JPH03186375A - Treatment agent application device - Google Patents

Abstract

PURPOSE:To minimize a loss due to the inferior quality of application by providing a constitution in which a treatment agent is applied to the upper surface of a work with a sprayed pattern stabilized in accordance with an air pressure. CONSTITUTION:An applicator 5 is controlled using a controller 4 according to the detection signal issued from a rotary encoder 9 which detects the moving speed of a work 2 and thereby the supply amount of a treatment agent to a spray gun 3 is adjusted. In addition, a linearizer 11 is activated based on the detection signal to control an atomization compressed air for adjustment. Subsequently, the film thickness of the treatment agent can be controlled with a sprayed pattern stabilized, and therefore, an entirely uniform coat can be obtained without any change in the application width and any unapplied portion.

Description

Detailed Description of the Invention: "Industrial Field of Application J The present invention is a method of applying a processing agent onto a workpiece using a spray gun that is controlled by compressed air into a thin string or atomized state while moving the workpiece in a predetermined direction. The present invention relates to a processing agent coating device in a coating device, and particularly to a processing agent coating device that can control a spray pattern applied to a workpiece to be constant even if a speed fluctuation of a conveyor for moving the workpiece occurs.

2 "Prior Art" Conventionally, a spray gun or other spraying device is placed on an object to be coated (hereinafter referred to as a work) that is conveyed in a predetermined direction using a conveyor or other conveyance means, and an applicator heats and melts the object. BACKGROUND ART A coating device is known that is configured to spray a pressurized hot-melt adhesive or the like (hereinafter referred to as a treatment agent) from a nozzle hole of the spraying device to apply a treatment agent onto the workpiece.

There is also known an apparatus in which a workpiece is placed on a conveyor line and a processing agent is applied to a predetermined film thickness onto the workpiece while moving the workpiece and the spraying device relative to each other.

This type of coating device is configured so that a constant film thickness of the treatment agent is coated on the workpiece by maintaining a constant spray amount from the spraying device, but voltage fluctuations occur during steady operation. It is quite difficult to maintain the workpiece speed constant due to such reasons, and the speed of the conveyor always fluctuates at the beginning of the start of the conveyor or just before it stops, and the coating film thickness changes greatly due to the speed fluctuation.

For this reason, in conventional devices, the rotational speed and piston displacement of the pump that supplies the processing agent to the spray gun are configured to be adjustable, and a flow rate adjustment valve or the like is provided downstream of the pump. Accordingly, the discharge pressure, supply amount, etc. of the processing agent supplied to the spraying device can be changed in accordance with the conveyor speed, thereby making it possible to control the film thickness of the processing agent applied onto the workpiece to be constant. A coating device has been proposed. (Unexamined Japanese Patent Publication No. 56-10297
(No. 2, JP-A No. 59-11286, etc.) "Problem to be Solved by the Invention" However, in all of the above-mentioned prior art, even when the discharge pressure of the processing agent is changed, the processing agent sprayed by the spray gun is This is based on the premise that it is possible to obtain a nearly constant spray pattern without fluctuations, and if the spray pattern changes due to changes in the discharge pressure, the coating width will change as a result and the coating will change. This also leads to the occurrence of leftover parts, etc.

In particular, in a spray gun-type spraying device that controls the processing agent into a thin string or atomized state while contacting or mixing compressed air and the processing agent, the discharge pressure of the processing agent is changed while keeping the compressed air pressure constant. If this happens, not only the spray pattern but also the spray particles will vary, making it impossible to form a uniform coating.

In view of the drawbacks of the prior art, the present invention provides a spray gun that is controlled by compressed air to form a thin string or atomized state, and provides a spray pattern that allows the workpiece to be coated even if the speed of the conveyor that moves the workpiece varies. An object of the present invention is to provide a processing agent coating device that can control the processing agent to a constant level, thereby minimizing losses due to poor coating.

In detail, it usually takes several tens of seconds for the speed of a high-speed conveyor line to rise, that is, from the time the conveyor line starts until it reaches the rated final rotation speed. A spray pattern cannot be obtained, resulting in loss of product due to poor coating of 200 to 300 meters per rise.

Furthermore, the conveyor line speed may be increased or decreased due to process reasons, and the purpose is to be able to obtain a normal coating pattern in response to these.

"Means for Solving the Problem" The present invention includes a detection means for detecting the moving speed of the workpiece, and a control section for controlling the amount of processing agent supplied to the spray gun based on a signal from the detection means. Although similar to the prior art in this respect, the present invention particularly includes means for generating an air pressure adjustment signal based on a predetermined algorithm in response to the detection signal, and adjusting the compressed air pressure based on the cough adjustment signal. The present invention is characterized in that the processing agent is provided with a means and configured to be able to apply the processing agent onto the workpiece while stabilizing the spraying pattern based on the air pressure.

