Positioning: Revolutionary 2D linear encoder

Encoder allows measurement of linear guiding and thermal drift errors during movements.

By Control Engineering Staff July 24, 2008

Schaumburg, IL Heidenhain Corp. introduced the 1Dplus encoder, claiming that it is a uniquely innovative 2D encoder allowing measurement of linear guiding and thermal drift errors during movements of a stage or machine. Knowing these errors allows immediate compensation of the errors, and results in very high accuracy and jobs done right the first time. The company expects the most likely applications include stacked stages, precise gantries, wafer processing, and large flat-panel display production and test.
The company says these encoders are frictionless, with gratings in two dimensions. Models feature two or three scanning units for simultaneous measurement of x and y directions. Three scanning units allow the calculating rotation angle of the bracket that houses the scanning units. Orthogonal encoder graduations, the company says, provide an exciting new dimension in precision as the encoder system measures left and right ( x axis), the up-and-down ( y axis) motion with compensation as well.
The company’s early and current 1Dplus encoders are in use as its interferential-type linear encoder, the LIF 400 with 1Dplus. The measuring standard is a diadur coating with a thermal expansion coefficient of 0 ppm/K. Current measuring length is 300 x 2 mm, with plans to increase that dramatically. The 1Dplus scale itself is 20 x 4.9 mm. The company claims x-axis measurement accuracy of
— Edited by C.G. Masi , senior editor
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