Abstract: An improved feedstock material for D-RIM type PIM processes to manufacture parts. The feedstock includes metal or powders or a mixture thereof which is coated with a surfactant to improve rheology and keep the powder from inhibiting a catalytic reaction which occurs during the process. A condensation thermosetting resin is mixed with a latent catalyst and added to the mixture. A modifier can also be added to the mixture, as can a latent catalyst which is a metal salt such as copper triflate. The constituents when mixed together form a uniform feedstock which is injected into a heated mold. The mixtures cures in the mold and a partial debinding occurs. When the part is removed from the mold, it is sintered. Addition of the copper triflate adds significantly to the green strength of the part, and allows parts to be made at least as quickly as parts made from other feedstock materials. Hydrating the copper triflate greatly increases the shelf life of the feedstock.
Abstract: Particulate bearing precursor components are formed into intricate shapes yet possess controlled porosity by injection molding a mixture of particulate materials, thermosetting condensation resins, and low temperature catalysts. The mixture, when flowed into a mold cavity of an appropriate shape and heated, initiates a curing reaction which binds particulates together with a film that leaves the space between the particulates open. A positive volume change occurs during cure, providing for a more uniform pressure profile in the part. Also, a condensate is produced during the curing step which, when vented from the mold in strategic locations, allows manipulation of the curing reaction. This provides the ability to affect local density in the vicinity of the vent. Thus, one can correct for artificially, or incorrectly induced density or porosity gradients, and improve dimensional accuracy and other attributes of the subsequent processing steps.
Abstract: Shaped parts are formed from a powder having the desired chemistry of the finished part by mixing the powder with a thermosetting condensation resin that acts as a binder. The resin may be partially catalyzed, or additives or surfactants added to improve rheology, mixing properties, or processing time. Upon heating, the inherently low viscosity mixture will solidify without pressure being applied to it. A rigid form is produced which is capable of being ejected from a mold. Pre-sintered shapes or parts are made by injection molding, by using semi-permanent tooling, or by prototyping. Binder removal is accomplished by thermal means and without a separate debinding step, despite the known heat resistance of thermosetting resins. Removal is due to the film forming characteristic of the binder leaving open the part's pores, by providing oxidizing conditions within the part's pores as the part is heated, and by insuring that the evolving resin vapor diffuses through the pores by heating the part in a vacuum.
Abstract: Shaped parts are formed from a powder having the desired chemistry of the finished part by mixing the powder with a thermosetting condensation resin that acts as a binder. The resin may be partially catalyzed, or additives or surfactants added to improve rheology, mixing properties, or processing time. Upon heating, the inherently low viscosity mixture will solidify without pressure being applied to it. A rigid form is produced which is capable of being ejected from a mold. Pre-sintered shapes or parts are made by injection molding, by using semi-permanent tooling, or by prototyping. Binder removal is accomplished by thermal means and without a separate debinding step, despite the known heat resistance of thermosetting resins. Removal is due to the film forming characteristic of the binder leaving open the part's pores, by providing oxidizing conditions within the part's pores as the part is heated, and by insuring that the evolving resin vapor diffuses through the pores by heating the part in a vacuum.