JPH01194976A - Coating method - Google Patents

Abstract

PURPOSE:To eliminate waste of paint discarded in the case of color change by allowing the material coated just before performing color change to next- color paint to be completely coated only by the paint filled in a paint hose. CONSTITUTION:When it is possible to fill paint having quantity sufficient to coat individual materials W1-Wn to be coated into a paint hose 1 connected between the color change valves V1-V8 and a coater 2, next-color paint is previously filled in the hose 1 which has been washed with a solvent and air after the coating of preceding-color paint has been finished. In the case of coating all the preceding and following materials with next-color paint, the preceding material is coated by feeding the next-color paint through the color change valves. On the other hand, when the following material is not coated with the next-color paint, feed of the next-color paint is stopped and instead thereof the color change valves are changed over so as to feed the solvent for washing and the next-color paint filled in the hose 1 is extruded with the solvent for washing fed from the color change valves at the same pressure as the feed pressure of paint and the preceding material is coated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention enables a coating machine to select a desired color of paint by switching color change valves connected to supply sources for each color of paint, cleaning solvent, and cleaning air. The present invention relates to a coating method for color changing painting of objects to be coated that are supplied and conveyed continuously.

[Conventional technology]

When painting objects that are continuously conveyed by a conveyor or the like with different colors, after the previous color paint has been painted, each color paint,
By switching the color change valve connected to the supply source of cleaning solvent and cleaning air, the previous color paint remaining in the paint hose connected to the color change valve and the paint sprayer is removed using the cleaning solvent and cleaning air. After cleaning and removing it, the next color paint is selectively supplied.

However, in this case, each time the paint color is changed, the previous color paint remaining in the paint hose is discarded, resulting in wasted paint.

For this reason, in recent years, the color change valve is switched on just before finishing painting the object to be painted with the previous color paint, leaving a certain unpainted area on the object to be painted. At the same time as the supply is stopped, the supply of cleaning solvent and cleaning air is started, and the previous color paint remaining in the paint hose is forced out by the pressure of the cleaning solvent and cleaning air, and the unpainted parts of the object to be painted are removed. A method of painting has been proposed (Japanese Unexamined Patent Application Publication No. 1983-1989)
61076, JP-A No. 60-61077).

[Problem that the invention seeks to solve]

However, among multi-color coating apparatuses that apply different colors of paint, there are some in which the above-mentioned painting method cannot be applied as is to effectively utilize the remaining paint.

For example, if the entire car body is automatically painted using a paint machine that moves back and forth with a reciprocator in response to changes in the shape of the car body, there will be unpainted areas and uneven coating, and it is troublesome to perform post-correction painting using a hand-spray paint machine. Therefore, recently, the entire car body is often painted using multiple dedicated paint machines installed opposite each other for each part, and in this case, when changing the paint color, it is common to The concept of painting unpainted parts of the car body with pre-colored paint remaining in connected paint hoses is not valid.

In other words, the painting time of a dedicated paint machine that divides and paints each part of the car body is approximately 1 hour per car body.
It takes a very short time of 2 minutes to 2 minutes, and the amount of paint discharged is about 5 minutes.
Since the amount of paint is very small at 0 to 100 cc/min, each car body is completely painted with a smaller amount of paint than can be filled into the paint hose connected between the color change valve and the paint sprayer. Therefore, the concept of stopping the supply of paint in the middle of painting and thereafter painting unpainted parts of the automobile body with the paint remaining in the paint hose cannot arise.

For this reason, when a small amount of paint is applied using a dedicated paint sprayer, the paint remaining in the paint hose during a color change is not effectively utilized and is wasted.

However, it is precisely in the case where an individual automobile body can be completely painted only with the paint filled in the paint hose that measures should be taken to prevent residual paint from forming in the paint hose.

Therefore, the present invention provides a method for filling the paint hose connected between the color change valve and the paint sprayer with a sufficient amount of paint to paint each object to be painted. To provide a coating method that can use paint efficiently and greatly reduce the amount of residual paint that is discarded when changing colors.

