A new incremental length gauge for precision measuring and in-process control applications in harsh environments has been introduced by Heidenhain. The length gauge is suitable for use in the working area of grinding machines, lathes and other metal-cutting machine tools, and produces results accurate to ±1 μm over its 30 mm measuring range.

Called Specto ST 3087RC, the unit has a special housing to protect its mechanism. A built-in spring keeps the plunger, surrounded by a rubber bellows, retracted behind a guard and splash cap when the gauge is in its rest position. The extension of the plunger to the measuring position is actuated by compressed air, normally with the coolant switched off.
An increase in productivity and a reduction in floor-to-floor time result from not having to transfer components to a measuring station external to the machine tool, or to a quality control department. Should rework be necessary after metrology functions have been completed, in-process gauging preserves accuracy by eliminating the need to set the component up again for a second operation.
High-accuracy positional values over the full stroke of the gauge allow diverse components to be measured from the same fixture. Furthermore, internal photoelectric scanning of plunger position by means
of a DIADUR scale grating with a 20 μm period, together with the use of a durable ball-bush guide, permit consistent repeatability of probing even when measuring oblique or curved surfaces.
The IP67-rated ST 3087 RC is protected against ingress of dust and unaffected by high-pressure coolant jets – and even short periods of immersion. The length gauge is also tolerant to extremes of temperature, vibration and shock.
For further information www.heidenhain.com