JPH0574432B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for cleaning a rotary atomizing electrostatic coating machine.

[Conventional technology]

Rotary atomizing electrostatic atomizers that can paint while changing multiple colors are used, and with such rotary atomizing electrostatic atomizers, the dye supply path can be cleaned after each color change. It's getting old.

[Problem that the invention seeks to solve]

During cleaning, the spray head is rotated and volatile cleaning liquid such as thinner is used to wash away the previous color paint, but it is not desirable to use too much thinner, so use as little thinner as possible for efficiency. It has been devised to allow thorough cleaning. However, cleaning while rotating at high speed will speed up the drying of the paint liquid to be cleaned.
There is a problem in that some paints dry before being washed away and adhere to the wall of the spray head as contaminants, causing incomplete cleaning.

[Means for solving problems]

In order to solve the above-mentioned problems, the cleaning method for a rotary atomizing electrostatic coating machine according to the present invention includes a rotatable spray head, a color change cleaning device that supplies paint to the spray head and also supplies a cleaning liquid at the time of color change. The rotary atomizing electrostatic coating machine is characterized in that the number of revolutions of the spray head during cleaning is lower than the number of revolutions during painting.

〔Example〕

FIG. 4 is a diagram showing a rotary atomizing electrostatic coating machine.
A spray head 10 is attached to a rotating shaft 14 of an air motor 12. The high voltage generated by the high voltage generator 16 is applied to the spray head 10 via the air motor 12, whereby the spray head 10 rotates and electrostatically coats the object to be coated in the ground area. I'm starting to be able to do it. The air motor 12 is supported at one end of an injection support 18, and the other end of the injection support 18 is attached to a movable or fixed frame by a stand 20. The paint is supplied to the spray head 10 from a color change cleaning device 24 via a trigger valve 26 and a hose 28 . The color change cleaning device 24 is connected to a supply tank (not shown) for each color via a valve, and is also connected to a supply diagram (not shown) for cleaning liquid such as thinner and cleaning air, and the spray head 10 The color changing cleaning device 24, the trigger valve 26, the hose 28, and the spray head 10 can be cleaned.

FIG. 2 is a sectional view showing the spray head 10, and the third
The figure is a front view of the spray head 10 viewed from the direction of the arrow in FIG. The spray head 10 is formed by press-fitting a cylindrical member with a round head into the center of a bell-shaped outer periphery, and a large number of ejection holes 10c are provided radially through the cylindrical member. The paint supplied to the rear side of 10 passes through the ejection hole 10c and reaches the spray head 10.
The spray head 10 flows toward the front side, spreads along the widened inner surface of the outer periphery of the spray head 10 by centrifugal force, and is blown toward the object to be coated. An axial hole 10d is formed in the center of the cylindrical member 10b.
The rotating shaft 14 of the air motor 12 is passed through 0d, so that the spray head 10 is supported by the rotating shaft 14.

FIG. 1 shows an enlarged view of part A of FIG. 3, where A shows no dirt on the spray head 10, B shows some dirt that has deviated from the spout hole 10c, and C shows a state where the dirt has become extremely dirty. It shows. This was used to judge the results of the cleaning test described below, and the condition A was determined to be good, the condition B was determined to be somewhat good, and the condition C was determined to be poor.

The cleaning test used a rotary atomizing electrostatic coating machine in operation, and used clear and white solid paints. The color change cleaning cycle takes out the white solid, washes it, takes out the clear, and then washes it. This cycle is 14
Repeated times. During each cleaning, cleaning air was supplied for 1 second, cleaning thinner was supplied for 0.5 seconds, and after this cycle was repeated four times, cleaning air was supplied for 6 seconds. Thinner discharge rate is 300c.c./min, clear discharge rate is 250c.c./min.
cc/min, solid discharge rate is 250c.c./min, air pressure is
It was 0.7Kg/ ^cm2 .

The rotational speed of the spray head 10 was 10,000 rpm during coating. On the other hand, the rotation speed of the spray head 10 during cleaning was 10,000 rpm in the first test, and 5,000 rpm in the second test. The result of the first test was the defect shown in Figure 1 C, and the result of the second test, in which the rotation speed during cleaning was lower than the rotation speed during painting, was the same as the first test.
It was as good as shown in Figure A.

Similar tests were conducted using yet another rotary atomizing electrostatic coating machine. As a result, in the first test in which the rotational speed of the spray head 10 was made the same during painting and cleaning, the defect shown in Figure 1 C was found, and the rotational speed during cleaning was lower than the rotational speed during painting. The results of the second test were slightly better as shown in Figure 1B. When using an air motor 12 such as that shown in FIG.
The rotation speed can be lowered.

〔Effect of the invention〕

As explained above, according to the present invention, by lowering the rotational speed of the spray head during cleaning compared to during painting, it has become possible to clean the rotary atomizing electrostatic coating machine.

[Brief explanation of the drawing]

Figure 1 is a partial view showing a part of the spray head in Figure 3, Figure 2 is an enlarged sectional view showing the spray head of the rotary atomizing electrostatic coating machine in Figure 4, and Figure 3 is the spray head in Figure 2. FIG. 4 is a front view as seen from the direction of the head arrow, and FIG. 4 is a side view of the rotary atomizing electrostatic coating machine. 10... Spray head, 10c... Spout hole.

Claims (1)

[Claims] 1. In a rotary atomizing electrostatic coating machine equipped with a rotatable spray head and a color change cleaning device that supplies paint to the spray head and also supplies cleaning liquid when changing colors, the rotational speed of the spray head during cleaning A method for cleaning a rotary atomizing electrostatic sprayer, characterized in that the rotational speed is lower than the number of revolutions during painting.