Managing Thermal Expansion Tolerances and Yield Loss across Scaled High Speed Stamping Dies
Active thermal control and cryogenic substrate stabilization eliminate shut-height drift and thermal scrap loss in high-speed progressive stamping dies.
Friction Work Conversion
Meaning
Physical processes where mechanical energy used for deformation becomes thermal energy dictate the heating of a die. Friction work conversion describes the specific portion of the press energy that turns into heat at the interface of the tool and the workpiece. The measurement is valid only while the surfaces are in relative motion under load.
Energy Efficiency
High friction levels indicate that more energy is being lost to heat rather than being used to form the part. Lubricants are used to reduce the friction work conversion and protect the tool surface from overheating. Minimizing this heat generation allows for higher stroke speeds without damaging the material.
Tool Degradation
Excess heat softens the cutting edges of the punch and leads to rapid wear. When friction work conversion is high, the surface finish of the stamped part often shows signs of galling or tearing. Monitoring the temperature of the die provides a way to estimate the efficiency of the lubrication.
Thermal Boundary
Heat flows from the interface into the body of the tool and eventually into the press frame. If the rate of friction work conversion exceeds the cooling capacity, the tool will expand and change the clearance. This imbalance eventually leads to part failure or tool seizure.