The multiple processing is a technical method, which is used at CNC- machining centres to increase economic efficiency, in particular when using small workpieces. Since the mid 1990s most of the machines that are used in the woodworking industry include this function.

Problems when one single workpiece is processed:

• Machine stops when placing new workpieces or when removing finished workpieces.
• While the processing of the workpieces the presence of an operator is not necessary.But normally there is not enough time to let the operator do other work.
• When using small workpieces, most parts of the machine table stay unused.

Solution through multiple processing :

At one part of the table the workpiece is being processed, while on another part a new workpiece can be placed, or finished workpieces can be removed.

In principle, this is possible without special features, simply by writing a program for several workpieces. This is not realised for several years now, due to a lack in flexibility and new security regulations.

Nowadays a machine with multiple processing is characterised by the following features:

• Every working sphere that can be freely equipped has its own workpiece reference point. As a result of this, one program can be attributed to one working sphere. In the simplest case, one workpiece reference point is one the left side of the machine, the other one is on the right side of the machine. Four fields can be provided in x-direction at long machines.

At very large machines or when processing small workpieces, the machine table can also be divided in y-direction, so that eight workpiece reference points can be used.

• For safety reasons it must be prevented that movable machine parts collide with the operator. Safety devices must ensure, that the operator (while placing new workpieces or removing finished ones) not gets into contact with the aggregates support.
• Bumper: A bumper is the ideal safety device in relation to multiple processing. Theoretically one can work with flexible field sizes, as safety is ensured in any case.
• Shut-off mat/light barrier: As the aggregate support has a certain width, a corresponding area in the middle must be active permanently, so that the operator is restricted in freedom of movement.

A special form of multiple processing is the mechanical division of the machine table. Usually this is used with fix gantry, moving tables. (Here y-axis are realised through the movement of the machine table.) By use of 2 tables, workspaces are completely separated. it is then possible to abstain from safety distance, even when using shut-off mats or light barriers.

Alternative keyword: alternating processing