Emerald Group Publishing Limited
Copyright © 2000, MCB UP Limited
Heidenhain in control at AIM
Heidenhain in control at AIM
Keywords: AIM, Heidenhain, Machining, Control systems
Like all precision aerospace contractors, AIM based in Cleveland, North Somerset, needs consistency of production, so throughout its factory each of the 28 CNC machining centres and milling machines features Heidenhain control systems. Says Managing Director Rob Kendall:
The Heidenhain system gives us total flexibility with operators and work load, so we can reschedule parts quickly from our smallest 500mm by 600mm worktable to our largest 2.5metre bed machine.
Founded 26 years ago and now based a short distance from the Clevedon exit of the M5, AIM has built a good reputation for supplying precision machined parts with aerospace industry taking 70 per cent of its business. It also machines parts for the car racing industry and other businesses where precision, quality and service are critical.
Batch sizes range from just one to 20 for most work; however, continuous production is used via dedicated lines of machines for certain aircraft parts. The company, which began life making special machinery and now employs 30 people, also builds mould tool, jigs, fixtures and welded fabrications.
Ken Kendall, Chairman, describes how he bought the first Heidenhain control on a Bridgeport machine tool some 14 years ago and now has 17 Interact 4s, eight VMCs ranging across a 1500 portal high speed vertical, a VMC 720 and VMC 800 with digital drives, a Mikron UME 900 universal milling and boring machine and two Beavers:
Although the controls are as varied as the machine types and ages, the common factor reads across ensuring familiarity for the workforce, thus reducing the likelihood of error and ensuring total confidence from job to job.
So dedicated is AIM to the Bridgeport pack that it is also used by the Leicester builder as a "beta" test site. So when Heidenhain introduced the new slim-line TNC 310 contouring control it was decided to get BRS of Bridlington to retrofit the system along with a new drive package during a re-build of the newest of the Interact 4s which had a TNC 150 system.
The Interacts are used to produce a family of aerospace parts and the retrofitted machine used to carry out a relatively simple task using very precisely ground and set milling cutters for machining the Airbus panels. Following the upgrade the machine can now perform any machining operation including full 3D work on the panels due to the power and advances made with the new Heidenhain system. Says Rob Kendall:
We produce a kit of parts for Airbus made up of a large elliptical blank that is profiled around the outside and totally machined over the top.
An inner blank of thin sheet is profiled, and a little spout is produced on a CNC lathe:
BAe ring up on a Monday to tell us how many kits they want to replenish their stock and we deliver from our buffer store on Tuesday. With the original TNC 150 control we were limited in the operations we could perform. Now with the TNC 310 we can profile and machine the outer panels flat and without distortion even though they are as thin as 0.75mm in places. The control has more functions than we need for work of this type but it gives us total flexibility to do other machining if there is overload elsewhere in the factory.
The managing director is now thinking there is little point in changing machines like the Interacts as they get older when they can be significantly enhanced with a re-build and the latest control added for half the cost of buying a new machine.
He extols the flexibility of the TNC control and quotes file management as an example:
We have some jobs with up to four different programs. We are able to preset the tools in the carousel and go through any program by accessing the control's file manager with instant call-up.
To program a path function, on the TNC 310, for instance, means the operator simply presses a key to initiate the plain language dialogue. This asks questions and gives prompts which help capture the information needed. Once a program is completed, the control graphically simulates machining in plan, three planes or three dimensions. Fixed cycle macros can also be easily constructed.
Control capacity is particularly important for some of the more complex three-dimensional surfaces that AIM is asked to produce. Rob Kendall recalls making a large mould tool for forming plastic aerofoil blades to be used in the construction of a wind tunnel. Each blade was about 1.3 metres long and the parting line of the mould ran in line with the twist of the blade:
If we'd tried to machine it using a control other than our TNC 426 we would have had to drip feed data from our shopfloor PC. Even the designer of the part was sceptical that we could machine it properly. But we took IGES files from the customer and a model of the blade and, once machined, the parting lines on the two halves of the mould fitted perfectly and the customer was over the moon! We have no plans to go away from using Heidenhain. We know, the control, everyone likes it and they have proven to be such good systems over the years, so why change?
Details available from Heidenhain (GB) Limited. Tel: +44 (0) 1444 247711.