[Means to solve the problem]

In order to achieve this object, the first invention of the present application selectively supplies paint of a desired color to a coating machine by switching color change valves connected to supply sources of each color paint, cleaning solvent, and cleaning air. , in a method of color-changing painting objects that are continuously conveyed, an amount of paint sufficient to paint each object to be painted is applied to the paint hose connected between the color-changing pulp and the coating machine. If the previous color paint can be filled into the paint hose that has been cleaned with the cleaning solvent and cleaning air supplied from the color change valve after painting of the previous color paint is completed, the next color paint is selected from the color change valve. If the next color paint is supplied and filled in advance, and the next color paint is to be applied to both the preceding workpiece and the subsequent workpiece that are continuously conveyed, the next color paint is applied to the next color paint. If the next color paint is not to be applied to the subsequent object, the supply of the next color paint is stopped and the next color paint is applied instead. The color change valve is switched to supply the cleaning solvent to the next color paint filled in the paint hose with the cleaning solvent supplied from the color change pulp at the same pressure as the paint supply pressure. It is characterized by applying pressure to paint the preceding object.

In addition, in order to achieve the above object, the second invention of the present application:
By switching the color change valves connected to the supply sources of each color paint, cleaning solvent, and cleaning air, the paint of the desired color is selectively supplied to the coating machine, and the continuously conveyed objects are painted with different colors. In a painting method, when the paint hose connected between the color change valve and the paint sprayer can be filled with enough paint to paint each object to be painted, When the cleaning of the remaining paint is finished, the color change valve is switched, and the paint of a specific color supplied from the paint supply source is pumped at a higher pressure than the supply pressure during painting, and the paint hose is filled in advance. Then, when the object to be painted reaches the designated painting position, the color change valve connected to the cleaning solvent supply source is opened, and the cleaning solvent is supplied at the same pressure as the paint supply pressure during painting. The method is characterized in that the paint filled in the paint hose is forced out using a solvent to paint the object to be painted.

[Effect]

According to the first invention of the present application, when there is a subsequent object to be painted with the same color paint, the paint is continuously supplied m and the preceding object to be painted is painted, while the same color paint is applied to the previous object to be painted. When there is no subsequent object to be painted with paint, the supply of paint is stopped before painting the preceding object and the preceding object is painted only with the paint filled in the paint hose. .

Therefore, even when painting a small amount of paint that can completely coat each object with just the paint filled in the paint hose, the amount of paint remaining in the paint hose can be significantly reduced when changing colors. You can eliminate waste of paint.

Further, according to the second invention of the present application, at the end of painting, the paint of a specific color supplied from the paint supply source is pumped at a higher pressure than the supply pressure during painting and is filled into the paint hose, and the paint is cleaned. The object to be coated is painted by pressing out with a solvent.

Therefore, waste of paint can be eliminated, as in the first invention, but since the paint is pumped under high pressure, the paint hose can be filled in a short time, improving work efficiency. be able to.

[Example I]

Embodiments of the present invention will be specifically described below based on the drawings.

FIG. 1 is a flow sheet diagram of a multicolor coating apparatus to which the method of the present invention is applied, and FIG. 2 (fa) and (bl) are time charts showing the steps of the method of the present invention, respectively.

In Fig. 1, 1 to 6 are color change valves connected to the supply sources of each color paint, and 2 and 8 are color change valves connected to the supply sources of cleaning solvent and cleaning air, respectively. It is integrally attached to a manifold 3 to which a paint sprayer 2 is connected via a paint hose 1, and by switching the color change valves V1 to V, the paint sprayer 2 is connected through a paint hose l.
Each color paint is selectively supplied to , and the color change valve v' and . A cleaning solvent and a cleaning air are selectively supplied from the openings.

The color change valves ■1 to V are connected to commonly used white paint and red paint supply sources, and metering pumps P+, Pz, and P3 are installed in each supply pipe, respectively, to continuously change color. When painting the same color paint on both the preceding workpiece and the subsequent workpiece being conveyed, the paint can be continuously supplied at a constant pressure and a constant flow rate.

