A new incremental length gauge for precision measuring and in-process control applications in harsh environments has been introduced by Burgess Hill-based Heidenhain (GB) Ltd (www.heidenhaingb.com).

The gauge, which can be used in the working area of grinding machines, lathes and other metal-cutting machine tools, produces results accurate to ±1μm over its 30mm measuring range.

Called Specto ST 3087RC, the unit has a special housing to protect its mechanism; a built-in spring keeps the plunger, which is 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 outside the machine tool, or to a quality control department; and should re-work be necessary after
in-process gauging has been completed, accuracy is preserved by eliminating the need to set the component up again for a second operation.

Furthermore, high-accuracy readings over the full stroke of the gauge allow a variety of components to be measured from a single fixture.

Meanwhile, internal photoelectric scanning of plunger position by means of a Diadur scale grating with a 20μm period, together with the use of a durable ball-bush guide, ensures consistent repeatability of probing — even when measuring oblique or curved surfaces.

The IP67-rated ST 3087 RC is protected against the ingress of dust and is unaffected by high-pressure coolant jets — and even short periods of immersion.

The length gauge is also tolerant of temperature extremes, vibration and shock.