Motion control products for the ultra-high vacuum environment

26 October 2010

At Vacuum Expo, taking place at the International Centre, Telford, UK, from 3rd to 4th November, Renishaw will focus on its position feedback encoders specifically designed for use in ultra-high vacuum conditions.

The products on show include its new range of TONiC™ UHV encoders, available in linear and angle encoder formats, which combine the benefits of high-accuracy linear scales with optical reference marks, high-fidelity position feedback, unrivalled ruggedness with fast and easy installation.

All of Renishaw's UHV encoders are constructed from vacuum-compatible materials and adhesives to give low outgassing rates and proven clean residual gas analysis (RGA), and are also suitable for bake-out temperatures of 120°C. They are all suitable for high performance, semiconductor and scientific applications.

Like the standard range of TONiC readheads, the new ultra-high vacuum variants use the latest generation of Renishaw's filtering optics, now optimised for ultra-low noise. The advanced optics design is further augmented by dynamic signal conditioning including auto gain control (AGC) and auto offset control (AOC). The results are output signals of exceptional purity, providing SDE of ±30 nm, noise (jitter) around 0.5 nm RMS and resolutions to 1 nm.

All TONiC scales include the unique IN-TRAC™ optical reference mark, directly embedded into the incremental channel, facilitating automatic electronic phasing with the press of a button - a function that can therefore be carried out remotely. The IN-TRAC reference mark also has the benefit that it remains phased at all speeds and throughout the entire operating temperature range.

For linear position feedback with the TONiC UHV range, motion system designers can choose between a variety of scales, all with proven clean RGA spectra, including RELM ZeroMet™ spars with “zero” thermal expansion coefficient and total accuracy guaranteed better than ±1 µm on lengths up to 1130 mm. Also in the range are high-accuracy RSLM stainless steel spars and RTLC stainless steel tape scales, along with Renishaw's well-known RGSZ tape scale.

For rotary applications, the TONiC UHV angle encoder readhead is compatible with Renishaw's precisely-graduated rotary scales with IN-TRAC optical reference marks, including RESM and REXM ultra-high accuracy rings. RESM rings are made from monolithic 300-series stainless steel without any coatings, meaning they can be subjected to specialist cleaning and de-greasing if required. To simplify design the rings also feature a large through-hole with a small cross-section, and a patented taper mount for fine run-out adjustment. For the highest performance rotary axes, designers can choose REXM ultra-high accuracy rings, which can also be used with dual UHV readheads to achieve total installed accuracy of better than ±1 arc second.

Find out more about the full range of Encoder products.

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