Styles of Automatic Screw Machines

automatic screw machineDon’t be fooled by the name, automatic screw machines – or the less formal ‘screw machine’ – are essentially lathes used to machine parts for industry or sale.? Automatic screw machines don’t screw things in (as a drill or screwdriver would), and while they are capable of threading material, that is not their sole function.

A screw machine is essentially a lathe which rotates a piece of material (i.e., wood, clay, metal) on an axis to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, or turning.

Automatic screw machines fall into two categories – Swiss and Turret – and while they function differently, their output and benefits are more-or-less identical.

Swiss Screw Machines

Swiss screw machines are further subdivided into automatic and computer numerical control (CNC).? Both operate on a similar principle but the CNC machine – as its name indicates – is controlled by a computer.? This computer control allows for a high RPM (10,000) and accuracy level (0.0002 to 0.0005 inches).

?Turret Screw Machines

swiss automatic screw machineThe turret-type screw machine orients the material on a vertical ram which then moves into the tool.? Turret-type screw machines produce results nearly identical to the Swiss-style machine.? The main difference between the two types is precision:? the Swiss-style machine is capable of a higher rate of accuracy.

While screw machines (Swiss or Turret) come equipped with a single spindle, double spindle machines (even quadruple spindle or more) are increasingly popular as they allow for increased output.? Using robotic integration, both Swiss-style and turret-style screw machines are capable of automatically transferring a part from one machine to another.

Swiss-style machines are becoming increasingly popular these days with both automatic and CNC screw machines being widely used in the IT, automotive, and consumer electronics industry.

Originally developed for high-quality, designer Swiss watch production, the automatic Swiss-style machines are prized for their accuracy and delicacy.? CNC Swiss-style screw machines are sought after for their quick production times, low variable costs, and largely un-supervised production methods.

Swiss-style machines of both types can handle exotic and common metals of varying strengths and composition making them widely applicable and integral in many different industries.

History Of The Automatic Screw Machine

The Evolution of Automatic Screw Machines

Fully automatic, high-speed lathes are commonly known as automatic screw machines. It could even be considered a highly developed type of turret lathe due to the fact that the cutting tools are carried in a turret of some form. They operate on a vertical or horizontal axis, depending on the machine tool style.

The machine tool itself is automatic in that it uses the cutting tools to automatically cut into the turning stock to form any quantity of duplicate parts. The machine operates mechanically, but the operator can set the machine up to form parts either by using mechanical controls or CNC controls depending on the style of machine. CNC stands for computer numerical controls

Automatic Screw Machine History

The first automatic screw machine was patented in 1865 by Brown & Sharpe and then by Christopher Spencer in 1873. The idea was taken from the turret lathe and was created as a way to produce small turned parts more efficiently.

The idea was to create a turning machine that could make the exact same turned part automatically and repetitively. It was called the screw machine because its intended use was to create screws and pins.

The first automatic screw machine had a single spindle; multiple spindle models were introduced in the later 1800’s. The multi-spindle machines were not widely used until the coming of World War I, since manufacturing efficiency became extremely important.

The design feature, predominate to the use of the turret, and making the automatic screw machine truly automatic is the use of drum cams. Drum cams are fixed upon a series of removable cam components. These are compatible with the size of the workpiece and parts to be formed. The cams allow the automatic movements of the different operative machining tools to be performed. It is the action of these cams that give this machine tool its automatic classification.?

This particular machine tool was initially designed to make screws, pins, and other small parts from bar stock, which was passed through the hollow spindle from the rear of the machine. When the chuck opened up large enough for the bar stock to be fed through it was pushed forward until it hit a stop located in one of the turret’s tool holes.

The bar feeding device was operated automatically by weight, and was called a wire feed because screws were once made from portions of straightened wire. This same machine tool is now capable of feeding rather large bars of stock, much larger than thought possible in the early years of machine development.

The Modern Automatic Screw Machine

Many modern automatic screw machines are equipped with multiple spindles and are capable of operations such as index drilling, screw slotting, threading, counter boring and more. They are also capable of operating by more than purely mechanical means; modern machines utilize hydraulic, electric, or CNC. Again, CNC stands for computer numerical controls.

Additional Automatic Screw Machine capabilities include:

  • Automatic loading of the workpiece
  • Automatic ?starting of the machine and coolant
  • Automatic changing of the tools, speeds and feed rate
  • Automatic inspection and measurement of the part
  • Automatic? unloading of the finished part
  • Automatic operation restart

Some screw machines can be equipped with a hopper or magazine in which metal parts can be fed. When they pass into the chuck, they will be gripped and machined according to operator specifications. This machine tool process is completely automated, meaning that the only thing required of the operator is to ensure that the hopper stays full and that tools stay sharp.