A plastic chair back electrostatic spray painting system

Abstract

The present invention relates to a plastic part surface processing process, and in particular to an electrostatic painting system for plastic chair backs, comprising a product transport line having a closed-loop structure, wherein the product transport line sequentially passes through a product upper and lower line area, a conductive liquid tank, a drying device, a painting device, and a thermosetting device. The product transport line is a suspended transport line, and the workpiece to be sprayed on the transport line is completely immersed in the conductive liquid inside the conductive liquid tank when passing through the conductive liquid tank. A plurality of spraying parts for spraying conductive liquid are also provided on both sides of the product transport line between the conductive liquid tank and the drying device. A dripping reflux trough is also provided between the conductive liquid tank and the drying device. The dripping reflux trough is connected to the outlet of the conductive liquid tank, and the bottom of the dripping reflux trough is inclined toward the outlet of the conductive liquid tank. The present invention can automatically perform the conductive liquid spraying procedure before electrostatic painting, and can achieve the effect of making the surface of the workpiece covered with conductive liquid and recycling and reusing the conductive liquid.

Description

Technical Field

[0001] The invention relates to a plastic part surface processing technology, in particular to an electrostatic painting system for a plastic chair back. Background Art

[0002] In order to protect the surface of workpieces and extend their lifespan, traditional processes often use surface spray painting to achieve this effect. In addition, surface spray painting can also play a certain decorative role, making the surface of the workpiece more beautiful and pleasant. In special fields, surface spray painting technology can also achieve special functions such as sound insulation, heat insulation, and fire prevention. However, traditional spray painting technology usually uses liquid spraying, manual hand spraying, etc., which has disadvantages such as large amount of paint waste, serious environmental pollution, and unstable surface quality. As people's vision for frequently used tools becomes more and more stringent, and with the rapid rise in labor costs, the development of traditional spray painting technology has begun to decline. A new spray painting method is urgently needed to solve the problem. Electrostatic spray painting technology, as a new technology that has rapidly developed at home and abroad in recent years, has been widely used in surface treatment in various industries.

[0003] For example, the Chinese invention patent with application publication number CN10490720A discloses an automatic track-type electrostatic paint spraying line, which includes a track and multiple rotatable hangers; the track has an arc-shaped portion, and multiple toggle rods are vertically arranged on the track; the top of each rotatable hanger extends into the track, and each rotatable hanger includes a translation rod, a rotating disk, a rotating hook, a hanging rod, multiple positioning covers and multiple oil-proof covers; by using the positioning covers to position the multiple support rods, and using the oil-proof covers to achieve the oil-proof function, the stability of the conductive contact is guaranteed, so that the electrostatic adsorption of paint is uniform; the detachable hanger can hang more workpieces, and the density is greatly improved, thereby effectively improving the utilization rate of paint, reducing the waste of raw materials, and also reducing costs; the invention is suitable for workpieces of different sizes and has a wide range of applications; in addition, with the toggle rod and the toggle slot, the detachable hanger can move and rotate in unlimited directions, which is conducive to adsorption and improves the uniformity of spraying.

[0004] It can be seen that electrostatic painting technology has been highly recognized by manufacturers in this technical field. However, due to the limitation of the principle of electrostatic painting, it is generally suitable for the treatment of metal surfaces under normal circumstances. For plastic parts, it is necessary to spray conductive solution or coating in the early stage to complete the electrostatic painting operation, which increases the process. However, considering the surface quality of electrostatic painting and the painting efficiency brought by its automation, an automatic production line that can automatically and evenly spray conductive liquid or coating is needed to be combined with the electrostatic painting in the existing technology to improve production efficiency and the quality of workpiece surface painting. Summary of the Invention

[0005] The present invention provides an electrostatic painting system for plastic chair backs, which solves the limitations of conventional electrostatic painting on the material requirements of the workpiece to be processed. The present invention can automatically perform the conductive liquid spraying procedure before electrostatic painting, and can achieve the effect of making the surface of the workpiece covered with conductive liquid and recycling the conductive liquid for reuse.