Further, the color change valves V, -
V: Connected to the supply source of each color paint through a regulator set to a higher pressure than the supply pressure of the paint supplied through I, and when the same color paint is not applied to the subsequent object to be painted, For example, while a workpiece to be painted with white paint is being conveyed continuously, a paint of a different color than the white paint (
For example, when only one object to be coated (blue paint) is transported, after finishing painting with the white paint and cleaning the paint remaining in the paint hose 1 and the coating machine 2, the paint hose 1 is It is designed so that blue paint can be applied quickly. Even if the paint is of a color that is frequently used (for example, red paint or white paint), if only one object to be painted with white paint is transported between two objects to be painted with red paint. Of course, it is also possible to connect the color change valves ① to V3 to a supply source of the same color paint.

The color change valves V1 to V3 are connected to a metering pump P that pumps the cleaning solvent at the same pressure as the supply pressure during painting of the paint, and the cleaning solvent is supplied through the color change valves V1 to V3. The paint filled in the paint hose 1 can be squeezed out to coat the object to be painted.

Note that the paint hose 1 connected between the color change valves ■1 to ■8 and the coating machine 2 has a length that can fill the interior with a sufficient amount of paint to paint each object to be painted. have.

Moreover, 4.4- is an electric motor for driving each pump P+, P2, P's, and P, and 5.5- is an inverter that controls the rotation speed of each electric motor 4-.

Opening/closing control of the color change valves ■, ~■8 and motor 4,
The rotation control of 4-...- is performed by a control signal output from a central control device 6, and the central control device 6 is equipped with a sensor that detects when the object to be painted has arrived in front of a predetermined painting position X. 7 is connected.

Then, the objects to be coated W+ and Wz are conveyed by the conveyor 8.

The coating machine 2 is installed at the coating position X where W3...W7 are transported, and the coating method according to the present invention is carried out as follows according to the time chart shown in FIG.

For example, a case will be explained in which the color has been previously painted with red paint and then the color is changed to white paint.

First, when painting with the red paint supplied from the color change valve ■1 is finished, the inside of the paint hose l and the coating machine 2 are cleaned with the cleaning solvent and cleaning air selectively supplied from the color change valves ■7 and ■8. When the cleaning is completed, the color change valves V7 and (1)8 are closed and the color change valve (2) is opened, and immediately before the first object W1 to be coated reaches the predetermined coating position X, the next color change valve V2 is opened. A white paint serving as a color paint is selectively supplied and filled into a paint hose 1 in advance.

Then, the central control unit 6 selects the color of the paint to be applied to the subsequent workpiece W2 that is transported following the preceding workpiece W1.
If the subsequent object to be painted W2 is also to be painted with white paint, the color is changed when the preceding object to be painted W arrives at the predetermined painting position X. When the white paint is continuously supplied from the valve 2, the white paint that was previously filled in the paint hose 1 is forced out and sprayed from the coating machine 2, and the preceding object to be coated W1 is coated. Ru. At this time, the paint hose 1 is filled with white paint continuously supplied from the color change valve V2.

Next, white paint is applied to both the objects W and W2, and the subsequent object W3, which is conveyed following the object W2, is coated with a paint of a different color than the white paint (for example, red). When painting object W1 (paint), close color change valve 2 and supply white paint after finishing painting object W1 and before starting painting object W2 preceding object W3. , and instead open the color change valve V, and pressurize the white paint filled in the paint hose 1 with the cleaning solvent supplied from the color change valve 7 at the same pressure as the paint supply pressure. and paint the preceding workpiece W2 (Fig. 2 (a)
(see l).

At this time, since the supply pressure of the cleaning solvent is set to be the same as the supply pressure of the paint during painting, it is possible to maintain uniform coating quality.

On the other hand, if white paint is not to be applied to the subsequent workpiece W2, fill the paint hose 1 with white paint before starting painting the preceding workpiece W, and then turn on the color change valve ■2. Close it to stop the supply of white paint and replace it with the color change valve V.
, and the white paint filled in the paint hose 1 is forced out by the cleaning solvent supplied from the color change valve ■7 at the same pressure as the paint supply pressure, and the previous object to be painted W is
.

