JP2001029853A - Powder coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform powder coating with uniform film thickness by keeping the quantity of a powder coating material discharged form a coating gun constant. SOLUTION: This device is provided with the coating gun 3 for discharging the powder coating material taken out from a powder coating material tank 2 toward a material A to be coated. In such a case, the coating gun 3 is formed from a gun body 5 installed to be fixed immovably and a nozzle part 6 installed movably to the gun body 5 by a reciprocator, the discharge quantity from the coating gun 3 is stabilized by preventing the waving of a hose 4 for communicating the coating gun 3 with the powder coating material tank 2 to perform the powder coating with uniform thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder coating apparatus provided with a coating gun for discharging a powder paint from a powder paint tank toward an object to be coated.

[0002]

2. Description of the Related Art Conventionally, an injector has been used when a powder paint in a powder paint tank is delivered to a coating gun.

[0003] As shown in FIG.
When compressed air is introduced into the main body from the nozzle, the suction force generated in the main body sucks the powder coating from the powder coating tank and discharges the powder coating together with the compressed air. The discharge port and the coating gun 3 are usually connected by a hose 4.

[0004] The coating gun 3 comprises a gun body 5 and a large number of nozzles 6 provided in a branched manner.

[0005]

By the way, when the coating area of the object to be coated is large, or when a plurality of objects to be coated are hung on the hanger of the coating booth, the coating gun 3 is connected to the reciprocating device. It is often the case that the object is moved up and down by the (elevating device) 7. However, when the paint gun 3 is moved up and down, the hose 4 connecting the injector 1 and the paint gun 3 is also moved up and down, whereby the bending amount of the hose 4 constantly changes, and the air resistance (pressure loss) in the hose 4 is changed.
Changes.

As a result, the suction force of the injector 1 changes every moment, and the amount of the powder paint sucked from the powder paint tank 2 is not stable, so that the film thickness becomes uneven, Depending on the shape of the object, there was a problem that some of the scalability was generated.

As a method for solving such a problem, conventionally, the pressure loss of the injector is checked to adjust the air amount of the injector, or the capacitance of the powder coating material passing through a tube positioned before and after the injector is conventionally known. Is measured, and the air amount of an air nozzle attached to the injector is adjusted.

However, all of these methods are:
Since the paint gun and hose are constantly moving, pressure loss and capacitance are detected, and the air amount of the air nozzle of the injector is adjusted based on the detected value. Since the position has already changed, it has been difficult to maintain a constant amount of powder coating discharged from the coating gun.

[0009] Further, the powder coating material discharged from the coating gun is discharged by a quantitative feeding device, for example, a table feeder, a vibration feeder, a screw feeder, etc., so that the powder coating material falls quantitatively into the suction port of the injector. There are also ways to keep the volume constant. However,
This method also has a higher discharge accuracy than the above-described method of detecting pressure loss and capacitance, but the movement of the hose greatly changes the contact point of the powder coating on the inner wall of the hose, so that the quantitativeness of the discharge amount is reduced. There was a problem.

In the case of a tribo-charging type gun, a charge is given to the powder coating by contacting a non-conductive tube, for example, fluoroethylene tetrafluoroethylene, provided in the gun with the powder coating. When the hose or gun moves, the powder inflow from the hose to the gun inlet may shift, or the contact ratio between the powder coating and the non-conductive tube in the gun may change, giving a stable charge to the coating. There was a problem that it was not possible.

Accordingly, an object of the present invention is to provide a powder coating apparatus capable of performing a powder coating with a uniform film thickness while maintaining a constant amount of powder coating discharged from a coating gun. .

[0012]

In order to solve the above-mentioned problems, the present invention comprises a coating gun for discharging a powder paint from a powder paint tank toward an object to be coated. In a powder coating apparatus, the coating gun is formed by a gun body fixedly installed so as not to be movable, and a nozzle portion provided at a tip of the gun body and installed movably with respect to the gun body. is there.

