JPH01293153A - Electrostatic coater of powder - Google Patents

Abstract

PURPOSE:To favorably stick coating even on the side of a material to be coated wherein a spray gun is not positioned by providing an electric insulating plate to the opposite side of the spray gun while pinching the material to be coated in the case of coating the material having the gaps capable of passing coating. CONSTITUTION:The face of the side opposed to a material W to be coated on an electric insulating plate 12 is charged to negative because the material W is charged to positive. Therein one part of coating sprayed from a powder spray gun 11 is spread around the material W or beyond the material W through the gaps thereof. When the sprayed coating is allowed to collide against the face of the side opposed to the material W on the electric insulating plate 12, it is repelled because this face is charged to negative and directed toward the material W and favorably stuck on the side of the material W opposite to the side wherein the powder spray gun 11 is positioned.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applied to a powder electrostatic coating device, for example, an object to be coated, such as a capacitor of an automobile air conditioner, which has a gap through which the paint can pass. This invention relates to a powder electrostatic coating device used for coating.

Conventional technology Generally, electrostatic powder coating equipment applies a positive high voltage to the object to be coated and a negative high voltage to the powder spray gun to create an electrostatic field between the two, and the powder spray gun charges the object negatively. The paint is sprayed and carried by an electrostatic field, causing it to adhere to the object being painted.

Problem to be Solved by the Invention When a workpiece is painted using the above-mentioned apparatus, the paint adheres well to the side of the workpiece where the powder spray gun is located, but the paint does not easily adhere to the opposite side. There is a point.

An object of the present invention is to provide a powder electrostatic coating device that solves the above problems.

Means for Solving the Problems The electrostatic powder coating apparatus according to the present invention is such that an electrically insulating plate is placed on the opposite side of the powder spray gun, sandwiching the object to be coated, so as to face the object to be coated. .

Operation: Since the object to be painted is positively charged, the surface of the electrically insulating plate facing the object to be painted is negatively charged.

A portion of the paint sprayed from the powder spray gun spreads around the object to be coated or through gaps between them, but when it hits the surface of the electrically insulating board facing the object to be coated, Because the surface is negatively charged, it is repelled and directed toward the object to be coated, and it adheres to the side of the object opposite to the powder spray gun.

Example Embodiments of the invention will now be described with reference to the drawings.

<Example 1> As shown in FIG. 1, the powder electrostatic coating device
An electrical insulating plate 1 is placed on the opposite side of the powder spray gun 11 while holding the
2 is arranged so as to face the object W to be coated.

The object W to be painted and the electrically insulating plate 11 are vertically suspended by a jig 13 at a distance of 10 w from each other.

The powder spray gun 11 is arranged horizontally toward the object W to be coated. The jig 13 is made of iron and also serves as an electrode.

A capacitor is shown as the object W to be painted. The capacitor includes a meandering flat tube 21 and corrugated fins 22 interposed between adjacent straight tube sections. The flat tube 21 and the corrugated fins 22 are
Both are made of aluminum. The size of the capacitor is 400 mm in length, 600 mm in width, and 28 mm in thickness.

The electrical insulating plate 12 is rectangular, one size larger than the capacitor, and is made of vinyl chloride.

In the above device, a comparative test was conducted under the same conditions with and without the electrical insulating plate 12. The results are shown in Table 1 for the case without the electrical insulating plate 12, and in Table 2 for the case with the electrical insulating plate 12. The test conditions are as follows.

Test conditions Distance between powder spray gun and object to be coated: 100 to 200 mm Powder spray gun; Horizontal applied voltage; 70KV Coating time: 30 seconds (3 baths) Surface area of object to be coated: 4M Paint discharge rate: 145 g/ The 1llin paint is polyester-based (50 wt%, average particle size 40M). Also, the distance between the object W to be painted and the electrical insulating plate 12 is 10 mm.
It is.

(Hereinafter, blank spaces) Table 1 Table 2 In the above clothing, the front and back refer to the side of the object W on which the powder spray gun 11 is located, and the opposite side to this is the back. Further, the thickness direction refers to the distance from the front and back sides of the object W to be coated.

As is clear from the above description, the coating performance is improved when the electrical insulating plate 12 is present compared to when it is absent.

Note that the distance between the object W to be painted and the electrical insulating plate 12 is 10 mm.
However, another test confirmed that the smaller the distance, the better the coating performance, and that if the distance exceeds 100 mm, the coating performance does not improve.

<Example 2> In Example 1, the object to be coated W and the electrical insulating plate 12 were both arranged vertically, and the powder spray gun 11 was arranged horizontally, but in Example 2, as shown in FIG. The object to be coated W and the electrical insulating plate 12 are both placed horizontally, and the powder spray gun 1 is
1 It is arranged facing downward. That is, an object W to be coated is placed on an electrically insulating plate 12 arranged horizontally via a horizontal bar 14, and a powder spray gun 11 is arranged vertically downward above the object W to be coated. The horizontal bar 14 is made of vinyl chloride and has a thickness of 10 mm.

In Example 2, a comparative test was also conducted in the same manner as in Example 1. The results are shown in Table 3 for the case without the electrical insulating plate 12 and in Table 4 for the case with it. The test conditions are as follows.

Test conditions Distance between powder spray gun and object to be coated: 100 to 150 mm Powder spray gun; Downward applied voltage; 70 KV Coating time: 30 seconds (3 passes) Surface area of object to be coated; 4-color paint discharge amount; 169. 2 g/min Also, the same paint as in Example 1 was used.

(The following is a blank space) Table 3 Table 4 Effects of the Invention According to the present invention, the paint can be well adhered not only to the side of the object to be painted where the powder spray gun is located, but also to the opposite side thereof.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of the invention, and FIG. 2 is a perspective view showing a second embodiment of the invention. 11... Powder spray gun, 12... Electrical insulation board,
W: Object to be painted. that's all

Claims (1)

[Claims] This is a powder electrostatic coating device in which an electrically insulating plate 12 is disposed on the opposite side of a powder spray gun 11 so as to face the object W to be coated.