Britain's leading ride-on garden machinery manufacturer, Countax, has installed a GBP1 million sheet metalworking cell in a purpose-built extension to its Oxfordshire factory.

Britain's leading ride-on garden machinery manufacturer, Countax, has installed a GBP1 million sheet metalworking cell in a purpose-built extension to its Great Haseley, Oxfordshire factory. The flexible manufacturing system (FMS) comprises two FINN-POWER Shear Genius punching, nibbling and shearing cells with component sorting and stacking facilities, fed from a 12-bay tower capable of storing 33 tonnes of sheet metal. Supplied last year by Press and Shear Machinery, the Finnish-built FMS works round the clock supplementing four older FINN-POWER TP2525 turret punch presses on site.

The new system was needed to meet increased production of components for 15 models of Countax tractor and rider mower plus 13 variants of cutter deck and various attachments.

Around 2,000 part programs are stored and more are being created all the time owing to the regular introduction of design modifications and new models.

Managing the project is Nick Whitman who comments, 'Two aspects of the FMS are worthy of special mention.

First, the proven shearing facility integrated into the two punch presses drastically reduces the time needed to cut straight lines.

For example, one side of a chassis member can be sheared in a couple of seconds with two strokes of the one-metre blade, whereas nibbling the same length used to take nearly two minutes and the edge finish was not so good.

'Secondly and unusually, FINN-POWER was willing and able to modify one of the Shear Genius machines so that it could be accessed from the opposite side.

This allows us to supply sheet metal from a single tower store to both machines by placing them back to back and at the same time to remove all sorted components and skeletons from one side of the FMS.

Reprogramming of the two conveyors feeding the sheet in either direction was necessary to ensure uninterrupted production on both machines.

The execution of all this has been flawless.' Countax started making garden tractors only 10 years ago and its growth has been meteoric.

The company is now the number one British manufacturer exporting up to 40 per cent of output; and its GBP23 million turnover last year will grow significantly in the current financial year owing to the recent acquisition of competitor, Westwood Engineering, Plymouth.

For most of the 1990s, the use of FINN-POWER equipment has been central to the successful implementation of sheet metal manufacturing on site and will continue to be for the foreseeable future.

Said Nick, 'It was by no means a foregone conclusion that we would continue with Press and Shear and FINN-POWER just because we had been using the TP2525s, even though they have been very good and are still operating reliably today.

They were one of the first hydraulic punch presses on the market and were quieter and had a higher punching capacity than the mechanical presses we considered at the time.

'We were, and still are, satisfied that FINN-POWER is among the leaders in the field technologically - if not the leader - but we still looked at all the major suppliers when we decided to invest again, this time in a lights-out, automated sheet metalworking system.

What swung us in favour of the incumbent punch press supplier was the good service we have received in the past.

We have never had to wait more than a day for a service engineer to arrive, and normally only a few hours.' Within three months of installation the FMS was working 24 hours a day.

An interesting feature is the remote monitoring and optimisation of Countax programs from Finland.

Nick says that it was eerie the first time he saw the machining parameters being changed on screen without the apparent intervention of anyone.

FINN-POWER engineers periodically log on remotely to evaluate speeds, feeds and other machine settings to see if they can be improved and to make the appropriate adjustments, not only to the machines but also to the material storage and handling elements of the system.

Fault diagnosis and advice is also easily provided from Finland over the same direct link.

Nick points out that modern punch presses are considerably more efficient than their predecessors.

The Shear Genius achieves 400 hits/min at 25mm hole centres, which is 50 per cent quicker than the TP2525.

The ballscrews have also been uprated to enable faster traversing speeds up to 100m/min.

He is also impressed with the effectiveness of the programmable clamp repositioning which allows about seven per cent more sheet area to be utilised by moving the clamps automatically during the cycle to present otherwise dead areas of the sheet to the turret tools.

The FMS at the Great Haseley factory is devoted to processing 2.5m by 1.25m sheets of mild steel of gauges between 1mm and 3mm, with some galvanised steel in the thinner range.

If a repeat program is not to be used, a newly designed component is downloaded from the company's 3D modelling CAD system to a Radan computer-aided manufacturing station which unfolds the part if necessary, writes the program for the Shear Genius and produces a tooling list.

This information is then downloaded directly to the appropriate punch press control.

Contributing to high production output is good planning of the tooling in the turrets of both Shear Genius machines.

Countax has worked closely with Wilson Tool which has provided tool/die sets with clearances able to span a range of material gauges.

For example, sheet in the range 1mm to 1.6mm thick may be punched with the same tooling, and so on.

Furthermore, careful attention has been paid to how the nine auto indexing stations are utilised in each of the 20-station turrets.

Seven of the nine stations carry indexing tools to produce slots at a variety of angles, avoiding tying up the non-rotating stations with tools set at fixed angles and the frequent tool changes that this would have necessitated.

The other two auto indexing stations in each turret are equipped with multi-tools, one containing eight tools and the other 10.

Punches in the diameter range 3mm to 20mm (the maximum is 24mm) are housed in these stations as well as a couple of square and rectangular tools.

In all, 72 tools are deployed across the two turrets and sheet is fed to the machine which is equipped with the appropriate tools to complete any particular set of nested parts.

In practice tool changes are rare - maybe one per Shear Genius per week compared with two or three a day on the TP2525s due to the smaller number of auto indexing tools.

In common with all modern FINN-POWER machines, the Shear Genius has the ability to up-form features to a maximum height of 16mm using a station in the lower portion of the machine frame to lift the die up towards the tool.

It is also possible to tap the walls of circular up-forms.

Nick is currently evaluating this technology as it would prove useful for producing formed features in bag lids and deck stiffeners which currently go onto a press for a second operation.