JPH08192081A - Apparatus for controlling stabilization of coating film thickness of coating material - Google Patents

Abstract

PURPOSE: To make it possible to obtain a specified coating material film thickness on a material to be coated even if the coating material temp. varies by respectively connecting the output section of a coating material temp. detecting means and the input section of an atomize air control panel and the output section of the atomized air control panel and the input section of the atomizing section of a discharge means. CONSTITUTION: The coating material is supplied at the stable and specified discharge rate fed back by a coating material flow meter 6 to a spray gun 7 as the coating material discharge means. However, the particle size of the coating material atomized by this spray gun is changed by a temp. change of the coating material even under stable supply conditions in this coating material flow rate control. The atomizing air pressure of the spray gun 7, i.e., central air (atomizing) 19B and pattern air 19A are controlled with a coating material temp. sensor 18 in order to stabilize the atomization particle sizes of the coating material in follow-up to the change in the coating material temp. The coating material temp. sensor 18 is disposed in mid-way of the coating material piping of the coating material flow meter 6 and the spray gun and the signal of the coating material temp. sensor is sent by a wiring 23 to the atomizing air control pane 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention automatically adjusts the atomizing air pressure supplied to the atomizing section of an automatic spray gun in accordance with the temperature change of the coating material supplied to the automatic spray gun in a fixed amount.
The present invention relates to a paint application film thickness stabilization control device that makes the paint film thickness applied to an object to be coated constant.

[0002]

2. Description of the Related Art In an automatic coating line used in an automatic coating machine, it is important to maintain a constant coating film thickness of the object to be coated. Therefore, the discharge amount of the paint supplied from the paint supply source to the spray gun is controlled. A certain amount of maintenance control is required. As a technique for stabilizing the discharge amount in an automatic coating machine, there is a paint flow rate control device for stabilizing the discharge amount of the paint from the spray gun. The paint flow rate control device will be described with reference to FIG. 2. The paint 2 stored in a paint supply source (hereinafter referred to as a paint tank) 1 is supplied to a paint supply pipe 4 by a pump 3 and an air operated control valve. It is sprayed from the spray gun 7 through 5 and the paint flow meter 6 toward the object to be coated. In the spray gun 7, the operation needle valve is driven forward / backward in association with the opening / closing drive of the solenoid valve 9 according to a control signal from the gun control panel 8, and the paint injection is turned on / off in response to this. Further, the air for spraying the spray gun 7 is turned on / off in conjunction with the opening / closing drive of the solenoid valve 9. Further, an opening / closing drive control signal (ON / OFF signal) for the solenoid valve 9 from the gun control panel 8 is sent to the timer unit 10.

The timer unit 10 transmits the ON / OFF signal of the gun control panel 8 as a control signal of the analog memory unit 12, and delays this for a predetermined time when the signal from the gun control panel 8 rises (OFF> ON). It is configured to be transmitted.

The paint flow meter 6 generates a pulse signal having a frequency corresponding to the paint flow rate, the pulse signal is appropriately amplified by an amplifier 11, and an analog memory having a D / A conversion means and a storage means. It is supplied to the unit 12. And this analog memory unit 12
When the control signal from the timer unit 10 is on, the input signal is output (through) as it is, and when it is off, the input signal at the time is held and output.

The output signal of the analog memory unit 12 is supplied to the controller 14 as a measured value of the flow rate. The controller 14 has the form of a PID controller that performs PID control of the control valve 5 or the flow rate, and for displaying the flow rate set value (target value) and the input value (feedback value) from the analog memory unit 12. It has a display 15 of. Then, the controller 14 compares the set value with the input value and outputs an error signal. The output signal is supplied to the electropneumatic converter 16. The electropneumatic converter 16 includes a pressure reducing valve 17
The flow rate of the compressed air supplied via the controller is adjusted according to the output signal level of the controller 14, and the compressed air is supplied to the air operated control valve 5 as control air. Then, the control valve 5 adjusts the valve opening degree according to the flow rate of the supplied control air, so that the deviation from the set value is minimized regardless of environmental factors such as adhesion of the paint to the paint flow path. The paint flow rate is controlled so that

[0006] Reference numeral 20 is a return path for branching the paint from the paint supply pipe 4 downstream of the paint flow meter 6 on the paint supply path and returning the paint to the paint tank 1. Reference numeral 22 denotes a switching valve provided at the branch point, which is interlocked with the opening / closing operation of the solenoid valve 9, that is, the on / off operation of the spray gun, so that the paint is transferred in the spray gun direction when the spray gun 7 is operated. On the other hand, when not operating, the flow of the paint is switched so that the paint moves toward the return path 20.

