• Patrick

Swiss Lathe CNC Machining




Swiss Lathes:

Swiss lathes are the “Swiss Army Knives” of turning. Originating from Switzerland's watch making industry the technology has since been applied to many industries. These machines are extremely versatile and offer advantages opposed to traditional lathes.


Turning, drilling, tapping and broaching can all be done internally. This versatility enables them to perform entire cycles, meaning full production of parts. Swiss machines excel at producing long length to diameter shafted parts; screws, threaded rod and axles. Micro Swiss machines produce micro parts smaller than a fingernail. At Anoesis | ​行深實業股份有限公司 we use Swiss lathes to create bicycle related parts like thru-axles, skewers and crankset shafts. Ø8-32mm stock on our Ge-Fong 326.


To say a Swiss machine produces parts faster than conventional tools would be technically incorrect. However, having two spindles it’s possible to work on two parts at a time. Also because of the support provided by the guide bushing it’s possible to take aggressive cuts as the deflection is minimal. These abilities combined with the reduction of separate machine setups leads to an overall lower cycle time. The benefit is lower priced parts due to a reduction in labor and setup costs.


Pros:

Produce High Tolerant Radial Cuts:

Radial cuts are performed close to the guide bushing reducing deflection leading to better held tolerances. ±0.001 are easily met while ±0.0002 is possible under specific conditions with certain machines.



Reduce Secondary Operations:

Swiss machines are widely used as they reduce secondary operations because of their Turning, drilling, tapping and broaching capabilities. On a basic lathe parts move between lathes for different operations or a mill for secondary operations on a different axis.


Work on Multiple Axii:

Cutting tools located on cross bars move on the X and Y axis. As Swiss machines can be equipped with many cross bars, the available axes increase. Increased crossbars allow for an assortment of tools; cutters, mills, taps, punches, saws, etc. It’s possible to purchase a lathe with a third spindle often called multi-spindle machines; the third spindle would allow cutting from almost any angle.



Example: a T style pipe, the main length would be produced on a lathe, then a mill would be used to drill and then tap at a 90* angle. On a Swiss machine the spindle would stop rotating and live tools on crossbars would drill and then tap the hole. Entire cycle of parts can be finished on one machine.


Two Spindles = Two Parts at a Time:

The sub spindle can move on the Z and Y axis, combined with a crossbar that moves on the X axis. Allowing you to perform drilling, tapping or broaching etc. operations on the rear of the part. The second spindle also delivers the finished part to the ejection belt



Work on Back Faces of Parts:

Swiss machines have a sub spindle which enables the rear face of the part to be machined.

Imagine you have an axle with holes with each side. You would need to remove the part, flip it, then re-chuck it on a lathe. On a swiss machine the sub-spindle receives the part then performs operations on the back face and rear portions of the part. The sub spindle can also be used as a live center for long parts.




Other Features:


Quick Machine setup:

Changing rod stock diameter requires changing of collets and guide bushings on the main spindle. The sub spindle also need a collet change. A collet is a round clamping part sized to a specific diameter of stock. Think of a drill chuck even better a small handheld router, they use a small collet to hold the cutting bits. The collet-chuck is tightened around the stock. The collet and rod stock are engaged and supported by the guide bushing. A few adjustments need to be made to the bar feeder pusher, tube and sensors. This process can be done well under an hour.


Live Tools:

The crossbars can also be equipped with live tooling. Live tooling means they are powered. These tools can independently drill or flat sides of the part while the part is not rotating. Allowing to perform operations that would require a moving to a mill.


Redundant Tooling:

In addition to having a large tool assortment is the ability to install redundant tooling. Redundant tooling meaning multiples of the same tool enabling “lights off” 24/7 manufacturing. If a tool breaks or passes it’s wear threshold the Swiss machine will use a backup tool.


Spindle Oscillation:

With the previous mention of 24/7 manufacturing, it's prudent to mention this feature. On some machines the spindles can change speeds and move forward and back to reduce the length of cut material (swarf) and reduce binding.


Things to think about:

Complexity:

Having access to multiple crossbars and two spindles magnifies the complexity of the machine. They can be programmed to do multiple operations at the same time. It’s difficult to follow along during the machining process as a lot is happening at a given time. It takes a high skilled operator to really use Swiss lathes at max efficiency.


Swapped +/-:

Swiss machines require a bit of retraining, the plus and minus movements are reversed.


Selective with materials:

Bar stock needs to be near perfectly straight as the whole length rotates. Bent material can damage the machine. Variance in stock diameter can potentially cause failure on tight tolerances. This is especially true for micro Swiss machines.



Not suited for large diameter parts:

Swiss machines are designed for smaller diameter parts. If you're looking to make parts over 38mm then a larger lathe should be used.


Length of the machine:

While this really doesn’t matter to a client, the physical length of swiss machine plus it’s feeder is quite long. We generally configure them parallel with Swiss machines at opposite ends. Think of two Ls that form a box.



Final Thoughts:

I hope I illustrated the versatility and benefits of Swiss lathes and why you should consider them for your next project. If you would like to discuss working with us or have suggestions or corrections contact me via email Patrick@anoesis.com.tw or drop a message in our website chat box.