One Circuit Cannot Hold a Die Even
Why zoning matters more than capacity
A die is not thermally uniform. The gate area runs hot from the metal flow, thin sections cool fast, and slides and cores sit on their own thermal island. A single cooling circuit averages all of this and produces a die that is neither hot enough at the gate nor cool enough at the extremities.
Separate circuits for fixed half, moving half, gate region, and each significant core allow the temperature field to be shaped. That is what controls the defects that get blamed on the alloy: cold shuts at the far end of flow, soldering near the gate, and shrinkage porosity where a thick section solidifies without feed.
Sizing is about heat removal rate, not tank volume
A TCU is sized by the heat it must remove per cycle, which comes from the metal mass, the superheat, and the cycle time. Oversizing wastes energy and can cool a die faster than the process wants; undersizing shows up as a die that never reaches steady state on a hot day. The useful number is the flow rate through the circuit and the temperature differential across it, not the nominal tank capacity.
Instrument the circuits. A TCU with logged inlet and outlet temperatures per zone turns a temperature argument into a comparison, and reveals a blocked circuit before it becomes a scrap batch. Coupled with die-spray practice, the temperature record is usually the fastest route to explaining a defect that appears at a particular hour of the shift.
FAQ
Why use multiple temperature control circuits on one die?
A die is not thermally uniform. Separate circuits for fixed half, moving half, gate and cores let you shape the temperature field instead of averaging it.
How is a TCU sized?
By heat to be removed per cycle — metal mass, superheat and cycle time — plus the required flow rate and temperature differential, not by tank volume.
What defects point to uneven die temperature?
Cold shuts at the end of flow, soldering or sticking near the gate, and shrinkage porosity in thick sections that solidify without feed.
Should TCU data be logged?
Yes. Logged inlet and outlet temperatures per zone make temperature comparable, expose a blocked circuit early, and shorten defect investigation.
All figures above refer to standard product data sheets; final confirmation is subject to written quotation.