Laser scale

As thermal effects are identified as the dominant error source in many applications, significant process improvements can be achieved by controlling the motion with the HS10 laser and HC10 thermal compensation system.

Since its introduction in 1995, the HS10 laser scale system has been incorporated into many precision motion systems providing direct position feedback at resolutions to 40nm. Applications range from machining aerospace components to laser writers (which produce photomasks for the electronics, flat panel display and semiconductor manufacturing industries), with the corresponding range of axis lengths being from sixty metres to less than one metre.

The HS10 system used in conjunction with the HC10 real time thermal compensation system enables one part per million (1 micrometre in a metre) positioning accuracy over a wide range of environmental conditions. The HC10 compensation system also includes a facility to compensate for thermal expansion of the machine structure or, more usually, the piece part.

This works by constantly calculating the current size of the part using its temperature (monitored by a precision temperature sensor affixed to the part) and the materials coefficient of expansion (stored within the HC10 system). The position feedback is then automatically modified to enable the machine to automatically track, in real time, the calculated expansion/contraction of the part.