The nozzle portion is formed of, for example, a flexible tube, and a moving device such as an elevating device is connected to the nozzle portion.

A plurality of the nozzle portions may be provided in a branched shape.

By fixing the gun body as described above, the hose connecting the powder coating tank and the coating gun does not move up and down or bend, so that the resistance in the hose can be kept constant.

Therefore, a certain amount of powder coating material is discharged from the coating gun.

Since the nozzle at the tip of the coating gun is movable with respect to the gun body, the powder coating can be uniformly applied to the object to be coated.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

In the powder coating apparatus according to the present invention, as shown in FIG. 1, the powder paint is drawn out from the powder paint tank 2 by the injector 1 and the powder paint is applied from the coating gun 3 to the work A. It discharges toward.

The injector 1 and the coating gun 3 are connected by a hose 4.

The coating gun 3 comprises a gun body 5 and a nozzle 6
The gun body 5 is fixedly installed on the gun mount 8.

The nozzle portion 6 is formed by a flexible tube into a shape branched into a plurality of branches. As a material of the flexible tube, a synthetic resin such as fluorotetrafluoroethylene, ultra high molecular weight polyethylene, or polyacetal can be used.

The nozzle unit 6 is provided so as to be movable with respect to the workpiece A by a moving device 7 such as an elevating device.
The powder coating is uniformly applied to the article A to be coated.

Next, the conventional apparatus shown in FIG. 2 for performing coating by moving the coating gun 3 up and down, and the gun body 5 of the coating gun 3 are fixed, and only the nozzle portion 6 branched at the tip is moved up and down. In the powder coating apparatus of the present invention shown in FIG.

As shown in FIG. 3, the change in the discharge amount was determined by dividing the coating surface of the rectangular object to be coated into 36 points and measuring the thickness of the coating film at the 36 points.

The results are as shown in Table 1. It was confirmed that the apparatus of the present invention had much less change in the film thickness than the conventional apparatus, and thus the change in the discharge amount was smaller.

Further, a tribo-charging type gun is used as a coating gun.
When the current value was compared with the deflection of the needle of the ammeter, the results were as shown in Table 2, and it was confirmed that the device of the present invention could obtain a more stable charge.

The experimental data is as follows. (Coating conditions)-Reciprocating stroke: 200 mm-Reciprocating speed: 25 m / min-Hanger pitch: 1200 mm-Conveyor speed: 1.2 m / min-Gun discharge amount: 70 g / min x 3 guns = 210 g / m
in ・ Gun distance to coating object: 200mm ・ Powder hose: Inner diameter 13mm × Length 11m ・ Gun voltage: -100kV

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

As described above, according to the present invention, since the powder hose connecting the powder coating tank and the coating gun is not bent during coating, the discharge amount of the powder coating can be kept constant. Therefore, there is an effect that powder coating with a uniform film thickness can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a powder coating apparatus according to the present invention.

FIG. 2 is a schematic view showing an example of a conventional powder coating apparatus.

FIG. 3 is a view showing measurement points of a film thickness of an object to be coated;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injector 2 Powder paint tank 3 Painting gun 4 Hose 5 Gun body 6 Nozzle part 7 Moving device 8 Gun mount

Continued on the front page F term (reference) 4D073 AA01 BB06 CA07 CA15 CB02 CB06 CB20 4F033 QA01 QB02Y QB05 QB12Y QB18 QD03 QD14 QE21 QE23 QF16Y QH02

Claims (4)

[Claims] In a powder coating apparatus provided with a coating gun for discharging a powder coating material from a powder coating tank toward an object to be coated, the coating gun is fixedly installed so as not to be movable. A powder coating apparatus comprising: a main body of a gun; 2. The powder coating apparatus according to claim 1, wherein said nozzle portion is formed of a flexible tube, and a moving device is connected to said nozzle portion. 3. The powder coating apparatus according to claim 2, wherein said moving device is a lifting device. 4. The apparatus according to claim 1, wherein said plurality of nozzles are provided.
Item 3. The powder coating apparatus according to any one of Items 3.