Automotive cylinder head manufacturer's CNC system could hardly cope with the growing size of programs so a new, faster CNC with more capacity was retrofitted to one of the machines.
CNC Heads, located in Stockport, UK, manufactures high performance gas flowed cylinder heads.
The secret of the performance boosts gained by CNC Heads lies in the accuracy to which a head is manufactured.
The process begins with the scanning of an original cylinder head using the latest digital scanning technology.
Complex digital information is then analysed by in-house tuning specialists and converted into computer code that can be used to modify valve throats, chambers and ports via computer numerical controlled (CNC) machine tools.
The result is that CNC Heads guarantees that each and every feature on the cylinder head is machined to the same dimensions and tolerances, achieving major gains in power output in the process.
At the extreme is a Mitsubishi EVO 400 engine that powers a drag racing car.
The original engine developed 300/320HP: with a new cylinder head and other engine tuning this figure is now in excess of 1200HP.
* Improving performance - CNC Heads typically achieves a 130HP gain from a full engine tune, with 40-50HP being directly attributable to cylinder head modifications.
However, the company's success led to a marked increase in demand for cylinder heads that, in turn, was causing an increase in delivery time, which was becoming unacceptable.
The first option, dismissed due to cost, lack of space and availability of skilled operators, was to increase capacity by investing in additional machine tools.
The second option was to improve the performance of the three existing Bridgeport Interact machining centres that are currently in use.
Alastair Heywood at CNC Heads explained that the machines themselves are perfectly good for the job they are doing, but the real problem lay in the capacity of a machine's CNC system.
The existing CNC was struggling to cope with the size of the programs that CNC Heads is writing.
Also the processing speed (30 milliseconds/block of information) was slowing down the machining process considerably.
So, CNC Head initially decided to retrofit a new control system to one of the machines.
* CNC selection - like any other business CNC Heads investigated the market and had a number of options when it came to the retrofit and choice of control system.
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 following.
* The Heidenhain system was a very attractive proposition in terms of cost.
* Heidenhain and HNC are able to maintain basic machine functions - something that other control manufacturers could not do, said CNC Heads.
* Machine performance improved - since retrofitting the first machine CNC Heads has noted a considerable improvement in machine performance and ease of use.
"The new control has many benefits over the old system," said 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".
Heywood continued: "We also have had, and continue to have, tremendous support from Halifax Numerical Controls.
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".
* Retrofitting - the retrofit was completed within a week, with disruption kept to a minimum as HNC did the work during a holiday period.
This was crucial to CNC Heads as its machines were running 24h/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 that very same day.
Within three days any questions/issues had been resolved and the machine is now running to its full potential.
* Outstanding improvement - the improvement in performance has been astounding, said Heidenhain to manufacturingtalk.com.
The processing speed has increased from the original 30 milliseconds to around 6 milliseconds.
Also cycle times when machining cylinder heads have been reduced dramatically.
CNC Heads claims that a batch of 20 cylinder 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 cylinder heads it manufactures.
Heywood concluded: "Comparing our old control system with the new Heidenhain TNC 320 is like comparing chalk and cheese.
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.".
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