It used to be so simple; round components were produced on a lathe and non-round parts on a mill. That was the case up until the introduction of the now-ubiquitous three-axis CNC machine tools as this brought in the opportunity to produce interpolated round features normally made on a lathe. With the addition of live tooling to CNC lathes, the boundaries have become a more complex as features normally the preserve of CNC mills have been introduced into the turning equation. With this potential for crossover between the two technologies, opportunities have opened up for designers and engineers to reap the advantages that the advanced production method bring.
Whereas many components with cylindrical features can be produced on a CNC mill from square or rectangular stock, there can be additional time spent removing unwanted corners. This not only wastes raw materials, but also consumes valuable machine time and ultimately has an effect on the cost of the component. Coupled with the fact that it’s hard to reach a good surface finish using milling cutters on round components, turning on a CNC lathe becomes even more attractive.
Take the same component onto a CNC lathe equipped with live tooling and designs with cylindrical forms can be quickly turned while accommodating additional features such as perpendicular axial and radial holes, flats, grooves and slots without the need to remove the work piece and transfer to a mill. Furthermore, surface finish is no longer an issue as CNC lathes are much better at generating the required cylindrical surfaces, so both the roundness and finish are much improved.
Due to the size of components and limits on the respective machine tool capacities, there will always be cases where a piece best suited for lathe will need to be produced on a mill and vice versa. For example, longer length-to-diameter pieces lend themselves to production on a CNC lathe.
Typically, CNC lathes equipped with live tooling can work to tolerances of +/-0.10mm in the following dimensions:
- Diameters ranging from 0.8mm to 75mm
- Lengths between 1.5mm and 228mm
- Wall thicknesses down to 0.5mm