Tubular Heaters Keeping Machined Parts Within Tolerances


A machine shop was involved in machining parts to very critical tolerances. The ambient temperature of the machine shop was not closely maintained. The customer was having a problem holding tolerances due to:

  • The varying temperatures of the parts being machined
  • The expansion of the parts from the heat produced during the machining operation.


Prior to Watlow's involvement, the cutting fluid was not heated. This was the cause of their problems.

By heating the cutting fluid and controlling its temperature, the expansion/contraction problem of the parts being machined and minimized.

The heater chosen was a stock tubular element formed in a special configuration with bulkheads. The heater had the required wattage, yet held permissible watt density to 23 W/in2 (3.5 W/cm2) and still fit within the container used to store the cutting fluid. A stock element was chosen to allow a fast delivery schedule.

Finally, a temperature controller regulated the heaters and held the cutting fluid temperature at a pre-determined point. This reduced the scrap rate to acceptable levels.