Serie TEMP 90°C — Water Temperature Control Unit

TEMP 90 °C Series — Water Mold Temperature Control Unit

A water-based series working up to 90 °C; it is the most widely used temperature band in plastic injection molding. It is used in open or closed tank designs, in single-circuit and multi-circuit installations.

Which materials this band suits

90 °C covers the large majority of standard thermoplastics: PP, PE, PS, ABS, SAN and most unfilled engineering plastics are processed in this range. If the mold temperature given by the material manufacturer is below 90 °C, this series is enough; if it is above, it is necessary to move to pressurized water systems.

The effect of mold temperature should not be underestimated: on the same material, working at 30 °C rather than 60 °C changes the cooling time noticeably and directly affects the internal stress, the warpage and the surface quality of the part. The subject is covered with calculations in the cycle time guide.

Why 90 °C is a limit

Water boils at 100 °C at atmospheric pressure. Boiling means vapor bubbles forming in the circuit and the heat transfer breaking down. For that reason open systems stay in the 90 °C band as a safe working limit; anything higher requires the circuit to be kept under pressure.

Number of circuits and distribution

If a mold has more than one cooling circuit, all of them have to be fed at the same temperature and at a sufficient flow rate. A temperature difference between the mold halves is the most common cause of warpage — the part always bends towards the cold side.

Multi-circuit distributors make it possible to monitor and balance several circuits separately from a single unit. How many independent circuits your mold has is as decisive in the selection of the unit as the pump flow rate.

Maintenance on the water side

In water systems what determines the service life is the water quality. Scale silently lowers the heat transfer within the circuit; the unit keeps working, but the mold reaches the target temperature later and the cycle time lengthens without anyone noticing. The symptom is usually looked for in the mold or the machine.

Items for periodic checking: the hardness of the circuit water, the condition of the filter, a comparison of the pump flow rate with its value on the first day, and the tightness of the hose connections.

The WDC version

This series also includes direct cooling (WDC) models; the cooling water is taken into the circuit directly rather than through a heat exchanger. The response time gets shorter, but in return the sensitivity to water quality increases.

Brand and technology

The shared features of Rummel temperature control units — self-optimizing PID control, a 7 inch touch screen, communication with the injection molding machine over OPC-UA / Profinet / Modbus, and the multi-circuit distributor option — are explained in detail on the mold temperature control range page.

For a higher temperature you can look at the 140 °C and 160 °C pressurized water series.