The use of coolant and lubrication has a large impact on process security in parting and grooving. If applied correctly, it reduces temperature at the cutting zone and improves chip evacuation.
Internal versus external coolant
When external coolant is applied in parting and grooving, the amount of coolant that actually gets into the groove, especially with deep grooves, is very small. Therefore the coolant effect is minor. With internal coolant delivered with precision, the coolant jets access the cutting edge even in deep grooves.
Advantages with precision coolant
- Higher cutting data or the ability to use a tougher carbide grade
- Improved chip control and surface finish
- Longer tool life
Over or under coolant? Or both?
Depending on machining conditions you can choose to apply tools with internal over or under coolant. Sometimes you just need one, but you get the best effect by using both at the same time.
The effects of over coolant
Over coolant improves chip control, which is the key to long tool life and few machine stoppages. Coolant from above and can also reduce edge build-up.
The effects of under coolant
Under coolant reduces temperature and at the same time flank wear. It also improves chip evacuation. Reduced temperature allows for the use of softer insert grades with potentially improved tool life and cutting data. When used in combination with tougher insert grades it results in a more predictable and secure machining process. Under coolant is beneficial in long cuts where temperature often is a limiting factor.