[0006] A plastic chair back electrostatic painting system includes a product transportation line, which is a closed-loop structure. The product transportation line passes through the upper and lower product line areas, a conductive liquid tank, a drying device, a painting device, and a thermosetting device in sequence. The product transportation line is a suspended transportation line. The workpiece to be sprayed on the transportation line is completely immersed in the conductive liquid inside the conductive liquid tank when passing through the conductive liquid tank. Several spraying parts for spraying conductive liquid are also provided on both sides of the product transportation line between the conductive liquid tank and the drying device. A dripping reflux groove is also provided between the conductive liquid tank and the drying device. The dripping reflux groove is connected to the outlet of the conductive liquid tank, and the bottom of the dripping reflux groove is inclined toward the outlet of the conductive liquid tank.

[0007] In the present technical solution, the main function of the conductive liquid tank is to soak the workpiece to be sprayed. However, due to possible external factors, the workpiece to be sprayed may not be completely covered with conductive liquid. Therefore, a spraying member is provided to continuously spray the workpiece to be sprayed to ensure that each area of ​​the workpiece to be sprayed can be covered with conductive liquid. The provided dripping reflux groove is used to collect and recover the conductive liquid dripping on the workpiece to be sprayed and the conductive liquid not covered on the workpiece to be sprayed by the spraying member. The conductive liquid in the dripping reflux groove flows back to the conductive liquid tank due to gravity and the guiding effect of the inclined groove inclined toward the conductive liquid tank, so that the conductive liquid tank has the function of recovering conductive liquid. The setting of the spraying member can ensure that the surface of the workpiece to be sprayed can be covered with conductive liquid even when there is no conductive liquid in the conductive liquid tank, and the uncovered conductive liquid can be collected by the conductive liquid tank.

[0008] As a preferred embodiment of the above technical solution, the conductive liquid inside the spraying part is drawn from a conductive liquid tank or a raw material tank through a pump body. A water level control system is provided inside the conductive liquid tank. The water level control system controls the source of the conductive liquid in the spraying part according to the water level in the conductive liquid tank.

[0009] The raw material tank is a raw material tank or raw material barrel containing conductive liquid raw material. The water level control system installed in the conductive liquid tank analyzes the water source of the spraying element based on the water level. It uses whether the workpiece to be tested is completely immersed and the maximum water level of the conductive liquid that the conductive liquid tank can accommodate as standards. When the water level in the conductive liquid tank is lower than the water level at which the workpiece to be tested can be completely immersed, the water level control system opens the valve of the raw material tank, and the spraying element draws conductive liquid from the raw material tank. At the same time, due to the presence of the drip return groove, the conductive liquid in the conductive liquid tank can be replenished while spraying the workpiece. When the solution in the conductive liquid tank reaches the maximum water level that the conductive liquid tank can accommodate, the water level control system closes the valve of the raw material tank and opens the valve communicating with the conductive liquid tank. The spraying element draws conductive liquid from the conductive liquid tank to complete the spraying. As the conductive liquid adheres to the workpiece to be sprayed, the water level in the conductive liquid tank gradually decreases. Based on this, the water level of the conductive liquid tank is always maintained within an appropriate range. There is no need to manually add conductive liquid to the conductive liquid tank. Only regular replacement of the raw material tank is required.

[0010] As a preferred embodiment of the above technical solution, one end surface of the drying device is connected to one end surface of the thermosetting device, and a blowing member is provided between the two to blow air from the thermosetting device to the drying device.

[0011] Make full use of thermal energy. Since the drying device does not require high heat, it only needs the residual temperature of the heat setting device to heat the workpiece.

[0012] As a preferred embodiment of the above technical solution, the drying device is arranged below the heat setting device.

[0013] By adopting the above technical solution, the floor space of the entire system is saved, making the system easier to set up in the workshop.

[0014] As a preferred embodiment of the above technical solution, the product transportation line passes through the interior of the painting device, and a number of electrostatic paint spray nozzles are arranged inside the painting device. The product transportation line is arranged in a runway-like annular belt structure with the point on the axis where the electrostatic paint spray nozzle is located as a turning point inside the painting device.

[0015] By adopting the above technical solution, the movement stroke of the workpiece in the painting device is increased, and the rotation around the electrostatic spray nozzle can also increase the time the workpiece is in the area near the electrostatic spray nozzle to improve the painting effect.

[0016] As a preferred embodiment of the above technical solution, a leveling tunnel is provided outside the product transport segment between the painting device and the thermosetting device.

[0017] The workpiece needs some time to level after the painting operation is completed, and the leveling needs to be carried out in a closed and clean environment to prevent external factors from affecting the molding effect.

