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Calculating Heat Load in a Mold & GPM of Coolant
Shot Wt. 34 lbs.
Cycle Time 65 sec.
Resin Polypro
spec heat .87 Btu / (lb. F) See Chart
spec heat H2O 1.003 Btu / (lb/ F) @ 55 F
Ejected Part Temp. 120 F
Melt Temperature 440 F
Delta T 320 F
Temp. Rise in H2O 5 F (This is max allowable temp rise 2-3 F is suggested)
One Gallon H2O 8.33 lbs.
One Ton Chiller 12,000 Btu
Heat Load (Resin Thru put x Spec Heat (Resin) x Delta T = lbs. / Hr. of coolant required
(Spec. Heat (Coolant) x temp rise of coolant)
Lbs. / Hr. of coolant required =GPM of Coolant Required
(Coolant lbs. / gal. X 60 x Min / Hr)
3600 / 65 Sec. Cycle = 55.3 Shots per hr. x 34 lbs. Per Shot = 1,880 Lbs./ Hr.
1,880 Lbs. Hr. x .87 Btu x 320 F Delta T = 523,447 Btu / Hr.
523,477 Btu / (1.003 Spec Heat x 5 F ( Temp Rise )) = 104,382 Lbs. Of Coolant Per Hr.
104,382 Lbs. Hr. / (8.33 Lbs. Gallon x 60 Min. / Hr). = 208.84 Gallon Per Minute
523,477 Btu Hr. / 12,000 = 43.6 Tons of Chiller Capacity Required
Resin Spec. Heat
ABS 0.49
CAB 0.39
HIPS 0.501
LDPE 0.76
HDPE 0.87
PA 6, 6/6 0.731
PC 0.438
PET 0.502
POM 0.715
PP 0.64
GF PPS 0.497
PVC 0.383
SAN 0.471
Cycle Time 65 sec.
Resin Polypro
spec heat .87 Btu / (lb. F) See Chart
spec heat H2O 1.003 Btu / (lb/ F) @ 55 F
Ejected Part Temp. 120 F
Melt Temperature 440 F
Delta T 320 F
Temp. Rise in H2O 5 F (This is max allowable temp rise 2-3 F is suggested)
One Gallon H2O 8.33 lbs.
One Ton Chiller 12,000 Btu
Heat Load (Resin Thru put x Spec Heat (Resin) x Delta T = lbs. / Hr. of coolant required
(Spec. Heat (Coolant) x temp rise of coolant)
Lbs. / Hr. of coolant required =GPM of Coolant Required
(Coolant lbs. / gal. X 60 x Min / Hr)
3600 / 65 Sec. Cycle = 55.3 Shots per hr. x 34 lbs. Per Shot = 1,880 Lbs./ Hr.
1,880 Lbs. Hr. x .87 Btu x 320 F Delta T = 523,447 Btu / Hr.
523,477 Btu / (1.003 Spec Heat x 5 F ( Temp Rise )) = 104,382 Lbs. Of Coolant Per Hr.
104,382 Lbs. Hr. / (8.33 Lbs. Gallon x 60 Min. / Hr). = 208.84 Gallon Per Minute
523,477 Btu Hr. / 12,000 = 43.6 Tons of Chiller Capacity Required
Resin Spec. Heat
ABS 0.49
CAB 0.39
HIPS 0.501
LDPE 0.76
HDPE 0.87
PA 6, 6/6 0.731
PC 0.438
PET 0.502
POM 0.715
PP 0.64
GF PPS 0.497
PVC 0.383
SAN 0.471
Hello, I want ,can I use your help about plastic molding flow diagram details.
Dear Sir,
We have an injection molding machine, using polyethylene Terephthalate ( PET). The machine injection unit have heaters ( for screw ) needs water temperature of 20 degree Celsius. Also the machine needs 20 deg. Celsius for Hydraulic oil cooling. The machine has hot runner needs water temperature of 7 Degree Celsius.
The data on name plate shows that
For injection unit - 176 A is the largest heat load
For hot runner - 94 A is the largest heat load
Also the machine has dryer needs cooling power of 34 kw.
I calculated the heat load in a mold using your equations. But I would like to know how to select chiller by considering the heat load for injection unit, hot runner and dryer. Also is there any consideration for atmospheric temperature?
We have an injection molding machine, using polyethylene Terephthalate ( PET). The machine injection unit have heaters ( for screw ) needs water temperature of 20 degree Celsius. Also the machine needs 20 deg. Celsius for Hydraulic oil cooling. The machine has hot runner needs water temperature of 7 Degree Celsius.
The data on name plate shows that
For injection unit - 176 A is the largest heat load
For hot runner - 94 A is the largest heat load
Also the machine has dryer needs cooling power of 34 kw.
I calculated the heat load in a mold using your equations. But I would like to know how to select chiller by considering the heat load for injection unit, hot runner and dryer. Also is there any consideration for atmospheric temperature?
Hi George
Im also looking the same ... Let me know if you find the answer for this
Im also looking the same ... Let me know if you find the answer for this
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