No scrambling to finish turn at Lampkin Engineering
08 April 2005
A couple of years ago when the Californians were having terrible problems with their power generation systems, it was a small Yorkshire three-man subcontract machinist that was called upon to produce within 2Ĺ weeks special oil wiper rings and remake segmented metal seals some one metre in diameter.
The company, A A Lampkin Engineering is owned and run by three members of Britainís most famous family name in motorcycle scrambling and trials riding, and is located up a little lane in Silsden, just outside Keighley. At the time of the Californian crisis, the company had only manual machines but bucketfulls of machinist skills gained through supplying some 30 customers with parts such as clutch, carburettor and general parts for scrambling bikes, and at the other end of the spectrum, large components for power generation and valve industries. Quite often stainless steel shafts up to 2 m long, heavy electrical brush gear and seals up to 4 m diameter were machined.
The Lampkin business trio of David, Alan and Stephen are well known in their sector for the supply and machining materials most engineers have never heard of. These include centrifugal spun nickel brass and bronzes where spinning is used to rid the material of imperfections. Cast nickel brasses and very tough stainless steels can also be a common find on the workshop floor. The material for some components can cost up to 2,000 (pounds sterling) for each part even before they are loaded to the machine tools.
The company had already installed a vertical machining centre and had considered a CNC lathe but the decision was forced when they got the chance of a contract to produce 20 special 50 mm stainless steel shafts 1.5 metres long. At that point they decided to call up local lathe builder, Colchester Lathe at Heckmondwike, to see if it could supply a machine.
Ex trials rider and director David Lampkin takes up the tale.
We told them: "We have some threads to produce."
"What type," they asked?
"ACME," was our reply.
To which they responded: "Oh?"
We added: "The threads are about 600 mm long on a 1,500 mm shaft and left-hand"
"Oh" was the reply again.
Then we told them: "They are two-start, 4 tpi" and the line went quiet.
"But," he maintains, "Colchester came up with the goods in the form of its new MultiTurn 2000 flat bed combination lathe and offered a special macro written to produce the ACME thread form which won us the contract against another supplier that planned to thread whirl the shaft."
Colchesterís solution was to use a special parting tool insert set at a compound angle to rough out the thread form then repeat the cut on each flank before going through the whole process for each individual start of thread. "What amazed us, bearing in mind the toughness of the material, was the level of finish we achieved on each thread. We also had to produce a nut to check the machined thread on each shaft and again we could not believe how perfect they were across the whole batch of 20 parts. Once one part was programmed at the machine control and produced, it was then a simple matter of repeat cycle direct from memory in CNC mode.
The MultiTurn 2000 has a 400 mm swing over the bed, 585 mm x 165 mm in the gap bed and 1,250 mm between centres. It has a 250 mm chuck and an eight-station 30 VDI electric turret. A 8.4 inch colour TFT flat screen and keyboard is carried on the saddle with electronic handwheels and the machine can be used in manual or CNC mode.
Programming can be by teach repeat using the electronic handwheel, through macros or ISO, DNC or CADCAM at the Fanuc Oi-TB control. Toolpath verification is included on the flat screen.
The family business of A A Lampkin Engineering was set up in 1946 by Davidís grandfather, his father Arthur and his uncle Alan. It was Arthur who was often followed on Saturday afternoon black and white TV for his very successful exploits in scrambling - and Alan, another top-class rider, who still works in the business with David and the other director Stephen.
The factory is a true Aladdinís cave of machine fixturing and tooling set in several workshops that lead warren-like from one to another. However, the work produced demonstrates high traditional toolroom skills of milling, turning and extremely high levels of creativity to engineer a solution, which is obvious in the continued success of the business.
As David Lampkin maintains, prior to the MultiTurn he had never touched a CNC lathe; his turning skills were traditional centre, capstan and turret lathe based: "When the MultiTurn was first installed I looked at it and wondered how to work it. Now you canít get me away from it," he says and he even runs the machining centre and MultiTurn together in automatic cycle, walking between each machine loading, unloading and checking parts.
Primarily they use the control system macros with manual data input in at the Fanuc Oi-TB control to set up the first piece. "The fact we can use the graphic simulation is an important comfort factor and we can easily slow down into creep feed or zoom in whenever we are not sure. This is most important if you have a stick of specially imported material from Sweden costing over 1,000 (pounds sterling) in the chuck," he says.
With such a high level of background manual machining skills, David Lampkin confirms the machine will operate the way each of them want to work and "we can do it in our own time." To produce the first part he reckons it takes about three-quarters of the time it would take on a manual machine. However, with the six-station automatic turret there is no contest for repeat cycles, the consistency of size and finish and, of course, the time taken.
Because of the success of the two-start threaded shaft, the Lampkins have taken more business from the same customer and describes a bronze shaft with a 6 tpi Whitworth thread where they were concerned over the surface area of the thread form. "We decided to break the thread into four passes with a 0.1 mm final skim to take out any spring in the shaft. This really proved to us the level of repeatability we can achieve and the blending on the final pass was absolutely perfect," he maintains.
He follows on to re-live the recent turning of a large vee-belt timing pulley with a trapezoidal groove. "When you lift it out of the machine and look at the surface finish in the groove and across the turned face, achieved because of the constant speed capability in the control, you could never equal this on a manual machine," he says. Then he comments with a smile: "You look at the part and feel really proud of what you have just achieved Ė but then, all three of us love engineering and making things. The youngsters of today donít know what they are missing!"
Tel: +44 (0) 1509 602667
PR Company Contact
Tel: +44 (0) 1634 832221