Wanting to increase its sheet metal working capacity , privately-owned, GBP2m turnover Westwood Automation, Plymouth, purchased a GBP500,000 RAS CNC Multibend Center 79.26.

Wanting to increase its sheet metal working capacity for a range of lock-up bicycle shed and garage tooling cabinets and similar products, privately-owned Westwood Automation in Plymstock, Plymouth, self-financed its own investment in a GBP500,000 RAS CNC Multibend Center 79.26. The investment in CNC folding, which includes installation, is a considerable one for a privately-owned company employing 35 and turning over GBP2m/year. The investment is planned to amortise in five years.

The savings, compared with programmable and CNC press brake operation are impressive.

Production time on some sections have been reduced by 70% and massive reductions in set-up times also realised - in some cases cut from 60min to under 1min.

The tooling cabinets used to comprise 13 panels, now they need only nine.

For example, the drawer front has been redesigned and integrated into the base and produced from one blank.

So one drawer, with integrated front, is finished in 150sec and welding and bolting operations have been eliminated.

Consequently, Westwood is assembling 70 cabinets/day against a maximum of 40 previously.

Owner of Westwood Automation, Gerry Hazelwood, OBE, said that previously it took typically 90sec to form a part with eight bends on a pressbrake.

The Multibend Center completes the same part in under 30sec.

Pressbrakes would produce 40 parts/h against 122 parts/h in the Multibend.

The Multibend Center has also made significant cuts in prototyping time: a series of six new office cabinets were prototyped in a few hours during an evening shift (Westwood operates on a 2 X 10h shift pattern).

Previously, such work would have been done at weekends in order not to disrupt production.

In operation, the Multibend Center picks up blanks from a stack and presents them to a measuring station (while a previous blank is still being folded).

Note that the measuring centre can use the flanging notches as the datum.

It saves having to 'square up' the blanks in a guillotine or as part of one of Westwood's Amada turret punch press or laser profiler programs.

An optical system in the measuring centre triangulates the part to fix the true square and transmits offset data to the CNC.

An AC servo-driven blank manipulator, which has a rotary positioning accuracy of 0.001deg.

takes the blank and positions it, at speeds up to 2100mm/sec, at the bend line.

Any taper present in a blank is restricted to the flange wall, so the 'box' or folded blank is square and true.

Tooling is essentially a range of different widths of clamping 'fingers'.

Two belt-driven robotic arms, one each side of the clamping beam centre-line, select fingers from magazines at either side of the beam and rapidly position them.

Typical tool changeover times, job-to-job are around 10sec.

A clever piece of tooling is an indexable corner tool for getting into folded corners to do a back fold.

When a blank is gripped between the top tool and table,, a servo-driven folding beam folds upwards or downwards as required, in tenths of a sec.

Control is through a dedicated RISC microprocessor running RAS software.

User-friendly conversational programming, combined with 'artificial intelligence' protocols allow the operator to input single and families of, automatically including all axes, collision checks and toolchange strategies.

RAS also builds presetable, programmable and CNC electro-hydraulic folders, supplied through John Murray Machinery.

One watched the Multibend Center quietly and efficiently working through a stack of pre-notched and punched blanks.

Completed, the folded panel was delivered to a growing stack.

The setter-operator, in between other jobs, walked by, took a professional view at the job-in-progress, checked blanks stack, did a quick routine check on the control console, and walked off.

Capacity of the German-built Multibend Center 79.26 includes a working length of 2560mm X 2mm thickness in mild steel, 1.5mm in stainless steel and 3mm in aluminium.

Maximum finished part length is 1500mm.

Working height is 1000mm.

RAS, located in Sindlefingen, near Stuttgart, builds a smaller version - the 79.22 - with a working length up to 2160mm.

The company also builds its Flexibend, manually-operated, programmable folding machines with a working length of 3200mm and 3mm thickness in mild steel.

Special-purpose, as well as a variety of manually-operated folding machines, are also built by RAS.