JPH05111666A - Masking method for thermal spraying - Google Patents

Abstract

PURPOSE:To improve efficiency by applying a liquid resin for forming a cured film which has thermal spraying resistance and is removable to a part not to be thermally sprayed and drying the resin to cure the resin, thereby forming a resist film for masking. CONSTITUTION:The entire part of a thread type screw shaft 1 is subjected to a blasting treatment to prescribed surface roughness in the case of subjecting only the blade edge 2 of the screw shaft 1 to wear resistant ceramic thermal spraying. A UV curing type epoxy acrylate resin, the cured film of which is of a water-soluble peelable type, is applied as a masking material at a prescribed thickness, for example, about 50 to 100mum on the shaft part 10 of the screw shaft 1 and is dried; thereafter, the coating is irradiated with a gaseous plasma flame, by which the resist film is formed. A chromium oxide material which is the wear resistant ceramic material is then thermally sprayed to the blade edge part 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is applied in various thermal spraying processes to protect the surface other than the thermal sprayed surface and to protect the non-sprayed surface when roughening the sprayed surface before the thermal spraying. Regarding masking method.

[0002]

2. Description of the Related Art Thermal spraying is widely used as a surface modification technique. In this thermal spraying process, masking is necessary to prevent thermal spraying to non-sprayed parts when partially spraying the sprayed object or dividing several types of spraying materials into parts and spraying. Is. This masking is usually carried out by covering the non-sprayed portion with a masking material such as a heat-resistant tape, sheet, plate or the like and spraying it, and then peeling or removing the masking material after processing.

[0003]

However, when the masking target portion has a complicated figure or pattern, or when various types of thermal spraying materials are to be sprayed separately, it is very difficult to process, attach or remove the masking material. It has become expensive due to the cost of man-hours. Further, when the shape of the object to be sprayed is three-dimensional or multi-curved, the cost increase becomes more remarkable.

Further, when the number of products to be processed is small and many, especially, the masking cost tends to occupy a large weight. For example, in the case of small quantities and large quantities, adopting a method of punching and cutting masking tape or sheets, and efficient means such as reusing the same masking plate or jig with high durability many times. Therefore, there is plenty of room to reduce the cost for masking. However, in the case of processing a wide variety of products in small quantities, there are few such efficient methods, and the cost burden for masking directly affects the thermal spray processing cost.

Further, in the case of thermal spraying of a figure or a pattern, masking of the non-sprayed portion is required for roughening such as blasting or etching as a pre-spraying treatment from the viewpoint of the coating performance of the finish. It Usually, when dividing and spraying many kinds of thermal spray materials, many masking materials of the same shape for pretreatment and thermal spray processing are processed according to the figures and designs, and each process is performed on the thermal sprayed object. A method of mounting and processing each is adopted.

However, this method requires a large masking cost as in the case of the previous method, and the quality of the product depends on the accuracy of the masking alignment between the pretreatment portion and the sprayed portion. This becomes a difficult process because the accuracy of alignment of the masking material decreases as the shape or design becomes more complicated or the sprayed body becomes larger.

The problem to be solved in the present invention is to provide a method in which the masking work in the thermal spraying process can be performed easily and efficiently from the pretreatment to the thermal spraying process, and which is excellent in accuracy and economically.

[0008]

The present invention provides a non-sprayed part,
A resist for masking by applying or printing a liquid resin having a thermal spraying processability and capable of forming a cured film that can be removed after thermal spraying, and curing the resin by a curing method such as dry curing, heat curing or photocuring. It is characterized in that a film is formed.

Further, the resist film formed on the non-sprayed portion is
The masking layer can be used as a masking layer for a blast treatment or an etching treatment for roughening the sprayed portion before the thermal spraying process, and the masking layer can be continuously used also in the subsequent thermal spraying process.

[0010]

The masking material used in the method of the present invention is a liquid resin material that can form a resist film whose cured film has strength such as heat resistance and impact resistance that can withstand thermal spraying. It is necessary to be. In addition to these conditions, a material that is easy to cure the resin and that physically and chemically removes and removes the cured film after the thermal spraying process and does not damage the thermal sprayed film. Is selected.

As the masking material which can be used for both the thermal spray pretreatment and the thermal spray processing, one having chemical resistance in addition to the above-mentioned characteristics is selected if the thermal spray pretreatment is an etching method. If the processing is blasting, a thick film type with excellent toughness is selected.

Such masking materials have recently been manufactured and sold as functional resin paints and adhesives used for patterning resist films or temporary protective films in the fields of electricity and electronics and printing. A peelable resin material can be used. In this case, the heat resistance of the cured film is
Generally at least 150 depending on the thermal spraying method and conditions
It is preferably at least ° C. In addition to this, in consideration of curing and peeling means, a heating or optical adhesive curable type, which is easy and inexpensive for resist film forming operation and peeling operation, can be selected and used from commercially available resin materials.

