Surface Finishes and Textures

All parts have a surface texture resulting from the injection mold that produced them.  Make sure to specify the desired finish you want before the start of mold production.

The Plastics Industry Association (PIA) is an independent trade organization in the USA that has created standards for surface finishes on injection molds.  They were previously known as SPI, or Society of Plastics Industry.

Standard PIA / SPI mold surface finishes are listed in this table.  Other texturing options such as Mold-Tech or VDI can also be utilized as references for mold finishes to provide the desired surface texture on your part.

A surface finish spec does affect mold cost. A-1 is the most expensive finish due to all the time and effort it takes to achieve.  Texturing cost decreases as you move down the table from A-1.

If left unspecified, SPI B-2 is our standard non-gloss surface finish.  SPI A-3 is what we typically use for a glossy finish. 

 

PIA/SPI Standard Finish Finishing Method Typical Surface Roughness Ra (um) A-1 Super High Glossy Grade #3, 6000 Grit Diamond Buff 0.012 - 0.025 A-2 High Glossy Grade #6, 3000 Grit Diamond Buff 0.025 - 0.05 A-3 Normal Glossy Grade #15, 1200 Grit Diamond Buff 0.05 - 0.10 B-1 Fine Semi-Glossy 600 Grit Paper 0.05 - 0.10 B-2 Medium Semi-Glossy 400 Grit Paper 0.10 - 0.15 B-3 Normal Semi-Glossy 320 Grit Paper 0.28 - 0.32 C-1 Fine Matte 600 Grit Stone 0.35 - 0.40 C-2 Medium Matte 400 Grit Stone 0.45 - 0.55 C-3 Normal Matte 320 Grit Stone 0.63 - 0.70 D-1 Satin Textured Dry Blast Glass Bead #11 0.80 - 1.0 D-2 Dull Textured Dry Blast #240 Oxide 1.00 - 2.80 D-3 Rough Textured Dry Blast #24 Oxide 3.20 - 18.0