A combination of multi-axis and mill-turn machining is providing growth and expansion opportunities at Canadian aerospace job shop, Cedonia. The company is prospering because it can meet tight delivery times, which range from five days to as quickly as overnight. Part of the credit for its growth goes to the quick, highly automated offline machine tool programming achieved with Edgecam software.
Based in Ontario, Canada, one of Cedonia’s main business streams involves prototype and short-run aircraft turbo-compressors, rotors and impellers, often demanding tolerances as tight as 0.5 micron and rarely greater than 10 micron. For short runs, design and engineering changes are frequent, with as many as five per job. Changes can consume about one-third of the total machining time.
Setting up the various machine tools used to take anywhere between 30 minutes to an hour. This is less of an issue during long production runs. However, on the very short runs that make up most of Cedonia’s work the setup time often exceeds the machining time and accounts for most of the variable costs.
Switching to multi-axis and mill-turn machining has increased efficiency because it combines several metal cutting operations. Prior to using this technology machining a part completely usually required two or more turning and milling machines and multiple setups. Eliminating nearly all of these setups has been a big part of Cedonia’s gains in productivity and reduction in delivery times.
That said, productivity gains have never been free and implementing any production advance presents several interlocking challenges for programmers and machinists. In multi-axis and mill-turn machining there are two main areas to consider.
Combining operations and eliminating most setups doesn’t cure complexity. Instead, the complexity is shifted upstream, and this has made mill-turn programming a challenge for many CAM software vendors. Addressing this, Edgecam automatically searches solid models and STEP files to find geometric features and user-defined surfaces, to program their cutting parameters.
Mill-turn machines have only eight or 10 cutting tools, a small fraction of what’s available on other CNC machine tools. That requires machinists and programmers to rethink their most basic approaches to mill-turn jobs. As many as six different steps - roughing, semi-finishing and finishing in both milling and turning - have to be combined into just two or three. To help with this, Edgecam Mill/Turn programming integrates feeds, speeds and depths of cut across as many as nine machine axes. Built-in simulation shows how it all comes together at the machine tool.
Aurel Nistor, co-owner and lead programmer at the 12-strong company, reports: “Using Edgecam, we became very competitive. It has increased our flexibility, shortened our delivery time and reduced our costs.” Prior to installing Edgecam, he says Cedonia sometimes struggled for hours to program multi-axis and mill-turn work, with several, less capable, CAM packages.
“Edgecam programs each machining operation in an average time of 15 minutes and the most complex jobs never take more than two hours,” he says.The gains in speed are a major portion of Cedonia’s competitive advantage. One aerospace customer relies almost entirely on Cedonia for its prototypes, which are wheel-like rotors and impellers. “These prototypes are delivered the next day,” he adds.
Cedonia’s machine shop is equipped with seven CNC machine tools. There are two simultaneous 5-axis milling machines - a DMG 100T and a DMG 60 Monoblock, both with Heidenhain controllers. There are two 4-axis mills from Haas, and two 2-axis turning centres - a Mazak 250 QuickTurn with a Mazatrol CNC and a Fortune 360V with a Fanuc CNC. The mill-turn is a 4-axis Mazak 200 MSY with a sub-spindle and a Mazatrol CNC.
This is where the programming challenges arise. “Edgecam does a very good job of ensuring that all the mill-turn functionality can be used efficiently,” says Aurel Nistor. “All the differences between machines and their CNC controllers are addressed in the postprocessors.”
He programs by importing files directly into Edgecam or through Solid Edge. Programming on simpler parts is made quicker by using Edgecam’s Feature Finder “to find standard geometric shapes like holes and bosses,” he says. “For complex parts with a lot of prismatic surfaces, we use Edgecam Surface Features, which is similar but the user has to define the surfaces to look for.”
Simulation of the program and verification of the machining steps are also very important. Aurel Nistor continues: “As a programmer, you need to see exactly how the part will be cut and, for that, simulation is great. It is very accurate for cuts and time needed and very easy to use. It is also a great help when programming multiple axes.”
Cedonia has identified four key elements within its customers’ demands. These are more complicated parts with more engineering changes; a greater variety of prototypes; shorter lead times for low-volume, first-run production; and ever-smaller quantities to hold down inventory costs and minimise the risk of obsolescence.
Meeting these demands has let Cedonia grow the business with more work, add new capabilities by taking on more complex jobs, and improve profit margins by focusing on short-run jobs where there is less competition.
It’s an interesting twist on global competition, to which many job shops in high-labour-cost areas like eastern Canada are still adjusting. Cedonia’s customers also face those same pressures, and to beat their own low-labour-cost competition they are accelerating the development of products with greater functionality and more user appeal.
For Cedonia, that translates into rising demand for prototypes and very short initial production runs. By keeping pace with its most demanding customers, Cedonia is prospering. To handle the grater flow of work, Aurel Nistor and his partner Valentin Dinoiu recently relocated to a much larger facility.
Aurel Nistor concludes: “We have grown the overall business volume by about one-third in the year since we started using Edgecam. These gains have been in that part of the business we want to grow, aerospace prototypes. Today, the mill-turn machines which carry out this type of work are fully loaded around 90 per cent of the time.”
And that is the only way to pay for new facilities. At 28,000 ft2 Cedonia’s new facilities are twice the previous size, although not all of it is used yet. More staff will be hired and Aurel Nistor expects to buy more 5-axis mills and a larger mill-turn machine.
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