In-depth analysis and tips created to provide you with the most beneficial information possible
The Benefits of Swiss-type CNC Lathes
Written by Chuck Austerberry
Published on September 1st, 2023
Why Swiss?
In one word: VERSITILITY
Swiss type machining, with sliding headstocks and guide bushings, has been around for over 100 years. Its roots date back to the Swiss watch-making industry, hence the term Swiss machine.
It excels at small parts and long turn-to-diameter ratios, but it can also do larger, shorter parts. You will be able to quote almost any part print you receive, regardless of shape, as long as it fits in the diameter of material your Swiss machine can handle.
Examples of parts made on a Swiss-type CNC lathe
How Large of a Part Can I Make?
As long as your bar stock length is, minus about 6-7 inches for the remnant of the bar.
In a Citizen Swiss-type CNC lathe, you are able to take the diameter of the bar you are machining and feed that same size as it comes out of the machine.
Do I Need Ground Stock?
No, you just need good quality stock. It needs to be round, it needs to be a consistent diameter, and it needs to be straight, that’s it.
70-80% of Swiss machining shops don’t regularly run ground stock.
Just because a bar is ground, it does NOT make it better. If bar stock is not ground by a shop that knows exactly what they’re doing, it will be very inconsistent, out of round, and will not run well.
There is a saying that goes “The best cold-drawn stock is better than the worst centerless ground stock.”
The cold-drawn process will produce a consistently round diameter within a given lot. Users should always check bar stock size. Lot-to-lot, bar stock size can vary within the steel supplier’s tolerance.
YES, bar stock suppliers have a tolerance that they must hold JUST LIKE YOU. The smaller the diameter of the bar stock, the tighter the tolerance requirement.
Dirty little secret: they don’t want you to check it! The supplier must take the bar stock back if it is out of tolerance, and they will.
Do I Need to Use Cutting Oil?
Swiss machines perform well with oil for two reasons:
1. The guide bushing has a better performance with oil as opposed to coolant
2. Since we take the whole cut in one shot, the machining process needs lubricity more than it needs cooling.
Today’s Citizen machines have sealed bearings, as well as lubrication to all parts of the slide and ball screw, so contamination and degradation within the machine is no longer an issue and customers are free to run water-based coolant if they still prefer this option.
However, oil is still recommended for the reasons stated above, the use of cutting oil also helps with the resale value of the machine.
Are Swiss Machines Only for High-Quantity Projects?
While Swiss machines are classified as screw machines, they have also found a role in the low-volume and prototype machining world.
With the ability to do secondary operations on the machine, parts can be prototyped faster which means the product can be brought to production in less time.
When parts require multiple set-ups to prototype, the production method may still be undecided. With Swiss machines, limited and even full production can be realized until the official production method is decided.
What Should I Do Right Now?
In the coming weeks, we will be educating you on the benefits that Citizen Swiss machines can bring your company.
In the meantime, if you have a part that you’re unsure of the best process on, let Dynamic Machine know and we will more than happy to process the part and complete a time study for you.
