Swiss screw machines
Swiss technology was invented to produce tiny parts for Swiss watches and now is combined with the power of CNC for automated production with the same precision. Many machined parts can be made on CNC turning centers as well as Swiss lathes, so this can help you decide the best kind of machine for the job.
How is CNC Swiss machining different from CNC turning?
CNC Swiss differs from traditional lathes and turning centers because of the way that the tool meets the stock. In a CNC turning center, tools are arranged on round turret with tooling slots. The bar stock is fed through a bar feeder and the turret is programmed to rotate and articulate on the X, Y & Z-axis to meet the bar stock to cut the material. Certain CNC turning centers have more than one spindle. In a dual spindle CNC turning center, the part is fed from the originated spindle to the secondary spindle where the other side of the part can have additional machining performed. The turrets on dual-spindle CNC turning centers have tool slots on both sides of the turret and can make more complex parts than those with a single spindle. The bar sizes that can be fed into a CNC turning center can be a lot larger than for Swiss CNC lathes. Bar feeders on CNC turning centers feed the bar but do not articulate it to the tool. The tool (on the turret) is programmed to move to the bar.
Swiss Lathes Make Smaller Parts from Bar Stock
CNC Swiss lathes typically make parts under 2 in outer diameter. They operate by moving a fixed tooling jig to the bar stock. These tools cut very close to the spindle makes tool changes very quick. The key difference between CNC Swiss and CNC turning centers is how the bar feeder and spindle work together to produce parts. The spindle on a Swiss CNC lathe controls the bar movement against a stationary tool on the tooling jig. The bar does the moving instead of the tool. All of the cutting is done right next to the collet. This differs from a CNC turning center where the cutting occurs as the tool moves to the bar.
CNC Swiss Lathes are Great for Long Parts
If you are making a cylindrical part that is OD by 6 long with some features like threads and slots, it could be made on either a CNC turning center or a Swiss lathe. However, on the CNC turning center, the tool would move along the length of the part which can introduce some slop in the cutting towards the end of the part. But in a CNC Swiss lathe, the cutting would always be near the collet, so the part would stay round and within the same tolerance range at the front of the part as the end of the part. This makes Swiss lathes great for any parts that need to be precise (+/-.001 is feasible) and long as compared to the outer diameter.
CNC Swiss Lathes are Great for Production Quantities
Swiss Lathes are great for high production work. When combined with a bar feeder, they are designed to run lights-out and produce parts unattended. With proper programming and operator input, they can make precise parts to specification with a high level of repeatability, often with cycle times under a minute. Many Swiss have a sub-spindle that allows live tooling work to be done on the back side of one part simultaneous to the front size of another part essentially cutting in half the cycle time.