Compression and Transfer Molds for Thermosets

Compression Molds

Built-Rite Tool & Die also specializes in the design and construction of compression molds for thermosetting materials such as Bulk Molding Compounds (BMC); Sheet Mold Compounds (SMC); Phenolic Molding Compounds; Diallyl Phthalate (DAP), and other thermosetting materials. Our design expertise includes Fully Positive Compression Molds, and Semi-Positive Landed Compression Molds. Each presents its own unique design criteria, which dictate the appropriate mold type to be selected.

Some of the criteria includes:

  • Proper mold design
  • Manufacturing ability machine to close tolerances
  • Matched metal die shut-offs between the Force and Cavity (which is critical to the ability to mold a successful part.)
  • Design assistance to maximize the outcome of the compression molded part design
  • Prototype or limited production development prototype tooling for engineering evaluation purposes
  • Production tooling constructed from H-13 hardened tool steel, chrome plated with engineering chrome
  • Molds supplied with insulator boards, thermocouples and the capability to be heated with hot oil or Calrod heaters
  • Mold sampling at Built-Rite’s molding facility, Reliance Engineering, and delivered with processing data necessary to mold acceptable parts.

Transfer Molds

Transfer molding of thermosetting materials is typically used when inserts are molded into the plastic part. As in compression molding, the design of the mold and the selection of tool steels are critical factors in the customer’s ability to mold a successful part. Transfer molding isolates the molding compound from the controls of the transfer-molding machine. This allows loading of inserts into the mold, closure of the mold to seal off the inserts and then introduction of the molding compound into the machine to mold the part.

There are several types of transfer molding systems including:

  • Standard Transfer Molding from the mold parting line
  • Pot Type Transfer Molding used to gate into the face of a part directly

Inserts, part geometry, dimensional requirements, and materials selected all influence the selection of a proper transfer mold system.

Other services include:

  • Limited production molds (typically constructed from pre-hardened H-13 steel) for limited production or engineering evaluation purposes
  • Chrome plating with engineering chrome

Mold sampling at our molding facility, Reliance Engineering, and delivered with processing data necessary to mold acceptable parts