Apparatus for cold runner transfer molding

Claim 1

A mold apparatus for the transfer molding of a plurality of small objects, comprising: a cavity block; a plurality of cavities in said cavity block; gate means for admitting a plastic molding material to each of said cavities; a runner block; runner means in said runner block for permitting the flow of plastic molding material therethrough; plunger means having a plunger tip for forcing said plastic molding material into said plurality of mold cavities and for maintaining said plastic material under high pressure in said cavities; insulating means for providing thermal insulation between said runner block and said cavity block; cooling means in contact with said runner block for inhibiting curing of said plastic molding material in said runner block; said cooling means comprising a plurality of coolant passageways at a surface of said runner block, said passageways being partially bounded by said insulating means; local heating means within said cavity block for heating said plastic molding material prior to said plastic molding material entering said plurality of cavities, said heating means being proximately located in a common passageway within said gate means abutting object cavities wherein curing of said small objects are to take place; and said cavity block further having an upper portion and a lower portion, said runner block further having a tapered inner bore, said cooling means being located in said upper portion of said cavity block and surrounding said runner block adjacent to said tapered bore of said runner block, said heating means being a solid plug member and located directly below said tapered bore of said runner block and in said lower portion.