 can recover the powder not coated on the workpiece 71 for continuous use, but since the recovered powder is electrostatically charged, if it is directly used, it will cause powder spitting problems, and this powder spitting will cause problems with the poor consistency of the coating film thickness of the workpiece 71. Therefore, adding an electrostatic discharge device in the recovery pipeline can solve the powder spitting problem when the recovered powder is directly used.

[0059] Preferably, the electrostatic discharge device is in the shape of a spherical multi-wing. The spherical multi-wing electrostatic discharge device can reduce the electrostatic charge of the recovered powder to below 500 V.

[0060] Further, to maintain the stable operation of the powder spraying system 4, in a timed and / or quantitative manner, the powder accumulated in the recovery box of the recovery and filtration device 42 is unloaded to avoid problems such as easy explosion in the spray booth 41 caused by excessive accumulation of magnetic powder.

[0061] Further, a conductive device is also arranged on the hanger 7, and the conductive device is arranged on the upper part of the uppermost workpiece on the hanger 7. Since the electrostatic powder during spraying is affected by electric charges and is easily concentrated in the corner areas of the hanger 7, in order to ensure the consistency of the coating film thickness on the workpiece 71 of the hanger 7, for the uppermost row of workpieces 71 on the hanger 7 that are prone to edge effects, a conductive device is arranged above them to avoid the occurrence of edge effects.

[0062] According to the present invention, the conductive device can be any conductive material or component. Preferably, the conductive device is an iron wire.

[0063] The present invention also proposes a spraying method for a high-uniformity suspended full-automatic powder spraying production line, as Figures 1 to 8 shown, this spraying method uses the above-mentioned high-uniformity suspended full-automatic powder spraying production line.

[0064] Among them, the spraying method includes:

[0065] The conveyor line 1 transports the hanger 7 along the production line process. When the hanger 7 enters the spray booth 41 through the conveyor line 1, the reciprocator 433 of the powder spraying device 43 controls the spray gun 431 to perform reciprocating motion, and the spray gun 431 reciprocally sprays the workpiece 71 on the hanger 7 in the vertical direction.

[0066] Preferably, the reciprocator 433 controls the spray gun 431 to reciprocally spray the workpiece 71 from top to bottom or from bottom to top. The reciprocating speed of the reciprocator 433 is asFigure 6 For the formula, the speeds of the 1st to 4th segments can be adjusted arbitrarily.

[0067] When the spray gun 431 runs reciprocally, the powder supply center 44 and the electric control center receive electrical signals. The electric control center controls the moving speed, residence time, and powder voltage of the spray gun 431, and the powder supply center 44 controls the powder spraying amount of the spray gun 431.

[0068] During the powder spraying process, the spray gun 431 sprays the workpiece 71 at a variable moving speed. Among them, the powder spraying amount of the spray gun 431 is inversely proportional to the moving speed of the spray gun 431, and the powder voltage of the spray gun 431 is inversely proportional to the moving speed of the spray gun 431. The powder spraying amount powder spraying curve is as Figure 7 shown, and the powder voltage curve is as Figure 8 shown.

[0069] Furthermore, the moving speed of the spray gun 431 from the topmost workpiece of the hanger 7 to the bottommost workpiece of the hanger 7 is a uniformly variable motion with a gradually increasing speed; the moving speed of the spray gun 431 from the bottommost workpiece of the hanger 7 to the topmost workpiece of the hanger 7 is a uniformly variable motion with a gradually decreasing speed.

[0070] When the reciprocator 433 starts to work, since the reciprocator 433 is electrically connected to both the electric control center and the powder supply center 44, while the reciprocator 433 is running, it triggers an electrical signal to the electric control center and the powder supply center 44. After the PCL controller of the electric control center and the powder supply center 44 receive the electrical signal fed back by the reciprocator 433, the PCL controller controls the reciprocating movement and residence of the reciprocator 433, and then controls the moving speed, residence time, and powder voltage of the spray gun 431. The powder supply center 44 controls the powder spraying amount of the spray gun 431. Thus, the movement, residence, powder spraying, etc. of the spray gun 431 are continuously adjusted.

[0071] Specifically, according to the structure of the hanger 7, the moving speed of the spray gun 431 from the first row to the last row of the hanger 7 is a uniformly variable motion with a gradually increasing speed, and the moving speed from the last row to the first row of the hanger 7 is a uniformly variable motion with a gradually decreasing speed.

