45. Laser interferometer

The tolerances guaranteed for GEISS machines are adapted to the ISO basic tolerance to DIN 7151 and thus depend on travel and machine size.

The tolerances we specify distinguish between 3- and 5-axes processing and machines with and without laser measuring. Sweeping tolerance statements such as "this machine has a tolerance of +/- 0.05 mm" are not serious.

Every CNC machine after construction has certain errors and deviations from the ideal geometry. Such errors are for example the spindle lead errors in ball screws, pitch errors of drive gear and transmission errors of gearboxes. Furthermore, all axes have slight deviations from shape. These errors indeed do not restrict the repetitive accuracy of the machine but they affect the absolute accuracy with reference to the coordinate system.

For machines that have to meet high requirements on accuracy, these errors can be measured by a laser interferometer. 

The errors can be compensated via error compensation curves that can be input into the NC control. 

The Sinumerik control permits error compensation curves to be input for spindle pitch errors and sag errors on all levels.

The measuring of the machine and the error compensation is a service which we normally perform after the assembly of the machine at the customer's plant.

For quality assurance purposes, the measuring and compensation can later be repeated at any time.

Further details on laser interfrometer and circle form test

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