(see Figure 2 (bl)).

[Example ■]

FIG. 3 is a flow sheet diagram of a multicolor coating apparatus to which another embodiment of the method of the present invention is applied, and FIG. 4 is a time chart showing its operating procedure. Note that parts that overlap with those in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

In this example, the inside of the paint hose is repeatedly cleaned and filled with paint every time the painting of each object to be painted is completed, and the supply of paint to the paint sprayer during painting is always done by pumping out the cleaning solvent. It is designed to be carried out by

Each color change valve ■, ~V4 is connected to the paint supply pressure (
1-2 kg/cI+ higher pressure (3-5 kg
/cJ) is supplied so that the paint can be filled into the paint hose 1 in a short time.

In addition, a cleaning solvent is supplied to each of the color change valves (■) and (6), and one of the color change valves (■5) is supplied with a cleaning solvent so that the paint remaining in the paint hose 1 and the paint sprayer 2 can be cleaned at high speed. The cleaning solvent is supplied at high pressure, and the cleaning solvent is supplied to the other color change valve (■) by a metering pump P so as to release the paint filled in the paint hose 1 at a constant pressure and at a constant flow rate.
High-pressure cleaning air is supplied to the color change valve V7.

The opening/closing control of each of the color change valves V, .

The above is an exemplary configuration of a coating apparatus to which the method of the present invention is applied. Next, the coating method according to the present invention will be explained with reference to FIG.

First, when the sensor 7 detects that the object W1 to be painted is in front of the painting position The supply color change valve (2) is opened, and the paint is filled into the paint hose 1 through the manifold 3.

Next, when the paint filling is completed and the color change valve (1) is closed, the color change valve (2) is opened for a short period of time to discard and blow away a small amount of the paint with the cleaning solvent.

When the object W to be coated arrives at a predetermined coating position X, the metering pump P starts driving at a predetermined rotation speed, and at the same time, the color change valve 6 is opened and the cleaning solvent is supplied in a fixed amount. The cleaning solvent forces out the paint filled in the paint hose 1 and sprays it from the coating machine 2, thereby coating the object W1.

In this case, the supply flow rate of the cleaning solvent is accurately controlled by the metering pump P, and unlike paint, the viscosity of the cleaning solvent does not change much with temperature changes, so paint can be discharged throughout the year regardless of temperature changes. The amount is stable and coating quality can be uniform.

When the coating of the object to be coated W is completed, the color change valve 6 is closed and the metering pump P is stopped at the same time by a control signal from the central control device 6. Next, color change valve■,
and (2) are alternately opened and closed to alternately supply high-pressure cleaning solvent and compressed air, thereby cleaning the inside of the paint hose 1 and the coating machine 2.

In this case, the cleaning solvent supply system is equipped with a high-pressure supply system exclusively for cleaning, in addition to the supply system for pumping the paint, so the high-pressure cleaning solvent will remove any residue remaining in the paint hose 1 and the paint m2. Paint can be cleaned in a short time.

When the cleaning is completed, for example, a color change valve V2 is opened according to a program input in advance to the central control device 6, and the white paint supplied at high pressure is filled into the paint hose 1 in a short time.

That is, each color paint is forced out by a cleaning solvent supplied in a fixed amount, and there is no need to control the amount of paint discharged during painting by the pressure of the paint supplied from the supply source. It can be set to a higher pressure (3 to 5 kg/cff1 or more) than the supply pressure of paint during painting (1 to 2 kg/Cil!), and therefore the paint can be filled into the paint hose 1 extremely quickly. can be done in a short time.

In this way, according to this embodiment, the color change cleaning work and the filling work of the next color paint can be completed to a great extent between the time when the painting of the preceding workpiece is completed and the time when the subsequent workpiece is painted. Since it can be done in a short time, the next painting job can be done immediately, which is very advantageous in terms of work efficiency.