[0072] When the material sensor senses that the hanger 7 enters the spray booth 41, the servo motor starts to control the reciprocator 433 to run, and at the same time the spray gun 431 also starts to work synchronously. The running trajectory of the reciprocator 433 is preset by the touch screen of the electric control system. The running trajectory of the reciprocator 433 can be accurate to 0.1 mm. At the same time, according to the film thickness requirement of the surface coating of the workpiece 71, the running trajectory of the reciprocator 433 can be set in 8 - 10 segments, and the running speed of each segment can be set separately on the touch screen of the electric control system.

[0073] Further, according to the different sizes of the workpiece 71, when the spray gun 431 runs to the first row of the hanger 7, due to the thin coating, the residence time of the spray gun 431 can be increased or the powder spraying amount of the spray gun 431 can be increased. Preferably, the residence time of the spray gun 431 is increased by 0 - 10 milliseconds.

[0074] Specifically, when the spray gun 431 runs to the upper end of the hanger 7, for powder saving considerations, the spray gun 431 will not run above the first row of workpieces on the hanger 7 at most. Since there will be no powder falling from above and adhering to the workpieces in the first row, the coating thickness of the workpieces in the first row will be relatively thin. Therefore, two methods can be used for adjustment to solve the problem of the relatively thin coating of the workpieces at the upper end of the hanger.

[0075] Adjust the powder spraying amount of the spray gun 431. Optionally, increase the powder spraying amount to 120% - 180%. Preferably, increase the powder spraying amount to 130% - 150%.

[0076] Adjust the residence time of the spray gun 431 at the upper end. The residence time of the spray gun 431 is T. Optionally, the residence time T is 0 < T < 10 s. Preferably, the residence time T is 3 ≤ T ≤ 8 s.

[0077] Among them, both the powder spraying amount of the spray gun and the residence time of the spray gun can be adjusted according to specific requirements. If the powder output is too high or the residence time is too long, the coating of the workpieces in the first row will be too thick, and the coating at the corners will be even thicker, resulting in the size of the workpiece product exceeding the upper standard limit. If the powder output is too low or the residence time is too short, the coating thickness requirement and size requirement of the workpiece product cannot be met.

[0078] Further, there is a distance H between the pipe orifice of the return air duct arranged in the spray booth 41 and the lowermost row of workpieces on the hanger 7. The range of the distance H is 20 cm ≤ H ≤ 60 cm. Optionally, the range of the distance H is 30 cm ≤ H ≤ 50 cm. Preferably, the range of the distance H is 35 cm ≤ H ≤ 45 cm.

[0079] Specifically, if the distance between the return air duct orifice in the spray booth and the hanger is too close, a large amount of powder sucked by the return air duct orifice will fall on the last row of workpieces on the hanger, resulting in a relatively large coating thickness of the workpieces and the size of the workpiece product exceeding the upper standard limit. If the distance between the return air duct orifice and the hanger is too far, the powder will diffuse everywhere, affecting the working environment and causing powder waste at the same time. Preferably, the distance between the return air duct orifice in the spray booth and the lowermost row of workpieces on the hanger is maintained at 40 ± 5 cm.

[0080] The high-uniformity suspended full-automatic powder spraying production line and its spraying method provided by the present invention solve the problem of inconsistent coating thickness of workpieces in different rows on the suspended powder spraying fixture. By adjusting the powder spraying amount, moving speed, residence time of the spray gun and the installation position of the return air duct, the thickness of the workpieces above and below the fixture is made consistent. At the same time, the recycled powder reduces powder waste, shortens the spraying time, reduces the spraying cost and improves the spraying efficiency.

[0081] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0082] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A high-uniformity suspended full-automatic powder spraying production line, characterized in that, the production line includes a conveying line, a feeding device, a dust removal system, a powder spraying system, a curing system, a discharging device and a control center. The conveying line is used to convey the hangers to move on the production line. The control center is used to control the overall operation of the production line. The feeding device, the dust removal system, the powder spraying system, the curing system and the discharging device are arranged in sequence along the conveying direction of the conveying line. The conveying line passes through the feeding device, the dust removal system, the powder spraying system, the curing system and the discharging device in sequence to form a circulating conveying line.

