Die Mount Cam Slide Return Force

The required slide return force for die mount cams needs to be calculated to determine if a cam pad or auxiliary pressure system is needed for the application. This applies to commercial cam units and homemade die mount cams.

The equation for die mount cam slide return force is:

• Fdsr = Fs + {(0.00981 • ms) • [0.20 • (cos β + sin β)]}

where:

• Fdsr = die mount cam slide return force (kN)
• Fs = stripping force (kN)
• β = work angle from horizontal (degrees)
• ms = working slide mass (kg)
• 0.20 = coefficient of friction
• 0.00981 = force due to gravity

NOTE: if there is a cam pad, then the stripping force (Fs) required by the die mount cam slide is equal to ZERO.

For example, assume a die mount cam has a working slide with 40 kg mass. The work angle is 10° from horizontal and 4.65 kN stripping force is required. There is no cam pad.

The required slide return force is:

• Fdsr = Fs + {(0.00981 • ms) • [0.20 • (cos β + sin β)]}
• Fdsr = 4.65  + {(0.00981 • 40) • [0.20 • (cos 10°+ sin 10°)]}
• Fdsr = 4.65  + (0.3924 • 0.3706)
• Fdsr = 4.8 kN slide return force

If the die mount cam slide return spring does not have the required force capability, then either a supplemental pressure system or a cam pad will need to be added to the cam.