How to Use
- Locate the material datasheet for the part and record the tensile yield strength (MPa). Convert from kgf/cm² to MPa if needed.
- In CAD software, measure the total core area enveloped by ribs and side walls with small draft angles: A (mm²).
- Select the coefficients (µ, P, and adhesion force) from the tables below and enter them into the calculator.
- Compare A (ejection stress) with B (tensile yield strength). If A > B, increase the ejection contact area (ejector pins/blocks/lifters). If A < B, the ejection area is sufficient.
Figures
Example Data
- Mold core area A: 18,000 mm²
- Minimum draft angle: 0.5°
- Design variants (total ejection contact area): 370 / 600 / 800 mm²
Coefficient Tables
Coefficient of Friction between Plastic Part and Steel, µ (0.1–0.3)
| Group | Material | Coefficient |
|---|---|---|
| 1 | GPPS, HIPS, TPS, PE-LD, PE-LLD, PE-MD, PE-HD, PP-H, PP-CO, PP-EPDM | 0.1 |
| 2 | PA6, PA66, PA11/12, PBT, PETP | 0.13 |
| 3 | CA, CAB, CAP, CP, EVA, PEEL, PUR/TPU, PPVC | 0.17 |
| 4 | ABS, AAS/ASA, SAN, MBS, PPS, PPO-M, BDS, POM | 0.2 |
| 5 | PMMA, PC/ABS, PC/PBT, PC | 0.25 |
| 6 | PES, PSU, PEI, PEEK, UPVC | 0.3 |
Coefficient of Holding Force per Unit Area on the Core, P
P (2.4–3.9) / (0.8–1.2) (107 Pa)
| Group | Material | Coefficient |
|---|---|---|
| 1 | GPPS, HIPS, TPS, PE-LD, PE-LLD, PE-MD, PE-HD, PP-H, PP-CO, PP-EPDM | 0.8 |
| 2 | PA6, PA66, PA11/12, PBT, PETP | 1.4 |
| 3 | CA, CAB, CAP, CP, EVA, PEEL, PUR/TPU, PPVC | 2.0 |
| 4 | ABS, AAS/ASA, SAN, MBS, PPS, PPO-M, BDS, POM | 2.6 |
| 5 | PMMA, PC/ABS, PC/PBT, PC | 3.2 |
| 6 | PES, PSU, PEI, PEEK, UPVC | 3.9 |
Adhesion Force between Plastic Part and Mold
(0.5–1.5) (MPa)
| Group | Material | Coefficient |
|---|---|---|
| 1 | GPPS, HIPS, TPS, PE-LD, PE-LLD, PE-MD, PE-HD, PP-H, PP-CO, PP-EPDM | 0.5 |
| 2 | PA6, PA66, PA11/12, PBT, PETP | 0.7 |
| 3 | CA, CAB, CAP, CP, EVA, PEEL, PUR/TPU, PPVC | 0.9 |
| 4 | ABS, AAS/ASA, SAN, MBS, PPS, PPO-M, BDS, POM | 1.1 |
| 5 | PMMA, PC/ABS, PC/PBT, PC | 1.3 |
| 6 | PES, PSU, PEI, PEEK, UPVC | 1.5 |
Enter the selected coefficients into the corresponding cells. The calculator will compute the results automatically and provide a judgement.
Finally, click “Print” to print the calculation and judgement results.