Urethane Casting

At a Glance

Applications

Lead Time

Materials

Finishing Options

Low volume production, complex elastomeric parts, visual models, EVT units
10 days
ABS-Like, Acrylic-Like, Opaque Elastomer, Waterclear Elastomer
Custom textures, precise color match

About the Process

Urethane casting (also known as RTV molding, cast urethane, and silicone molding) is a fabrication method that uses silicone molds to produce production-quality parts, without the high costs and lead times of steel or aluminum tooling.

Urethane Casting production consists of three main steps:

  1. Build a master pattern using 3D printing or CNC machining
  2. Build the mold by pouring platinum silicone around master
  3. Pour liquid polyurethane resin into mold, create polyurethane casting under vacuum

Materials

ABS-Like

A general-purpose opaque material that simulates ABS thermoplastic. Good for most hardware product enclosures.

Acrylic-Like

A stiff, transparent material for simulating acrylic (PMMA). Good for see-through applications such as light guides.

Opaque Elastomer

Simulates all kinds of rubber-like materials such as TPE, TPU, and silicone rubber. Great for wearables, gaskets, and overmolds. Available from Shore 20A to Shore 90A in 10A increments.

Waterclear Elastomer

Simulates all kinds of rubber-like materials such as TPE, TPU, and silicone rubber. Great for wearables, gaskets, and overmolds. Available from Shore 20A to Shore 90A in 10A increments.

Colors & Finishing Options

Standard

Pigment is added to the liquid polyurethane prior to casting, so each casting has as-molded color. Customers may provide Pantone code for approximate color matching.

Precise Color Match

Paint is recommended for parts that require exact color matching. Very light colors or specific shades of white may only be achievable with painting. Pantone code or sample swatch must be provided for precise color matching.

Custom Textures

A variety of textures can be achieved by texture painting the master prior to mold making or by painting the parts after casting.

Design Recommendations

If you are familiar with designing parts for injection molding, you can apply the same best practices and rules of thumb to design parts for urethane casting. For a detailed resource on how to design your parts for urethane casting, download our free Urethane Casting Design Guide.

Related Resources

Urethane Casting Design Guide