Specific examples of the masking material satisfying such conditions are as follows.

(1) Heat-curing type, ultraviolet ray-curing type having properties such as acid resistance, water solubility and oil solubility of polyester acrylate type, epoxy acrylate type or urethane acrylate type used in the fields of electricity, electronics, printing, etc. Type photoresist agent.

(2) A UV-curable adhesive having peelability such as water solubility and oil solubility.

(3) A heat-curable type used as a temporary protective film on the surface of metal products, plastic products, etc.,
Dry-curable polyurethane-based strippable paint.

Among these materials, among the materials belonging to the categories (1) and (2), the stripping solution is water or an aqueous solution system, which is easy to handle, inexpensive, and excellent in economic efficiency. It is included.

As an actual masking method for thermal spraying,
The boundary line is clarified along the figure and shape of the masking portion, and the masking resin is applied to the mask portion using a tool such as a brush or a brush. After that, the coating film is cured by heating, irradiation with ultraviolet rays, or the like, and then a pretreatment for thermal spraying is performed, followed by the steps of thermal spraying process → dissolution or peeling of coating film → washing and drying. Further, even after the hardened layer of the masking resin is formed, the hardened layer can be used as the masking material even when the blast treatment or the etching treatment is performed to roughen the sprayed portion. And
Even after this roughening, the hardened layer can be used as it is for masking, and the thermal spraying process can be completed.

Further, in the case where the masking portion occupies a large area, the masking is applied only in the vicinity of the boundary line between the figure and the shape, and the other portions are roughly cut and the conventional masking material having a low processing cost is used together. You can also In this case, costs such as the amount of masking resin used and the labor of processing can be further saved.

Further, a negative or positive type original plate of paper quality and film quality on which a figure and a pattern are transferred like a photoresist film is prepared, and a photoresist resin is applied to a material to be sprayed, and then the original plate is placed on it and exposed and developed. Create a masking material that removes the figure and pattern shape part by the thermal spray coating. After that, pre-treatment for thermal spraying is applied, thermal spraying process → coating film dissolution or peeling →
It is also possible to perform the procedure of washing and drying. In this case as well, the hardened layer for masking can be used for masking during the roughening in the pretreatment, and can be continuously used as a masking material in the thermal spraying process thereafter.

Further, a masking material from which the figure and the pattern shape portion formed by the thermal spray coating is removed is manufactured not on the object to be sprayed but in another place, and the manufactured product is attached to the object to be sprayed for masking. You can also

As still another similar method, a resin capable of viscous printing, such as printing patterning, is selected, a masking resin is printed on the sprayed object by screen printing, and then heating, ultraviolet irradiation, etc. are performed. It is also possible to carry out the procedure of thermal spraying processing → coating film dissolution or peeling → washing and drying after the coating film is cured and then subjected to thermal spraying pretreatment. In this case as well, the masking layer can be continuously used from the roughening treatment stage to the thermal spraying treatment. However, in this method, since the coating film thickness is thin, the blasting treatment is generally impossible as the pre-spraying treatment of the material to be sprayed, and the etching method is adopted.

Further, by repeating the above-mentioned work procedure while shifting the masking portion, a multicolor sprayed coating can be easily formed.

[0024]

EXAMPLE The masking method of the present invention was applied to the thermal spraying process on the screw type screw shaft for the purpose of corrosion resistance and wear resistance. FIG. 1 is a front view showing the outline of a screw shaft.

The thermal spraying apparatus used was a gas plasma type. As the procedure, first, the entire screw shaft 1 was subjected to blast treatment, which is a pretreatment for thermal spraying, with SG-100 steel grit to roughen the surface to a surface roughness R _{Z of} about 100 μm. After that, for the purpose of corrosion resistance, a thermal spraying process was performed with a thermal spraying powder of Ni—Cr alloy to a thickness of about 150 μm.

Next, in order to spray ceramics having abrasion resistance only on the blade edge 2 of the screw shaft 1, the shaft portion 10 of the screw shaft 1 was masked according to the present invention.
A UV-curable epoxy acrylate resin whose cured film is water-soluble and peelable is used as a masking material, and this masking material is applied with a brush to a thickness of about 50 to 100 μm. The coating film was cured and dried by irradiating with flame light for 2 minutes. Subsequent to this, a wear-resistant ceramic material such as a chromium oxide-based material was subjected to thermal spraying at a blade edge 2 portion with a thickness of 150 μm under the following thermal spraying conditions.

Thermal spraying conditions Equipment output: 900 A × 40 V, primary gas (Ar): 50
psi, secondary gas (He): 80 psi, material supply gas (Ar): 60 psi, material supply rate: 3.5 kg / h
r, Thermal spraying distance: 100 mm As a result of thermal spraying, a small amount of the ceramic coating adhered to the coated surface of the masking material. However, the adhered ceramic coating can be completely and easily removed by subsequent dissolution and peeling of the coating by washing with water. I was able to. Finally the furnace temperature is 100
Moisture was removed in a drying oven at ℃, and a sealing treatment was performed with phenolic paint to finish.

