WHAT IS A SWISS-TYPE SCREW MACHINE?

A Swiss-type screw machine is an automatic lathe that has a sliding headstock and a guide bushing. The sliding headstock is the part of the machine that holds the bar stock (usually 12 foot metal or plastic bars) and rotates it at a specified RPM depending upon the diameter and type of material to be cut. The cutting tools move in and out of the material to create the required diameters while the headstock moves the material forward or back to create the required lengths. Unlike many other types of screw machines, Swiss-type machines generate the features of the part by moving the material and the tool at the same time.

The headstock contains the collet which clamps the material. The material is then fed through a guide bushing which is usually made of carbide. The bushing is adjusted so that the material can 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 hold very tight tolerances over long lengths in relation to part diamenter. On a conventional lathe, longer parts tend to bend away from the cutting tool.

Swiss-type screw machines were originally developed in Switzerland to make watch parts. This was done to remain competitive by producing precision parts in high volume. Older machines were cam operated, so each different part required a new set of cams and a new set-up. Newer Swiss-type machines are computer numerically controlled (CNC). With CNC a change to a different part can often be done with the push of a few buttons. CNC machines are generally equipped with automatic bar loaders that feed new material, remove remnants and allow long periods of operator free run time.