Services

Plastic Casting

Dinsmore & Associates, Inc. delivers plastic prototypes with material properties similar to production plastics. We do this with RTV molding, which produces cast urethane or epoxy prototypes with the look and feel of injection molded parts.

The benefits of RTV molding:

  • Provides precise parts
  • Assist engineering design before hard tooling
  • Offers low cost tooling, allowing easy modification while staying in budget
  • Reduced time to market
  • Used to evaluate potential markets
  • Assist in U.L. approval and in house testing
  • Offer aesthetic application where appearance is critical
  • Used in sales for presentations and marketing shows
  • Provide high degree of accuracy is maintained in the copy; including surface finish
  • Use parts without draft, or with undercuts, can be reproduced
  • Have fast turn-around of castings
  • Allow different materials can be used for each casting, making it possible to test your design with a variety of material properties

Dinsmore & Associates, Inc. casts all parts under a vacuum with molding machines using computer control. This allows us to produce void-free castings with consistent properties in each part. Colors are cast in, matching your specifications. Paint, texturing and/or graphics can be added. RTV rubber molds fulfill your need for multiple plastic prototypes with superior material properties. To get production quality urethane castings you need two things: RTV silicone tooling and vacuum casting machines. Vacuum casting gives you consistent void free urethane parts that can be molded in color and texture.

In the RTV tooling process, liquid silicone rubber is poured around a master pattern typically an SLA or CNC part. The resulting mold is pulled from the pattern and cured, then subsequently used to cast urethane parts. The key advantage of this process is being able to obtain higher quantities of parts at relatively low cost.

The process begins by generating and finishing an SLA pattern part which is then set in a silicone based liquid rubber. Once the rubber sets, the SLA part is removed by slicing the rubber at a "parting line". The rubber mold is then closed and filled with a Urethane based resin that matches the customer's needs, and performs very similar to the production injection molded part.

Since the process is based on an SLA (or even CNC) pattern, RTV molds can have features that are difficult and expensive for other tooling methods. Features such as: zero draft, undercuts, indented features, complex parting lines, side pulls, convoluted channels, etc.

The extensive selection of urethane casting materials allows for a variety of aesthetic and functional properties that serve everyone from the lighting industry to the cosmetics industry, including materials that are UL listed, optically clear, highly durable, heat resistant, and a variety of colors.

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