In addition to minimizing localized part heat-up, coolants prolong tool life. HOWEVER there are Dangers .....
Except for drilling and parting, coolants are not typically necessary for thermoplastic machining operations.
- Keeping the cutting area cool generally improves surface finish and tolerances.
- When coolants are required, water-soluble coolants generally do very well. They should, however, not be used when machining amorphous thermoplastics, such as PC 1000, RADEL ® PPSU 1000, ULTEM ® PEI 1000, PSU 1000 and SEMITRON® ESd 410C, because these materials are susceptible to environmental stress-cracking. The most suitable coolants for these materials are pure water or compressed air.
- When the use of water-soluble coolants or general purpose petroleum based cutting fluids cannot be avoided during the machining of amorphous thermoplastics (e.g. during drilling of large diameters and/or deep holes or during tapping operations), the parts should immediately after machining, be thoroughly cleaned with isopropyl alcohol first and rinsed with pure water afterwards in order to reduce the risk of stress-cracking.