What is Polymer Plastic Casting?
Polymer plastic casting is a low- to medium-volume manufacturing process where liquid polymer resin is poured into a mold and left to cure into a solid shape.
Unlike injection molding, it doesn’t require high pressure — making it great for prototypes, specialty parts, or large shapes without expensive tooling.
How it works
Mold Preparation
A mold is made (commonly from silicone, metal, or plastic) based on the desired part shape.
Mixing
Liquid polymer resin is mixed with additives (color pigments, fillers, catalysts, etc.).
Pouring
The liquid resin is poured or injected into the mold cavity.
Curing
The resin chemically reacts and hardens, either at room temperature or with heat.
Demolding
Once hardened, the part is removed from the mold.
Finishing
Any flash or imperfections are trimmed, sanded, or polished.
Why it’s used
Low tooling cost
Molds are cheaper than injection molding steel molds.
Flexibility
Works for both small runs and custom parts.
Large part capability
Can cast large, thick pieces without huge machines.
Material variety
Works with epoxy, polyurethane, acrylic, polyester resins.
Detail & finish
Captures fine details from the mold surface.
Common uses in manufacturing
4 axle CNC machining shows up in nearly every sector:
Prototyping
Quick, cost-effective production of test parts.
Signage & displays
Clear acrylic letters, decorative panels.
Custom components
Specialty housings, low-volume enclosures.
Art & design
Sculptures, decorative castings, resin art.
Industrial parts
Gaskets, bushings, rollers.
Why it matters
Polymer casting is more accessible and affordable than high-pressure molding processes, making it ideal for small-batch or custom production. While not as fast or scalable as injection molding, it’s perfect for flexible manufacturing, low startup costs, and complex designs.