| |
|
The velocity of the press ram must be determined at the
point on cushion contact. On a hydraulic press, this
is the velocity of the main press stroke and is constant throughout the
stroke. On a mechanical press, the ram velocity is constantly
changing and must be determined individually for each press.
Special type of RAPID die cushions have been developed
for high speed forming.
|
|
|
|
Maximum Allowable Linear Speeds |
Cushion Size |
All Steel Cushion |
Rapid Die Cushion |
10" dia. |
125 ft/min |
185 ft/min |
12-16" dia. |
100 ft/min |
150 ft/min |
18-22" |
75 ft/min |
110 ft/min |
24-30" |
60 ft/min |
90 ft/min |
|
| |
Maximum Allowable SPM Formulas |
| Cushion Size |
All Steel Cushion |
Rapid Die Cushion |
| 10" dia. |
478/S |
707/S |
| 12-16" dia. |
382/S |
573/S |
| 18-22" |
287/S |
420/S |
| 24-30" |
229/S |
344/S |
|
| S - Press Stroke |
| SPM - Strokes per Minute |
| |
| Formula to calculate maximum linear velocity
of mechanical press: |
Maximum Linear Velocity
(S x Π x SPM)/12 |
|
|
| Formula to calculate linear velocity
of mechanical press at any crank angle: |
Linear Velocity
(cosθ x L x Π x SPM)/12 |
|
|
| S - Press stroke in inches
L - Press stroke
SPM - Strokes per minute of the press
θ = angle of crank, in this case 50 degres
The cos(50) = .64 factor is the percentage of maximum linear ram speed
derived from the maximum linear ram velocity formula. If θ = 0 degrees,
its cos(θ)= 1, so the ram develops its maximum speed. At 90 degrees,
cos(θ)= 0; there is no linear movement, the ram is at dead bottom.
|
| Additional Information |
| Die
Cushion Tonnage |
| Press
Tonnage |
| Tonnage
for drawing shells |
| |
Dayton
Die Cushions
