JPH03226505A - Manufacture of sintered body having continuous or repeated marks in the fixed direction - Google Patents

Abstract

PURPOSE:To manufacture a sintered body having solid mark in the fixed direction by inserting marking into powder compacting process. CONSTITUTION:Raw material pellet composed of powder of metal or ceramic and binder is charged into an extruding machine 1, and the formed body 3 is continuously extruded through a mouth ring 2. Coating material dispersing material powder different from raw material powder is charged into an ink storing vessel 7 and a roll 5 engraved with minute holes to be mark on transfer surface is brought into contact with the just extruded formed body 3. By rotating the roll 5, the coating liquid is stucked on the roll 5 and the excess liquid is scraped with a doctor blade 6 to remain the liquid only in the fine holes engraved on the surface of roll 5. This liquid is transferred on the formed body 3 to form the mark. This formed body 3 is degreased under Ar atmosphere, etc., and sintered under vacuum, etc. In this way, the sintered body solidly marked is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention [Field of Industrial Application] The present invention relates to a method for marking products obtained by powder metallurgy.

[Conventional technology]

In general, it is sometimes necessary to apply markings to sintered products, and conventionally, for example, anisotropic barium ferrite,
In the case of so-called magnets, it may be necessary to clearly indicate the polarity and orientation direction of N and S on the product. In addition, the manufacturer's name may also be clearly indicated for other sintered products such as soft magnetic materials.

In such cases, conventionally, stamping or printing using paint or the like was applied after sintering as part of post-processing of the product. Due to the characteristics of the paint used in this method, there is a high possibility of wear and tear, and additional steps for stamping and printing are required, resulting in an increase in costs.

[Problems to be Solved by the Invention] In order to eliminate these drawbacks, the present invention provides a compacted powder sintered body with markings that is more robust than conventional methods and can be applied at a lower cost by incorporating markings into the powder molding process. The present invention aims to provide a manufacturing method for manufacturing a sintered body having continuous or repeated marks in a certain direction.

1. Structure of the invention [Means for solving the problem] In order to solve the above-mentioned problem, the present invention provides a marking that is more robust than the conventional method of stamping or printing on a sintered product divided into individual pieces. There is a need for a method for manufacturing marked sintered bodies that can be easily automated and that can be printed and displayed at lower cost.

Therefore, as a method to obtain products with complex shapes that are impossible with the conventional manufacturing process of sintered products, we added 10 to 20% by weight of powder to the raw material powder.
In recent years, a method of producing a powder compact for sintering by extrusion molding using a mixture containing a binder containing an organic polymer as a main component has attracted attention, and from this point of view, the present inventors have Metal or ceramic powder, which is a powder that can be sintered and which, unlike the raw material powder of the compacted body, does not easily diffuse into the sintered body after sintering and can be visually identified as a sintered body, is added to a solvent at a predetermined concentration. A method was developed in which a product with markings was obtained by printing on the powder compact using an ink dispersed in the powder, followed by degreasing and sintering.

That is, the present invention processes a molded body that has a constant cross-sectional shape in the longitudinal direction by extrusion molding a mixture consisting of raw material powder of metal or ceramics and a binder, and then removes the binder (or degreases). In a manufacturing method for obtaining a sintered product by sintering, the mixture is extruded using a paint in which metal or ceramic powder of a material different from the raw material powder of the molded body is dispersed at a constant concentration. A method for producing a sintered body having marks that are continuous or repeated in a certain direction, the process comprising continuously or repeatedly printing the molded body immediately after it is discharged from the mouth of a machine, removing the binder and sintering the molded body. This is what we provide.

[Effect]

After sintering, the sintered product is manufactured by stamping it in the form of a continuous molded product by extrusion molding with an ink containing metal or ceramic powder that can be visually identified as a sintered product with minimal diffusion that does not impair the properties of the sintered product. This reduces the cost of marking and produces a highly reliable sintered body with marks that are resistant to wear and tear.

〔Example〕

Examples will be described below with reference to the drawings.

