Manufacture of parts from particulate material
AssigneeParmatech Corporation
InventorRaymond E. Wiech, Jr.
Life of this patent
Estimating the term…
Abstract
The disclosure relates to a method of binder removal from a green body before sintering or the like wherein the green body is initially heated to a temperature above the flow point of the binder to liquify the binder and, at this elevated temperature, surrounded by a solvent for said binder in the vapor phase and at a temperature slightly above the melting point of the binder. The solvent vapor enters the green body slowly and dissolves the binder therein so that excessive stresses are not provided within the body due to binder expansion until binder-solvent substantially ceases to exude from the body. The body is then placed in a bath of the solvent, the solvent being maintained at a temperature above the flow point of the binder to remove remaining binder from the body.
Claims63
The method of producing a fired particulate configuration, whereby binder material is removed from the particulate configuration prior to firing without swelling the particulate configuration and consequent imparting of shear or tensile force to the particulate configuration prior to the firing thereof, comprising the steps of:
- (1) mixing together predetermined amounts of particulate material and a binder at a temperature above the melting point of the binder wherein the binder hardens upon cooling and can thereafter be melted by heating,
- (2) forming said mixture from (1) into the desired configuration with heat and pressure and then causing said binder to be hardened by cooling,
- (3) heating said formed mixture of (2) to a temperature above the melting point of said binder to liquify said binder in the absence of solvent from the binder,
- (4) placing said heated formed mixture of (3) in a vapor of a solvent for said binder at a temperature above the melting point of said binder whereby said binder dissolves in said solvent for a time sufficient to cause exudation of combined solvent and binder from said mixture without rupture of said configuration,
- (5) placing said formed mixture from (4) in a bath of a liquid solvent for said binder maintained at a temperature above the melting point of said binder, whereby said binder is substantially completely stripped from said formed mixture, and
- (6) sintering said stripped and formed mixture from (5).
The method of producing a fired particulate configuration, whereby binder material is removed from the particulate configuration prior to firing without swelling the particulate configuration and consequent imparting of shear or tensile force to the particulate configuration prior to the firing thereof, comprising the steps of:
- (1) mixing together predetermined amounts of particulate material and a binder whereby the binder covers substantially all of the surfaces of the particles of said particulate material,
- (2) forming said mixture from (1) into the desired configuration,
- (3) heating said formed mixture of (2) to a temperature above the flow point of said binder to liquify said binder in the absence of solvent from the binder,
- (4) placing said heated formed mixture of (3) while said binder is liquified in a solvent for said binder at a temperature above the flow point of said binder whereby said binder dissolves in said solvent at a sufficiently slow rate to cause exudation of combined solvent and binder from said mixture at a rate greater than the formation of new combined solvent and binder in said formed mixture to prevent rupture of said configuration, and
- (5) sintering said mixture from (4).
The method of producing an article comprising the steps of:
- mixing particulate material and a thermoplastic binder until substantially all of the surfaces of the particles of said particulate material are covered with said binder to form a mixture;
- forming said mixture into a desired configuration;
- heating said configuration to cause said binder to be liquidus;
- removing said liquidus binder by application of a solvent to said binder while said binder is liquidus, at a temperature above the flow point of said binder, and subsequently sintering the substantially binder-free configuration.
The method of producing a fired particulate product comprising the steps of:
- (1) mixing together predetermined amounts of particulate material and a liquid binder which hardens upon cooling until substantially all of the surfaces of the particles of said particulate material are covered with said binder to form a mixture;
- (2) forming said mixture into the desired configuration and causing said binder to be hardened by cooling;
- (3) and removing said binder from said configuration prior to firing same by returning the binder to its liquid state and thereafter exposing said liquified binder to a leaching agent while said binder is liquified at a temperature above the flow point of said binder and causing said binder and leaching agent to flow from said configuration, whereby the latter can be fired free of said binder.
Dependencies are inferred from the claim text.