An EDM toolmaker-come-general subcontractor wanting to expand into prismatic metalcutting has bought a Hurco machining centre to offer a one-stop service

What should a toolmaker-come-general subcontractor with a shop full of electric discharge machining (EDM) equipment buy when he decides to expand into prismatic metalcutting? The answer, according to Chas Hudson, managing director of Birmingham-based Forum Services, is Hurco machining centres. The subcontractor's customers had for some time been pressing the company to provide a one-stop-shop including milling of 3D forms onto wire-eroded moulds and dies.

Even more encouraging was that over 30 existing customers were interested in giving prismatic machining work to Forum because of the quality and speed of its EDM service.

So at the end of last year (1999), with limited knowledge of machining centres, Chas researched the market and discovered a strong consensus among his peers in favour of Hurco.

The principal reason given by more than a dozen subcontractors was the user friendliness of the 'Ultimax' twin-screen control, which was said to be far easier to operate than all other CNC systems.

One 12 inch colour monitor displays graphical representations of the component as it is being created by manual data input (MDI) whilst simultaneously on the second screen the NC program is automatically generated - all in background while another component is being produced on the machine.

Additionally, some Hurco users that Chas spoke to had been using their machines for over 15 years, indicating longevity beyond that which is usual for a machine tool.

The price was also considered to be competitive.

Consequently in February 2000 Chas purchased a Hurco BMC 4020 HTM machining centre, which has a X:1,020 mm / Y:510 mm / Z: 610 mm working envelope, 8,000 rpm spindle (although a high speed spindle option is available) and 24 m/min rapids in all axes.

As part of the package he also bought a 4th axis for fully interpolative 4-axis machining of complex parts.

Forum has recently invested œ1.1 million in new equipment, including a CADCAM system capable of importing designs from customers and producing programs to run on the company's 11 wire EDM machines and the machining centre.

Alternatively, some components are reverse-engineered by digitising a prototype on a co-ordinate measuring machine, after which the data is processed through the CADCAM system to produce the NC program.

However, as Chas points out, about half of the jobs come in as drawings and many are more quickly and easily programmed by MDI at the machines.

In any case, the CADCAM department may be occupied on another job at any given time, and this will become more likely in the future when there are several Hurco's on site.

After a couple of days' training on the PC-based Ultimax control, a Forum operator with no previous CNC experience can produce viable programs to run on the Hurco machining centre, helped in part by powerful built-in routines such as a very fast pocket roughing macro.

A typical example of a prismatic component programmed by Forum at the Hurco control is a set of steel plates for a plastic injection mould involving machining cycles comprising relatively simple holes and cavities.

The conversational programming is said to be logical and self explanatory, whilst the option of ISO (G-code) programming is retained for the more experienced programmer.

An Intel Pentium processor, 128 MB of RAM and a 2 GB hard drive provide the requisite built-in power for these operations, as well as for running optional software such as direct import of Autocad DXF files and high speed profiling.

Around half of Forum's wire edm work is from other toolmakers and encompasses moulds, dies, cut-off tools, and stamping and rolling units.

The remainder is to fulfil direct toolmaking orders as well as various component production contracts received from firms such as gun makers and jewellery producers.

The Hurco machining centre is also deployed across a similar spread of toolmaking and production applications.

In the first five months of operation, some 15 metalcutting jobs had been completed in batches of 100 down to one-off, the majority programmed by MDI on the Ultimax control.

Two projects required use of the 4th axis.

Tolerances go down to 10 microns total, well within the compass of the machine.

Work is building quickly and it will not be long before Forum needs to install the next Hurco machining centre.

Indeed, Chas Hudson's intention is to go as strongly into metalcutting as he did into wire EDM during the 1990s.

Ten years ago he started with one EDM machine and Forum is now the biggest wire eroding subcontractor in the Midlands with an expanding die sinking capability, selling well in excess of œ1 million of machining time annually.

It would be a brave person who would bet against Chas developing a similarly successful metalcutting side to the business with his Hurco machining centres.