In the above construction, when the spray gun 7 is deactivated, that is, when the gun control panel 8 outputs the OFF signal of the solenoid valve 9, the switching valve 22 switches the paint flow path to the reflux flow path 20 side at the same time, Pump 3, paint supply pipe 4, control valve 5, paint flow meter 6, reflux path 20
Paint circulates through. Further, the analog memory unit 12 is in a hold state in response to an off signal from the timer unit 10, and holds and outputs the flow rate value immediately before the spray gun 7 is in the inoperative state. Therefore, the controller 14 keeps the opening of the control valve 5 constant based on this value.

When the spray gun 7 is activated, at the same time, the switching valve 22 switches the paint passage to the spray gun 7 side to supply the paint. On the other hand, the detected flow rate detected by the paint flow meter 6 is passed through the amplifier 11 to the memory unit 12
Is input to the controller 14 and supplied to the controller 14. The output (PID control signal output) corresponding to the comparison between the fed back flow rate and the set discharge amount is the electropneumatic converter 1.
6, the opening of the control valve 5 is controlled based on this, and the flow rate is adjusted.

Until the preset time of the timer unit 10 elapses, the analog memory unit 12 holds and outputs the flow rate value when the operation of the spray gun 7 was stopped last time, and the controller 14 keeps this value. The opening of the control valve 5 is kept constant based on the above. Further, the flow of the paint is not interrupted when the spray gun 7 is stopped, but the paint is circulated, and the same valve opening is set when the spray gun 7 is operated.
Even when the operation is restarted, the disturbance of the paint flow is extremely small, and a stable flow rate or discharge amount can be obtained immediately after the restart of the operation.

[0010]

However, when the coating temperature changes even when the amount of coating material discharged is stably supplied, the viscosity of the coating changes and the atomization characteristics and the coating efficiency also change. It will change. Further, even if only the paint temperature is stabilized, there is a problem that the resistance of the paint passage changes and the discharge amount changes due to clogging of dust in the paint filter, resulting in a change in the film thickness. The object of the present invention is to maintain the discharge amount of the paint at a constant amount by the paint flow rate control device in order to solve the above-mentioned problems and maintain and control the stable coating film thickness under various conditions. It is therefore an object of the present invention to provide a paint coating film thickness stabilization control device that controls atomization air pressure in response to changes in paint temperature.

[0011]

To this end, the present invention provides a paint discharge means, a means for supplying the paint to the discharge means, a flow path for connecting the discharge means and the supply means, and the flow path. An automatic coating apparatus comprising: a paint flow meter disposed in a road; and a paint flow rate controller that feeds back a fixed amount of paint to the discharge means by the paint flow meter, wherein the paint flow meter and the paint flow meter are provided. A paint temperature detecting means for detecting the temperature of the paint is provided in the paint flow path between the discharging means, the output part of the paint temperature detecting means, the input part of the atomizing air control panel, and the atomizing air control. It is an object of the present invention to provide a paint coating film thickness stabilization control device in which an output part of a board and an inlet part of an atomizing part of the discharging means are connected to each other.

[0012]

