Stripper force
5.2.7
Fig. 1
stripper force deep drawing
Ap effective area d punch diameter Ffrom stripper force hu frame height with clearance uZ clearance
In cylindrical drawing operations, the stripper force depends on several factors including:8
- Area size of the clamping frame Ap
- surface finish
- clearance uz
- Hardness of the sheet to be formed
- Friction & Tribology
With soft materials (aluminium), a clearance is often used. The actual drawing process is thus superimposed with an implicit ironing process. The end of the frame end often fills the clearance completely, so that the stripper force Fab can be determined for this zone by means of an effective adhesive tension σH with the following relationship:
In the case of slide ironing or leveling, the entire frame height must be taken into account as the effective area in the calculation. According to8 , the effective adhesive tension is between 0.2 and 1 MPa. The lower value applies to soft and the upper to hard materials.
Eqn. 1
| Stripper force | Fab | = | kN |
| Adhesive tension | σH | = | MPa | |||
| Area with Drawing Clearance | Ap | = | mm2 |
Calc 1
8
Oehler; Kaiser / Schnitt-, Stanz- und Ziehwerkzeuge / Springer Verlag / Berlin / 1993 / 7. Auflage