Rapid Prototyping and Low Volume Manufacturing Services
424 Main Street, Gardner, MA 01440  /  Ph: 978.632.3700  Fx: 978.632.3777

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Polyurethane Molding
Polyurethane Molding
Polyurethane Molding

Polyurethane Molding

Mack Prototype has achieved a reputation as the premier source for high quality polyurethane molding through continuous research and attention to detail. Polyurethane molding is the precision alternative to injection molding, RIM, structural foam molding, or machining. Especially effective in low volume applications of 3 - 100 parts, with first parts in as little as one week. Typical deliveries range from 2 to 4 weeks.


The Polyurethane Molding process

A master pattern is created through 3D printing or CNC machining from your data. The master is lightly painted with primer and attached to a parting line board. Any required cores or side actions are added, and one side of the master is covered with a mold box. This box is filled with RTV silicone rubber. After curing, the parting line board is removed, the other half of the mold box is attached, and the process repeated. The master pattern is removed from the mold. It may now be used as an engineering model, or to produce multiple RTV molds for enhanced production.

Conventional polyurethane resin is injected at low pressure into the RTV mold and allowed to cure for 2 - 12 hours in tanks maintained at 65 PSI to allow for proper material density. Available resins include custom colored, clear and custom tinted clear, glass-filled, and UL94-VO, in a range of durometers from 40A to 90D.

Our precision meter mixing system allows for rapid production of parts (up to 10 per day, per mold) using a UL94-VO rated, 80D polyurethane. This system also exhibits a heat deflection of 200 F.

The finished part is removed from the mold after curing and sent to the finishing department to receive your specified finish treatment.