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Medical device manufacturer Bespak has installed a Smartscope CNC 500 multi-probe compact co-ordinate measuring machine from OGP UK to measure a range of components for inhalers and respirators.

The company said the Smartscope CNC 500 is already offering extensive programming, set-up and cycle-time savings.

Peter Haken, metrology engineer at Bespak, said: ‘We have many conventional tactile-based CMMs on site but for a new project we were looking for a system that would be both quicker and easier to use.

‘Vision seemed the way to go as it provides more control over the critical dimensions being measured.

‘Once we had settled on vision, OGP was the only supplier worth considering as it offers a good production-based system that is both cost-effective and easy to program.

‘Many comparable systems seem only able to accommodate lab-based work,’ he added.

Many of the components for Bespak’s products are precision plastic parts (typically polypropylene) manufactured on injection presses in two-, four- or eight-cavity moulds.

The OGP Smartscope CNC 500 performs production acceptance checks on a four-hourly basis; in other words, six times a day across 24-hour operations.

Haken said: ‘The operator will take a shot, allow it to cool and mount it in a purpose-designed fixture on the table of the Smartscope CNC 500.

‘He then simply clicks an icon on the Measure X menu and the program runs automatically.

‘Most programs take around two minutes to complete, although some are longer at around five minutes.

‘In comparison with conventional CMM technology, I would estimate the system is at least 25 per cent quicker.

‘However, in some instances, features that might take three or four minutes on a CMM only take around one minute using an OGP vision system,’ he added.

OGP’s Measure X metrology software provides the user with all the tools needed to make geometric measurements.

The software quickly controls all probe changes, while inspection routines are recorded automatically and edited easily using icon-driven commands.

Data outputs can be customised with reports available in printed or digital formats.

Additional analysis of surface, profile, SPC and part-to-CAD comparisons can be collated by using integrated companion application programmes.

At Bespak, results from Measure X are output to an SPC package called QC-CALC.

Parts measured on the Smartscope CNC 500 are typically no more than 10mm long and no larger than 8mm in diameter, and despite the inclusions of several complex features, programs are quick to create using Measure X.

Haken said: ‘Programming is definitely one of the system’s core strengths.

‘They can be created easily and quickly despite the fact that we need to test against all features, as well as validate fixtures and complete repeatability and reproducibility (RandR) studies.

‘We need to ensure that the system and the operator do not take up more than 20 per cent of the tolerance,’ he added.

Considering the parts are plastic, there are some challenging tolerances such as +/-0.05mm and +/-0.025mm in some instances.

However, Smartscope CNC has a high-quality 12:1 zoom lens that is said to provide good optical performance over its entire range.

The Accucentric lens maintains accuracy by calibrating itself automatically with each magnification change.

Illumination is provided by Smartring, OGP’s vector light that gives total control of lighting angles, making it easy to pick out important features for repeatable and accurate optical probing.

Bespak specified its Smartscope CNC 500 complete with Renishaw TP200, a compact, module-changing probe that uses strain-gauge mechanisms for higher accuracy and longer life than kinematic touch-trigger probes.

According to Haken, the touch probe comes in useful for features such as bores, where vision technology can typically measure at the top or bottom.

Smartscope CNC can be fitted with a Renishaw touch probe and a TTL laser probe facilitating the measurement of full 3D geometry and fast and accurate surface scanning.

The range has a measurement envelope of up to 1,500 x 2,000 x 400mm (X, Y, Z) making the machine suitable for large components or for multi-loading batches of smaller parts.

Bespak has three other OGP vision systems on site: two Smartscope ZIP 250 models that are both fitted with Renishaw tactile probes; and a Smartscope ZIP 400 with laser probe.

The laser probe will be used at Bespak when a new device comes on stream featuring high quantities of depth measurement – the type of feature that can be measured rapidly using a laser probe.

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