The use of a guide bushing is the key difference between a Swiss turning center and a conventional lathe. The support to the workpiece provided by the guide bushing allows a Swiss lathe to maintain a high level of precision in the cutting process from start to finish. The workpiece is held so close to the tool that there is essentially zero deflection from cutting force.
If a shop is running high volume parts and needs the ability to run lights out, then a Swiss type-lathe is totally worth it. Swiss lathes are great for large quantity batches and family groups of parts. Changeover on a Swiss lathe is minimal, especially when running a family group of similar style parts together. With the exception of changing out collets, an operator can load a new program and start cutting in typically a few hours at the most. A family of parts means that if a lathe is running a particular part, and a new part comes along that is similar to the existing part, it is easier to set up because the parts are similar enough that the machine is already tooled-up to be able to switch from one part to another with minimal downtime for setup.
Another added benefit of Swiss machining are components that are reliably turned to meet high accuracy specifications. Cutting these on a Swiss, as opposed to a conventional lathe, reduces costs related to returned parts, such as shipment and restocking expenses as well as delayed lead time and retooling costs.
The main purpose of Servo Learning Oscillation is to eliminate long stringy chips from gathering around the part and cutting tool during the machining process. By constantly changing frequencies through the X, Y, and Z axes combined with interrupting cutting on the part, the chips will break away clean allowing for continual flawless cutting. Chips tend to pile up around the part or the tool, which can either destroy the cutting tool or scratch the outside finish of the part, all of which are undesirable. Applying this feature during the cutting process is how the phrase “Breaking the Chip” was born. The Servo Learning Oscillation feature on Nexturn Swiss CNC lathes is best used on materials such as aluminum or stainless steel.
This all depends upon the coolant or oil that is being used in the machine during the cutting process. If a shop is using oil, most companies will segregate chips by the material type, i.e., stainless with stainless. Some places will spin their chips to get all the oil off of them before they recycle. If plastic is being machined, then often the plastic can be melted down again.
Segregating chips by type and oils/coolants is a process. In order to recycle properly, these shops must have the room to keep chips separated. Water soluble chips cannot be mixed with oily chips. If you are running 12L14 steel and the next job is stainless, in order to properly recycle the chips, an operator would have to clean out the machine, remove the chip bucket or drum containing the steel chips and put a new one under the chip conveyor for the stainless chips that are being made on the next job. All these factors have to be considered when a company implements a proper and responsible recycling program.
Another significant attribute for the metal cutting industry has been the design of CNC Swiss machines that can accommodate 20 or more tools in the tool zone, many with live tooling. This array of tools combined with a sub-spindle and backworking stations can virtually eliminate the need for secondary operations on complex parts — allowing Swiss machines to often produce finished, ready-to-ship components.
Yes, Swiss lathes should be automated by using a bar feeder. Efficiency and throughput with be increased dramatically by automatically feeding 12’ long bar into a Swiss lathe. This also makes it important to plan for families of parts. Less time is wasted changing to different bar sizes if the same bar size can be used for multiple applications.