SPI Surface Finish Standards
The SPI is that Society of the Plastics Industry sets standard for plastics industry in the United States that identifies the cosmetic quality of plastics, Upmold uses the SPI standard to define finish of plastic injection molded parts.
There are twelve grades of finishes specified by the SPI in four categories that range from shiny to dull. Each grade has different requirements for allowable deviation from perfect, with lower numbers allowing for less deviation and higher numbers allowing for more deviation.
Below specifications provide guidelines for mold surface finishes as provided by the UP MOLD. For more information visit Tooling Manufacturing.
- SPI texture standard
- SPI mold finish standards
- Plastic surface finish chart
- SPI mold finish Guide
- Mold surface finish standards
- SPI Mold finish comparison
- Injection mold surface finish standards
- Injection molding surface finish
- Mold surface finish
- SPI surface finish specification
- SPI surface finish chart
- SPI surface finish standards
| SPI Finish | Guide | Typical Applications | Steel | Hardness |
|---|---|---|---|---|
| A-1 | Grade #3 Diamond | Lens / Mirror – requires 420 SS material | S136 | 54HRC |
| 8407 | 52HRC | |||
| A-2 | Grade #6 Diamond | High Polish parts | DF-2 | 58HRC |
| XW-10 | 60HRC | |||
| A-3 | Grade #15 Diamond | High Polish parts | S136 | 300HB |
| 718SUPREME | 300HB | |||
| B-1 | 600 Grit paper | Medium Polish parts | ||
| B-2 | 400 Grit paper | Medium Polish | ||
| B-3 | 320 Grit paper | Med – Low polish | ||
| C-1 | 600 Stone | Low Polish parts | ||
| C-2 | 400 Stone | Low Polish parts | ||
| C-3 | 320 Stone | Low Polish parts | ||
| D-1 | Dry Blast Glass Bead | Satin finish | ||
| D-2 | Dry Blast # 240 Oxide | Dull Finish | ||
| D-3 | Dry Blast # 24 Oxide | Dull finish |
SPI surface finish chart for roughness technology
SPI a1 is comparable to RA.0-1 made by #3 diamond buff
SPI a2 is slightly finer than a1 and RA.1-2 made by #6 diamond buff
SPI a3 has more imperfections than a2 and RA.2-3 made by #15 diamond buff
SPI b1 is finer than a3 and RA.2-3 made by 600 grit
SPI b2 is slightly finer than b1 and RA.4-5 made by 400 grit
SPI b3 is comparable to RA.9-10 made by 320 grit
SPI c1 is finer than b3 and RA.10-12 made by 600 stone
SPI c2 is slightly finer than c1 and RA.25-28 made by 400 stone
SPI c3 is comparable to RA.38-42 made by 320 stone
SPI d1 is finer than c3 and RA.10-12 made by #11 glass bead sandblasting
SPI d2 is comparable to RA.26-32 made by 240 aluminum oxide sandblasting
SPI d3 is a little more coarse than d2 and RA.190-230 made by #24 aluminum oxide sandblasting
SPI surface finish Gloss
Shiny Finishes
SPI-A1, A2, A3
Semi-Gloss Finishes
SPI-B1, B2,B3
Matte to Dull
SPI-D1,D2,D3
Texture
SPI-D1,D2,D3
