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Graphite Permanent Mold Process - GMP

Castechnologies, Inc. uses exclusively the Graphite Permanent Mold (GPM) process, which combines the low cost of easily machined graphite molds with a high-strength, highly engineered, zinc-aluminum alloy, ZA-12, to provide an economical alternative to other manufacturing processes in annual volumes of 500-15,000.  These annual volumes are an approximation and higher or lower amounts may be competitive with other casting processes.  Allow us to quote on a wider range of anticipated annual volumes for comparison purposes.


Benefits include:

  • Cast precision (+/-.005), which reduces secondary machining and cost

  • Cast surface finish of 125 RMS or better

  • Piece-to-piece repeatability

  • Bearing qualities superior to bronze

  • Tooling lead times of 3-6 weeks, depending on mold shop backlog

  • Homogeneous castings

  • Reduced internal voids



Through CAD/CAM, the precision molds are designed and then rapidly machined on CNC equipment according to customer specifications.Mold prices vary according to the size and complexity of the casting.Generally, molds cost between $3,500 and $7,500.The advantages of graphite molds are its high thermal conductivity, stability and minimal expansion.


​Material - Zinc aluminum alloy ZA-12 

  • Non-magnetic (suitable for electronic shielding)

  • Easily machined

  • Non-Incendiary

  • Spark-proof

For material specifications contact our material supplier, Eastern Alloys, Inc.


​By having a full range of machining capabilities, Castechnologies can supply a complete, functional component. ZA-12’s features, along with our process’ near-net-shape capabilities, can demonstrate considerable cost savings over other manufacturing methods, whether the castings are machined at our facility or our customer’s facility.



 When ZA-12 is cast, it exhibits an attractive, bright finish.Over time, the surface color softens to an appealing, pewter-like appearance, which is fully acceptable for most applications.However, for protective or aesthetic reasons, some castings require an added finish.Similar to die castings, these finishes include chromate, polymeric coatings and paint (polyurethane, powder, e-coat, etc.).As well, like die castings, ZA-12 can be plated.However, strict plating process controls must be followed to obtain proper adhesion and long lasting durability.

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