[0018] As a preferred embodiment of the above technical solution, a quick cooling zone is provided between the upper and lower line areas of the product and the heat setting device.

[0019] As a preferred embodiment of the above technical solution, the transport line is distributed in multiple sections of bends in the thermal setting device.

[0020] By adopting the above technical solution, the movement stroke of the workpiece in the thermosetting device is increased, so that the thermal energy in the thermosetting device is fully utilized.

[0021] As a preferred embodiment of the above technical solution, the dripping reflux groove is set from the conductive liquid tank to the inlet end of the drying device, and a plurality of the spraying members are evenly distributed on both sides of the product transportation line from the conductive liquid tank to the inlet end of the drying device.

[0022] By adopting the above technical solution, it is ensured that the surface of the workpiece to be sprayed can be continuously sprayed with conductive liquid before entering the drying device, thereby further improving the painting quality.

[0023] As a preferred embodiment of the above technical solution, the product transportation line is further provided with a hanging bracket for hanging the workpiece to be sprayed.

[0024] In summary, the present invention has the following advantages:

[0025] 1. The present invention broadens the application scope of fully automatic electrostatic painting lines, making electrostatic painting of plastic parts more convenient and improving the quality of the paint on the plastic parts. The electrostatic painting method and system of the plastic chair backs involved in the present invention require manual placement and removal of the upper and lower parts. All other work, including the replenishment of the conductive liquid, is completed automatically, thereby improving the efficiency of the painting work and reducing the degree of environmental pollution caused by the electrostatic painting method.

[0026] 2. Since the surface of the plastic part needs to be coated with conductive liquid or a film first to prepare for the subsequent spraying, the present invention uses a conductive liquid tank, a drip return groove and a spraying element to automatically coat the surface of the plastic part. At the same time, the conductive liquid in the conductive liquid tank can be replenished according to the change of the water level. Except for the necessary manual operations such as regular replacement of the conductive liquid used for a long time and regular replacement of the raw materials in the raw material box for replenishing the conductive liquid tank, the painting process is completely automated.

[0027] 3. The present invention fully considers the setting space of the entire system and sets the workpiece movement stroke at each stage of the electrostatic painting process in an optimal manner, saving unnecessary space waste. The thermosetting device and the drying device are connected in a structure, and the drying device can draw heat from the thermosetting device to achieve efficient energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a simplified diagram of the system configuration of the embodiment of the present application;

[0029] Figure 2 This is a simplified implementation diagram of a water level control system in an embodiment of the present application;

[0030] Among them, 1-product transportation line, 2-up and down line area, 3-conductive liquid tank, 4-drying device, 5-painting device, 5.1-electrostatic paint spray nozzle, 6-thermosetting device, 7-raw material box, a-drip reflux trough, b-pumping pipe, b-1-pumping main pipe, b-2-first branch pipe, b-3-second branch pipe, c-control valve. DETAILED DESCRIPTION

[0031] In this specification, directional terms such as up, down, left, right, front, back, front, back, top, and bottom, which are mentioned or may be mentioned, are defined relative to the configurations shown in the accompanying drawings. The terms "inside" and "outside" refer to directions toward or away from the geometric center of a specific component, respectively. These are relative concepts and may vary depending on the location and usage of the component. Therefore, these or other directional terms should not be construed as restrictive.

[0032] The present invention will be further explained below in conjunction with embodiment:

[0033] Example 1:

[0034] A plastic chair back electrostatic spray painting system, please refer to Figure 1, including a closed-loop product transportation line 1, the product transportation line 1 is provided with a hanging bracket for hanging the workpiece to be sprayed, and the product upper and lower line areas 2, the conductive liquid tank 3, the drying device 4, the painting device 5, and the thermosetting device 6 are sequentially arranged on the product transportation line 1, the conductive liquid tank 3 is a water storage tank with an open upper end, and conductive liquid is arranged inside. The product transportation line 1 is located above the conductive liquid tank 3 and is bent downward to ensure that the workpiece to be sprayed on the hanging bracket can be completely immersed in the conductive liquid; a dripping reflux groove a connecting the conductive liquid tank 3 and the drying device 4 is provided below the product transportation line 1 section between the conductive liquid tank 3 and the drying device 4, and the bottom of the dripping reflux groove a is inclined toward the conductive liquid tank 3. A plurality of spraying parts are also evenly arranged on both sides of this section of the product transportation line 1 to ensure that the workpiece to be sprayed can be continuously moistened before entering the drying device 4, and the setting of the dripping reflux groove a ensures that the conductive liquid dripping from the workpiece to be sprayed after it exits the conductive liquid tank 3 and the conductive liquid sprayed by the spraying part are collected and reused.

