JPS5953108B2 - Electrostatic coating method for synthetic resin powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for electrostatically coating synthetic resin powder, and more specifically, the present invention relates to a method for electrostatically coating synthetic resin powder. This invention relates to a method of electrostatically coating resin powder.

BACKGROUND ART The sprinkling method and the electrostatic coating method are conventionally known as methods for coating electronic components such as capacitors and resistors with lead wires connected in the axial direction with plastic powder for insulating purposes.

In the sprinkling method, the object to be coated is heated in advance to a temperature at which the plastic powder melts or adheres, and the plastic powder is sprinkled onto the heated object. Painted electronic components such as capacitors and resistors generally have a small heat capacity, and the lead wires are often soldered, so there is a problem in that there is a limit to the heating temperature when heating them. Furthermore, due to the nature of sprinkling plastic powder, there was a drawback in that plastic powder adhered to areas to be painted that should not be adhered to.

On the other hand, the electrostatic coating method is a method in which plastic powder is charged to a single polarity, the surface of the object to be painted is held at the opposite polarity, and the plastic powder is attached to the surface of the object using static electricity. However, with this method, it is possible to coat the object to be coated without heating it, so it is possible to solve the problems of the above-mentioned sprinkling/sprinkling method. It is difficult to remove plastic powder attached to wires, and the charged plastic powder tends to migrate to areas where the surface is not covered with plastic powder, making it extremely difficult to dispose of the plastic powder. There was a drawback.

In this way, all of the above methods have the common drawback that plastic powder adheres to the lead wires of the electronic components to be painted, which deteriorates the accuracy of the border between painted and non-painted parts. Therefore, in view of this drawback, a painting method is used in which a masking jig is attached to parts that do not want to be painted, such as lead wires, in order to make the border between the painted part and the non-painted part a specified size. Not only is the manufacturing cost of masking jigs high, but the plastic powder adhering to the masking jigs melts when heated.
Plastic powder adhering to the masking jig cannot be recovered and is wasted, and bridging occurs at the boundary between the masking jig and the object to be painted, and furthermore, when removing the masking jig from the object to be painted, Another problem was that the plastic powder on the masking jig fell and adhered to non-painted areas, resulting in an adverse effect on the processing of the painted object.

The present invention relates to an electrostatic coating method for synthetic resin powder that eliminates such conventional drawbacks, and is applicable to electrostatically rotatable coating and wheel coating of synthetic resin powder through an electrostatic powder coating device. Then, at the same time, the coating is applied by bringing the object to be coated into contact with or in close proximity to this coating and the coating portion of the wheel.
By blowing air or other gas onto the parts of the object that you do not want to paint (non-painted parts) and removing the synthetic resin powder that has adhered or is about to adhere to the non-painted parts, it is possible to remove the painted parts such as electronic parts. A synthetic resin powder coating that completely prevents plastic and other synthetic resin powder from adhering to lead wires, etc. that you do not want to paint, and allows you to easily and efficiently paint only the necessary parts. Its purpose is to provide a coating method.

Hereinafter, the present invention will be explained based on illustrated embodiments.

Reference numeral 1 denotes a drive wheel of the loading chain 2, which is rotated via a reduction gear device 4 of an electric motor 3.

Reference numerals 5 and 5 denote fittings for mounting electronic components 6, which are objects to be painted, which are placed oppositely on the conveyor chain 2;
Connect the lead wires 7, 7 of the electronic component 6 to the . The electronic parts 6 are mounted across the chain and moved integrally with the conveyance chain 2.

Reference numeral 8 denotes an electrostatic powder coating device, and as shown in FIGS. 3 and 4, this coating device has a pressurized gas introduction pipe 10 provided at the bottom of the coating tank 9. An electrode 14 connected to a high voltage generator 13 is disposed in a pressurized gas chamber 12 in a coating tank 9 partitioned by a perforated plate 11, and gas is supplied while the high voltage electrode 14 is energized. Pressurized gas is introduced into the pressurized gas chamber 12 from the introduction pipe 10 to negatively charge the plastic powder 15 on the porous plate 11.

16 is a coating, a wheel, this coating,
The coating portion of the wheel] 6 is placed in the coating tank 9 so as to be in contact with or close to the part to be coated of the electronic component 6 attached to the mounting fittings 5, 5, and the coating portion 7 is placed in the coating tank 9 at an appropriate position. The central shaft 19 is rotatably supported by bearings 8 and 18 which are mounted facing each other, and is rotated by the drive of an electric motor 20.

