JPH0256261A - Electrostatic coating apparatus of powder - Google Patents

Abstract

PURPOSE:To prevent difficulties in sticking coating by arranging a spray gun of powder in the surface side of a material to be coated while pinching the space wherein the material to be coated is arranged and also arranging an electrically-insulated plate in the rear side while similarly pinching the above- mentioned space. CONSTITUTION:A spray gun 11 is horizontally arranged toward the transverse direction in the surface side of a material N to be coated. An electrically- insulated plate 12 is vertically arranged in the rear side of the material W to be coated. A fan 14 is arranged in the rear side of this electrically-insulated plate 12. The circumference of the fan 14, this fan 14 and the film of the plate 12 are covered with a cover 15. Thereby coating can be excellently stuck even on the rear side of the material to be coated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention uses a powder electrostatic coating device to coat objects having gaps through which the paint can pass, such as condensers and perforated plates for automobile air conditioners. This invention relates to a powder electrostatic coating device used for.

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 device, the paint adheres well to the front side of the workpiece where the powder spray gun is located, but it is difficult to adhere to the reverse side of the workpiece. There is a problem.

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

Means for Solving the Problems In the powder electrostatic coating apparatus according to the present invention, a powder spray gun is arranged on the front side of the space in which the object to be coated is placed, and an electrically insulating plate is arranged on the back side of the space. is,
Ventilation holes are scattered in an electrically insulating board, and a blower is placed on the back side of the electrically insulating board.

Function: A powder spray gun is placed on the front side of the space in which the object to be painted is placed, and an electrical insulating board is placed on the back side of the space, so that the object to be painted is positively charged during painting. As a result, the front side of the electrically insulating plate is negatively charged, and an electrostatic field is generated between the object to be coated and the electrically insulating plate in the opposite direction to the electrostatic field generated between the powder spray gun and the object to be coated.

Since ventilation holes are scattered in the electrical insulating board and the blower is placed on the back side of the electrical insulating board, the air sent from the blower flows through the vents toward the object to be coated.

A part of the paint sprayed from the powder spray gun mainly adheres to the front side of the object to be painted, and the rest passes through the object and spreads. Since it is negatively charged, it is reflected by the electrically insulating plate, and is carried toward the object to be coated by the electrostatic field in the opposite direction, and mainly adheres to the back side of the object to be coated.

The wind flowing in the direction toward the object to be painted through the ventilation holes helps the paint to be carried by the electrostatic field.

Example This embodiment will now be described with reference to the drawings.

An aluminum capacitor is shown as the object W to be painted. The capacitor has a serpentine flat tube T and corrugated fins F interposed between adjacent straight tube portions, and a jig J is used so that the straight tube portions are vertical.
is suspended by. The size of the capacitor is
It is 400 mm long, 600 mm wide, and 28 m1 thick.

Jig J is made of iron and also serves as an electrode.

The spray gun 11 is placed on the front side of the object W to be painted.
It is arranged horizontally towards the

On the back side of the object W to be painted, an electrically insulating plate 12 is arranged perpendicularly toward the object W to be painted. A gap of approximately 10 mm is formed between the object W to be coated and the electrically insulating plate 12. The electrical insulating board 12 has a rectangular shape that is one size larger than the object W to be coated, and is made of vinyl chloride. The electrically insulating plate 12 is provided with ventilation holes 13 evenly distributed therein.

A blower 14 is arranged on the back side of the electrically insulating plate 12. Around the blower 14 and the blower 14 and the electrical insulation board 1
2 is covered with a cover 15.

In the above device, a comparative test was conducted under the same conditions with and without the electrical insulating plate 12 and the blower 14. The former results are shown in Table 1, and the latter results are shown in Table 2. The test conditions are as follows.

Test conditions Distance between powder spray gun and object to be coated: 100-200 mm Powder spray gun: Horizontal applied voltage, 70 KV Coating time
; 30 seconds (3 baths) Surface area of the object to be painted; 4. Amount of paint discharged; 145 g/Iain Air blowing pressure; Several mmH2O The paint is polyester-based (50vt%, average particle size 40p)
)belongs to.

(The following is a margin) Table 1 Table 2 In the above table, the adhesion length refers to the distance in the thickness direction from the front and back sides of the object W to be coated.

As is clear from the above table, the coating performance is improved when the electrical insulating board 12 and the blower 14 are present than when they are not present.

Note that the distance between the object W to be painted and the electrical insulating board 12 is 10 degrees,
Although the distance was kept constant, tests conducted separately with different distances confirmed that the smaller the distance, the better the coating performance was, and that if the distance exceeded 100 cities, the coating performance did not improve.

Effects of the Invention According to the present invention, the paint can be carried from the back side of the object to the object by the electrostatic field generated between the object and the electrically insulating plate and the flow of wind. The paint can adhere well not only to the front side but also to the back side.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, with FIG. 1 being a vertical sectional view;
FIG. 2 is a perspective view. 11... Powder spray gun, 12... Electrical insulation board,
13...hole, 14...blower, W...object to be coated. Patent applicant Showa Aluminum Co., Ltd.

Claims (1)

[Claims] A powder spray gun 11 is placed on the front side of the space in which the object to be coated W is to be placed, and an electrical insulating plate 12 is placed on the back side of the space, and ventilation holes 1 are provided in the electrical insulating plate 12.
This powder electrostatic coating device has openings such that the numbers 3 are scattered, and a blower 14 is arranged on the back side of an electrically insulating plate 12.