One Friday morning in August 2005, a mince pie arrived in a taxi at the Crewe works of subcontractor, Vector Precision, with the request that the crust be reverse-engineered and a mould made for its volume production. Owners Tony Bourne and Les Ford set about measuring the dimensions of the nine thumb impressions around the periphery of the pie, which was the unique feature of the product. It then took them around 15 minutes to program their Hurco VM1 machining centre to mill the required mould.
Said Mr Ford, "The program was written using Hurco's conversational programming software, for which we had bought the supplier's 3D mould and simulation packages. The resulting program consisted of just seven lines, whereas the number of G-code instructions they represented was over 80,000 and took 20 minutes to download to the VM1.
"To prepare the program conventionally would have been error-prone and taken two or three days. It would not have been economic so we would probably have had to turn down the job. As it was, we delivered the aluminium mould to the customer on the Sunday, ahead of the bank holiday Monday deadline."
Although a job of this complexity is exceptional, Mr Ford commented that it illustrates the power of the Ultimax control system control and software, a copy of which he uses off-line rather than on the shop floor so that the machine is not tied up unnecessarily. What is not exceptional is the one-off order; most of Vector's work is in batches of one- to 20-off, for which conversational programming is ideal, as it shortens the non-productive part of the manufacturing process.
Mr Bourne is a chartered engineer and time-served toolmaker, while Mr Ford, also a toolmaker, was for many years a manager of another subcontracting business in the area. Having established their business in July 2001 with a manual milling machine and lathe, they set about designing and manufacturing automated machinery for the MOD as well as pharmaceutical and food companies. Vector still undertakes work of this type, and is currently rebuilding two round (ie cartridge and bullet) gauging machines for British Aerospace, at the same time converting them to measure a different gauge of ammunition.
Now employing six people in a larger unit in Radway Green, near Crewe, the ISO 9001:2000-approved business has diversified to serve also the rail and aerospace sectors. Forty per cent of its turnover comes from providing a breakdown repair service, from troubleshooting and design through to component production and machine refurbishment in short time scales, allowing customers to resume manufacture quickly.
When they moved into the current premises in 2003, Messrs Bourne and Ford still did not have any CNC machines, but soon bought a second-hand Hurco knee-type mill from a local firm. Quickly they realised how much faster and more accurate it was than the manual machine, so a year later they decided to invest in a new Hurco VM1 machining centre with 660 x 356 x 457 mm working area and 16-station magazine for 40-taper tools.
Advised Mr Bourne, "We looked at different machines on the market but liked the simplicity and user-friendliness of the Hurco control software so much that another Hurco machine was really a foregone conclusion.
"At the same time, Hurco upgraded our CNC mill with an electronic, variable-speed head so that it would use the same programming software, giving us production flexibility."
Typical prismatic machining jobs now coming off the CNC machines include a thread-milled acetyl assembly for a quiche-dosing machine, and stiffener plates for a fiberglass moulding that forms part of the cab for an off-road vehicle. Positional accuracy of each drilled and reamed hole is ± 0.01 mm, so the plates fit precisely to the moulding when assembled with dowels.
When the time came to upgrade its turning capacity from manual to CNC, Vector turned again to Hurco for a TM6 lathe, which has a 254 mm maximum turning capacity and 12-station turret for fixed tooling. It uses a conversational programming system similar to that on the manufacturer's machining centres, allowing efficient one-off and small batch production. The operator simply inputs the profile dimensions and the control does the rest, calculating all intersection points, even for blend arcs and chamfers. It also sets speeds and feeds according to the tooling selected, while automatic constant surface speed calculation ensures good surface finish on the machined component.
Components turned by Vector range from small gauge, solid copper bullets through prototypes for cold-rolled products to driving bands for automated machinery that need to be accurate to 0.01 mm total tolerance. Other examples of precision turned parts are taper threads for BSPT fittings; and, for specialised vehicles such as dust carts and fire engines, 40 mm diameter steel shafts that need to have a near-ground 0.8 Ra finish to take a bush, and a tolerance of +0, -0.02 mm.
Vector is now in a period of consolidation, as despite expanding into the adjoining unit in March 2004, there is little room to install further machines. Any increase in business will be accommodated by moving from a single shift plus overtime to a double shift. They are actively seeking extra mouldmaking work, such as the mince pie mould, as well as contracts to produce other complex 3D parts for which its CNC machines are proving ideal.