Contrary to popular belief, a lathe used for CNC Swiss turning is not necessarily made in Switzerland. It is a turning center that was developed for the watch industry in Switzerland where the turning of small, complex and precision parts was needed. On a Swiss-type turning machine, a four-inch long part with a diameter of 0.059 inches and a roundness of 0.0002 inches can be achieved.
How It Works
Unlike conventional lathes where the part is stationary and the tool moves, in CNC Swiss turning the part moves through a guide bushing along the Z-axis and the tool is stationary. The outer diameter turning tool can then always cut the part near the bushing that is near the point of support, regardless of the length of the work piece. The part is fed out of the machine and past the tool. This makes a Swiss-type CNC lather particularly suitable for turned parts that are long and slender.
A Difference in Approach
Using cnc swiss turning requires a different approach on the part of machinists and programmers to adapt their way of thinking about the machining cycle.
First, the motion of the Z-axis comes from moving the part instead of the tool. This is important when it comes to offsets with regards to the Z-axis. Drilling a pass deeper or making a longer turn would be an offset of a negative nature on a conventional lathe, but would be a positive one on a Swiss CNC lathe.
A Swiss CNC lathe also requires a change in the order of cuts. On a conventional lathe, it is typical to rough turn & finish turn the work, and machine features such as outer diameter grooves or threads to complete the part. With a Swiss CNC lathe, the part needs to be segmented so that the work is done in sections of smaller sizes.
Most Swiss CNC lathes use oil as the cutting fluid rather than water that reduces friction and wear. Advantages of using oil mean less odor from bacteria and hands that become less dried out from being exposed to water-based coolant all day. However, oil is less effective at dissipating heat so a Swiss CNC lathe can quickly become hot inside the work area.
Often CNC Swiss-type machines can deliver many cost savings over conventional CNC machines.