[0035] During the use of the conductive liquid tank 3, it is not difficult to find that since the workpiece to be sprayed continuously passes through the conductive liquid tank 3 and takes away the conductive liquid inside, under long-term production, the conductive liquid level inside the conductive liquid tank 3 will eventually drop, resulting in the workpiece to be sprayed being unable to be completely immersed in the conductive liquid. Although there is a spraying part to help spray the conductive liquid, it is not as uniform as the immersion method. Please refer to Figure 2Taking this into consideration, the present embodiment provides a water level control system in the conductive liquid tank 3, and opens an opening on the side of the conductive liquid tank 3, which is connected to a water pumping pipe b. The water pumping pipe b is divided into a water pumping main pipe b-1, a first branch pipe b-2, and a second branch pipe b-3, wherein the first branch pipe b-2 is connected to the opening on the side of the conductive liquid tank 3, and the second branch pipe b-3 is connected to the raw material tank 7 for extracting the conductive liquid. The water pumping main pipe b is connected to the spraying member and is provided with a water pump thereon. A control valve c is provided at the intersection of the water pumping main pipe b-1, the first branch pipe b-2, and the second branch pipe b-3. The control valve c controls the spraying member to draw conductive liquid from the raw material tank 7 or from the conductive liquid tank 3. The control valve c is controlled by an adjusting switch. The water level control system is a floating ball, which is connected to the adjusting switch of the control valve c by a connecting rod. When the level of the conductive liquid in the conductive liquid tank 3 drops to the lowest water level line that the workpiece to be sprayed can be immersed in, the floating ball just rotates the gear of the adjusting switch. In the first position, the control valve c blocks the first branch pipe b-2 so that the second branch pipe b-3 is directly connected to the water pumping main pipe b-1. At this time, the spraying part draws conductive liquid from the raw material box 7 through the pump body and sprays it on the workpiece to be sprayed. The conductive liquid dripping from the workpiece to be sprayed and the conductive liquid sprayed from the spraying part enter the conductive liquid tank 3 through the dripping reflux groove a. The spraying part not only continuously sprays the conductive liquid on the surface of the workpiece to be sprayed, but also replenishes the conductive liquid in the conductive liquid tank 3. When the conductive liquid level in the conductive liquid tank 3 rises to a high level, the conductive liquid level in the conductive liquid tank 3 is increased. When the water level is about to overflow from the upper end of the conductive liquid tank 3, the floating ball just rotates to another gear of the adjustment switch, and the control valve c blocks the second branch pipe b-3 so that the first branch pipe b-2 is directly connected to the water pumping main pipe b-1. At this time, the spraying member draws conductive liquid from the conductive liquid tank 3 through the pump body and sprays it on the workpiece to be sprayed. In this way, the water level of the conductive liquid in the conductive liquid tank 3 is kept within a limited range to ensure that the conductive liquid in the conductive liquid tank 3 can completely immerse the workpiece to be sprayed without overflowing.

[0036] Please refer again Figure 1 The drying device 4 is fixedly connected to the heat-setting device 6, and a blowing part is provided on the contact surface of the two to blow the wind from the heat-setting device 6 to the drying device 4. In order to save the workshop area, the drying device 4 is arranged below the heat-setting device 6 in the workshop space. In order to ensure that the workpiece can fully absorb heat in the heat-setting device 6 or the drying device 4, the product transportation line is designed with multiple sections of bending inside the two to ensure that the workpiece has sufficient time to absorb heat inside the two.

[0037] Inside the painting device 5 is a closed paint room with two electrostatic paint spray nozzles 5.1. The product transportation line 1 is arranged in a runway-like annular belt structure around the point on the axis where the electrostatic paint spray nozzle 5.1 is located inside the painting device 5. Since the workpiece needs some time to be leveled after painting, a leveling tunnel is set outside the product transportation line 1 between the painting device 5 and the thermosetting device 6. The workpiece after thermosetting needs to be cooled to improve the surface quality and facilitate the staff to remove the workpiece, so a quick cooling zone is set between the product upper and lower line areas 2 and the thermosetting device 6.

