SPI Mold Finishes
| Finish | SPI Standard | Finishing Method | Typical Surface Roughness Ra (μm) |
|---|---|---|---|
| As Machined | - | Finished to machinist's discretion | 3.20 (with visible machining marks) |
| Super High Glossy Finish | A-1 | Grade #3 6000 Grit Diamond Buff | 0.012 to 0.025 |
| High Glossy Finish | A-2 | Grade #6 3000 Grit Diamond Buff | 0.025 to 0.05 |
| Normal Glossy Finish | A-3 | Grade #15 1200 Grit Diamond Buff | 0.05 to 0.10 |
| Fine Semi Glossy Finish | B-1 | 600 Grit Paper | 0.05 to 0.10 |
| Medium Semi Glossy Finish | B-2 | 400 Grit Paper | 0.10 to 0.15 |
| Normal Semi Glossy Finish | B-3 | 320 Grit Paper | 0.28 to 0.32 |
| Fine Matte Finish | C-1 | 600 Grit Stone | 0.35 to 0.40 |
| Medium Matte Finish | C-2 | 400 Grit Stone | 0.45 to 0.55 |
| Normal Matte Finish | C-3 | 320 Grit Stone | 0.63 to 0.70 |
| Satin Textured Finish | D-1 | Dry Blast Glass Bead #11 | 0.80 to 1.00 |
| Dull Textured Finish | D-2 | Dry Blast #240 Oxide | 1.00 to 2.80 |
| Rough Textured Finish | D-3 | Dry Blast #24 Oxide | 3.20 to 18.0 |
Material Recommendations
Glossy Finish
| Material | A-1 | A-2 | A-3 |
|---|---|---|---|
| ABS | Average | Average | Good |
| Polypropylene (PP) | Not Recommended | Average | Average |
| Polystyrene (PS) | Average | Average | Good |
| HDPE | Not Recommended | Average | Average |
| Nylon | Average | Average | Good |
| Polycarbonate (PC) | Average | Good | Excellent |
| Polyurethane (TPU) | Not Recommended | Not Recommended | Not Recommended |
| Acrylic | Excellent | Excellent | Excellent |
Semi-Glossy Finish
| Material | B-1 | B-2 | B-3 |
|---|---|---|---|
| ABS | Good | Good | Excellent |
| Polypropylene (PP) | Good | Good | Excellent |
| Polystyrene (PS) | Excellent | Excellent | Excellent |
| HDPE | Good | Good | Excellent |
| Nylon | Good | Excellent | Excellent |
| Polycarbonate (PC) | Good | Good | Average |
| Polyurethane (TPU) | Not Recommended | Average | Average |
| Acrylic | Good | Good | Good |
Matte Finish
| Material | C-1 | C-2 | C-3 |
|---|---|---|---|
| ABS | Excellent | Excellent | Excellent |
| Polypropylene (PP) | Excellent | Excellent | Excellent |
| Polystyrene (PS) | Excellent | Excellent | Excellent |
| HDPE | Excellent | Excellent | Excellent |
| Nylon | Excellent | Excellent | Excellent |
| Polycarbonate (PC) | Average | Not Recommended | Not Recommended |
| Polyurethane (TPU) | Good | Good | Good |
| Acrylic | Good | Good | Good |
Textured Finish
| Material | D-1 | D-2 | D-3 |
|---|---|---|---|
| ABS | Excellent | Excellent | Good |
| Polypropylene (PP) | Excellent | Excellent | Excellent |
| Polystyrene (PS) | Excellent | Excellent | Good |
| HDPE | Excellent | Excellent | Excellent |
| Nylon | Excellent | Excellent | Good |
| Polycarbonate (PC) | Excellent | Not Recommended | Not Recommended |
| Polyurethane (TPU) | Excellent | Excellent | Good |
| Acrylic | Average | Average | Average |