By the paint flow rate control device which feeds back a fixed amount of paint to the discharging means by being fed back by the paint flow meter, it is possible to supply a constant amount of paint to the discharging means, and between the paint flow meter and the discharging means. In the paint flow path,
A paint temperature detecting means for detecting the temperature of the paint is provided, and an output part of the paint temperature detecting means, an input part of the atomizing air control board, an output part of the atomizing air control board, and an atomizing part of the discharging means. Since it is configured to communicate with the respective inlets, the air pressure of the atomizing unit is changed by the signal from the paint temperature detecting means according to the change of the paint temperature, and the electropneumatic air is supplied based on the output signal of the atomizing air control panel. It can be controlled via a converter, and a constant paint film thickness can be obtained on the object to be coated even if the paint temperature changes.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 shows an embodiment of the present invention.
As described in the paint flow rate control device, the spray gun 7 as the paint discharge means is fed back by the paint flow meter 6 and is supplied with a stable and constant paint discharge amount. Stable supply in this paint flow control Even under conditions, the particle size of the paint atomized by the spray gun changes due to changes in the paint temperature. For example, air of the same pressure is supplied to the air pipes 19A, 19
If the temperature of the paint is high and the viscosity of the paint is low even if it is supplied from B, the atomized particles of the paint become finer and the finish of the coating surface improves, but the coating efficiency decreases and the coating on the object to be coated The film thickness becomes thin. On the contrary, when the coating temperature is low and the viscosity of the coating is high, the atomized particles of the coating become coarse and the finish of the coating surface is deteriorated, but the coating efficiency is improved and the coating film thickness on the object to be coated becomes thicker. Therefore, in order to keep the atomized particle diameter of the paint stable by following changes in the paint temperature, the atomization air pressure of the spray gun 7, that is, the central air (atomization) 19 is passed through the paint temperature sensor 18.
B and pattern air 19A are controlled.

The atomizing air circuits 19A and 19B are provided with an air source 21.
Solenoid valves 9A, 9B from electro-pneumatic converters 16A, 16B
Is sent to the spray gun 7 via the atomizing air control panel 2
The pressure is controlled by the electric signal from the No. 4. The atomizing air circuit is divided into a central atomizing air 19B and a pattern air (corner) 19A so that the pattern width can be controlled.

The paint temperature sensor 18 is provided in the paint pipe of the paint flow meter 6 and the spray gun 7, and the signal of the paint temperature sensor is sent to the atomizing air control panel 24 by the wiring 23. In the atomizing air control panel 24, for example, the temperature is 20 ° C.
The control output at the time is set to A%, and the control output is changed based on the arithmetic expression stored in advance according to the change in the paint temperature. Based on the above configuration, the atomizing air pressure of the spray gun 7 under the condition that the amount of paint discharged by the paint flow rate control device is stabilized is based on the signal of the paint temperature sensor 18 due to the change of the paint temperature, and the atomizing air control board 24 is operated. Atomized air pressure control is made,
Stabilization of atomized particles can be obtained regardless of the paint temperature.

[0016]

As described above, according to the present invention, when a spray gun is used to coat an object to be coated, a constant amount of paint is supplied to the spray gun by a paint flow control device, and at the same time, The atomizing air pressure of the spray gun is controlled by the temperature sensor and controlled by the atomizing air control panel, so even if the paint temperature changes, the coating efficiency is kept constant and the stability of the coating film thickness is maintained. It is possible to improve the quality of the finished surface.

[0017]

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of a flow rate control device, a paint temperature sensor, and a spray gun atomizing air control panel according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of an automatic coating machine using a flow rate control device.

[0018]

[Explanation of symbols] 3 pump 4 paint supply pipe 6 paint flow meter 7 spray gun 9, 9A, 9B solenoid valve 16, 16A, 16B electro-pneumatic converter 18 paint temperature sensor 19A pattern air (corner) 19B central air (atomization) ) 24 Atomizing air control panel

Claims (3)

[Claims] 1. A paint discharge means, a means for supplying paint to the discharge means, a flow path connecting the discharge means and the supply means, and a paint flow meter disposed in the flow path. An automatic coating device comprising a paint flow rate control device for feeding back a fixed amount of paint to the discharge means by being fed back by the paint flow meter, in the paint flow path between the paint flow meter and the discharge means. Is provided with a paint temperature detecting means for detecting the temperature of the paint, and an output part of the paint temperature detecting means and an input part of the atomizing air control board, an output part of the atomizing air control board and the atomizing means of the discharge means. Control device for stabilizing the coating film thickness, which is connected to the inlet of each part. 2. The coating film thickness according to claim 1, wherein the atomizing air control panel and the atomizing section are connected to an electropneumatic converter via an electromagnetic valve. Stabilization control device. 3. The paint application according to claim 1, wherein the pressure of the air supplied to the atomizing section is controlled independently of the central atomizing air pressure and the pattern air pressure. Film thickness stabilization controller