When the filling of the white paint into the paint hose 1 is completed, the object to be painted W2 waits until it is conveyed by the conveyor 8, and when detected by the sensor 7, the painting operation is performed in the same procedure as described above.

In addition, in the above description, the preceding object to be painted W.

Although a case has been described in which the following painting target W2 is sequentially painted with paints of different colors, it is of course possible to use paints of the same color successively.

In this way, in this example, the cleaning solvent supply system is
Two systems are provided, one for pushing out the paint and one for cleaning, and the supply pressure of the cleaning solvent for cleaning is set at a high pressure, so that the preceding object to be painted W.

After the painting work is completed, the color change cleaning time required until the preparation for painting the subsequent object W2 to be painted can be carried out in an extremely short time.

In addition, the supply of paint during painting is controlled by the color change valve V, ~
■It is designed so that the cleaning solvent is supplied in a fixed amount regardless of the pressure of the paint supplied in step 4, so an expensive metering pump can supply cleaning solvent regardless of the number of colors to be painted. One unit is sufficient for each use, reducing equipment costs.

〔Effect of the invention〕

As described above, according to the method of the present invention, the object to be painted immediately before changing to the next color paint can be completely painted only with the paint filled in the paint hose. Eliminate waste of paint when changing colors, even when painting an extremely small amount of paint on each object, less than the amount of paint filled in the paint hose. It has the excellent effect of being able to

[Brief explanation of the drawing]

Fig. 1 is a flow sheet diagram of a multi-color coating apparatus to which the method of the present invention is applied, Fig. 2 (a) and (b) are time charts showing the steps of the method of the present invention, and Fig. 3 is a flow sheet diagram of a multicolor coating apparatus to which the method of the present invention is applied. FIG. 4 is a flowchart of a multicolor coating apparatus to which the embodiment is applied, and FIG. 4 is a time chart showing the procedure. Explanation of symbols 1-paint hose, 2-painting machine, 3-...~manifold,
6- Central control unit, 7- Sensor, 8 Conveyor, V, -V, Color change valve, Wl, W2. W3-Object to be painted.

Claims (2)

[Claims] (1) By switching the color change valves connected to the supply sources of each color paint, cleaning solvent, and cleaning air, the paint of the desired color is selectively supplied to the coating machine, and the continuously conveyed object to be painted is colored. In a painting method that involves repainting, a) if the paint hose connected between the color change valve and the paint sprayer can be filled with a sufficient amount of paint to paint each individual object, the previous color After finishing painting the paint, the paint hose is cleaned with a cleaning solvent and cleaning air supplied from the color change valve, and the next color paint is selectively supplied from the color change valve and filled in advance, b), and when applying the next color paint to both the preceding workpiece and the subsequent workpiece that are continuously conveyed, the next color paint is continuously supplied from the color change valve. c) If, on the other hand, the succeeding object is not to be coated with the next color paint, the supply of the next color paint is stopped and a cleaning solvent is applied instead. The next color paint filled in the paint hose is pushed out with the cleaning solvent supplied from the color change valve at the same pressure as the paint supply pressure. A painting method characterized by painting an object to be painted. (2) By switching the color change valves connected to the supply sources of each color paint, cleaning solvent, and cleaning air, the paint of the desired color is selectively supplied to the coating machine, and the continuously conveyed object to be painted is colored. In a painting method that involves repainting, a) If the paint hose connected between the color change valve and the paint sprayer can be filled with a sufficient amount of paint to paint each object to be painted, the paint When cleaning of the paint remaining inside the hose and the paint sprayer is completed, the color change valve is switched, and the paint of a specific color supplied from the paint supply source is pumped at a higher pressure than the supply pressure during painting to pre-paint the paint. b) Then, when the object to be painted arrives at the predetermined painting position, the color change valve connected to the cleaning solvent supply source is opened to adjust the paint supply pressure during painting. A painting method characterized in that the paint filled in the paint hose is forced out with a cleaning solvent supplied at the same pressure to paint the object to be painted.