Page 52 - Plastics News Issue December 2024

TECHNOLOGY NEWS

3 Ideas To Optimize Your

Costs in Injection Molding

part cost in injection molding. A detailed analy-
sis of three aspects may give you a competitive
cost advantage.

Make Cooling a Priority

Between 50% and 70% of injection molding time
is spent cooling. So prioritize keeping your mold
channels up and running at the top of their ca-
pacity. Besides reducing cooling temperature,
ensuring that the water running is kept within a
turbulent flow regime is crucial.

ontrolling cooling, energy consumption, Installing equipment to measure flow and keep-
and downtime can help you reduce your ing flowmeters clean and unobstructed will lead
Ccost per part using the resources you al- to more reliable measurements. In Table 1, the
ready have in your shop. recommended water flow ensures a turbulent
flow above a Reynolds number of 4000, de-
High-quality production is a shared priority for pending on the cooling channel diameter and
all molders. However, But an opportunity to dif-
ferentiate is to control parameters determining water temperature.

Minimum Flow by Temperature

Nominal Pipe Size (in) (GPM)
40 F 120 F 200 F
o
o
o
0.250 0.88 0.31 0.18
0.375 1.16 0.42 0.24
0.500 1.41 0.51 0.29

Also, make sure you avoid scaling. Water serves of service and keep a record, to account for the
as a cheap and abundant medium for heat trans- need for more drastic cleaning of the mold chan-
fer, but its mineral content tends to deposit on nels.
cooling channel surfaces. This problem is great-
er with open cooling systems, such as cooling Reduce Energy Consumption
towers. Energy comes into the injection molding system
in the form of heat. Heat is brought into the sys-
To avoid scaling, use a pump to circulate chemi-
cal descaling agents through the cooling sys- tem by friction (around 65% is generated by ef-
tems. Also, measure flow as the mold goes out fect of rotation and back pressure) and electric
resistances (around 35%).

52 PLASTICS NEWS December 2024