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Sewtec Automation, a supplier of production and packaging systems, has increased machining output by adding five Haas machine tools with Renishaw touch probes and a new system of shift work.

Bernard Meehan, Sewtec’s managing director, said: ‘At the end of 2009, we had six CNC machine tools and did 140 hours of machining a week.

‘In July 2010, with 11 CNC machines, we have increased capacity to 1,180 hours per week,’ he added.

The new approach has included an investment in Haas vertical machining centres, which were supplied with the Haas wireless intuitive probe system (WIPS).

‘All machines are fitted with spindle- and tool-setting probes, because we have to keep the machines running, and the resultant cost savings directly affect the cash flow,’ said Meehan.

With the knowledge that the parts they design will mainly be manufactured in house, Sewtec engineers can match the capabilities of their machines to how part features are specified.

An important element of this is value engineering – a systematic method of maintaining the basic function of the part but reducing the costs by taking different approaches to manufacture.

Design reviews are critical to controlling this process, preventing the chance of being blinded by the project on which the engineers are working.

The engineers are changing processes to reduce the number of machining operations, aiming to produce most parts using a one-hit machining process, while also addressing multiple parts at a time.

Both of these require feedback from the spindle-mounted Renishaw touch probes, enabling the machine to use its datum shift function and relate machining to previously machined features after indexing.

An example is a ‘rod-eye’ component, redesigned so it could be made in three ops, all on the same machine and with one set of fixturing.

The raw billets of material are loaded in minutes, after which the Renishaw spindle-mounted touch probe is used to find the position of the billet accurately and adjust the part offsets, to which the machining program refers.

Once this op is finished, the operator moves the part onto the next fixture, rotating it to address the next face.

The touch probe then finds the position of the previously machined features, again adjusting the offsets; if this was not done accurately, the part could easily be scrapped, but by using the probe it is done in a few seconds.

Jerry Elsy, production manager, said: ‘Previously, it could take 1.5 hours to set a job that took 4.5 hours of machining; that was totally unacceptable.

‘Now we can do the same setup in 10 minutes, immediately freeing up one hour and 20 minutes to cut more metal, which we make money on.

‘This, along with the performance of the new Haas machines and increased hours, is how we have increased the productive hours by 850 per cent, but with only five more machines.

‘We bought our first machine tools 15 years ago – two Bridgeport knee mills.

‘Then we bought a Bridgeport VMC [vertical machining centre] with spindle and tool-setting probes.

‘We then did a lot of research on other machines and Haas machines stood out,’ he added.

Sewtec now has 11 machine tools, of which nine are from Haas – a combination of VF2, VF3 and VF4 models, plus a VF9 for very large parts.

Moving towards unmanned production, Sewtec has decided to invest time in refining the setup of its machines, with the intention of leaving them to run on their own as much as possible.

A skeleton night shift has been created, with four operators running between eight and 10 machines, depending on the production needs.

The spindle probes and tool-setting probes are an important factor in enabling this.

The machining workforce is multi-skilled, with nine skilled programmers working on the shop floor and about 75 per cent of programming being done on the machines.

This can mean that, when there are multiple parts being made with automated processes, the machines are over-manned and over-skilled; however, retaining that skill is seen as very important.

Renishaw

A world leader in engineering technologies, Renishaw’s core skills in measurement and precision machining serve sectors as diverse as dimensional metrology, spectroscopy, machine calibration, motion control, dentistry and surgical robotics.

A world leader in engineering technologies, Renishaw’s core skills in measurement and precision machining serve sectors as diverse as dimensional metrology, spectroscopy, machine calibration, motion control, dentistry and surgical robotics.

Sensors for co-ordinate measuring machines (CMMs) are an industry standard, from basic touch-trigger probes through to automated stylus and probe changers, motorised indexing probe heads, and revolutionary five-axis measurement systems.

Machine probes for CNC machine tools allow automated tool setting, workpiece set-up, in-cycle gauging and part inspection. Products include laser tool setters, contact tool setters, tool breakage detectors, touch probes and high accuracy inspection probes.

For motion control, Renishaw supplies laser encoders, optical linear encoders, optical angle encoders, optical rotary encoders, magnetic rotary encoders, magnetic chip encoders and magnetic linear encoders.

To analyse the static and dynamic performance of position-critical motion systems, Renishaw’s laser interferometer and environmental compensation system offers a linear measurement accuracy of 0.5 ppm, readings of up to 50 kHz and a linear measurement speed of up to 4 m/s, with a linear resolution of 1nm.

Renishaw’s Raman spectroscopy products exploit the Raman effect to identify and characterise the chemistry and structure of materials. A diverse range of analytical applications include pharmaceutical, forensic science, nanotechnology, biomedical and semiconductors.

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