Size 150 for decoration and anti-slip purposes
FIG. 2 shows an application example of the masking method of the present invention in forming a pattern with a ceramic sprayed coating on the surface of a ceramic style having a gloss of mm × 150 mm and a thickness of 7 mm.

First, using a copy machine from the original drawing,
A positive pattern original plate was made with a transparent film. next,
On the surface of the tile 3 degreased with trichloroethane, a UV-curable epoxy acrylate type photoresist agent having a water-soluble peelable cured film was brushed to a thickness of 200.
It was applied to a thickness of about μm. Then, a transparent wrap for protecting the original plate and a film which is the original plate were superposed on the coated surface, and exposed for 5 minutes by an ultraviolet irradiation device to cure the light transmitting part which is the non-pattern part 40. After that, the wrap and the original plate were removed, and the uncured portion of the pattern portion 4 was removed with a water spray to develop and further dry. Then, pretreatment was performed by blasting # 20 alumina grit to roughen the sprayed portion to about Rz 70 μm, and the dark blue alumina-titania material was sprayed to a thickness of about 200 μm by a gas plasma spraying device. Then, a silicate-based sealing treatment was performed in this thermal spraying state, and finally the masking coating film was peeled off by hand. As a result of this processing, there is no defective portion such as a treatment mark due to blast on the glossy surface of the non-pattern portion 40 other than the thermal spraying portion on the surface of the tile 3, and the boundary line of the pattern portion 4 which is the thermal spraying portion is It was clear.

Application of the masking method of the present invention in forming a polka dot pattern with a ceramic sprayed coating on the surface of a SUS304 steel plate for building materials having a size of 1000 mm × 500 mm and a thickness of 1.2 mm for the purpose of decorativeness, corrosion resistance and anti-slip. An example is shown in FIG.

First, a screen original plate is prepared from the original image of the design, printed and coated on the steel plate 5 with a thermosetting photoresist ink having acid resistance, and dried and cured under the conditions of a drying temperature of 180 ° C. and a drying time of 2 minutes. It was Next, the non-ink-coated portion that becomes the water drops 6 formed on the surface of the steel plate 5 using ferric chloride and hydrochloric acid was chemically etched to a depth of about 50 μm. The surface roughness at this time etching portions was approximately R _Z 3 to 5 [mu] m. Then, after the steel plate 5 is washed and dried, a Ni-Cr alloy having a thickness of 30 μm is applied to the entire surface of the steel plate 5 by a gas plasma spraying device as a bonding spraying process, and subsequently an alumina-cobalt oxide system which is a blue ceramic material is used. The material was applied with a thickness of 50 μm. Finally, the resist ink was dissolved and peeled off by washing with a 10% NaOH solution (solution temperature: 30 ° C.).

The result of this treatment is that there is no defective portion such as etching marks or spray coating on the ink application surface 60
It retained the luster peculiar to US steel plates. Further, the boundary portion with the polka dots 6 which is the thermal spray coating was clear.

[0033]

The masking method of the present invention has the following effects.

(1) When spraying a complex figure, a pattern, or several types of materials for thermal spraying, and even when the sprayed object has a three-dimensional or multi-curved surface shape or a large area, the resin Since only the step of applying is required, the work is simplified and the cost is reduced.

(2) Since masking is performed by coating with a resin, even when a sprayed coating is formed on various shapes or only on a minimal portion, the spraying technique can be easily applied, and the spraying processing technique can be applied to the decorative field such as figures and patterns and patterning. It can be easily applied to various fields, and the field of application of thermal spraying can be expanded.

[Brief description of drawings]

FIG. 1 is a front view of a screw shaft to which a method of the present invention is applied.

FIG. 2 is a plan view of a ceramic tile to which the method of the present invention is applied.

FIG. 3 is a plan view of a steel plate having a polka dot pattern, which is a target to which the method of the present invention is applied.

[Explanation of symbols]

 1 Screw shaft 2 Blade edge 3 Tile 4 Design part 5 Steel plate 6 Polka dot

Claims (2)

[Claims] 1. A non-sprayed part is coated or printed with a liquid resin having a spraying-processable property and capable of forming a cured film which can be removed after the spraying, and by a curing method such as dry curing, heat curing or light curing. A masking method in thermal spraying, which comprises curing the resin to form a resist film for masking. 2. A resist film formed on a non-sprayed part is used as a masking layer for blasting or etching for roughening the sprayed part before the spraying process, and the masking layer is also used for the subsequent spraying process. 2. The masking method in the thermal spraying process according to claim 1, wherein the masking method is used continuously.