August 24, 2022

Application Procedure

1. Select material from the table at right and calculate BTU/hr using the formula below. Shot weight is the total drop
   including cold runner (if any).
   
   BTU/lb x Shot Weight (oz.) x 225 = BTU/hr
   Cycle Time (sec)
   
2. Find BTU/hr along the X axis of the graph below. Locate the desired steel temperature along the Y axis of the graph. Find the spot where the X and Y values intersect.
   
3. The graphed line nearest this intersection point represents the difference in temperature between the incoming water and the Mold Temperature Regulator set point (ΔT).
   
4. The Smartflow Mold Temperature Regulator should work in your application if the sum of the incoming water temperature and the ΔT value is between 80° and 120°F.
   
   Every mold is different! The effectiveness of the Mold Temperature Regulator relies on the ability of the resin shot to heat the mold, and the efficiency of the cooling lines inside the mold.

NOTE: These graphs and information are intended as a general guide for sizing and initial setup of the mold temperature regulator. Due to the different mold designs, results may vary from the graphs.

Typical Heat Values of Plasticized Resin*

Material BTU/lb
ABS …………………………………………………………… 81
Acrylic ………………………………………………….. 109
Nylon …………………………………………………….. 183
Polycarbonate ……………………………………. 112
Polyethylene – High Density ……… 276
Polyethylene – Low Density ……… 202
Polypropylene ………………………………….. 291
Polystyrene …………………………………………. 88
SAN ………………………………………………………… 88

Example:
A molder is using nylon material in a four-cavity mold with a shot weight of .90 ounces (including the runner). The cycle time is 12.5 seconds with a mold steel temperature of 180°F. BTU/hr formula is as follows:

183 BTU/lb x .90 oz. x 225 = 2964.6 BTU/hr
12.5 sec

See the One Water Circuit Graph below left for the differential temperature (ΔT) value. Add 70°F incoming water temp. to
the ΔT value (20°F). This is the beginning set point for the mold temperature regulator, and may be adjusted as needed.

These graphs were generated by simulated molds, with BTU input varied by electric heaters. The water line path through each mold was 7∕16″ dia.