JPH0522528U - Injection molding powder metallurgy mold - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a mold which is used for injection molding powder metallurgy and can accurately manufacture products with various patterns or marks and which can be manufactured easily and at low cost. With the goal. [Structure] A resin tape is heated and held, and a rubber mold having a predetermined pattern is pressed by a press to form a tape portion 3 having an uneven portion 5 having a predetermined pattern 4. The tape portion 3 is adhered to the cavity surface of the cavity 2 of the die portion 1 with an adhesive to form a die. [Effect] A mold capable of accurately forming various surface patterns or marks can be obtained, and can be manufactured easily and at low cost.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an injection molding powder metallurgy mold for producing a product having a pattern or a mark on the surface by the injection molding powder metallurgy method.

[0002]

[Prior Art]

 As a method for producing metal products having a three-dimensionally complicated shape such as mechanical parts, electrical parts, and decorative products requiring good surface accuracy, raw material powders and binders have been conventionally used. There is known an injection molding powder metallurgy method in which a kneaded product obtained by kneading and is subjected to injection molding at a temperature equal to or higher than the softening temperature of the binder, and the injection molded product is debindered and then sintered. In this method, it is also known that the binder used is an organic substance such as wax and polyethylene, and that it contains a wetting agent to improve the wettability between the metal powder and the binder. Furthermore, it is also known to place the injection molded product on a ceramic setter for the convenience of transportation to the sintering step during the debinding process.

However, various patterns and marks are provided on the surface of the product manufactured by this method. Therefore, in the injection molding, it is necessary to use a mold manufactured so that the pattern or mark can be formed.

[0004]

[Problems to be solved by the device]

 For this purpose, it is necessary to form the pattern or mark on the required place of the mold by electrical discharge machining, etc. However, the more complicated the injection molded product is, the more difficult it is to process the mold used for it. However, it is difficult to use expensive dies for decoration products because it is a high-mix, low-volume production of decorative products. Therefore, there is a problem that a mold that can be manufactured with high accuracy and at low cost is desired.

An object of the present invention is to provide a mold used for manufacturing an injection-molded powder metallurgy product, capable of manufacturing the product with high accuracy, and easily and inexpensively.

[0006]

[Means for Solving the Problems]

 The inventors of the present invention have made efforts to solve the above-mentioned problems and achieve the above-mentioned object, and as a result, a tape having concave or convex patterns or marks is adhered to the cavity surface of the mold cavity. We have completed the present invention by recognizing that the purpose can be achieved by using a mold.

That is, according to the present invention, a kneaded product comprising powder and a binder containing an organic substance is injection-molded, and the injection-molded product is debindered and then subjected to a sintering treatment to obtain a powder with a pattern or mark on the surface. In a metal mold for obtaining metallurgical products, an injection molding powder metallurgical metal which is obtained by adhering a tape having a concave or convex portion with the above-mentioned pattern or mark to a required portion of the cavity surface of the cavity of the die portion. It is a type.

The raw material powder to be injection molded using the mold of the present invention may be metal powder, alloy powder, a mixture of these and ceramic powder, or the like.

As the binder, a mixture of an organic substance such as paraffin wax and polyethylene with a wetting agent such as a surfactant added to improve the wettability of the raw material powder and the binder is used.

As a tape having a concave or convex pattern or pattern, since injection molding is performed at a temperature of 80 ° C. or higher, a thermosetting plastic having a heat resistance temperature of 200 ° C. or higher with a thickness of about 0.05 to 1 mm is used. As a tape, for example, a rubber mold is pressed with a press under heating and is shaped. The depth or height of the irregularities is preferably 0.5 mm or less.

Further, in order to bond the tape to the cavity surface of the mold, a 3 to 10 wt% solution of sodium silicate or potassium silicate can be used, and any material having the same heat resistance will not be a problem. Absent.

The applied mold part may be manufactured by a usual method.

[0013]

[Action]

 It is possible to obtain injection-molded products by injection-molding using this mold in accordance with the usual method, debinding and sintering, and only modeled heat-resistant tape that can be manufactured at low cost. By exchanging, it is possible to manufacture injection-molded products with the same shape but different surface patterns or marks with good shape accuracy, easily and at low cost without using expensive dies each time. It is a thing.

[0014]

【Example】

 Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a side view showing an embodiment of a tape forming a mold of the present invention, and FIG. 2 is a side sectional view showing an embodiment of a die portion to which the tape of the present invention die is adhered. 3 is a plan view showing an example of the shape of a product manufactured by the mold of the present invention, and FIG. 4 is a side view of the example of the product shown in FIG.

Reference numeral 1 denotes a mold part, which is manufactured by a usual method and is provided with a cavity 2 having a shape corresponding to a shape of a target product. 3 is a tape portion, for example, a 1 mm-thick phenol resin tape is heated and held at 200 ° C., and a pattern 4 corresponding to the target product surface pattern is formed into the same shape as the pattern 4. The formed rubber mold is pressed by a press and shaped as an uneven portion 5.

The mold of the present invention is attached to the cavity surface of the cavity 2 of the mold part 1 as shown by the arrow in FIG. 2 with the tape 3 of the present invention as shown in FIG. 1 and a 5 wt% aqueous solution of sodium silicate. It was formed by adhesion as an agent.

This was mounted in an injection molding machine as usual, and gas atomized SUS316 powder having an average particle size of 14 μm was mixed with 60% by weight of polystyrene, 30% by weight of vinyl acetate copolymer and 10% by weight of stearic acid. 7% by weight of an organic binder is added and kneaded, and the resulting kneaded product is injection-molded at a molding temperature of 80 ° C. and a mold temperature of 30 ° C., and has a length of 9 mm, a width of 18 mm, a height of 3 mm, and a flat surface area of 0.6 cm. ^2. 500 pieces of the ornamental parts having complicated shapes shown in FIG. Then, a binder removal process was performed in a debinding furnace in which the temperature was raised to 300 ° C. in nitrogen gas at a heating rate of 20 ° C./h and then cooled. The obtained binder-removed body was sintered at 1300 ° C. for 1 hour to obtain a product.

As a result of investigating the shape of the flat surface portion of the sintered body, a depth of 0. It was confirmed that the pattern of 5 mm or more was accurately formed.

The tape was not damaged or peeled during the continuous molding of 500 tapes.

[0021]

[Effect of the device]

 Since the present invention is a mold in which a tape having a pattern or mark shaped in a predetermined irregularity is adhered to the cavity surface, it can be easily applied to the production of a wide variety of small quantity products, and various types of surface patterns or marks can be accurately manufactured. A well-formed product can be manufactured easily and inexpensively by injection molding powder metallurgy, and a very large effect is recognized.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a tape forming a mold of the present invention.

FIG. 2 is a side sectional view showing an embodiment of a die unit for adhering a tape of the inventive die.

FIG. 3 is a plan view showing an example of a product shape produced by the mold of the present invention.

FIG. 4 is a side view of the example product shown in FIG.

[Explanation of symbols]

 1 Mold part 2 Cavity 3 Tape part 4 Pattern (or mark) 5 Concavo-convex part

Claims (1)

[Scope of utility model registration request] 1. A powder metallurgical product having a pattern or a mark on the surface thereof, which is obtained by injection-molding a kneaded material comprising a powder and a binder containing an organic substance, debinding the injection-molded article, and then performing sintering treatment. In the mold, the pattern or mark (4) is concave or convex at the desired location on the cavity surface of the cavity (2) of the mold (1).
An injection-molding powder metallurgical mold comprising a tape (3) bonded to the (5).