The use of a Heckert H55 machining centre from Starrag has enabled renowned hand-tool manufacturer SWM to not only reduce cutting times by around 40% on certain parts, but identify new machining concepts there were previously impossible.

By way of example, SWM recently recognised the potential to optimise the production of its large pliers. Clamping of the plier heads was taking too long, as was the milling of these workpieces due to the limited spindle speed available with existing machinery, which also severely limited product variety and made retooling very time consuming.

The way to shorten the production process – to 30 seconds per plier head – and minimise the set-up times of 26 different workpieces was, SWM discovered, to capitalise on the capabilities of a Heckert H55 machining centre boasting high levels of rigidity (and therefore accuracy), fast traverse rates of 80 m/min and an ability to handle loads of 800 kg on pallets of 500 x 500 mm (optionally 500 x 630 mm).

But why use such a high-precision machining centre on components where tolerances are usually only a few tenths of a millimetre? In SWM’s case, machining accuracy was not the decisive factor; what is important is machine stability (for machining repeatability) and flexibility (to handle a range of component types/batch sizes), as well as the need for minimal space requirements (the H55 is a compact machine occupying a floorspace of just 6.8 x 2.9 m).

Another example of the benefits to SWM of the Heckert machine concerns certain very large parts that previously required half a shift to machine manually. Today, because the Heckert table can easily handle the required half-tonne fixture, it enables the company to redeploy the machinist formerly required.
For further information www.starrag.com

In the production of many optical components such as lenses and mirrors, the specified form accuracy and surface roughness are generally an order of magnitude higher than for other machining processes. That is why Son-x GmbH in Aachen, Germany, a spin-off from the renowned local Fraunhofer Institute for Production Technology, uses a five-axis machining centre built by another German firm, Roeders. The manufacturer’s machines are available in the UK and Ireland through sole agent, Hurco Europe.

Son-x manufactures metal components made from various alloys, including high-strength steels, as well as parts made of clear plastic. Quantities range from single pieces to several hundred per year, while dimensions extend from a few millimetres up to half a metre diameter in the case of metal mirrors, for example.

Dr Olaf Dambon, a director of Son-x, says: “Our early work involved ultra-high-precision diamond turning, but parts started coming along that needed a prismatic machining platform able to achieve similar accuracies. We drew up a specification sheet for the machine we wanted and designed a challenging test part for prospective suppliers to produce. Five machining centre manufacturers were shortlisted, including three from Japan, but we chose the Roeders because its trial machining results were the best.”

An order was therefore placed for a Roeders RXP 601 DSH five-axis machining centre.

Dr Benjamin Bulla, another director of Son-x, says: “We have many jobs that run for extended periods, so the long-term stability of the machine’s reference point is crucial. In one instance we had to mill moulds for arrays of hundreds of plastic lenses whose shape required control to within 316 nm. This tolerance was reliably maintained throughout 50 hours of machining.”
For further information www.hurco.co.uk

With the accelerating emergence of electromobility and hybrid technology, the components machined by German firm Stöferle Automotive GmbH are becoming more and more complex, while dimensional accuracy and surface finish requirements are steadily increasing. As a result, the Laupheim-based company started looking for high-quality horizontal machining centres on which to produce mild steel hybrid car components in diameters ranging from 240 to 320 mm with fits between H6 and H7.

After evaluating numerous machines, Stöferle decided to invest in two second-generation HF 5500 five-axis machining centres from Heller. The machines (at the time installed ahead of their official launch) are now part of a production line operating three shifts, seven days a week, producing annually up to 350,000 components. In addition, Stöferle has bought two H 2000 four-axis models from Heller’s fourth generation H-series.

Joint managing director Erich Stöferle says: “We perform real endurance tests on Heller machines lasting years. We run them to the maximum, operating at a small percentage below the performance limits specified by the manufacturer. If the maximum weight of a milling cutter is specified as 16 kg, for example, we go up to 15.5 kg. We use a 160 mm diameter milling cutter at 15,000 rpm, which may not be a problem in single part manufacture, but we produce continuously over three shifts.”

He adds: “Another aspect of the tests is that the two HF 5500s are part of a manufacturing line comprising five or six machines. As annual production quantity has been set at 350,000 pieces, a high level of reliability is crucial. Our tests show that Heller’s aim of delivering machines capable of high productivity and precision day in day out has again been implemented in the new-generation HF-series.”
For further information www.heller.biz