2. The high-uniformity suspended full-automatic powder spraying production line according to claim 1, characterized in that, the powder spraying system includes: a spray booth for performing the powder spraying process; a recovery and filtration device which is communicated with the spray booth and is used for powder recovery and dust filtration; powder spraying equipment for spraying powder on the workpieces passing through the spray booth; a powder supply center for supplying powder to the powder spraying equipment; and, an electric control center for controlling the operation of the powder spraying system. Among them, the recovery and filtration device, the powder spraying equipment, the powder supply center and the electric control center are all set and installed in the spray booth.

3. The high-uniformity suspended full-automatic powder spraying production line according to claim 2, characterized in that, the powder spraying equipment includes a plurality of spray guns, a fixing frame for fixing the spray guns and a reciprocating machine for controlling the spray guns. The fixing frame is fixedly connected with the reciprocating machine, and the reciprocating machine controls the spray guns to perform reciprocating motion; the spray guns are connected with the powder supply center, and the powder supply center controls the powder spraying amount of the spray guns; a plurality of workpieces are arranged in an array on the hanger, and the spray guns spray electrostatic powder on each workpiece; the reciprocating machine is connected with the powder supply center and the electric control center through electric signals, and the electric control center controls the moving speed, residence time and powder voltage of the spray guns.

4. The high-uniformity suspended full-automatic powder spraying production line according to claim 3, characterized in that, the powder spraying equipment further includes a servo motor which controls the operation of the reciprocating machine. The electric control center further includes a PLC controller which controls the servo motor, and the PLC controller receives the feedback signal during the operation of the reciprocating machine and controls the moving speed, residence time and powder voltage of the spray guns according to the feedback signal.

5. The high-uniformity suspended full-automatic powder spraying production line according to claim 3, characterized in that, a material sensor is further arranged in the spray booth. After the material sensor senses the hanger, the reciprocating machine and the spray guns work, and the reciprocating machine controls the spray guns to spray electrostatic powder on the workpieces on the hanger according to the preset operation route and operation speed.

6. The high-uniformity suspended full-automatic powder spraying production line according to claim 3, characterized in that, the recovery and filtration device includes an electrostatic discharge device, a recovery pipeline and a return air duct. The electrostatic discharge device is installed in the recovery pipeline of the recovery and filtration device, and the distance between the pipe orifice of the return air duct and the lowermost workpiece of the hanger is 35 - 45 cm.

7. The high-uniformity suspended full-automatic powder spraying production line according to claim 3, characterized in that, A conductive device is further provided on the fixture, and the conductive device is arranged on the upper part of the workpiece at the uppermost position of the fixture.

8. A spraying method using the high-uniformity suspended full-automatic powder spraying production line according to any one of claims 1-7, characterized in that the spraying method includes: The conveyor line transports the fixture along the production line process. When the fixture enters the spray booth through the conveyor line, the reciprocator of the powder spraying equipment controls the spray gun to perform reciprocating motion, and the spray gun reciprocally sprays the workpiece on the fixture in the vertical direction; When the spray gun performs reciprocating operation, the powder supply center and the electric control center receive electrical signals. The electric control center controls the moving speed, residence time and powder voltage of the spray gun, and the powder supply center controls the powder spraying amount of the spray gun; Wherein, the spray gun sprays the workpiece at a variable moving speed, the powder spraying amount of the spray gun is inversely proportional to the moving speed of the spray gun, and the powder voltage of the spray gun is inversely proportional to the moving speed of the spray gun.

9. The spraying method of the high-uniformity suspended full-automatic powder spraying production line according to claim 8, characterized in that The moving speed of the spray gun from the workpiece at the uppermost position of the fixture to the workpiece at the lowermost position of the fixture is a uniformly variable motion with a gradually increasing speed; the moving speed of the spray gun from the workpiece at the lowermost position of the fixture to the workpiece at the uppermost position of the fixture is a uniformly variable motion with a gradually decreasing speed.

10. The spraying method of the high-uniformity suspended full-automatic powder spraying production line according to claim 9, characterized in that When the spray gun moves above the fixture and sprays the workpiece at the uppermost position of the fixture, the residence time of the spray gun at this position is increased or the powder spraying amount of the spray gun is increased.

Images