Derbyshire, UK - Handily located close to an airport in England’s industrial and geographic heartland, a specialist component manufacturer is discovering that the sky’s the limit in the field of virtual machining.

While planes fly noisily overhead, on the factory floor at Paul Fabrications in Castle Donington, Derbyshire, in England’s eastern Midlands, work continues apace to keep up with growing demand from the aerospace sector.

Having successfully weathered the worst of the recession, this high-tech precision manufacturer of custom-made components, complex fabrications and high-value assemblies was enjoying a fruitful year in 2010. However, one particular job — forming and shaping a component in a Rolls-Royce airplane engine — was proving to be problematic. With deliveries falling behind and problems on the factory floor, computer software brought the project back on track.

Paul Fabrications was already using CAD/CAM technology, but as it struggled to find a solution for a job on a titanium engine access plate, project engineer Dave Rolley turned to Sandvik Coromant area sales engineer Paul O’Brien for help.

“We asked Sandvik Coromant to come in and look at it with us, because it was a large volume job,” says Rolley. “We were falling behind with deliveries, and it was causing us environmental problems on the factory floor. We wanted to reduce time so we could get deliveries out to the customer, but it was also turning out to be a very noisy operation.”

Noise can be a major issue on the factory floor.

Machining Challenges

There were several challenges, not least the extensive machining involved in cutting and maintaining the bottom of a pocket to within 0.004 inch of flatness (the thickness at the pocket base ends up 0.079 inch thick, which is less than half the original material thickness, and covers 90 percent of the component area) as well as trying to reduce cycle time to free up capacity while improving tool life to provide a more cost-effective solution.

Due to the concerns Paul Fabrications had over capacity on the machine, Sandvik Coromant could not carry out any trials onsite without further affecting deliveries to the customer. To overcome this problem the drawings and data were taken to the Sandvik Coromant Aerospace Application Center to determine what improvements could be made. Using CG Tech’s Vericut simulation software to understand the current process, the problems with the machining strategy immediately became apparent.

O’Brien says “Using the experience and knowledge we have in machining strategies and programming methodologies, we were able to provide a customized solution using the Master-Cam X2 Cam software. Also, by using our CoroMill 300 and CoroMill 490 concepts with PL geometry in grade GC1030, we were able to halve the number of tools required from four or two.”

Back at Paul Fabrications, the results were immediate. “The new plans showed we could reduce the previous cycle savings by a further seven minutes,” says Rolley. “This may not sound like much, but with more than 2,500 components over a 12-month period, it soon mounts up.”

Numerous Benefits

The time savings, in conjunction with a different type of tooling that reduced insert costs, added up to a total savings of some $43,000 over the year. Meanwhile, an additional seven weeks’ capacity was freed up, along with a reduction in the number of cutting tools and inserts required.

A further benefit was also apparent on the workshop floor. Colin Last, the first engineer to work in the factory with the new tooling, says: “Working on these components changed dramatically. One of the noisiest jobs in the factory turned into one of the quietest.”

There are also quality and reliability benefits. “When you come to actually machining the job, you are 99 percent sure that it is meeting the tolerances required,” says Rolley. “If you don’t need to develop the job on the machine itself you don’t waste valuable manufacturing time or components. It becomes expensive if you scrap components trying out different methods on machines, but with virtual machining you can change strategies, change the method and see the results instantly on the screen without any physical waste.”

Flexibility is also a key factor in virtual machining, says O’Brien. “In the shorter term,” he says, “we can take a headache away from the customer. In the longer term, although we mainly use this process in aerospace, it can be applied to any sector — automotive, nuclear, general engineering and even for designers.”

For Sandvik Coromant, the more that customers such as Paul Fabrications use this kind of technology, the more it underlines its commitment not only to R&D and new product introductions, but also to the aerospace industry.

At a glance

Formed more than 70 years ago, Paul Fabrications is a high-tech precision manufacturer of custom-made components, complex fabrications and high-value assemblies in the aerospace, nuclear and engineering industries. Based near the East Midlands airport, near Derby, in the U.K., the company maintains business activities not only in the domestic market, but also across Europe, Asia and the United States.

EMPLOYEES: 109
REVENUES: $17 million
FACILITIES: 5-axis milling machines, 4-axis milling machines, CNC lathes and 6-axis laser machines as well as a CAD/CAM system.
CUSTOMERS: Rolls-Royce, FACC, Meggitt & Pattonair and more.

Virtual Benefits

The Virtual Machine is purely a software solution that includes almost every function of a real machine, and complements it with additional complements it with additional components. By copying workplace characteristics, it allows the user (in this case Paul Fabrications) to try out complete programs and programming changes to maximize productivity, avoid potential problems during a machining cycle and ensure that machine hours are dedicated to production rather than running trial programs on real machines. It is possible to run the program on the machine or with a CAM system, but in both cases it simulates the exact machining.

Non-Virtual Method
Machining in the more traditional way can take more time as several attempts are sometimes necessary for the desired result. It can also cause unnecessary waste.

Virtual Method
The virtual way can almost guarantee that the job is done correctly with a precise calculation of the time needed and the cost.

Materials

The materials have to be heat resistant, strong and light, so much of the work involves titanium, Nimonics, Inconel and other high-value heat-resistant alloys and difficult-to-machine materials. This makes machining them a very expensive process, so waste has to be minimal.

Originally published in Metalworking World 2.2011, a business magazine published by Sandvik Coromant.

Text: Geoff Mortimore
Photo: Samir Soudah