GlossaryKind of term: Manufacturing termSwiss-type turning
What is Swiss-type turning?
Swiss-type turning runs on a sliding-headstock lathe in which the bar is supported in a guide bushing close to the cutting edge.
On a Swiss-type lathe the headstock slides the bar lengthwise past tools that sit just in front of a guide bushing. The bar is supported close to the cutting edge, which lets long, slender parts be turned accurately: pins, shafts, contacts and small screws. A bar feeder loads the bars, live tools drill and mill in the same cycle, and a sub-spindle can finish the back end. The name refers to the principle's origin in the Swiss watch industry; it is also called a sliding-headstock lathe.
What decides what a Swiss-type lathe can do in one cycle?
With a guide bushing the result depends partly on the bar: the small clearance in the bushing calls for bar with a tight, even diameter, often ground or precision drawn. Many Swiss-type machines can also run without a guide bushing; the bar is then less critical and the remnant shorter, but the achievable length-to-diameter ratio of the part is lower. The number of tool positions, the live tooling and the sub-spindle decide which features can be made in one cycle.
How does Swiss-type turning work in practice?
Swiss-type turning is used mainly for batches. Setup can take a long time: many tool positions, the program and the guide bushing set to the bar size. How much it weighs per piece depends on batch size and on how your estimate spreads setup time. Material is costed differently: ground bar usually costs more than drawn bar, and the remnant with a guide bushing is longer than on a fixed-headstock lathe. For a small batch, or a short and thick part, a fixed-headstock lathe can be the better route. Swiss-type machines with a bar feeder often run unattended.
What is Swiss-type turning often confused with?
A Swiss-type lathe is not a CNC lathe with a bar feeder: on a fixed-headstock lathe the workpiece sticks out of the collet or chuck with no support near the cutting edge. Nor does Swiss describe where the machine was built; it names the sliding-headstock design.
How do you see Swiss-type turning in Blake?
You record a Swiss-type lathe in your machine park with its envelope, axes and hourly rate. Turned work sits in the estimate with material, setup and machining as separate lines, per piece and per batch, and the quantity breaks show how setup time carries through over larger quantities. More on turning.
Frequently asked questions
When does Swiss-type turning pay off over conventional turning?
Often on long, slender parts with a small diameter in larger quantities. Setup then weighs less per piece and the guide bushing keeps the part stable. On small batches, or short and thick parts, a fixed-headstock lathe is often the cheaper choice.
Why does a Swiss-type lathe often need ground bar?
Because the bar slides through the guide bushing with little clearance. A tight, even diameter keeps the part straight and the size stable. Without a guide bushing this is less critical. Ground bar usually costs more, and that belongs in the material price.