automotive sector report
High
performance
engine tuner
boosts output
thanks to
machine tool
control retrofit
The Heidenhain TNC
320 control retrofitted
by Halifax Numerical
Controls is delivering a
dramatic increase in
productivity for CNC
Heads.
A finish machined
cylinder head. Based
in Stockport, Cheshire,
CNC Heads is part of
Whitegates Garage, a wellestablished
company
owned and run by Richard
Wood. Specialising in
motor sport, competition
engines and high quality
vehicle repair and
maintenance, CNC Heads
has a well-earned
reputation for high quality
and performance. It has
gained this by applying
strict quality control
standards to every aspect
of its business.
Getting ahead
STOCKPORT-BASED CNC Heads makes highperformance
gas flowed cylinder heads. The aim is to
achieve optimum performance, whether for a race car or a
road car; the secret lies in the accuracy to which the new
head is manufactured. The process begins with the
scanning of an original cylinder head using digital
scanning technology. This information is analysed by inhouse
tuning specialists and converted into computer code
that can be used to modify valve throats, chambers and
ports via CNC machine tools.
The result is a guarantee that every feature on the
cylinder head is machined to the same dimensions and
tolerances, boosting power output in the process. At the
extreme is a Mitsubishi EVO 400 engine for a dragster. The
original engine developed 300/320 hp: with a new cylinder
head and other engine tuning the figure now tops 1200 hp.
Typically you get a 130 hp gain from a full engine tune,
with 40-50 hp attributable to head modifications.
When the company’s success sparked an increase in
demand, one consequence - extended delivery times -
became unacceptable. Increasing capacity with extra
machine tools was dismissed on the grounds of cost, space
and availability of skilled operators. The alternative was to
improve the performance of the three Bridgeport Interact
machining centres currently in use.
‘The machines themselves are perfectly good for the job,’
says CNC Heads’ Alastair Heywood. ‘The real problem lay
in the capacity of the control system, which was struggling
to cope with the size of the programs that we are creating;
and the processing speed (30 milliseconds/block of
information) was slowing down the machining process. So,
the decision was taken to, initially, retrofit a new control
system to one of the machines.’
The decision to opt for the Heidenhain TNC 320 control
system and to work with Halifax Numerical Controls
(HNC), an approved Heidenhain TNC retrofitter, was
based on the cost of the Heidenhain system and, more
importantly, Heidenhain and HNC’s ability to maintain
basic machine functions.
Since retrofitting the first machine there has been a
marked improvement in machine performance and ease
58 MWP march 2008
of use. ‘The new control has many benefits over the old
system,’ says Heywood. ‘For instance, the hard drive is large
enough to hold complete programs, so we are not having to
‘drip feed’ them any more. Program data transfer is much
simpler as we can now use a USB memory stick. We also
have tremendous support from HNC. This has taken their
involvement beyond that of just a simple retrofit job. They
have developed software to improve the automatic
toolchange system as well as software that speeds up the
referencing of the machine should it crash, which saves
time and avoids the risk of damage to a cylinder head that
may have had a lot of time spent on it at that point. In fact,
with any problems that we do encounter, we are reassured
by HNC always having an answer.’
The retrofit was completed within a week, with
disruption minimised as HNC did the work during a
holiday period. This was crucial to CNC Heads as its
machines were running 24 hours per day at the time just to
keep up with current orders. The first day back after the
holiday HNC went through the operation of the TNC 320
with Heywood and the retrofitted machine was producing
parts the same day. Within three days any questions/issues
had been resolved and the machine is now running to its
full potential.
With the processing speed improved from 30 down to
around 6 milliseconds, machining cycle times have been
reduced dramatically - a batch of 20 heads can now be
produced in the same time as it previously took to machine
six. Accuracy and repeatability are also improved, which
enables CNC Heads to further boost the performance of
the heads. Says Alastair Heywood: ‘Comparing our old
control system with the new Heidenhain TNC 320, the
difference is huge, both in the improvement in
productivity that we are seeing and in the ease of use that is
making programming the machine at the control so much
faster. Having witnessed what the TNC 320 and Halifax
Numerical Controls can deliver, we will be looking to
upgrade the other two machines as soon as possible.’
www.hncl.co.uk
www.cncheads.co.uk
www.heidenhain.co.uk
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