1. Find the max injection speed in Cubic in/sec located in the molding machines manual.

2. Find the actual screw diameter in molding machines manual. Caution make sure that the screw has not been changed If the screw has been changed, find out what the new screw diameter is.

3. CALCULATE THE AREA OF THE SCREW & MAX INJECTION SPEED

Screw Diameter (SD) x Screw Diameter (SD)  x .7854 = Area

4. Cubic in/sec divided by area = Max speed in IN/SEC


5. If the  max injection speed is in a percentage on the injection molding machine then you will have to multiply the maximum injection speed x  10 % or(.10) to find what the in/sec  rate is at 10 % of the maximum velocity for that machine.

Continue to do this for each % of speeds on your work sheet to determine the actual in/sec for all percentages from 10% to 99 %.

Example:

The maximum speed for machine #A9 is 22.63 =cubic in/sec according to the machines owners manual.
The Screw Diameter is 130mm screw or 5.11” diameter according to the machines owners manual.

CALCULATE MAX SPEED

Cubic in/sec / screw diameter = max speed

22.63 cu in/sec divided by  5.11" diameter = 4.42 in/sec max speed at  99% of the total available injection speed for a machine.
 

cALCULATE WHAT EACH OF THE SPEEDS ARE IN iN/SEC.

multiply the percentage(%) times the max speed from the machines manual.
 

Percent of speed Max injection speed = Actual speed in in/sec

10% speed = .10 x 4.42 = .442 in/sec
20% speed = .20 x 4.42 = .884 in/sec
30% speed = .30 x 4.42 = 1.326 in/sec
40% speed = .40 x 4.42 = 1.768 in/sec
50% speed = .50 x 4.42 = 2.210 in/sec
60% speed = .60 x 4.42 = 2.652 in/sec
70% speed = .70 x 4.42 = 3.094 in/sec
80% speed = .80 x 4.42 = 3.356 in/sec
90% speed = .90 x 4.43 = 3.978 in/sec
99% speed = .99 x 4.42 = 4.376 in/sec