Reference numerals 21 and 21 denote a pair of pressurized gas blowers arranged on both sides of the coating wheel 16, and a pump (not shown) is provided through a pressurized gas introduction pipe 22.

), and is supported by support rods 23, 23 attached to appropriate positions of the coating tank 9, and as described later, pressurized gas is supplied from below by this pair of pressurized gas blowers 21, 21. The plastic powder 15 is sprayed onto the lead wires 7, 7 of the electronic component 6 to prevent the plastic powder 15 from adhering to the lead wires 7, 7. 24 is a pressurized gas blower 21
, 21. The plastic powder collected by the collection hood 24 is collected by a dust collector (not shown).

) to be collected and reused. Reference numeral 25 denotes a heater for heating and melting the coating, the plastic powder adhered by the wheel 16.

Next, to explain the present invention in more detail based on the above configuration, as shown in FIGS. 3 and 4, the plastic powder 15 is negatively charged by the electrostatic powder coating device 8.

Then, this charged plastic powder 15 is moved upward by the pressurized gas from the gas introduction pipe 10 and the repulsive force generated because it is negatively charged, and is coated on the coating part of the wheel 16. It attaches to 17.

Since the coating wheel 16 is rotated by the drive of the electric motor 20, the electronic parts 6 transported by the transport chain 2 and the coating portion 17 of the coating wheel 16 are transferred through the attached plastic powder 15. Alternatively, the plastic powder 15 may be attached to necessary portions of the electronic component 6 by rotating in direct contact with the electronic component 6.

In this case, the electronic component 6 can be coated and rotated separately from the rotation of the wheel 16, or in some cases, the plastic powder 15 can be attached without being rotated.

Coating: As described above, a countless number of negatively charged plastic powders 15 are attached to the coating portion 17 of the wheel 16 in a layered manner. Plastic powder adheres with relatively strong force,
The farther away from the surface of the coating part 17, the weaker the adhesion force is, and rather the state where the adhesive force tends to separate due to the repulsive force generated between the lower layer part and the upper layer part.

Therefore, when the electronic component 6 that has been transported comes into contact with or comes close to the plastic powder layer of the coating portion 17, the plastic powder 15 is transferred to and completely adheres to the electronic component 6. In this case, the plastic powder 15 is used as the electronic component 6.
At this point, a pair of pressurized gas blowers 21 placed on both sides of the coating wheel 16 are applied. , 21 from below toward the lead wires 7, 7, the plastic powder 15 that is about to adhere to the lead wires 7, 7 is completely removed, and the plastic powder 15 is removed from the lead wires 7, 7.
It is possible to paint only the necessary areas without any adhesion.

Note that when pressurized gas is sprayed from the pressurized gas blowers 21, 21, the parts of the electronic components 6 that need to be coated are on the coating portion 17 of the wheel 16, so the effect of the sprayed pressurized gas is not affected. I won't receive it at all.

According to the present invention, as is clear from the above description, coating is applied to the necessary portions of the object to be coated using the coating and the wheel, and at the same time, the coating is applied to unnecessary portions that are not desired to be coated, or The method uses pressurized gas to remove synthetic resin powder such as plastic that tends to adhere, so when painting various electronic parts that have lead wires, it is possible to paint only the necessary parts and avoid unnecessary parts. Since it is possible to completely prevent synthetic resin powder from adhering to the lead wires, it is possible to significantly improve the accuracy of the boundary between painted and non-painted parts, and to perform such painting easily and efficiently. The effects obtained by the present invention are remarkable.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a schematic front view of the whole, FIG. 2 is a perspective view showing the main parts, and FIGS. 3 and 4 are schematic explanatory diagrams of the main parts. . 6... Object to be coated (electronic parts), 7, 7... Non-painted part of the object to be coated (lead wire), 8... Electrostatic powder coating device, 9... Coating tank, 15. ...Synthetic resin powder for plastics, etc., 16...Coating, wheels,
17... Coating, wheel coating part,
, 2], 21... pressurized gas blower.

Claims (1)

[Claims] 1. Synthetic resin powder is electrostatically applied to the rotatable coating and the coating portion of the wheel using an electrostatic powder coating device, and then the object to be coated is brought into contact with or in close proximity to the coating and the coating portion of the wheel, and the coating is applied. At the same time, the synthetic resin powder that has adhered or is about to adhere to the non-painted parts is removed by blowing air or other gas onto the parts of the object to be painted that are not desired to be painted (non-painted parts). An electrostatic coating method for synthetic resin powder, characterized in that the coating is applied only to certain areas.