Friday 9 January 09 - 02:28
 

Pressworking

Long bed presses stamp out inefficiency

Precision stampings specialist Batten & Allen has invested in seven Bruderer high-speed presses since the year 2000, bringing the total on its Cirencester site to twenty-six. All of these latest machines have long beds that allow the use of complex progression tools with multiple stages. 

Up to fourteen components can be produced at each blow of the press, some of them with very complex forms and extremely tight tolerances
Up to fourteen components can be produced at each blow of the press, some of them with very complex forms and extremely tight tolerances

Currently up to fourteen components can be produced at each blow of the press, some of them with very complex forms and extremely tight tolerances, although a fourteen-station die would typically produce flat, two-dimensional parts. These so-called multi-out tools have revolutionised productivity in the manufacture of electrical, electronic, telecommunications, medical and many other components from a wide range of materials in gauges ranging from 50 microns to 1.2 mm.

All presses have pallet decoilers and auto recoilers, as nearly all production is automated reel-to-reel stamping. Over 95 per cent of output is exported directly to world markets via agents in many countries. The company also produces its own range of standard edge clip leadframes for the hybrid, thick film and printed circuit board industries. Customers include such well-known names as Tyco, Molex, AVX, Bosch, Nokia, Siemens and Schneider Electric.

Shawn Batten, Managing Director, explained, “Being able to accommodate large, multi-out progression tools on the bed of our most recent presses has allowed us to become much more competitive, helping to keep down the prices we charge to customers.”

The family-owned stamping manufacturer is unusual in that it also runs its own plating facility. This comprises eight high-speed, reel-to-reel electro plating lines, the latest installed in 2008. Only a very small amount of specialist work involving gold and other precious metals is subcontracted.

Another activity that defines the company’s service is its in-house design and manufacture of tools, mostly of the interchangeable modular variety. The well-equipped toolroom has EDM machines, grinders, mills and machining centres, plus inspection equipment. 

Continued Mr Batten, “Our customers’ components often require forming tolerances as small as 25 microns. This requires complex tools and most of our competitors would struggle to hold such tolerances on blanked dimensions, let alone formed features.

“By making our tools in-house, we ensure they are manufactured economically to the highest quality. It is in our own interests not to cut corners, as good tools produce longer runs before they need refurbishing, saving costs and maximising the up-time of the Bruderer presses.

“A typical punch and die set might now be run for eight million blows, up from five million a few years ago. This is testament not only to the high accuracy and surface finish of our tools, but also to the precision and rigidity of the presses, without which the tools would wear faster, irrespective of how good they are.”

He added that further benefits of using top quality tools are minimal returns and scrap. The latter is 30 per cent down in the last four years and decreasing from a very low level by 0.1 per cent annually. Some of this improvement can also be attributed to substantial investment in wire erosion, with three new Agie machines purchased in the last three years.

Another initiative in recent years was to install a panel of remote on-off switches in the quality control room to enable any of the 24 Bruderer presses on the shop floor to be stopped immediately if inspection results show that parts are starting to drift out of tolerance. As Mr Batten points out, presses running at up to 1,200 strokes per minute (spm) can produce a lot of scrap in the time it takes someone to walk out to a machine and press the stop button.

Production efficiency has risen by 40 per cent since 2000, according to Mr Batten. This is due to a combination of factors, including the use of longer, high accuracy, multi-out tools, reduced frequency of tool repair and higher stroke rates. Faster set-up of the presses between batch runs is another factor, especially as runs have been getting smaller in recent years as an increasing number of customers demand more frequent, just-in-time supply of lower quantities.


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Batten & Allen Ltd

Stevens Rowsell is a specialist precision sheet metal engineering company in East Sussex