Right CNC machine tools critical to expectations

Paul Boughton

The history of the development of Numerical Control (NC) is closely linked to the rise of the aerospace sector in the US and the technical challenges faced by engineers as they designed and made craft and power plants to fly faster, higher, further and with greater safety.

The aircraft builders pushed their suppliers, and for a while, the technical challenges outstripped manufacturing capability. Then, in the 1970s, thanks to the availability and proliferation of low cost microprocessors, NC evolved to become Computer Numerical Controlled (CNC), and manufacturing technology and airplane design accelerated into the future, with one or the other alternately setting the pace.

For aircraft passengers, the golden age of aviation might have been the 1950s and 60s, but for aircraft manufacturers and their suppliers, the new golden age is now.

Air travel is burgeoning; aircraft and engines are becoming more efficient and reliable, and airlines are buying them in greater numbers. Parts manufacturers willing to invest in the right technology, people and processes, can find themselves working for some of the biggest and best-known names in the sector. Take Connecticut-based AeroCision, for example.

Founded 50 years ago, AeroCision’s original owners relied mostly on local business for their livelihoods. It’s unlikely, back in those relatively dark ages of manufacturing technology that they could have imagined that one day they’d be making parts for the latest passenger jet engines, let alone for a customer more than 3000 miles away.

“There are no borders any more,” says AeroCision CEO, Andrew Gibson. “When my business partner and I took over this company a few years back, the big names in the aerospace sector were rationialising their supplier lists.” To have a chance of being on a short-list meant investing heavily in quality control, new product introduction (NPI) processes and the best-available machining technology. “It didn’t matter to the customer that we are here in Connecticut,” adds Mr Gibson, “it only mattered that we could achieve the precision, quality and efficiencies that they were demanding.”

AeroCision specialises in turned ‘ring’ parts for turbofan engines: typically, parts between 150mm and 750mm. According to Operations Manager Glen Fournier, orders for the larger components are becoming more common simply because engines are getting bigger.

“We’re making turned and milled parts for the hot areas of a high-bypass aero engine built by a very well-known company. These are the engines being used to power the biggest new ‘planes, such as the Boeing 787.”

AeroCision’s workshop is spotless, as you’d expect for a company with aerospace standards. Towards the back of the current floor space is 15,000sq. feet available for expansion, but in the foreground are two busy, Haas-populated manufacturing cells, one with CNC vertical machining centres and the other with CNC lathes.

“Two of the most important things for us and our customers,” says Mr. Fournier, are on-time delivery and zero defects. There are strictly applied penalties for not delivering on time, even if we deliver too early. So, the biggest challenges for me are scheduling, controlling and reducing set-up and cycle times. Speeds and feeds are critical because there’s a lot of material removal. Our runs are 20 to 25 pieces, so we need to be quick when we’re changing set-ups. The larger parts necessitate well-designed set-up and shuttle plates and our latest Haas machines have tool setters. We’re also moving towards SPC and certifying our operators as inspectors, which will help us enormously. The SPC will allow us to gather the data, and we’ll be able to chart out trends live on the shop-floor screens. On-machine probing will allow us to measure the parts and send those measurement to our database, so the operators will be able to move the parts through the shop that much more efficiently.”

AeroCision has a continuous, live link to its UK customer, whose system downloads a schedule to Chester every Monday morning, where it is imported into the company’s ERP system. People, machines and other resources can be scheduled for the week.

“Our matrix is 98 per cent on time delivery,” says Mr. Fournier, “but I’m happy to say we have never delivered late and we have never delivered a part that was out of control.”

During the development phase of one particular, complex ring-part, Mr. Fournier managed to have the process resolved and the first-off component made, well ahead of schedule. “We took on the job in the October and it was supposed to be delivered in April of the following year,” he says. “But, we had the first finished part just before Christmas. We had all 4 Haas mills running but needed more turning capacity, so we bought the ST30s. We took a photograph of the guys on the shop floor holding the part and we sent it to the customer with the message, Happy Christmas! They were very pleased.”

CEO Mr Gibson believes that choosing the right CNC machine tools was critical in being able to exceed customer expectations and will be just as important for the future success of the company.

“Many of the large aerospace companies are sourcing a lot of parts from lower-cost regions. We have to focus on making higher-value, more complex parts and assemblies and spend our resources making the processes more efficient.” There was a time when a relatively small company like AeroCision might have struggled to buy CNC machine tools with sufficiently high precision, but that’s not the case any more. The machines are available to almost everyone. Using them well is the key. “Our parts are complex and difficult to make, and tolerances are very tight, but it’s having a robust and reliable process that means we can still be strong and competitive in Connecticut.”

Guy Nigro is the company’s Lathe Cell Supervisor: “I think the Haas ST lathes are very good machines,” he says. “We had the SL lathes for five years and in all that time we didn’t have any problems. They were good, rigid reliable machines, but our new STs are better. They’re more rigid, which means we can easily achieve tolerances on materials such as Inconel. They’re also easy to programme, either manually or from our programming room, and they’re straight-forward to operate.”

When OEMs rationalise their supplier bases, there’s usually only a brief and single opportunity for a company to be included. Once on board, though…

“Our customers are moving some of their production and assembly to countries like India,” says Mr Gibson, “where they will build for the local market. We hope to move with them, setting up new, adjacent facilities so we can deliver parts quickly and to the same high-standards they expect from this plant. We want to use Haas CNC machines wherever we are in the world.”

The aerospace industry is pushing its suppliers more than ever to come up with new technology, processes and quality control - just like in the early years of NC. These days, however, manufacturing technology may actually be setting the pace on some fronts, as CNC machine tools in particular become more affordable and precise. Expect to see engine and aircraft development getting faster and more cost-efficient and precision part suppliers like AeroCision getting a bigger piece of the action.

 For more information, visit www.haascnc.com

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