[0038] Example 2:

[0039] The difference from the above-mentioned embodiment 1 is that the water level control system in the conductive liquid tank 3 is a gravity sensor. The water level in the conductive liquid tank 3 is limited by pre-setting the range of the conductive liquid mass inside the conductive liquid tank 3. When the mass is lower than or higher than a certain value, the gravity sensor sends a signal to control the control valve c to limit the water source of the spraying part.

[0040] The method adopted in Example 2 is more accurate than that in Example 1, but the cost is higher from an economic point of view. Those skilled in the art can select the best one according to their needs when implementing the solution of this application.

[0041] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0042] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A plastic chair back electrostatic painting system, comprising a product transport line (1), wherein the product transport line (1) is a closed loop structure, wherein the product transport line (1) sequentially passes through a product upper and lower line area (2), a conductive liquid tank (3), a drying device (4), a painting device (5), and a thermosetting device (6), and is characterized in that: The product transport line (1) is a suspended transport line. The workpiece to be sprayed on the product transport line (1) is completely immersed in the conductive liquid inside the conductive liquid tank (3) when passing through the conductive liquid tank (3). A plurality of spraying parts for spraying the conductive liquid are also provided on both sides of the product transport line (1) between the conductive liquid tank (3) and the drying device (4). A dripping reflux groove (a) is also provided between the conductive liquid tank (3) and the drying device (4). The dripping reflux groove (a) is connected to the outlet of the conductive liquid tank (3), and the bottom of the dripping reflux groove (a) is inclined toward the outlet of the conductive liquid tank (3); the conductive liquid tank (3) and the raw material tank (7) are connected to the spraying parts through a branch pipeline, and a control valve ( c); a water level control system is provided in the conductive liquid tank (3), and the water level control system is a floating ball, and the floating ball is linked to the control valve (c) through a connecting rod mechanism; when the liquid level in the conductive liquid tank (3) is lower than the lowest water level threshold, the floating ball triggers the control valve (c) to close the water supply pipeline of the conductive liquid tank (3) and open the liquid supply channel of the raw material tank (7), and the spraying member draws conductive liquid from the raw material tank (7) to spray the workpiece, and the sprayed liquid flows back to the conductive liquid tank (3) through the drip return groove (a); when the liquid level rises to the highest water level threshold, the floating ball triggers the control valve (c) to close the liquid supply channel of the raw material tank (7) and open the self-circulating water pumping pipeline of the conductive liquid tank (3), and the spraying member circulates liquid from the inside of the conductive liquid tank (3).

2. The electrostatic painting system for plastic chair backs according to claim 1 is characterized in that One end face of the drying device (4) is connected to one end face of the heat-setting device (6), and a blowing member is provided between the two for blowing air from the heat-setting device (6) to the drying device (4).

3. The electrostatic painting system for plastic chair backs according to claim 1, characterized in that: The drying device (4) is arranged below the heat-setting device (6).

4. The electrostatic painting system for plastic chair backs according to claim 1, characterized in that: The product transport line (1) passes through the interior of the painting device (5), and a plurality of electrostatic spray paint nozzles (5.1) are arranged inside the painting device (5). The product transport line (1) is arranged in a runway-like annular belt structure around a point on the axis where the electrostatic spray paint nozzles (5.1) are located, which is a turning point.

5. The electrostatic painting system for plastic chair backs according to claim 1, characterized in that: A leveling tunnel is provided outside the product transport line (1) section between the painting device (5) and the thermosetting device (6).

6. The electrostatic painting system for plastic chair backs according to claim 1, characterized in that: A quick cooling zone is provided between the product upper and lower line areas (2) and the heat setting device (6).

7. The electrostatic painting system for plastic chair backs according to claim 1, characterized in that: The product transport line (1) is distributed in multiple sections of bending within the thermal setting device (6).

8. The electrostatic painting system for plastic chair backs according to claim 1, characterized in that: The dripping reflux groove (a) is provided from the conductive liquid tank (3) to the inlet end of the drying device (4), and a plurality of the spraying members are evenly distributed on both sides of the product transport line (1) from the conductive liquid tank (3) to the inlet end of the drying device (4).

9. The electrostatic painting system for plastic chair backs according to claim 1, characterized in that: The product transport line (1) is also provided with a hanging bracket for hanging the workpiece to be sprayed.

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