Product category:
5-axis (3+2 axes and continuous path) machining centres
News Release from: DMG (UK) | Subject: DMU 50 eVolution five axis machining centre
Edited by the Manufacturingtalk Editorial
Team on 22 May 2001
Five-axis M-Cs steer company to high
productivity
Installation of three Deckel Maho DMU 50 eVolution five axis machining centres at steering system specialist Pailton Engineering, Coventry, has provided a marked improvement in productivity.
Installation of three Deckel Maho DMU 50 eVolution five axis machining centres at steering system specialist Pailton Engineering, Coventry, has provided a marked improvement in productivity Whereas a typical diecast aluminium housing used to be produced in three or four separate operations, and require about 25 minutes of machining time, the DMU 50 evolution machines can completely machine these components in less than ten minutes
This article was originally published on Manufacturingtalk on 21 Jun 2001 at 8.00am (UK)
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Pailton is the UK's leading specialist manufacturer of steering columns for heavy goods vehicles, off-highway vehicles and specialist luxury cars.
The company offers a complete design, test and manufacturing service for steering columns to satisfy OEM requirements; in many cases these are highly complex assemblies incorporating pneumatic clamping for reach and rake adjustment.
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In addition it also manufactures steering arms and track rod ends for a wide variety of vehicular applications.
As well as supplying UK based vehicle manufacturers the company has a very healthy export trade.
Production engineer Mick Drakeford oversaw installation of the DMU 50s.
he explains.
"We have a regular requirement for small batches of pivot clamps, gear cases and other components.
The nature of our production is such that 200 per month of any finished assembly constitutes a high volume so we need a manufacturing method that is repeatably accurate but also flexible." One of the difficulties inherent in machining these components is that many of them are quite delicate.
This arises from weight considerations which lead to execution of quite sizeable components as thin wall aluminium alloy diecastings.
Moreover, most have a multitude of bores and drilled and tapped holes which are positioned at various angles to one another.
Tolerances are tight, with bores of 25mm diameter or more being held to 0.020mm; this may not sound ultra accurate until you consider that in some cases the bore is split down one side.
"Although the completed components do not appear to be very complicated the number and distribution of the machined features makes a lot of demands of the machining process." Mr Drakeford added.
"Prior to installing the DMU 50e's it was not uncommon to need three or four set-ups on different fixtures to complete machining.
It was apparent that a single hit machining capability would provide a number of important advantages as it would reduce lead time to that needed to machine one component.
Therefore, smaller batch quantities became supportable and it would also provide improved accuracy, as all machining operations would be conducted from a common datum point so spatial alignments would be better.
In addition there was also the potential to reduce tooling costs and workload as each component can be machined using one fixture, rather than three or four." From the outset Mr Drakeford realised that only a five axis machining centre could provide the flexibility of component positioning to satisfy the machining requirements.
These covered a variety of components (the current tally is 36 but the range is constantly expanding) produced from both die castings and EN8 steel forgings.
Machining requirements are fairly straightforward in content if not in execution, and cover facing, drilling, tapping and boring.
"One of the problems in machining thin section aluminium components is that they can begin to move under the applied clamping forces as material is machined from them." Mr Drakeford explained.
"For that reason we have had to develop interrupted machining cycles whereby the component is semi-finish machined and the fixture clamping is slackened off before being precisely torqued down prior to the finishing cuts on key features.
Although this extends the cycle time we still achieve single hit machining of the parts and we hold very good accuracy over a batch." Pailton Engineering selected the DMU 50eVolution following an appraisal of the small-to-medium capacity five axis machines then available.
Although most of the work to be machined is not heavy machining, one of the benchmark tests that Pailton required was to direct tap a M48 x 2mm pitch thread into an EN8 forging.
"In practice we thread mill this feature but we wanted to have confidence in the machine's basic machining capabilities," said Mr Drakeford.
"The DMU 50e 'walked it'; together with the very good value for money that they represent this convinced us to purchase the machines." The operational benefits of the machines have extended well beyond simple productive efficiency.
Improved geometric alignment of the finished components makes assembly quicker and easier.
This is particularly so on gear cases where what used to be a fitting exercise has become an assembly operation.
Mr Drakeford continued.
"Without the five axis machines I do not think that we would be competitive on these components.
Over the last few years the company has invested heavily in CNC machining facilities which has paid dividends as it has made it relatively easy to diversify into related areas such as steering arms and track rod ends.
We've recently gained a major contract to manufacture track rod ball joints and sockets for a US-based customer for which new CNC turning capacity was needed.
Partly as a result of the performance of the DMU 50 eVo machines we've elected to install two new Gildemeister CTX 400 CNC lathes to replace existing CNC turning capacity." The components being machined on the Gildemeisters will be the socket ends, for which the requirement is 36,000 units per annum.
The machines are being installed to turn the shank contour of the socket -1.1in diameter to a tolerance of 0.001in for a length of 4.25in prior to a thread rolling operation.
Current turning capacity at Pailton Engineering can accomplish this operation at a rate of 40 parts per hour; however the CTX 400s, which have greater spindle power and are equipped with automatic doors, have achieved 55 parts per hour during pre-delivery trials.
"We're committed to servicing a kan ban delivery regime on these parts so the improved performance of the Gildemeister machines is necessary." Drakeford concluded: "We've been very happy with the performance of the DMU 50e's and we expect the same of the Gildemeister lathes.
In both cases the machines represent a major advance on the manufacturing systems that they superseded but without them our manufacturing operations would ultimately cease to be competitive.
As it is the company is investing at a rate intended to maintain our leading position in the market.".
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