Swiss Screw Machining
A Swiss screw machine is an automatic lathe that has a sliding headstock and a guide bushing. The sliding headstock contains a collet which clamps and holds the bar stock (typically 12-foot metal or plastic bars) and rotates it (usually between 1000-10,000 RPM based upon the diameter and type of material). The cutting tools move in and out of the material to create required diameters while the headstock moves the material forward to create required lengths.
Swiss machines create the features of the part by moving the material and the tool at the same time. This is in contrast to other types of screw machines, which often form part shapes by using tools premade with built in specific shapes.
The material is then fed through a guide bushing, which is usually made of carbide. The bushing is adjusted for the material to slide through it, but tight enough to keep the material from flexing away from the cutting tool. The guide bushing allows Swiss-type screw machines to create fine surface finishes and hold very tight tolerances (+/- .0001") over long lengths in relation to part diameter.
For example, a Swiss-type screw machine is necessary for turning a .100" diameter over a 3" length. The material would bend away from the cutting tool on a conventional lathe.
Originating in Switzerland in the late 1800’s to manufacture high-volume, precision parts for the Swiss watch industry, Swiss screw machining has evolved into a precision machining technology that produces critical parts and components for many industries and applications across the globe.
Over the years, these cam-driven machines were enhanced with various attachments that were integrated into the Swiss screw machine and allowed drilling, milling, boring, tapping, thread-whirling, knurling and other operations to be performed in conjunction with the primary turning operations, thereby allowing parts to be produced complete, or with a minimum of secondary operations.
Technological advancements and the continued “miniaturization” of products have led to increased demand for the small, thin, tight-tolerance components that Swiss screw machines excel at producing. That progression has made Swiss screw machining a key aspect of many technologically advanced industries.