Method of manufacturing a composition for use in injection molding powder metallurgy

• US 5,095,048 A
• Filed: 10/01/1990
• Issued: 03/10/1992
• Est. Priority Date: 10/01/1990
• Status: Expired due to Fees

• Current Assignee: Sumitomo Metal Mining Company Limited
• Original Assignee: Sumitomo Metal Mining Company Limited
• Inventors: Takahashi, Nobuji, Kibayashi, Kouhei
• Primary Examiner(s): Michl, Paul R.
• Assistant Examiner(s): SZEKELY, PETER A
• Application Number:
  US07/591,982
• Time in Patent Office: 526 Days
• Field of Search: 264/328.18, 264/328.1, 264/109, 264/15, 264/342, 523/223
• US Class Current: 523/223
• CPC Class Codes: B22F 1/065 Spherical particles
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 3/22 for producing castings from a slip
• CPC Class Codes: B22F 3/225 by injection molding
• CPC Class Codes: C08K 7/16 Solid spheres
• CPC Class Codes: C08L 23/02 not modified by chemical after-treatment

Abstract

A composition for use in injection molding powder metallurgy, is provided by applying mechanical sphericalization to a metal powder of an irregular shape and having an average grain size of not more than 50 μm to form a sphericalized metal powder, and then mixing and kneading a binder of not more than 9 parts by volume relative to 11 parts by volume of the sphericalized metal powder.

Claims

1. A method of manufacturing a composition for use in injection molding powder metallurgy, which comprises the steps of:

(a) providing a metal powder whose grains are of irregular shape and wherein the average grain size does not exceed 50 μ

m,

(b) mechanically sphericalizing the metal powder of step (a) to provide a sphericalized metal powder,

(c) mixing a binder into said sphericalized metal powder at a ratio of 9 parts by volume of binder to 11 parts by volume of powder, and

(d) kneading the mixture of step (c), thereby providing said composition.

2. The method according to claim 1, wherein the metal powder of step (a) has a average grain size of not more than 20 μ

m.

3. The method according to claim 1, wherein in step (b) the grains of metal powder are impacted against one another or against a hard surface.

4. The method according to claim 1, wherein said binder is selected from the group consisting of ethylene polymer and wax.

5. The method according to claim 1, wherein in step (c) a wetting agent is mixed into said sphericalized metal powder.

6. The method according to claim 5, wherein in step (d) the mixture is kneaded in a planetary mixer.