Our customer, a manufacturer of casting prototypes, operates 18 machine tools at its production site.

The production hall is not air-conditioned and in hot summer months there were an average of ten days of machine downtime. The reason for this was the high ambient temperatures in the hall, created by the machines themselves and their cooling systems, as well as the summer heat.

The tool spindles, motors and coolant systems of the machine tools were mainly cooled by cooling units with air-cooled condenser. During operation, these units dissipated enormous amounts of heat to the surrounding air. Attempts were made to rectify this situation by means of ventilation, which resulted in high temperature fluctuations, which

further impaired the accuracy of the machines. The required manufacturing tolerances could no longer be complied with and the machines had to be switched off.

The manufacturer presented this problem to us and asked the HYDAC experts for help.

The on-site analysis showed that the best solution for this temperature problem was to convert the machines to water-cooled cooling systems in order to increase the system availability in the long term and reduce the resulting costs.

The customer decided to convert 16 coolant systems to the HYDAC fluid cooling distributor WTRE and a further 6 machines to motor spindle cooling with HYDAC FWKS (fluid-water cooling systems).

The required cold-water supply with corresponding piping in the production hall was realised by an external partner.

The HYDAC fluid cooling distributor WTRE, which is used to cool the coolant systems, consists of a plate heat exchanger with closed-loop electronic control and a ball valve for closed-loop control of the amount of cold water. All of this is installed in a compact housing, which enables simple piping to the consumer and to the cold water supply.

An external pump conveys the coolant through the plate heat exchanger. A sensor detects the temperature, and the electronic controller evaluates the data and controls the amount of cold water via the control ball valve so that the coolant temperature can be kept at a constant fixed value regardless of the ambient temperature. Even consumer power fluctuations with higher return temperatures to the cooler or fluctuations in the cold water temperature are no longer a problem, as they are balanced out by the closed-loop control.

“The WTRE system is a simple and clever solution. The original cooling unit, which is also integrated into the system electronically, is retained and the cooling unit’s pump conveys the coolant through the WTRE. While this does not save any space, it reduces costs and noise levels, along with the amount of heat dissipation in the hall.”

In six machines, the spindle cooling was converted to the HYDAC fluid-water cooling system. The FWKS constitutes an intermediate circuit in between the cold water supply and the consumer. The tank contains water glycol, which is pumped to the consumer (in this case the spindles), where it absorbs the heat. In the return flow to the cooling system, it flows through the plate heat exchanger, where it is recooled by the plant’s own cold water, before flowing to the tank.

The intermediate circuit of the FWKS system has two major advantages:

1. The coolant for cooling the spindles has a consistently high quality and corrosion protection is guaranteed at all times.
2. The required pressure and the flow rate are guaranteed, even if the pressure of the cold water supply fluctuates or is generally too low.

“The FWKS cooling system that is used is a small, compact system with astonishing power. The system is a standard product, which enables rapid and straightforward implementation.”