Product category:
Vertical machining centres (VMC)
News Release from: Mills Manufacturing Technology | Subject: OKK VMCs,
Edited by the Manufacturingtalk Editorial
Team on 02 October 2001
Cells and new investment boost Formula 1
output
To achieve faster deliveries and at the same time to manage more effectively the simultaneous flow of custom and standard components Hewland Engineering has rearranged its machine tools into manufactu
To achieve faster deliveries and at the same time to manage more effectively the simultaneous flow of custom and standard components Hewland Engineering has rearranged its machine tools into manufacturing cells Hewland Engineering invented the bespoke racing car gearbox and is one of the world's leading suppliers to virtually all levels of motorsport, principally American CART (formerly Indy Cars) and World Rally but including Single Seat, GT and Touring Car
This article was originally published on Manufacturingtalk on 23 May 2001 at 8.00am (UK)
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A 10 per cent year-on-year growth rate over the past five years has resulted in the company investing over GBP3 million in new production equipment and reorganising its machine shop at White Waltham, near Maidenhead.
Thirteen Daewoo lathes and a vertical machining centre from the same Korean manufacturer accounts for a high proportion of the financial outlay, while three vertical machining centres from the Japanese builder, OKK, complete the machine tool purchases to date.
Mills Manufacturing Technology is UK agent for both principals.
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Said Managing Director William Hewland, son of the company's founder, "In the motorsport industry you have to buy the best technology to remain competitive and win the constant battle against ever higher quality and shorter lead times.
"Furthermore, what we might have supplied to teams 15 years ago would have been taken straight out of the stores, whereas now there is an enormous amount of tailor-made content.
In fact there is more mechanical transmission technology involved in a World Rally car box than for a Formula 1 car." Adoption of hard turning on the Daewoo lathes has been instrumental in improving component quality and productivity, and also in giving Hewland's designers and its customers more freedom to create lighter, stronger, more compact components which could not be made any other way, according to Dave Radley, Operations Director.
One example he cited was a final drive wheel for a Japanese customer.
The 266mm diameter EN36 wheel started life as a 32mm wide disc which was gear cut and then case hardened.
To take weight out of the part, the web was hard turned down to a thickness of just 3mm.
"The case hardened surface was turned away to leave an unbelievably thin web," said Mr Radley, "yet the gear worked well in the car." Clearly this was exceptional, but Hewland is no stranger to extreme engineering.
As Mr Radley points out, road car manufacturers calculate dimensions for a component and add a safety margin whereas the motorsport industry tends to take off a percentage and still look for more weight savings.
Presently about one sixth of all turning at White Waltham is performed on hardened steel, mainly a Hewland-specified type of EN36, and much of it involves intermittent cutting.
Yet before the first two Daewoo Puma 10 lathes were installed in 1996, hard turning was restricted to turning out distortion on the occasional final drive wheel plus skimming differential casings prior to welding.
Minimal exploitation of hard turning was a handicap as Hewland, in common with all motorsport manufacturers, looks to remove material wherever possible to reduce weight.
Section thicknesses therefore tend to vary dramatically, which is a recipe for disaster if one tries to heat treat after machining owing to the different rates of distortion.
It is now a straightforward matter to heat treat sections of consistent thickness and hard turn afterwards.
"The rigidity of the Daewoo lathes compared to the turning machines they replaced is key to their ability to hard turn to close tolerances," commented Mr Radley.
"For the same reason they result in good surface finish and integrity, which is important for racing car gearbox components to avoid stress raisers which can lead to failure.
Our machining techniques are closer to those used in the aerospace industry than to traditional automotive production engineering." He went on to say that the Puma 10s were installed with "very little pain".
The Mills lorry turned up on schedule, the machines were wheeled into the exact position instructed by Hewland and were running flat out almost immediately.
In contrast, the attitude of some machine tool suppliers is to deposit the machine at the door and leave the customer to sort out the craneage and installation.
Everything else was right with the Daewoo machines as well - price, delivery, feeds, speeds, cutting trials, on-site service, telephone help-desk - so buoyed by this experience Mr Radley installed four smaller Puma 8s and two larger Puma 12s a year later.
He then systematically purchased for the new White Waltham site a Puma 250, a 300LB with hydraulic steady, and a 300MB with C-axis and driven tooling as well as a Daewoo Mynx and two OKK PCV vertical machining centres.
He also bought two Daewoo Lynx lathes for one of the three original Hewland factories in Boyn Valley Road.
Continued Mr Radley, "In common with most manufacturing organisations these days, we have to be more customer-focused and provide higher levels of quality and service.
Ever shorter lead times are demanded for bespoke components and standard gearbox parts are expected off-the-shelf.
"For example, an order was placed recently for the supply of a complete bespoke gearbox for which we received final designs during the first two weeks of August (2001) and delivered the finished box on 14th September.
This was not unusual, although generally we have the relative luxury of a 12 week lead time." To achieve these faster deliveries and at the same time to manage more effectively the simultaneous flow of both custom and standard components through the factory, the company has rearranged the machine tools at White Waltham into manufacturing cells.
The size of the logistical problem may be gauged from the make-up of a typical gearbox containing, say, 200 components of which half are minor (washers, etc), 50 are off-the-shelf parts and the remainder are bespoke.
Overall, the company's parts catalogue has increased from 1,500 to over 8,000 in the last 10 years.
There was a need to compress as many machining operations as possible for a family of products into the smallest practicable area on the shop floor.
This was achieved by investing in lathes like the Puma 300MB mill-turn centre which is capable of one-hit production of complex parts, and by grouping machines into cells.
An example of the latter is the shaft production cell comprising the Puma 300LB and 250 for turning, followed by a gun drill, then the Mynx VMC which compresses four operations into one - spline and slot milling, drilling and engraving of part number and ratio number, and a lastly a gear cutting machine.
The 300LB with NC steady has been especially helpful.
Whereas the previous lathe had a manual steady which necessitated stopping the machine mid-cycle, on the new lathe the hydraulic steady comes in automatically to absorb lateral forces generated when, for example, threadcutting a thin neck on a shaft.
This was often a separate operation before due to the difficulty and inconvenience of completing the operations in one hit.
Similarly, the NC steady is ideal for internal turning; Hewland frequently 'pockets out' material from the inside of shafts to minimise weight.
"Cell working has been very successful," offers Mr Radley.
"Our machine operators, who generally look after two machines each, organise their own workload and have become expert in their particular disciplines, generating ideas as to how things can be improved.
"Work-in-progress is much reduced and so too is the risk of bottlenecks.
Production moves through the shop at a regular pace now, with batch sizes generally between 5- and 50-off.
"Ours is a cyclical business which needs very fast resolution of problems at certain busy times of the year; and we are essentially a large, fast-moving prototype shop in which it is necessary to manage risk and try to get parts right first time.
Cellular manufacture assists in both respects, and also helps us to innovate on the shop floor when time is tight and customers are pressing for early delivery.".
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