Workholding system helps Norgren double throughput

When IMI Norgren purchased a new machining centre for the short batch production of complex valve blocks and manifolds, it also selected a tailored Chick workholding system

Product customisation and miniaturisation are familiar enough requirements within the electronics sector.

But pressures to reduce product size, increase capabilities and minimise costs are just as strong throughout other sectors of manufacturing industry.

Nowhere is this more true than in the production of pneumatic control equipment.

With its vast range of actuators, cylinders, control valves, air line equipment and fittings, IMI Norgren knows this better than most.

So, when the company purchased a new machining centre for the short batch production of complex valve blocks and manifolds, it also recognised the importance of selecting a tailored Chick workholding solution from Kitagawa Europe in order to gain the maximum return on its investment.

IMI Norgren is a leading international producer of pneumatic control equipment.

One of its manufacturing sites based in Lichfield, Staffordshire, supplies a huge selection of standard modular equipment.

But increasingly, it is being asked to produce compact, multi-valve units for application in equipment ranging from automatic bottling plants to process equipment across all sectors of manufacturing industry.

With several hundred precision drilled and counterbored holes and galleries in a single aluminium section measuring perhaps 200 mm x 100 mm x 50 mm, a typical multi-valve block fulfils the role of up to 16 individual valves.

Components are worked on all sides and, prior to Norgren's investment in a Heller MC 16 horizontal machining centre, the units would be produced in three separate metal cutting operations, with individual set-ups using multi-vices.

According to Manufacturing Engineer, Tony Meese, the machining of individual blocks could take up to 60 minutes.

"But with the growth in demand for these products, we not only wanted to minimise production costs, but could also foresee potential manufacturing capacity problems.

We were therefore keen to streamline our operations in order to increase throughput, as well as our ability to respond to customer requirements," he explains.

With its multi-pallet loading system and 160 capacity tool magazine, the Heller machine provides the capability to combine all the machining operations into a single set-up and, thanks to a Chick workholding system from Kitagawa Europe, has effectively enabled machining times on these complex components to be halved.

"Through the use of standard setting plates and the ability to pre-program the machine for a number of different valve block variants, we have also eliminated set-up time altogether on these components," Meese notes.

In order to further speed up production, Norgren has opted for diamond tipped finishing tools, particularly on the all-important valve bores, which must be held to extremely high surface finishes.

According to Meese, the accuracy and repeatability of the Chick system are well able to support the required quality standards.

"This is reflected in the units' rigidity.

Yet their ability to cope with the heavy roughing cuts employed is achieved without the bulk associated with some workholding systems," adds Meese.

"This in turn, means a significant reduction in fixturing weight, and therefore the indexed masses; improving the life of both the indexing units and the machine itself." By condensing all operations onto the Heller, Norgren has managed to reduce machining time to around 30 minutes per component.

What's more, this figure now includes a series of de-burring operations that were previously regarded as second operations.

The selection of the workholding solution from Kitagawa was based on Norgen's previous experience of Chick units; backed by the Salisbury-based company's service, support and applications engineering expertise.

As a result, a turnkey package including 4 off 4-sided MML 1550 and 2 off 6-sided MML 1550 units was specified, along with extended bases and jaws to enable maximum utilisation of the Heller's machining envelope.

In operation, two valve blocks are mounted on each face of the Chick units, allowing up to 12 components to be processed in a single cycle.

Through the versatility of the installation, Norgren now makes to order against a daily production schedule.

Even so, with the machining centre's six-pallet work handling system, components need only be loaded twice a shift - providing further cost savings, and permitting up to 8 hours 'lights-out' production if required.

A further benefit of the Chick system is its ability to optimise gripping loads - providing positive retention of the workpiece without over clamping or causing surface damage.

"This is particularly important," says Meese, "not just because of the close tolerances we are working to, but because die cast valve block variants have pre-painted bodies." More than a year after installation, the Chick equipped Heller is performing well up to expectations.

In a typical week, it will process around 20 different valve block types, with the most popular model being manufactured in batches of up to 50 units.

Meese also confirms that the workholding solution from Kitagawa has been backed by first class customer support and has helped to make the most of the new machining centre's capabilities.

It also provides a proven method for enhancing production capacity on other short run components.

"We currently use straight cut, parallel jaws, but could just as easily swap to profiled versions to suit any number of other components in the future, should the need arise," he concludes.

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