EDGECAM Solution to Plastic Molders Bottleneck

November 25, 2002

Torfield Engineering, based in Tonbridge, Kent, a recent convert to the
benefits of Pathtrace's EdgeCAM system is already reaping rewards with work
throughput increasing by some 30 per cent. The software was introduced to
the specialist plastic injection mould making company by production
director, Malcolm Ward who has nearly 20 years experience of using
Pathtrace's off-line programming software.

When Malcolm Ward joined Torfield Engineering three years ago, the
30-year-old company was making only steady progress. The creation of NC
code to make electrodes for three EDM sink machines was very slow, being
initially worked out on paper followed by programming on the machine. "It
was so inefficient," says Malcolm Ward, "so I said 'you really need EdgeCAM
here' and sold the concept to the managing director. Since we have
installed EdgeCAM, business has significantly improved and we can be
machining within an hour of receiving a job."

A suite of mould tools produced by Torfield can be anything from a single
assembly to a batch of 10 multi-impression tools. The components produced
by its tooling ranges from disposable medical parts, to white goods
components, and takes in areas such as packaging and the building industry.
Medical components include needle butterflies for hypodermics, which have
two flaps that are taped to the skin to hold the needle in position,
through to breathing pipes to assist with windpipe injuries. All these
diverse parts are now manufactured with the aid of EdgeCAM, as Malcolm Ward
states: "We have made some very intricate tooling which would have been
impossible before."

Malcolm Ward claims to be one of the very first users of the Pathtrace
software over 18 years ago. He reflects: "In those days it was on a single
51/4" floppy disk and I have followed its development ever since. As the
software grew in complexity and features, it required two floppy disks, and
so on until the hard disk drive was invented. Over the years it has
progressed in leaps and bounds."

Claims Malcolm Ward: "EdgeCAM is easy to use, even for a novice. It leads
you through the task with the icons showing exactly what they do. You can
even put what icons you like where you like, it's so flexible and simple.
The training courses run by Pathtrace are very thorough, with
stage-by-stage tuition. And, when you go back to your place of work, you
always have the help line support which I have used on two occasions, and
both times Pathtrace's engineers have been able to put things straight very

Today, EdgeCAM helps Torfield satisfy its customer-base of plastic
injection moulders. Of the 100-plus companies on the customer list, around
10 per cent will be active at any one time. Rarely do they see paper
drawings, as more and more, electronic files are sent for quotation. "We
prefer it that way as we can convert it into a solid model, and literally
see in 3-D what we are quoting to produce," says Malcolm Ward.

He goes on to say: "Today we can make a mould for just about anything in
plastic. We are often sent physical parts, in which case I will sit down
and model them up on the screen and then transfer it to our designer, who
inserts the heating and cooling channels as he develops out the moulding

As well as electrodes for internal use, Torfield also produce them for
other EDM users. Currently, this accounts for around 10 to 15 per cent of
the turnover. "It's a nice addition to our everyday business," Malcolm Ward
says. "If someone sends us a file for an electrode to be produced by the
next day, we normally try to fit it in because we know EdgeCAM is so

Torfield has found there are no translation problems between EdgeCAM and
its in-house CAD design system. Malcolm Ward confirms: "We work very
closely with the designer producing the plate work around the model. The
code is then created in EdgeCAM and we machine all the electrodes. For
smaller jobs, or if the designer is busy, I can complete the whole job in

Most of Torfield's injection moulds are under 350 mm3. Bolster plates are
produced from a EN8 or P20, while the block cavity and core is produced
from nickel chrome steel, such as 2767, P55 or G1, which is rough machined
in its soft state. After hardening to Rockwell C48-52, the finished shape
is sunk into the block using the copper electrodes which have also been
produced by EdgeCAM.

The electrodes are machined to suit the specific requirement of the mould,
as Malcolm Ward explains: "We have a spark gap allowance on a roughing
electrode of 0.5 mm and 0.05 mm for finishing. We can apply this in
EdgeCAM, make one model, decide what tool we're going to use, and then
build into the Pathtrace program an allowance for either leaving on or
removing metal."

The turnaround for a typical mould tool is generally between five and eight
weeks, although some complex tools may take up to 14 weeks. At the other
end of the spectrum, Torfield has just finished a small, hand-operated
moulding tool in just nine days. The tool was a two-material mould made in
steel because the customer wanted to mould one part in one type of plastic,
then mould around the first moulding with another material.

As Malcolm Ward explains: "This was an experimental job, very small and
intricate using very fine pins of 0.4 mm diameter. We had to ensure these
pins would pass right through the inside of the tool for location. The
mould worked very well first time."

Malcolm Ward explains how they have modifications to carry out on most of
the tooling they produce. "With the pace of development today, the customer
is not always certain at the beginning of a project what the final
component will look like. As we work with the customer, we can advise on
the tool and can usually solve most problems. This is where EdgeCAM proves
to be absolutely vital as a support tool. We can quickly take-in
modifications and create a new program without any worries about errors."

With work throughput increasing by almost a third, the existing machining
centre is now proving to be a bottleneck. For the future, plans are in
place to buy a high speed machining centre, which will involve some
significant investment. However, Malcolm Ward is very confident: "EdgeCAM
is so productive, it could keep a high speed machining centre busy all

For more information about EdgeCAM, please visit www.edgecam.com or email Email Contact.

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