How Swiss Screw Machines Work

Screw machines are automated lathes which can machine turned parts.  The machine components spin very quickly on a rotating lathe, which shaves down metal to the size desired.  There are two types of screw machines: Turret and Swiss machine.  The Turret, also known as. Brown & Sharpe after its first manufacturer, mounts the workpiece on a vertical ram which works into the lathe.  The Swiss type, named after its place of origin and used by watchmakers for precision components, mounts the workpiece on a rotary slide. 

There are two main types of Swiss Screw Machines: automatic and CNC.  The automatic screw machine functions with a disc cam, which helps rotate the tools to the work piece bay.  A collet holds the workpiece in place, the disc cams move the tools in a radial motion and alter headstock positioning in order to account for any longitudinal discrepancies with the workpiece.  The automatic Swiss Screw Machine features very close spindle collets, which prevent much deflected debris from getting into the way. 

CNC Swiss Screw Machines, otherwise known as CNC turning machines or lathes, operate largely on the same principle as an automatic Swiss Screw machine, except that the operation is controlled by a CNC unit.  These turning machines can feature more sets of tooling, allowing for the machine to perform several operations on the same piece in a shorter amount of time due to the increased direction provided by the CNC.  Automatic Swiss Screw Machines can also perform several operations at once but it lacks the precision and swiftness of a CNC Machine.  A CNC Swiss Screw Machine can rotate a part at up to 10,000 RPM at an accuracy level of 0.0002 to 0.0005 inches.

The CNC Swiss Screw Machine and the automatic screw machine are cost-efficient for longer projects because once they are properly tooled and program-oriented, many machines can run under the supervision of one operator.  Preparation time can be up to an hour so shorter projects’ fixed costs might balance out for another tooling process but Swiss Screw Machines are able to do more precision work due to the tight collet, work-piece and tooling. 

Turret-type screw machines produce very similar results to Swiss Style Machines but the CNC Swiss Screw Machine can have more tooling fixtures applied leading to the possibility of a double spindle machine.  This feature cuts down on time and an operator since the part is automatically transferred from the screw machine to another machine for secondary operations.  Turret-style machines come equipped with a transfer attachment that can also perform this function. 

Both types of Swiss Style Screw Machines are found in the automotive, IT and consumer electronics industries.  Swiss Screw Machines were originally developed for Swiss watch production due to their accuracy and delicacy.  Since these machines have quick production times and low variable costs, Swiss Screw Machines can produce a large number of small, precision parts relatively quickly at low cost.  These machines can handle both exotic and common metals of varying strengths and composition they are widely applicable in many different industries. 

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