Swiss Machining: Six Things You Need to Know with Experts from Swistek
Swistek is a Swiss-style machine tool builder that serves the aerospace, medical, defense, automotive, and many commercial industries, and its employees are well-versed in all things Swiss machining. We sat down with experts John Schuld, Founder and President of Swistek Machinery America, and Greg Kaday, Applications Manager at Swistek, to find out just how important Swiss machining is becoming.
What is Swiss machining?
Swiss machining is a type of machining that was developed in Switzerland in the 1800s. It started out in the watch-making industry. Lots of tiny screws, pins, and other small pieces for the watch industry required a different type of machining. Generally speaking, conventional lathes hold the part in a fixed headstock while the tools move to it. In a Swiss machine, the part is held by a collet in the main spindle that moves back and forth. The bar stock is fed through a guide bushing. The tools are cutting right at the bushing so that there is no deflection of the bar stock from cutting forces. Today, many Swiss-type CNC lathes can also run without the guide bushing for making shorter parts. By removing the guide bushing housing, it reduces the length of your bar remnant and helps to make rounder, more concentric parts.
The cutting tools can be 20 to 80 thousandths (0.020”–0.080”) away from the headstock, so the bar is held by a collet and when feeding the bar stock into the tools it is supported by the guide bushing very close to the cutting edge of the tool for turning long slender parts. This support also helps with deeper depths of cut. On our machines, you could take a deep depth of cut and feed it in one continuous feed, up to nearly 12 inches in length without having to support the end of the bar.
What is the value of Swiss machining?
The value of Swiss machining, as opposed to conventional machining, is that you can finish most parts complete. This is because of the amount of tooling options, live spindle attachments, and the ability to use the sub-spindle to independently finish the back side of parts. This also creates the added benefit of a faster cycle time than conventional CNC lathes due to the tools being closer together, which allows for faster index times. Notoriously, the industry has depended on doing things the “set” way. You would blank the part on a lathe or screw machine and finish it in one or multiple secondary operations. What Swiss does is eliminate those secondary operations by making the part complete out of 12-foot bar stock.
When there are fewer operations on a part, there is a smaller chance of making scrap due to improper handling of that part and making scrap does happen frequently in many shops that do secondary operations. Scrap can add up quickly. In some cases, we have seen as much as 20–30 percent scrap fallout because of work holding in multiple secondary operations.
What are the applications of Swiss machining?
If you look at most of the parts coming off Swiss machines, you’ll see that they’re long and skinny. You just couldn’t make that with a conventional style lathe, because of the deflection issue. The tools would be too far away. When the tools are only one to two millimeters away from the headstock, there is minimal, if any deflection. It is best to use a Swiss when you need to make parts whose length is greater than three times its diameter.
The applications are anything from bone screws to electronic connectors to hydraulic valves. We regularly work with parts for the defense, medical, aerospace, and automotive industries, just to name a few. Really almost every industry has parts being made on Swiss-type CNCs.
When should a shop consider expanding into Swiss machining?
Typically, if their parts have multiple operations, tighter tolerances, and the volumes increase from hundreds to thousands on multiple parts, I recommend looking into the possibility of making them on a Swiss. It’s a matter of return on investment at that point—trying to minimize cycle times and maximize part profits. There are many high-production shops out there that are blanking parts on CNC lathes and screw machines and have to do multiple secondary operations. Many of those jobs just can’t compete on quality and finished cycle times. When you have to handle a part even once or twice more than your competitor, you could possibly lose that job. With Swiss CNCs, you put 12-foot bar stock in and a finished part comes out.
What does a shop need to do to expand into Swiss machining?
We’ll talk to them about what parts they are currently making and any problems they may have, to learn if a Swiss-type CNC machine would fit their needs. Once we figure out if they are a good candidate for a Swiss, we then go over all the requirements of their parts (minimum/maximum diameters, design features) to determine the best size and model that will fit their needs. We also discuss programming and set-up experience to figure out how much time would be needed for training. Typically, after a shop purchases a machine, they want a CAM system to go along with these machines, and we always recommend Mastercam.
How can Mastercam help Swiss machine shops?
Mastercam is particularly helpful for Swiss shops because it takes all of the guesswork out of programming difficult turning/milling applications. Hours and days of programming and troubleshooting are cut down to a fraction of the time with Mastercam. What’s more, Mastercam is staffed with experts who have decades of machining and manufacturing experience, so if we do run into a problem on the programming end, there is a whole group of people able to help us who know exactly what we’re trying to do when they see a part drawing.
Mastercam is a key part in helping us turn customer drawings into actual working programs that cut chips and drop perfect parts.