Silicone Rubber Tolerance Chart
(DIN ISO 3302-1 Standard)
When producing silicone molded parts, tolerance is a key factor that determines product quality and assembly reliability. Unlike rigid plastics or metals, silicone is an elastomer with flexibility and compressibility. This means its tolerance ranges are governed by international standards such as DIN ISO 3302-1, ensuring consistency in design and manufacturing.
This chart provides a reference for the dimensional tolerances of silicone rubber components. By understanding these tolerance classes, engineers and buyers can make better design choices and balance accuracy with production cost.
| Nominal Dimension (mm) | Tolerance Class M1 (Very Fine) |
Tolerance Class M2 (Fine) |
Tolerance Class M3 (Medium) |
Tolerance Class M4 (Coarse) |
|---|---|---|---|---|
| 0 – 6.3 | ±0.10 | ±0.15 | ±0.25 | ±0.50 |
| 6.3 – 10 | ±0.10 | ±0.20 | ±0.30 | ±0.70 |
| 10 – 16 | ±0.15 | ±0.20 | ±0.40 | ±0.80 |
| 16 – 25 | ±0.20 | ±0.25 | ±0.50 | ±1.00 |
| 25 – 40 | ±0.20 | ±0.35 | ±0.60 | ±1.30 |
| 40 – 63 | ±0.25 | ±0.40 | ±0.80 | ±1.60 |
| 63 – 100 | ±0.35 | ±0.50 | ±1.00 | ±2.00 |
| 100 – 160 | ±0.40 | ±0.70 | ±1.30 | ±2.50 |
| >160 | ±0.50% | ±0.70% | ±0.80% | ±1.50% |
Notes on Using the Tolerance Chart
- Class M1: Very fine, rarely specified except for high-precision silicone parts.
- Class M2: Fine, used for components requiring accurate fit (e.g., medical devices, sealing rings).
- Class M3: Standard choice for most molded silicone parts.
- Class M4: Coarse, suitable for large parts or non-critical applications.
