US-manufactured Chick System 5 work-holding equipment, supplied in the UK through Salisbury-based sole agent 1st Machine Tool Accessories Ltd (www.1mta.com), is helping to increase machining productivity and efficiency at Axminster Tools & Machinery (www.axminstertools.com).

Based in Axminster (Devon), the company is an on-line and High Street retailer of tools and machinery that it imports from global suppliers. However, it chooses to manufacture some machine accessories in-house to ensure consistently high quality; these include jigs and chucks — such as the popular Clubman SK80 wood-turning chuck.

Historically, standard wind-up vices were used to fixture components for machining on CNC mills and machining centres, but as production levels rose, these vices became too inefficient. Several years ago, a new job (still on-going) came along, and it required particularly accurate clamping of multiple small parts — namely, steel jaws for chucks.

Conventional vices were not suitable, as it was not possible to present a sufficiently large number of parts to the spindle. An initial work-holding solution was to use a steel fixture plate machined to retain the parts by bolting them individually into position, but this approach meant that it took 2hr to change over to produce the next batch.

Reduced set-up times
1st MTA proposed its Chick Qwik-Lok system. This significantly reduced set-up times, as the jaws secure components quickly and to a high level of repeatability for milling and drilling operations; and while one large part can be clamped between two jaws, to allow more parts to be loaded at a time, a pair of components (or multiple components) are held in two stations.

Moreover, aluminium jaws machined with the profile of the parts to be held ensure that they are retained firmly during machining.

With Qwik-Lok, turning a single handle advances the two movable jaws simultaneously towards a fixed central jaw to clamp the parts; this jaw configuration also has the effect of cancelling opposing forces and creating a reliable reference point for machining.

A further benefit of clamping more parts faster was an increase in ‘walk-away time’, allowing operators to undertake work in other parts of the factory.

With this clamping 30min — four-times faster than was previously possible. Moreover, the use of aluminium jaws meant that a programming error was less likely to damage a cutter.

The machinable soft jaws were soon found to be a versatile solution to other clamping problems, such as how to retain chuck bodies without the risk of the cylindrical components rotating during machining.

Previously, these parts were bolted to a fixture plate, necessitating a 30min set-up time; now, the bodies are swapped in the line of Qwik-Lok jaws in 2min.

Axminster Tools & Machinery initially mounted the vice units directly onto the machining-centre table, which meant that when a clamp was removed, it was a time-consuming task to re-align the unit for a new job.

Two years ago, Jake Knight (head engineer at Axminster) bought Chick foundation plates for two three-axis VMCs on-site — a Mazak VCN-530C and one of a pair of VTC-200Ms.

Manufactured to suit the size of the machining-centre table, the cast-iron plates have a grid of accurately drilled holes at 50mm centres, with hardened bushings and threads at each location; these allow Qwik-Loks to be positioned anywhere over the surface rapidly and repeatably, to an accuracy within 10µm.

Moreover, the use of round and diamond pins at two positions allows the Qwik-Loks to be located and mounted quickly and easily; and alpha-numeric labelling of the grid allows accurate relocation of each base and jaw set, so that the same part program can be used every time a job repeats (all unused holes in the plate are sealed with plugs to prevent the ingress of swarf that could compromise location accuracy).

Mr Knight said: “Overall, we use about 20 Qwik-Lok bases and have three-times as many soft-jaw sets machined to hold a multitude of components that we machine from stainless steel and other steels, as well as aluminium and plastics.

“We have chosen Chick’s 1040 base size, with a jaw width of 100mm and an overall length of 400mm, as this supports most of the components and accessories we produce.

“For another project, 1st MTA regularly supplies us with machinable steel chuck jaws for our four Mazak turning centres. These jaws are especially useful for clamping a variety of rotational parts to a high degree of concentricity for turning chuck bodies for our wood-turning lathes, for example.”