Surface Finishes for plastic injection molding

Release time:2020-04-17

Plastic injection moding Finishes

Plastic Injection molding offers hundreds of thermoplastic resins that are flexible, strong, and can have fine cosmetic finishes. At Ideal Group, aluminum molds can be quickly produced by three-axis milling and easily hand polished or textured to one of eight surface finishes, which range from non-cosmetic to high-gloss polish:

PM-F0: Non-cosmetic, finish to Protolabs discretion
PM-F2: Non-cosmetic, EDM permissible
PM-F1: Low-cosmetic, most toolmarks removed
SPI-C1: 600 grit stone
SPI-B1: 600 grit paper
SPI-A2: Grade #2 Diamond Buff
PM-T1: Light bead blast
PM-T2: Medium bead blast

All polish and texture is applied directly to the mold itself and transferred to the parts during the injection molding process. For this reason, secondary finishing is not available, which makes material selection critical in some cases. Typically, the link between the surface finish and material is small, but glass, mineral, or soft and high-shrink materials can produce parts that don’t always reflect what you may be looking for in a finish.

We can easily add a custom finish as long as you follow these simple rules:

Provide a clearly marked, color-coded image (jpg or pdf) of your part indicating the finishes required.
The part has clearly defined surfaces with a minimum of 0.015 in. (.38mm) of feature height definition, so we can mask off areas for polish or texturing.
A CAD model is provided with the aforementioned required draft angles for the chosen textures.

Geting and part ejection on clear or cosmetic parts is another consideration to keep in mind. If you have a clear lens, or if the side with the most retention is actually the cosmetic side of the part, . Ejector pins vary in size, location, and quantity ect . Some materials may lend themselves to be extracted manually. Another alternative is to use an ejector plate that covers more surface area and can be added, depending on part geometry.

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