JPH0434459B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to the application of different paints on one side and the other side of an object to be painted, such as the body of a passenger car, on which a decorative stripe tape is pasted. How to spray and paint with an air spray gun.

Problems to be solved by conventional techniques and inventions For example, decorative stripe tape with the car model name printed on it is pasted on the body of a passenger car, and the upper and lower sides are painted in different colors. However, in order to perform this type of painting, the surface of the striped tape must be covered with a removable protective film, and two upper and lower stripes must be placed near the conveyance line of the object to be painted.
The upper spray gun sprays paint only on the upper edge of the striped tape and the surface to be painted above it, and the lower spray gun sprays paint on the lower edge of the striped tape and the surface below it. It is preferable in terms of work efficiency to spray the paint only on the painted surface and peel the protective film from the stripe tape after the paint has dried, but if the width of the stripe tape is 20 mm or less, Some of the paint sprayed on the lower surface to be painted may be scattered by the airflow that bounces off the surface, cross over the stripe tape and adhere to the other surface to be painted, or Conventionally, it is difficult to avoid coating defects caused by the paint applied to the surface of the stripe tape running down the surface of the stripe tape and reaching the surface to be painted below. A common method is to paint one surface to be painted and allow the paint film to dry, then mask that surface and then paint the other surface. The disadvantage was that it was complicated and costly.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a method that can eliminate such drawbacks and efficiently color-code coat two surfaces separated by a stripe tape.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

As shown in FIG. 1, the object to be painted x in this example has a flat plate shape, and the surface on which characters, etc. are printed is coated with a removable protective film z in the vertical center of the object for decoration. A striped tape y with a width of 20 mm or less is pasted over the entire width,
The lower painted surface A and the upper painted surface B of the striped tape y are painted with different paints.

In Fig. 2, reference numeral 1 denotes a conveyor, in which a large number of objects to be coated x are suspended by hangers 2 hanging at regular intervals so that the striped tape y faces in the horizontal direction, and conveyed in the direction of the arrow. Near the conveyor 1, two stands 3 and 4 are set up with an interval in the conveyance direction, and on the upper part of the stand 3 on the rear side in the conveyance direction, the object to be coated The first step is to spray paint on the lower side of the painting surface A in contact with the stripe tape y.
The air spray gun 5a is in a diagonally downward position, and at the lower part of the stand 4 on the front side in the conveyance direction, there is a second air spray gun that sprays paint on the part of the upper surface to be painted B that is in contact with the stripe tape y. With the gun 5b facing diagonally upward,
It is attached by an arm 7 bent in an L-shape, and the remaining parts of each of the surfaces A and B are covered by a third stand attached to each stand 3 and 4 by a straight arm 8 in a substantially horizontal position. , fourth air spray guns 6a, 6b.

Each air spray gun 5a, 5b, 6a, 6b
has a ring-shaped air nozzle around the paint nozzle that discharges paint at low pressure, and the discharge and stop of paint is controlled by opening and closing of a needle valve driven by an air cylinder installed at the rear end. This is a conventional method in which the discharged paint is atomized by collision with pressurized air ejected from an air nozzle, spread in a fan shape by the air flow, and reaches the surface to be painted.
The first one attached to the stand 3 at the rear in the transport direction
The paint supply hoses 9a and 10a of the third air spray guns 5a and 6a are connected to pressure control valves 11, respectively.
Second and fourth air spray guns 5b, 6b are connected to the first paint pump 13a via a, 12a, and are attached with a stand 4 at the front in the conveying direction.
The paint supply hoses 9b, 10b are connected via pressure control valves 11b, 12b, respectively, to a second paint pump 13b which pumps a different paint than the first paint pump, and each air spray gun 5a,
5b, 6a, 6b, the air supply hose 14 for paint atomization is connected to a pressurized air supply source 17 via a pressure reducing valve 15 and an electromagnetic opening/closing valve 16, and the air supply hose 18 for controlling needle valve opening/closing is connected to an electromagnetic opening/closing valve. It is connected via a valve 19 to a source of pressurized air 17 .