"Operation" According to this technical means, the spray pattern is stabilized in order to control the amount of processing agent supplied to the spray gun as well as the compressed air for atomization based on the detection signal that detects the moving speed of the workpiece. While letting me.

Since the film thickness is controlled, it is possible to obtain a uniform coating over the entire area without changing the coating width or leaving uncoated areas.

Generally, the compressed air for atomization may be controlled proportionally according to a linear function or a quadratic function. In an apparatus using a processing agent, the change in the compressed air pressure causes a temperature fluctuation of the processing agent due to adiabatic expansion during mixing, and the ejection amount changes due to a change in viscosity. A problem arises.

Therefore, the present invention does not directly change the air pressure based on a detection signal that detects the moving speed of the workpiece, but instead generates an air pressure adjustment signal based on a predetermined algorithm in response to the detection signal, and then adjusts the air pressure to the adjustment signal. Based on this, the compressed air pressure is adjusted.

That is, since the change in viscosity changes based on the air pressure, it was experimentally confirmed that the change in the spray pattern was caused by two factors: a change in air pressure and a change in the viscosity of the processing agent, and based on this, By generating a predetermined algorithm, it is possible to stabilize the spray pattern with high layer accuracy.

"Embodiments" Hereinafter, preferred embodiments of the present invention will be described in detail by way of example with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative arrangements of the components described in this example are not intended to limit the scope of this invention, but are merely illustrative examples. It's nothing more than that.

FIG. 1 shows a hot melt coating apparatus according to an embodiment of the present invention, in which an air spray gun 3 sprays a thin string or atomized state onto the entire area or appropriate locations on a workpiece 2 that is conveyed in a predetermined direction via a conveyor l. It is configured to be able to apply hot melt lO sprayed onto the surface.

The air blow gun 3 has a hot melt applicator 5 controlled by a controller 4 on its melt supply side.
The air supply side is connected to an air source via a heat air supply unit 6 and a pneumatic converter 7, and as is well known, the melt material in a desired spray pattern is applied onto the workpiece 2 while the heat air and hot melt are mixed. It is configured to

On the other hand, a detection sensor 8 for detecting the workpiece 2 is located on the conveyor 1 side.
A rotary encoder 9 is attached to detect the conveyor speed, and these detection signals are all sent to the controller 4, which sends signals for hot melt supply/stop control and pressurization control to the applicator 5 side. Configure to enable sending.

On the other hand, the signal beam nearer 11 of the rotary encoder 9
Also supplied. In order to always obtain a constant spray pattern as shown in FIG. 2, the linearizer 11 stores linear graph data representing the correlation between conveyor speed signal and air pressure, and by inputting the signal,
Obtain the corresponding air pressure adjustment signal.

Note that the linear graph data is predetermined data confirmed through experiments in advance.

Then, by inputting the adjustment signal to the pneumatic converter 7,
Compressed air pressure corresponding to the graph data is obtained, heated by a heated air supply unit 6, and supplied to the air blowing gun 3.

According to this example, when the heat air pressure was controlled to be constant as shown in FIG. 2, a stable spray pattern could only be obtained with the width of the diagonal line and a very limited speed range, but in this example, a wide conveyor It is possible to obtain a stable spray pattern over a range of speeds, and this makes it possible to obtain a stable spray pattern not only due to speed fluctuations caused by conveyor voltage fluctuations, but also over a wide range from the beginning of startup to just before stopping. This makes it possible to form a uniform spray pattern over the entire workpiece.

"Effects of the Invention" As described above, according to the present invention, in an air spray gun, the spray pattern applied to the workpiece can be controlled to be constant even if the speed of the conveyor for moving the workpiece varies. The effect is great when applied to hot melt coating equipment.

It has various effects such as

[Brief explanation of drawings]

1 and 2 show a hot melt coating apparatus according to an embodiment of the present invention, FIG. 1 is a schematic diagram showing the overall configuration including an electric circuit, and FIG. 2 is a conveyor speed signal stored in a beam nearer - air This is linear graph data representing pressure correlation.

Claims (1)

[Claims] 1) In a device that applies hot melt or other processing agent onto a workpiece using a spray gun that is controlled by compressed air in a thin string or atomized state while moving the workpiece in a predetermined direction, the moving speed of the workpiece is controlled. A detection means for detecting, a control section for controlling the amount of treatment agent supplied to the spray gun based on a signal from the detection means, and a means for generating an air pressure adjustment signal based on a predetermined algorithm in response to the detection signal. and means for adjusting the compressed air pressure based on the adjustment signal, and is configured to be able to apply the processing agent onto the workpiece while stabilizing the spray pattern based on the air pressure.