The installation of machining STRATEGIST, off-line computer-aided programming (CAM) software by NC Graphics (Cambridge) at GT Tools, has created an air of self-sufficiency to its CNC machinists which are now looking after their own department, controlling workflow and producing machining programs they are confident will work. This has resulted in an overall saving in lead times and shorter machining cycles equating to around a 50 per cent increase in productivity.
Maintains Richard Mee, works director of the 90 man company based in Sutton-in-Ashfield, Nottinghamshire:
"The machining STRATEGIST installation has influenced the way we work to such an extent that it has been one of the most exciting things that has happened to the company in the last three years. Considering it was not expensive, this means payback is quick and, most important, has been the initiation of roll-on benefits with our team of people on the shopfloor."
Richard Mee describes how the company produces around 120 tools a year for plastic injection moulders that weigh up to 12 tonnes and measure up to 2 metres.
"With machining STRATEGIST installed and the way we now work there is no reason why we can't improve output to 200 tools a year without increasing our production costs. That is a tremendous boost in productivity and we know the workforce will be with us all the way because they are in control of what they are doing," he insists.
For GT Tools, the benefits of using CAM are well defined, having systems installed for some 15 years out of the company's 25 years toolmaking history. Like many toolmaking companies, it was originally established by two highly skilled craftsmen with a plan linked to a steady business growth. This culminated in the relocation of the company to its present 30,000 ft2 facilities.
But the steady, positive growth of GT Tools changed four years ago when a London-based consortium, purchased the business. Since then the consortium has invested over �1 million, including a new 500-tonne Sandretto plastic injection moulding machine and an extension to the building to house it. The new machine provides the capability to conduct pass- off trials for customer moulds and also run short pre-production batches for customers, such as those in the automotive sector.
Following the company's investment in three seats of the NC Graphics software, Richard Mee, explains why they changed from using 10 seats of another system, which had been installed in the drawing office for some 15 years.
“We had started to exceed its capability and although it had helped to keep us competitive, the capability of our guys on the shopfloor had become way ahead of the software. They are all very skilled toolmakers, who have always been encouraged and trained to do the best job they can. So as part of our internal improvement policy, we decided to look at what other dedicated CAM packages could offer and it transpired that NC Graphics could give us the edge we needed."
Richard Mee is very complimentary on how NC Graphics helped in the evaluation of its software.
"They were prepared to let us evaluate the system on-site without any commitment from us," he says. “The machining STRATEGIST package was connected to nine CNC mills and two days of on-site cutting trials were provided. "This was followed by one day a week support for the next five weeks," he says and continues, "there are very few companies around that are prepared to go to such lengths to prove what they can do and the resulting installation has lived up to everything that was promised."
Richard Mee feels the way the team works under an 'empowered' philosophy is one of the main reasons for the company's continued success. He says:
"At present, we have 75 people including five apprentices on the shopfloor. They work two shifts with the majority covering the day and eight provide a full 12 hour night shift. Everyone on the CNC section has been trained so it does not matter which shift they work, they still have the capability to control what is done."
He explains that there is no point having only a couple of key people trained, it should apply to everyone.
"Of course, some people take longer to learn than others, but we have a team of people that are encouraged by the management and their peers. We discuss problems, they try to resolve them, and that's how the team works together."
Prior to the installation of machining STRATEGIST the design office would have produced the NC cutter paths for mould tool machining. However, now that all the NC code is created on the shopfloor, it is now planned that EDM electrodes are programmed the same way with the code going straight to the machine CNC control via DNC, using customised post processors written by NC Graphics.
The quality of the cutting path produced by the NC Graphics systems has certainly helped build the team working environment. As Richard Mee says:
"The toolmaker on the job is now, in effect, tied to the machinist, who is tied to the designer, so they all get together and form tasking teams. They agree the project, discuss what stock material is needed, how much shut out is required and where the flash line will be. They are also responsible to pass-off each others work."
As the software is capable of maintaining a constant surface offset path, when the mould is roughed out, it is left with an exact finishing cut. This allows GT Tools to carry out more consistent finishing operations without problems such as digging in and generate higher surface finish in less time. The capability of the software is further exploited with the adoption of Depo cutting tools that are now used for both rough and finish cores and cavities.
The accuracy of the data from the CAM system also allows GT Tools to start roughing on the day shift, and follow through with finish cutting during the night and at weekends.
"It doesn't matter if it runs for eight or 10 hours," says Richard Mee, "because we have the confidence that the roughing cutter has produced exactly what it was programmed to do, leaving a constant stock for finishing. Of course, this level of confidence takes months to gain, so the benefits are only just being fully reaped. You also have to bear in mind that we had to do this on live jobs, there was no room to practice and any problems created by the software would require either repair machining or replacement of the mould. But I must say, there were none and we are now much further along the learning curve with very high levels of confidence."
He compares a recent mould tool, which would have required a machining time of 4.5 hours using the previous CAM system. This was completed in just 1.5 hours with code generated from machining STRATEGIST.
"All in all, we should be looking at total savings of between 30 and 50 per cent, with various levels of input coming from every department. The accuracy of the cutting path, the speed of machining, reduced 'bed out' time for the bench finishing of the moulds, all these elements impact on the time required to complete the tool," he insists.
Taking a long term view he says:
"Any reduction makes us more competitive and it has become an important proactive step to help in an aggressive world-wide market with our customers in South Africa, Brazil, Hungary and North America.”
As part of the purchase deal NC Graphics provided a comprehensive training package with the three seats of machining STRATEGIST. Four of GT Tools' staff have been away for training, including the two team leaders.
"The rest of the training will be carried out here on the job," says Richard Mee, "with the people that understand the system showing others how it works. However, there is a provision for the two team leaders to go for further training with NC Graphics at Cambridge, on a more advanced course."