JPH10277704A - Metal injection-forming method with placed core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an integral product without using machining, pressing, welding, etc., as the other working method to an under-cut part by inserting a placed core into the under-cut part at the time of welding. SOLUTION: A low m.p. of material or a waste material soluble in organic solvent ordinarily obtd. from a plastic work, is utilized for the under-cut part. The under-cut part in the product to be obtd. is molded by using this material and inserted into a metallic mold as the placed core so as to obtain the metallic forming product. The green sand mold inserting the placed core is infiltrated with the organic solvent at 1 hr/mm of thickness. At this time, water incorporated in an outer vessel is set to the temp. at 80 deg.C so as to made the organic solvent temp. in an inner vessel becomes at about 70 deg.C. The green sand mold having the under-cut part with the placed core is charged into a prescribed vacuum sintering furnace to remove binder except the binder removed in the low temp. range with the organic solvent. Thereafter, the binder in a sintered pattern is removed in the log temp. range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a metal
This is molding in injection. Conventionally, a method of manufacturing metal that is difficult to mechanize in the undercut is inserted into a mold by inserting a plastic that reacts to organic solvents and temperature into a mold, and then eroded by the organic solvent after molding. It is. The organic solvent device for removing plastics is a device in which water is set to 80 ° C in the outer container.The organic solvent in the inner container reaches the boiling point, but the lid is closed so that the vapor does not come into contact with the atmosphere. Then, a chiller device is set at the same time [Claim 3]. In a metal injection molded product (green body), the “place core” in the undercut portion is eroded and removed with an organic solvent. After the removed molded product (cavan body) is dried, the remaining binder is removed from a low-temperature region to an ultra-high temperature region in a vacuum sintering furnace (JP-A-7-216).
404) Sinter in a pattern combining time, temperature, inert gas and the like. "Claim 4". When a binder is added to these metal powders, the composition of the binder is the same as the composition of the “place core”. The reason is that, when eroding with an organic solvent, if the composition is the same as that of the binder, the time in the sintering furnace is shortened, which is economical. Also, depending on the type of metal, several percents of C and Ti are added together with a binder in order to obtain the required hardness of the metal after sintering.
This apparatus is a "claim 5" in which the mixer is evacuated and an inert gas is introduced to knead the metal powder and the binder. Use of this device helps to prevent oxidation of the metal powder in the atmosphere. In molding with plastics,
The two materials having different melting points are used as the "low core" for the low melting material, and the "low core" inserted in a vacuum furnace or an organic solvent is removed for the high melting material as a base material.

[Industrial applications] In recent years, metal products,
Finished products such as ceramics and plastics have been widely used from general industrial products to electronic components, optical fiber components, automobiles, and medical-related components. Strict demands have been made on the dimensions, physical properties and shape of these products. As a means of responding to such demands, materials that could not be used in the past have been integrated into new fields as “placement cores” by integrating shapes that are impossible with the processing method in the shape of each product. Available to According to the present invention, bearings to meet these industrial demands have conventionally been manufactured by machining a press and a product in a separate process from a housing and a retainer and assembling a pressed product. By being integrated, the degree of freedom in product design is widened, and there is great marketability in conventional materials and industrial fields.

[Prior art] In a conventional metal product, the undercut portion is cut by machining or press working.
It relied on welding and screwing processes. In addition, products having different shapes and thicknesses were deformed, distorted, cracked, etc., and could not be produced. However, in the metal powder molding, the mixing of the metal powder and the addition of the binder made the impossible possible in the molding of the near net shape. In addition, for materials such as plastics, according to their respective shapes, by inserting a “place core”, the conventional metal forming method, other forming methods,
It is possible to produce a product that integrates what could not be machined.

[0004] In view of the above, the present invention provides a product in which an undercut portion is integrated without using other processing methods such as machining, pressing, and welding. In order to obtain the above, insert the `` place core '' in the undercut part at the time of molding, and achieve the above-mentioned object in a short time by using a metal molding method or a plastics molding method with a shape or material that can not be done conventionally I found a method to insert a "place core" into the undercut.

