Method for controlling the dimensions of bodies made from sinterable materials

• US 6,733,703 B2
• Filed: 09/20/2001
• Issued: 05/11/2004
• Est. Priority Date: 09/26/2000
• Status: Expired due to Fees

• Current Assignee: Ourtef Corporation
• Original Assignee: Hanh Thi Nguyen, Romain L. Billiet
• Inventors: Nguyen, Hanh Thi, Billiet, Romain L.
• Primary Examiner(s): Fiorilla, Christopher A.
• Application Number:
  US09/962,526
• Publication Number:
  US 20020037232A1
• Time in Patent Office: 964 Days
• Field of Search: 419/10, 419/31, 419/38, 419/65, 264/656, 264/669, 264/670, 264/40.1, 264/40.3
• US Class Current: 264/40.1
• CPC Class Codes: B22F 1/10 Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 2203/05 thermal expansion
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 5/007 of moulds
• CPC Class Codes: B28B 7/346 Manufacture of moulds
• CPC Class Codes: B29C 37/005 Compensating volume or shape change during moulding, in general
• CPC Class Codes: B29C 67/04 Sintering combined with compression B29C43/00
• CPC Class Codes: B29K 2105/246 Uncured, e.g. green
• CPC Class Codes: B29K 2995/0049 Heat shrinkable
• CPC Class Codes: C04B 35/622 Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
• CPC Class Codes: C04B 35/634 Polymers C04B35/636 takes precedence
• CPC Class Codes: C04B 35/638 Removal thereof
• CPC Class Codes: H01L 21/565 Moulds
• CPC Class Codes: H01L 23/293 Organic, e.g. plastic
• CPC Class Codes: H01L 23/295 containing a filler H01L23/296 takes precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Precise control of the shrinkage upon sintering of bodies made from mixtures of particulate materials and organic binders is achieved through precision pycnometry of the particulate materials and of the resulting sintered bodies, thus allowing a single molding tool to be used to produce parts in different sizes and from different materials and to tight manufacturing tolerances.

Claims

1. A method for achieving a preset shrinkage upon sintering of bodies made from mixtures of sinterable particulates and a thermoplastic organic binder by establishing the necessary volumetric composition of said mixtures needed to achieve said shrinkage, comprising:

a. providing sinterable particulates and determining their density,

b. sintering said sinterable particulates and determining the density of the resulting sintered body,

c. determining the ratio of the sintered density to the density of said sinterable particulates,

d. determining the desired shrinkage factor by dividing a mold cavity or green dimension by the corresponding desired sintered dimension, and

e. establishing the necessary volumetric fraction of said particulates in a mixture of said particulates and a thermoplastic organic binder in order to achieve said shrinkage factor by dividing said density ratio by the cube of said shrinkage factor.

2. The method as set forth in claim 1 wherein a plurality of sintered parts of identical composition but of different dimensions are achieved.

3. The method as set forth in claim 2, wherein the plurality of sintered parts of identical composition but of different dimensions are achieved using a single mold.

4. The method as set forth in claim 1 wherein a plurality of sintered parts from different materials but of identical sintered dimensions are achieved using a single mold.

5. The method as set forth in claim 1 wherein said sinterable particulates are selected from the class of metals and their alloys, ceramics and their alloys and mixtures of metals and ceramics or their alloys.