Here, each air spray gun 5a, 5b, 6
Considering the painting conditions in a and 6b, if the amount of paint discharged per unit area of the surface to be painted is large and the viscosity of the paint is low, the applied paint will run off and the pressure of the air for paint atomization will increase. If the distance between the nozzle and the surface to be painted is high and the distance between the nozzle and the surface to be painted is short, the paint will be bounced off the surface to be painted.As a result of various experiments, it was found that it was necessary to perform painting under the following conditions.

Paint viscosity 10~15secFC#4, distance between nozzle and surface to be painted 50~150mm, paint outlet diameter 0.3~1.0mm, air pressure for paint atomization 2~3Kg/ ^cm2 , paint discharge rate 20
~100 g/min, the relative speed of the object to be coated to each air spray gun is 10 to 14 m/min (in this example, each air spray gun was fixedly installed, so the relative speed is equal to the conveyance speed of the conveyor). second air spray gun 5a,
5b is set at an angle of 20° to 45° from the side to which the stripe tape y is attached (a in Figure 3) to each painted surface A and B, so that the bounced paint reaches the other painted surface. It was also confirmed through experiments that this was not the case.

Under these conditions, paint is sprayed onto both the upper and lower painted surfaces A and B, and after the paint has dried, the protective film z is peeled off from the stripe tape y.

Structure and effects of the invention As specifically explained in the above embodiments,
In the two-color spray painting method of the present invention, a decorative striped tape with a width of 20 mm or less whose surface is covered with a removable protective film is attached to the object to be painted, and one side of the striped tape is separated from the other side by separating the striped tape. In a method of separately spray painting a first paint and a second paint on a side surface to be painted, the object to be painted is transported along a transport path so that the striped tape is parallel to the transport direction, and the transport A first and a second air spray gun are respectively directed at the one side and the other side of the stripe tape to be painted along the stripe tape at the center line of the sprayed paint stream to the paint surface. Arrange the air spray guns so that the angle from the side is 20° to 45°, and spray paint with a viscosity of 10 to 45° from each air spray gun.
15secFC#4, distance from nozzle to surface to be painted 50
~150mm, paint spout diameter 0.3~1.0mm, paint pressure 0.3
~0.8Kg/ ^cm2 , air pressure for paint atomization 2~3Kg/
cm ² , paint discharge rate 20-100g/min, relative speed of the object to be painted with respect to each air spray gun 10-15
The gist of this method is to peel off the protective film from the stripe tape after painting each of the surfaces to be painted by spraying the paint at a speed of 500 m/min, and even when the width of the stripe tape is narrow. To achieve the effect that one side and the other side can be coated with different paints continuously and efficiently without causing color mixing.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an object to be painted, FIG. 2 is a perspective view of a painting line according to an embodiment of the present invention, and FIG. 3 is a sectional view of the painted state. 1: conveyor, 5a: first air spray gun, 5b: second air spray gun, 13a,
13b: paint pump, 17: pressurized air supply source,
x: object to be painted, y: stripe tape, z: protective film, A, B: surface to be painted.

Claims (1)

[Claims] 1. A decorative striped tape with a width of 20 mm or less whose surface is covered with a removable protective film is attached to the object to be painted, and the first paint is applied to the surface to be painted on one side and the other side of the striped tape. and a second paint separately, the object to be coated is transported along a transport path so that the striped tape is parallel to the transport direction, and along the transport path,
The first and second air spray guns are oriented separately at the one side and the other side of the striped tape to be painted, so that the angle from the striped tape side of the center line of the sprayed paint flow to the painted surface is 20゜～
From each air spray gun, paint viscosity 10-15secFC#4, distance from nozzle to surface to be painted 50-150mm, paint nozzle diameter 0.3.
~1.0mm, paint pressure 0.3~0.8Kg/ ^cm2 , paint atomization air pressure 2~3Kg/ ^cm2 , paint discharge amount 20~100g/cm2
min, and the paint is sprayed at a relative speed of 10 to 15 m/min of the object to be painted with respect to each of the air spray guns to coat each of the surfaces to be painted, and then the protective film is peeled off from the stripe tape. A two-color spray painting method.