Core-Pull Cylinder Bore Calculator
Hydraulic cylinder bore for a core pull, from projected area, number of cylinders and supply pressure.
Inputs
Projected area in mm², pressure in MPa.
Results
Unrounded values
How this calculator works
Side actions and core pulls on PDCPD molds are usually driven by hydraulic cylinders. The cylinder must hold the core against the molding pressure acting on its projected area and pull it free afterwards.
This calculator returns the minimum cylinder bore from the projected area on the core, the number of cylinders sharing the load and the hydraulic supply pressure.
Formulas
- Cylinder bore
√[(projected area × 2 × 3.5) / (pressure × 10 × quantity × 3.1415926 × 100)] × 2 × 10
Calculated value only. Round up to the next standard bore size when selecting a cylinder.
Worked example
A core with 100,000 mm² projected area, held by 2 cylinders at 10 MPa:
| Part projected area | 100000 mm² |
|---|---|
| Number of cylinders | 2 pcs |
| Hydraulic supply pressure | 10 MPa |
| Cylinder bore | 66 mm |
|---|
When to use it
- Selecting cylinders for slides and core pulls
- Deciding whether to use one large cylinder or two smaller ones
Frequently asked questions
How do I size a hydraulic cylinder for a core pull?
Bore = √[(projected area × 2 × 3.5) ÷ (pressure × 10 × quantity × π × 100)] × 2 × 10, with area in mm² and pressure in MPa. 100,000 mm² on 2 cylinders at 10 MPa gives a bore of about 66.8 mm.
Should I round the bore up or down?
Always round up to the next standard cylinder bore. The calculator shows the whole-number value truncated, and the exact value in the unrounded results.
What happens if I use more cylinders?
The load is shared, so each cylinder can be smaller. Doubling the number of cylinders reduces the bore by a factor of √2.
Related calculators
Results are estimates from empirical rules used in PDCPD mold development. Verify critical dimensions before cutting metal.