How to Choose a Temperature Control Unit for Injection Molding

Mold temperature has a direct effect on cycle time, surface finish, warpage and dimensional stability. A temperature control unit (TCU) that is undersized, oversized or running the wrong medium will show up as a quality or throughput problem long before anyone thinks to check the TCU itself. A few practical points to check before selecting one.

Water or oil. Water units cover most standard plastics up to around 90°C. For processes that need higher mold temperatures — engineering plastics, high-gloss surface finishes, thin-wall parts that need to fill before freezing — an oil unit rated up to 150–160°C, or higher for specialty processes, is the right choice. Oil circuits also avoid the scale buildup that hard water can cause in a water circuit over time.

Heating and cooling capacity. Match the unit's heating power (kW) to how quickly the mold needs to reach process temperature after a cold start or color change, and match cooling capacity to how much heat the process actually rejects per cycle — larger, thicker parts and faster cycles reject more heat and need more cooling capacity, not just more heating power.

Pump capacity and pressure. The pump needs enough flow (l/min) and pressure (bar) to push coolant through long or narrow mold channels without excessive pressure drop, especially on molds with several parallel circuits.

Maintenance features that pay for themselves. Automatic mold drainage speeds up mold changes. A leak-stopper function lets the unit run in vacuum mode so a developing leak in the mold doesn't flood the shop floor. Digital flow monitoring flags a blocked channel before it causes a scrapped shot.

Perotec Systems supplies the Swiss Tool-Temp range of temperature control units — from compact single-circuit models to high-temperature oil units — and can help size the right unit for your mold and process. Contact us with your mold's cooling channel layout and target cycle time.