JPS6154108B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a so-called "wire bar" used for finishing parts in paint coating using a coating machine.

There are various methods of coating machines used to coat paper, film, etc. with various paints, and a particular method is adopted alone or in combination, taking into consideration the properties of the product and paint. There is. The present invention relates to a bar (also called a "rod" or "metering bar") which is a main part of a coating machine that employs a coating method called a "rod coater,""barcoater," or "metering bar coater." ). According to the bar coater method, first, an excessive amount of paint is applied to the material to be treated by an applicator roll, and then the excess is scraped off by the bar, and the coated surface is made to have a uniform thickness and a good finish. This bar is generally a round bar with a polished surface and a diameter of about 3 to 20 mm, and its material is usually stainless steel to avoid rusting. Furthermore, some bars are not completely round, but have thin grooves cut into them, or have a satin finish, depending on the properties of the paint, the purpose of the product, etc. Furthermore, for the purpose of making the coating surface more precise, there is a bar that uses a round bar like the one above as a core material and winds extremely thin stainless steel wire with a diameter of about 0.02 to 1.0 mm around it, and this is called a "wire bar". It is called.

Since the wire bar is rotated in contact with the coating surface, it subtly smooths the coating applied to the material to form a smooth and uniform coating surface, while also adjusting the thickness of the wire wound around the core material. It has the advantage that the amount of application can be greatly adjusted depending on the application. The adjustment range of the coating amount can be found, for example, in the "Paper Processing Handbook" (published in 1981)
According to , for a paint with a viscosity of 300 centipoise, the round bar method has a viscosity of 5 to 10 g/m ² and the wire bar method has a viscosity of 5 to 50 g/m ² , and the wire bar method is significantly advantageous.

However, as is obvious from its structure, wire bars are more expensive than round bars, and they also have the disadvantage of having a relatively short useful life, depending on the quality tolerance of the coated product. . Regarding the useful life, since the winding of this wire bar is an extremely thin metal wire, even if the degree of wear due to use is slight, the denting rate at the outer periphery of the cross section of the winding is quite large. Therefore, it causes subtle changes in the leveling of the paint and the amount of paint applied, resulting in a deterioration of product quality.Also, if the wire breaks due to wear during use, the wire will bounce due to its restoring force and the product will be damaged. It may cause damage to itself.

Naturally, in order to improve the wear resistance of the wire bar, it is conceivable to use a wire with higher hardness as the winding. Generally, there are various surface hardening methods to increase the hardness of metals, such as carburizing hardening, flame hardening, induction hardening, gas nitriding, salt bath nitriding, and ion nitriding. However, even if the hardness of the wire is increased using these methods, as the hardness increases, flexibility is lost and brittleness occurs, resulting in a wire having a strong rebound and restoring force against bending and becoming easily broken. In addition, a wire whose hardness is increased only in the surface portion to prevent it from becoming easily broken will cause cracks to occur in the surface portion due to bending. Therefore, even if the hardness of the wire itself were improved, it would be difficult to tightly wind the wire around a core rod with a diameter of about 3 to 20 mm without causing bending or surface cracks to form a wire bar. It is rather impossible.

Due to the existing technical knowledge as described above, conventional wire bars were constructed by winding untreated stainless steel wire with a hardness of about 200Hν around a core rod, or in cases where particularly high hardness was required. This wire bar is constructed by applying chrome plating (the hardness when chrome plating is applied is approximately 400 to 600Hν, depending on the condition of the plating layer).
). Even if the hardness of the wire is improved by this chrome plating, since the chrome plating layer is porous by nature, the abrasion resistance will not be sufficiently improved despite the increased hardness, and uniform plating will be difficult. Therefore, the plating layer tends to have uneven thickness, which lowers the accuracy of the wire bar, making it impossible to avoid the occurrence of defects.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method of manufacturing a wire bar that completely avoids and overcomes the above-mentioned deficiencies in conventional wire bars.

The wire bar according to the present invention is characterized in that at least the surface portion of the core rod and the wire wound on the core rod is made of nitrided steel, and has a hardness of 1000 Hv or more.

According to the method of the present invention, such a wire bar is made by tightly winding a stainless steel wire with a polished surface around a stainless steel rod with a polished surface, and fixing the starting and terminal ends of the wire to the rod to form a wire bar base body, Next, the wire bar base material is placed in an ion nitriding furnace, and the wire bar base material is nitrided using the furnace body as an anode and the wire bar base material as a cathode.

According to the method of the present invention, the hardening process is performed after the wire is wound around the core rod, so the bending resilience and restoring force that the wire originally had is reduced by the hardening process. The wire maintains a good coil condition, so
The wire bar according to the present invention is extremely stable in use, and even if the wire breaks due to temporary wear or the like, there is no risk that the broken wire will bounce off and damage the product. Moreover, according to the method of the present invention, the ion nitriding method is adopted for the hardening treatment, and the treatment temperature is relatively low and the treatment time is also relatively short, so that the deviation and distortion during the hardening treatment are extremely small. Since the accuracy of the original wire bar is maintained even after the hardening process, there is no need for re-correction, which is an advantage.

Next, the present invention will be explained in more detail with reference to a manufacturing example using SUS304, which is considered to be the most common stainless steel material.

Manufacturing example: A surface-polished stainless steel wire (SUS304, diameter 0.08mm) is tightly wound on a surface-polished stainless steel rod (SUS304, diameter 6mm) using a conventional method, and the starting and ending ends of the wire are fixed to the above rod. The wire bar material was manufactured.

This wire bar material is set in an ion nitriding furnace, and after exhausting the air in the furnace, nitrogen gas (if necessary, a mixture with hydrogen gas, etc.) is introduced, the furnace body is used as an anode, and the wire bar material is was used as a cathode and a direct current was passed through it to generate a glow discharge. After the temperature of the wire bar material reached approximately 550° C., it was held for approximately 2 hours and ion nitriding treatment was performed.

The surface hardness of the wire portion of the wire bar thus obtained is approximately 1200Hν, and the hardness of both the wire portion and the core rod portion is approximately 1000Hν up to a depth of approximately 20μ.
It had a hardness of 1100Hν. The surface of the wire part is extremely smooth, and when this wire bar was compared with a correspondingly manufactured chrome-plated wire bar, the wear resistance was 3 to 5 times higher, and a significant difference in effective life was observed. Ta.

Claims (1)

[Claims] 1. A stainless steel wire with a polished surface is tightly wound around a stainless steel rod with a polished surface, and the starting and ending ends of the wire are fixed to the rod to form a wire bar mass, and then the wire bar mass is placed in an ion nitriding furnace. A method for manufacturing a wire bar, characterized in that the furnace body is used as an anode and the wire bar raw material is used as a cathode for nitriding treatment.