[Means for Solving the Problems] The present invention provides:
In the conventional bearing, the housing, the retainer, and the pressed product were assembled into one part, but there was no way to integrate and process the undercut part, which required a part called a retainer. For this reason, the present invention has solved the problem by sintering in a vacuum sintering furnace after inserting waste plastic as a “placement core” into an undercut portion, removing it with an organic solvent, and sintering in a vacuum sintering furnace.

[Operation] In the operation of the present invention, the undercut portion having a different thickness is machined and then welded or screwed. As a result, defects such as thermal deformation and distortion occurred, resulting in a change in the design shape and an increase in the number of processing steps. The use of the “place core” has a great effect on design flexibility, reduction of total cost, and expansion of marketability.

[Embodiment] Waste material from a plastics factory is usually used for the undercut portion. This is a material that has a low melting point and melts in an organic solvent. This material creates the undercut of the desired product, inserts it as a "place core" and inserts it into the mold as required for the metal part. The inserted green body was eroded by an organic solvent for one hour per 1 mm thickness of the organic solvent. At that time, the outer container was set at a water temperature of 80 ° C,
The temperature of the organic agent was about 70 ° C. At this time, if the temperature is high, the solvent boils and evaporates, and the shape of the binder cannot be maintained. The evaporating solvent was covered, and the chiller was used to prevent the vapor from coming into contact with the atmosphere. [Claim 3] An undercut portion having a thickness of 4 mm was removed in 4 hours. At this time,
9 g of Ti and 5 kinds of binders are added simultaneously to the metal powder in a weight ratio, and kneading is carried out in a pressure kneader at 180 ° C. for 2 hours. Insert molding was performed. The green body undercut by the “place core” is removed in a predetermined vacuum sintering furnace in the same time as the thickness of the binder except for the binder removed by the organic solvent in a low-temperature region. Kaihei 7-21
6404) using the apparatus of claim 4 for removing the binder in a low temperature range using time, temperature, vacuum, and an inert gas. At this time, the organic solvent used and the curved body removed by the apparatus were sintered, but the conventional metal injection molding method (O
NE-STEP method) Degreasing of the binder in a vacuum sintering furnace at a low temperature range, which is no different from metal injection molded products. It was confirmed that the binder used in sintering (Japanese Patent Application Laid-Open No. Hei 7-216404) can also be used for an organic solvent. Products,
No crack or deformation was observed.

[Effects of the Invention] According to the present invention, the method of insert molding a "place core" into a product shape that cannot be performed by the conventional molding method can be applied to an undercut portion and a welding that cannot be performed by a machining method. Required parts processing method,
Integrating the product shape by screwing has a great effect industrially. INDUSTRIAL APPLICABILITY The present invention can be applied to a metal injection molding method and a plastics molding method, and has great industrial and commercial effects, and its meaning is significant.

[Brief description of the drawings]

FIG. 1 is a retainer diagram in which an undercut portion whose shape is manufactured by plus technology in FIG. 1 is formed by metal injection and removed by a solvent like an Aa-b cross section.

FIG. 2 Conventionally, a housing and a retainer were separately manufactured, and a ball was put in the housing and used.

[Explanation of symbols]

 [FIG. 1A] Retainer part plan view [FIG. 1B] Cross-sectional view ab [FIG. 2C] Cross-sectional view of retainer and housing

Claims (6)

[Claims] 1. A metal injection molding production method in which a "place core" is inserted into an undercut portion in a metal mold in a metal injection molding. 2. The "placement core" is one that can withstand molding.
In addition, it reacts to organic solvents and temperature. 3. A method and an apparatus for removing a “place core” after molding. 4. A method and an apparatus for determining the high hardness of a product obtained in a vacuum sintering furnace from the molded product removed in [3]. 5. A method and an apparatus for adding an additive to a metal powder for obtaining hardness of a sintered product around HRC60. 6. "Place core" in plastic molding
Molding method.