F manufactured by water atomization method with an average particle size of 10 μm
Ethylene-vinyl acetate with an average molecular weight of about 110,000 and a vinyl acetate content of 14 wt%; 2 parts by weight of polybutyl methacrylate having an average molecular weight of about 150,000; 2 parts by weight of the copolymer, 1 part by weight of high-density polyethylene with an average molecular weight of about 180,000, and 1 part by weight of dibutyl phthalate were added, kneaded in a pressure kneader at 140°C for about 1 hour, and then pulverized. Raw material pellets were obtained. This raw material was put into an extruder 1 with a screw diameter of 40 mm and L/D=22 as shown in FIG.
The extrusion molded body 3 was continuously extruded through the die 2 so as to have the cross-sectional shape shown in FIG. In the ink reservoir 7 shown in FIG. 1, 100 parts by weight of Ni-Zn ferrite calcined powder with an average particle size of 0.3 μm was surface-treated by adding 1 wt % of a silane coupling agent. 5 parts by weight of the above-mentioned butyl polymethacrylate powder, 50 parts by weight of toluene, and 50 parts by weight of dibutyl phthalate were added and stirred thoroughly. The diameter in Figure 1 is approximately 1101, and the width is approximately 2.
The outer periphery is mirror-polished with a 5 mm stainless steel roll 5, and dot-like fine holes are cut into the transfer surface so that the marks shown in FIG. 2 are formed. The direction is 18 in Figure 2.
The direction of mm is the width direction of the roll, and the entire circumference of the roll is divided into 35 equal parts, and one piece is provided in each part. 1st
The printing roll 5 shown in the figure is rotated in the direction of the arrow in the drawing by coming into contact with the extrusion molded body 3, and at this time, the above-mentioned ink liquid adheres to the surface.

A doctor blade 6 in FIG. 1 scrapes off excess liquid adhering to the surface of the printing roll 5, so that the liquid remains only in the dot-shaped micropores. This liquid is transferred to the molded body to form a mark.

The molded body thus obtained was cut into 30 m long pieces, degreased in an Ar atmosphere, and sintered in a vacuum.
A product was obtained in which the blackish brown marks peculiar to ferrite as shown in FIG. 2 were applied at equal intervals. In this case, sintering causes dimensional shrinkage, so of course the size of the mark becomes smaller, but the mark is less likely to wear out and is marked firmly.

In addition, the characteristics etc. were not different from those without the seal as originally expected.

Furthermore, the present invention is not limited to the examples shown here, and it goes without saying that it can be applied to various inks and powder compacts without departing from the scope of the claims.

C0 Effects of the Invention [Effects of the Invention] As explained above, the marking according to the present invention is strongly bonded to the product surface by sintering, so it is much more robust than conventional marking methods. In addition, since the present invention does not require a separate process as described above, there is little increase in cost.
Conventionally, economical manufacturing methods are provided.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating extrusion molding and printing steps used in a method for manufacturing a sintered body according to an embodiment of the present invention. FIG. 2 is a diagram showing the shape of a mark printed on the lower surface of the extrusion molded product shown in FIG. 1. FIG. 3 is a cross-sectional view showing the cross-sectional shape of the extruded body shown in FIG. 1. DESCRIPTION OF SYMBOLS 1... Extrusion molding machine, 2... Mouthpiece, 3... Extruded body, 4... Taking-off machine, 5... Printing roll, 6...
...Doctor blade, 7...Ink reservoir, 8...
belt conveyor.

Claims (1)

[Claims] 1. Process a molded body with a constant cross-sectional shape in the longitudinal direction by extrusion molding a mixture consisting of metal or ceramic raw material powder and a binder, then remove the binder (or degrease), and then sinter it. In the manufacturing method of obtaining a sintered product by applying the mixture, the mixture is applied to the nozzle of an extrusion molding machine using a paint in which metal or ceramic powder of a material different from the raw material powder of the molded body is dispersed at a constant concentration. 1. A method for producing a sintered body having marks that are continuous or repeated in a certain direction, the method comprising printing continuously or repeatedly immediately after being discharged from the molded body, removing the binder and sintering the molded body.