Metal Casting (aluminum or zinc)


Specializing in rapid prototype aluminum, zinc, and bronze castings using the plaster, sand, investment and permanent molding processes, the GPI Prototype & Mfg. Services name has become synonymous with quality, reliability, and service. Whether your need is for rapid prototyping your precision casting design, for design verification or production quantities GPI Prototype & Mfg. Services can efficiently handle your project from start to finish. Being one of the only companies within our industry to offer Rapid Castings in less than 2 weeks, rest assured that the quality of your projects remains our highest priority.


The Process

  1. A master model is created.
  2. "Master Molds" are made from the master model.
  3. The "Master Molds" are used to generate a plaster molds.
  4. Plaster molds are then allowed to dry (typically 3-5 days).
  5. Aluminum is poured into the plaster mold.
  6. After removal from the plaster mold, each casting is cleaned and prepared for shipping or machining.
  7. Castings being machined in CNC milling station.
  8. Final part cast, machined, and ready to ship.


Mold Production

The plaster mold casting process we employ involves pouring a plaster slurry onto a master pattern. Molds are poured one at a time. After they set, they are stripped from the pattern and baked in ovens to evaporate all the remaining moisture and ensure consistent surface appearance and top casting quality.

The replication from mold to mold and part to part is highly accurate and can be used effectively for both prototype and production volumes.




Metal Casting

Virtually any aluminum or zinc alloy can be poured using any of our casting methods (plaster, sand, investment). Alloy A-356 achieves high strength and replicates aluminum die castings very closely, while 713 is often chosen for applications requiring high cast strength with stability such as optical housings.




Washout and Finishing

After sufficient cooling time has been allowed for complete solidification, the casting is broken out from the mold. High-pressure water jets are applied to remove all traces of mold material from the part prior to mechanical clean up.

Mechanical clean-up includes such steps as cutting off the gating, where metal enters the mold, and removing the flashing that occurs naturally at the mold joints or parting lines on the casting. These operations are performed by grinding and careful hand filing.

Subsequent grit blasting removes the thin oxide skin found on all aluminum castings and prepares the surface for plating and/or painting by providing a finished, uniform appearance.



 
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