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Product category: Machinery and Production Equipment
News Release from: Leader Chuck Systems | Subject: MultiChuck MMY clamping system
Edited by the Engineeringtalk Editorial Team on 20 July 2000

Major award for MultiChuck MMY clamping
system

The ability of the Leader MultiChuck MMY clamping system to reduce set-up times and achieve rapid concentric clamping of components proved a hit at the International Machine Tool Industry Awards

The ability of the Leader MultiChuck MMY clamping system to reduce set-up times and achieve rapid concentric clamping of components was publicly acknowledged at the International Machine Tool Industry Awards when the system was hailed as the Best Workholding Product MultiChuck MMY was demonstrated by Birmingham-based Leader Chuck Systems at MACH 2000 on a vertical machining centre, though the benefits on offer can also be gained by users of grinding, drilling and milling machines - as Bernard Owen, CNC milling manager at specialist machinist, B and D Morris, can testify

"The use of MultiChuck MMY is generating "great improvements" in terms of our overall efficiency levels through reduced machine downtime," he says.

MultiChuck MMY has these main advantages: [] Rapid clamping with high clamping force [] Component centralisation [] Easy top-face operation [] Internal or external gripping of workpiece [] First and second operations in the same chuck [] Long jaw stroke [] Short set-up time [] Low height to maximise machine's Z axis.

It is these features, among others, that prompt B and D Morris to describe MultiChuck MMY as a revolutionary system that is much quicker to use than traditional set-ups.

Because the system is sealed against the ingress of swarf "production downtime is minimised since there is no need to stop the machine to keep cleaning the chuck", comments Bernard Owen.

In winning the prestigious International Machine Tool Industry Award, which was judged by a distinguished panel of industry specialists and members of the technical press, MultiChuck MMY also brought to industry's attention the production design and engineering skills of the system's inventor, John Leader.

As chairman of Leader Chuck Systems, John Leader is no newcomer to the machine tool business - nor, in fact, is he a novice at developing world-beating products.

Testament to this is the comprehensive range of Leader chucks that have for over 30 years been successfully applied on most makes of turning machines.

John Leader's long association with the workholding industry stretches back to the days when he developed power chucks for his own use at the family precision production engineering company, as he explains: "While we were supplying machined parts to first-tier aircraft sub-contractors, we were presented with an opportunity to develop a device to consistently check the shuttle on textile looms operating at a rate of about one million cycles per week.

"To cut a long story short, the subsequent global success of the hydraulic Leader Shuttle Control supplanted our sub-contract machining work - and indirectly led me into the world of workholding." He continues: "Meeting the production requirements for the shuttle control (circa 2,000 units/month) meant we were making thousands of turned components on capstans.

We needed to frequently change these bar machines to chuckers, but at that time (in the 1960s) we couldn't find anything that would allow us to do that quickly.

"So, we re-rigged a secondhand power chuck by adding an integral air cylinder plus springs to provide both actions - which is still the basic form of Leader power chucks.

After designing a series of chucks for our own use, we began developing and manufacturing power chucks for general sale." Promoted using the message, 'If your cycle time is under 2.5 minutes, a Leader chuck can double your output', Leader became a leading supplier of power chucks and collet systems, for example, to turning machine users and OEMs - and remains so today.

But by concentrating on lathes, John Leader also knew he was missing out on the enormous machining centre market.

Leader Chuck Systems' first move into this area was with the Leader MultiVice MMX vice system for machining centres, mills and grinders.

"MultiVice MMX satisfies a wide range of applications," comments John Leader, "but we felt there was also a need for a workholding system that could offer concentric clamping for second operations on turned parts, and for forgings and stampings." The design brief for MultiChuck MMY was simple.

What was needed was a self-centring system that could be 'banked' together to handle multiple loads.

It had to be of low height to maximise the machine tool's Z axis with ample jaw opening and clamping force.

And it had to easily fit onto T-slot tables.

"I began thinking about combining the attributes of the power chuck base jaw design with the benefits of a mechanical closing mechanism plus extended jaw stroke.

I wanted to create a fail-safe product that didn't require a supply line.

"I did a few sketches and, in fact, today's version doesn't vary too much from the original concept which sees all parts located on a central pin." Those original drawings were input into CAD for subsequent CNC machining, which is all sub-contracted.

John Leader describes the need to minimise the system's height (25 mm to 40 mm across the range) as both a personal quest and as a prerequisite for success.

"I wanted to maintain as much of the machine's Z axis as I could, so shaving every 1 mm I could off the height was in my mind essential." He continues: "I wanted to drive the unit from the front (top) face unlike the traditional side face lock/unlock design, to allow the chucks to be mounted close together.

Also, to prevent the ingress of swarf, the base jaws had to provide a sliding seal coupled with angled front plate slots that would prevent packing the swarf solid.

By using a progressive two-stage cam form rather than a scroll for jaw movement, the result is fast initial travel followed by a slower, powerful clamping.

The base jaws are connected by pins to the cam profiles (two/three to suit two/three-jaw chucks) which are driven by the key through a gear train providing sufficient mechanical advantage to achieve irreversible high clamping force (up to 1,450 da/N on model MMY 150).

The Leader MultiChuck MMY was prototyped in June 1999, with the first pre-production model shown at Tooling 1999.

Today, the range embraces four chuck sizes of 80 mm, 100 mm, 125 mm and 150 mm having base dimensions of 80 mm by 80 mm, 100 mm by 100 mm, 125 mm by 125 mm and 150 mm by 150 mm.

Jaw strokes are 4 mm, 5 mm, 8 mm and 10 mm across the four variants, and the very low height (from 25 mm to 40 mm across the range) satisfies John Leader's desire to maximise the machine's Z axis (though height can be increased if required using blocks).

Also, quick change top jaws can be supplied to suit most materials/components.

"I deliberately kept everything as simple as possible," concludes John Leader.

"I designed parts out not only for ease of production and longevity - the fewer the number of moving parts the less likelihood of wear - but also to reduce cost." "This design uses proven mechanical principles subtley blended together in a minimalist form until they satisfied the original design brief.

The whole point is not to develop something to win a Nobel prize, but to launch a product that gets customers' jobs done in the most cost-effective way.".

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