Keep check of inspections
March 1st 2008

The use of Metronics Gage-Chek digital readout systems is playing a key role in enabling Rotary Precision Instruments (RPI) UK to maintain its reputation for the supply of high precision rotary table solutions that satisfy user demand for accurate and repeatable, yet cost-effective, applications

An established supplier of rotary table products for metrology and machining tasks, RPI provides solutions to meet every demand – and every budget – in the aerospace, automotive, power generation, machine tool, scientific and general engineering sectors, for example.

Using a wide range of rotary tables – brands primarily gained through acquisitions and the amalgamation of manufacturers such as Eimeldingen UK, Airmatic Engineering, Hortsmann Rotary Tables and OMT – the Bath-based company specialises in the development of bespoke solutions: hence the use of the Gage-Chek DROs for repetitive quality control procedures and easily-assimilated data interpretation.

"The trend is for customers to collect and analyse larger quantities of measured data from an increasingly wider variety of components," says RPI technical manager Ian Whitehead.

"So we're confronted by a diverse range of situations for measuring workpiece roundness, concentricity, flatness and parallelism, for example, where customers want cost-effective – yet highly appropriate – solutions." RPI depends on its extensive inhouse skills base of engineering and mechatronics expertise to develop solutions based around a wide range of tables of differing sizes and types – for example, air bearing, mechanical bearing, direct drive as well as horizontal, vertical, inclinable and NC rotary tables.

Once the software needs are identified, Ian Whitehead says it's very often the case "that we simply 'plug in and program' the Metronics Gage-Chek systems".

He continues: "Aside from the fact that Gage-Chek offers rich functionality, and therefore more flexibility than competitor products, it is easy to use and it also looks the part – it is not just a box with a screen." Gage-Chek embraces comprehensive yet easy-to-use functionality that makes 'go/no-go' component gauging – of even complex parts – both cost-effective and efficient. With a full set of mathematical expressions, programmable digital input/output as well as programmable relay outputs, the system can maximise inspection efficiency by providing instant feedback when dimensions are out of tolerance.

The system can accommodate up to eight encoder or LVDT/Half Bridge inputs – including length gauges, and linear and rotary encoders, as well as a wide range of measuring instruments – and is able to measure up to 16 dimensions per part.

Gage-Chek's go/no go display combines familiar DRO functionality with colour graphics and audio alerts to provide fast and accurate measurement feedback.

Inputs can be algebraically and mathematically combined for dimensions such as thickness, flatness, dwell angles and maximum tip heights, for example, and results can be displayed numerically, graphically or archived for process studies such as simple statistical process control (ie, X-Bar and Range charts). The addition of events, variables, programme loops and user-defined functions also allows complex functions to be evaluated.

The device's DRO mode also provides icons indicating process study has been performed, complete with in/out-of-tolerance alert. It also contains many other features such as Dynamic Max and Dynamic Min, in real-time if using digital inputs and triggering of data logging from a second channel criteria.

Other features for the LVDT/Half Bridge market are the ability to set recalibration times and a check on limits of change for recalibration of LVDTs. In addition, there is a USB port for printing and/or storage to a memory stick and a serial link to a PC for long-term storage and analysis of data is available and also allows transfer of parts and settings to a PC via either port.

In one example at RPI, Gage-Chek systems are successfully applied with the VCG Series machines designed for measuring roundness on components of 3m high by 2m diameter and weighing up to 11,000kg.

In conclusion, Ian Whitehead says: "Producing successful turnkey inspection solutions depends on marrying in-house knowledge and skills with close co-operative working arrangements with customers and technology partners like Metronics."

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