Product category:
Probes, sensors, tool detection for machine tools
News Release from: Newall Measurement Systems | Subject: MAG-TS incremental linear encoder
Edited by the Manufacturingtalk Editorial
Team on 10 August 2007
Linear encoder ensures accurate
cutting-off
An incremental linear encoder fitted to a billet cutting-off saw enables tighter tolerance cutting, so avoiding wastage in cutting expensive nickel alloys stock.
When Hereford, UK-based Special Metals Wiggin wanted to improve process repeatability and reduce waste from its cut-off operations for high nickel, high performance alloys, the company selected an established sawing machine supplier Burkett Cutmaster and their strategic partner and special purpose machinery builder Ripon Technical Services The result was an automated sawing and bar/profile handling system that exceeded the company's existing manual cut-off capability in terms of reliability and accuracy, thanks largely to a MAG-TS incremental linear encoder supplied by Newall Measurement Systems
This article was originally published on Manufacturingtalk on 31 Jan 2002 at 8.00am (UK)
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Birkett Cutmaster and Ripon Technical Services have developed a healthy niche in the design, manufacture and commissioning of cutting-off, special purpose machinery and materials handling equipment for a broad range of industrial and analytical environments and applications.
The project for Special Metals Wiggin involved combining pooled expertise, as Ripon's managing director, Andrew Stott, explained: "Together we've done a number of cut-off saws with end-stop capability," he said.
"We are gaining a strong reputation for this kind of project, which in this instance involved producing a system that would replace manual methods currently being deployed by the end user".
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Offering OEMs, retrofitters and end users unbeatable value for money, a compact, easy-to-use, single-axis digital readout system is specifically designed to increase productivity.
Magnetically-encoded tape scale is supple, tough
Encoder system features a supple, magnetically-encoded tape scale, which is ideal for both rotary and linear applications, including long-bed machine tools.
Special alloys for the aerospace and power generation industries, such as Inconel, Incoloy, Nimonic and Monel, cost up to GBP 25-30/kg.
Special Metals Wiggin was using manual methods that carried a tolerance of several millimetres.
Therefore a more accurate and consistent billet cutting-off system offered potential savings.
"We could have used a traditional 'hard stop' to control the cut-off length," said Stott, "But due to the variety of sections involved (bar, profile, etc), the customer was keen on achieving greater accuracy with respect to end-stop positioning".
Ripon Technical Services had already had Newall linear encoders retrofitted to two borers in its Leeds machine shop and so approached Newall again.
Newall recommended its cost effective MAG-TS incremental linear encoder.
The Newall MAG-TS encoder is comprised of a flexible tape scale mounted on a fixed machine surface.
A reader head, which is fastened to the moving part to be measured, is arranged such that it travels in alignment with the scale.
A stainless steel cover strip protects the encoded tape.
* How the encoder works - the tape scale is made up of a flexible magnetic rubber strip, sandwiched between a backing strip and a cover strip made from thin stainless steel.
The encoded tape contains magnetic poles that are placed at 2mm intervals along its length.
As the incremental sensor in the reader head passes over the tape, the magnetic field is converted to an electrical signal, which is sampled by a micro controller.
The field between the markers varies sinusoidally, from which the micro controller can determine the position of the sensor in relation to each marker.
The analogue information is converted into an industry standard RS422 (TTL) differential quadrature signal.
For applications where the mounting surface is uneven the tape scale can be attached to an optional twin-track backing bar, supported by stand-offs, while the flexible nature of the tape scale makes the encoder ideal for rotary as well as linear applications.
In terms of accuracy, the MAG-TS encoder (+/-0.025mm) far exceeds any applications required by Special Metals Wiggin.
Installed in February 2007, the capability of the system is well inside their cutting tolerances of 6mm, potentially saving the company several millimetres of material with every cut.
Furthermore, the repeatability of the special machine with MAG-TS encoder ensures there is no longer any danger of cutting the stock short, so it avoids wastage of a whole length.
The MAG-TS linear encoder is part of the Newall family of linear encoders which includes a range of inductive linear encoders featuring IP67 sealing.
The devices are available in incremental versions.
Ripon updated the proven Birkett Cutmaster saw design to meet current legislative requirements and also integrated three conveyors, measuring, guarding, electrical control and transfer systems to provide a bespoke full turnkey solution. Request a free brochure from Newall Measurement Systems ...
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