Material gains

In 2007 the company decided to replace its Exact knife cutter with conveyor bed tables, and also needed to upgrade an existing CAM system to provide an integrated nesting and ply identification system.

Kevin Hudson, senior manufacturing engineer at Aircelle explains: “At the time we were producing static nests by hand as they were more efficient than the ones nested by the previous software. We re-used the nests as it was too difficult for operators to unload complex dynamic nests. What was key for us was that we had a software system that could make more efficient use of material and also integrate with a laser identification system to help with the unloading of plies.”

There were other problems that Aircelle needed the new system to address. Plies were marked using a retrofitted inkjet marker which could not be driven directly from the previous CAM system. “We developed a separate program in Visual Basic that would provide the NC code for the ‘Videojet' marker separately,” Mr Hudson adds. “The problem with this was that if the job stopped halfway through we could not just continue from that point – we had to scrap the nest and start again. Also, when we reached the end of a roll, if it was shorter than any of our nests we couldn't use it.”

Manufacturing engineer, Neil Stansfield, concurs: “We had to rely on manual nesting as automatically produced nests using previous software were never as good as the ones we could produce manually.”

On recommendation

Aircelle decided to purchase two conveyorised knife cutters. Although the company had considered upgrading its existing software and also looked at an alternative CAM system, the machine dealer recommended that they evaluate Jetcam for both the nesting and laser identification system. The company reports that in tests, Jetcam outperformed the existing static nests by an average of 20%, so the decision was made.

Aircelle also worked with Jetcam to develop a custom specification for the laser identification to meet its requirements. A large LCD screen was mounted by one of the cutters, with the laser mounted directly above the machine table. The machine operator is provided with means of controlling the laser to indicate next or previous ply or kit.

The software was purchased in 2008 and a license of Jetcam Expert with High Performance Automatic Nesting and Remote Control Processing (RCP) modules for ‘hands-off' automation was installed. The RCP module takes instructions for orders to be processed and nested from two licenses of Jetcam Orders Controller (JOC), which are running on workstations remote from the system.

Automating the process

In day to day operation, staff would identify required orders in JOC as individual plies or whole assemblies by simply dragging these into JOC's ‘orders' window. When ready to cut, the job queue is passed onto RCP and on instruction from the RCP module, Jetcam will automatically locate already processed ply files if they exist. Alternatively it will locate required ply geometry files and import and process them by healing any geometry problems and applying relevant machining information. Jetcam Expert then automatically nests the ordered plies, creates the CNC code and any specified reports, and updates JOC to show that the job is complete.

A JETTerm workstation is located at each cutter, which allows direct download of CNC programs to the machine. JETTerm was modified to integrate into Jetcam's laser identification system, providing an on screen visual representation of the nest and the next ply to be unloaded, which is also highlighted directly on the machine bed by the laser. This was also linked into a large high definition monitor making it easily visible from all sides of the machine bed.

Going live

After the system went live and Aircelle started to migrate static nests to dynamically produced versions a number of benefits immediately came to light. The problem with the videojet marker was resolved through a modification to Jetterm. If a nest was stopped halfway through it stored the marker's location so that it continues from the same point. Mr Hudson notes: “Previously this was happening almost daily, which meant the nest had to be scrapped.”
Manufacturing engineer, Tolbot Boulton, adds: “We assigned a cost reduction exercise on the production of Rolls Royce Trent engines to try to achieve a reduction of 25 hours per person per unit and where savings other than time were achieved we calculated a time value to them. We analysed a week's production of static nests versus the new dynamic nests and achieved a 10.5% material saving which alone comfortably met this target before considering any other savings. We expect this figure to further improve as we expand the system's usage.”

As nests became more efficient, machine runtime improved as fewer nests were being cut, reducing loading/unloading time of material. With empty rolls being replaced with new ones several times per day across the two machines this can add up to a significant manpower saving over time. Aircelle noted that with one set of four nests it achieved a 20.5% improvement in runtime.

Nests had often needed to be completely re-run in the past, perhaps either because a ply had been damaged or because of a quality issue with the material. “Sometimes material width would change because of supply, which wasted all of our static nests.” Mr Hudson reveals. “We often have variances of material width – with some rolls including up to 40mm of sacrificial material on the edges so we could be losing 10-15% before we started. Nests can now be easily recreated to fit the exact width of the material currently available. If a single ply needs to be remade we simply add it into the orders list in JOC. Also, if we have say, 2m left on the end of a roll we can now quickly create a small nest of parts to make full use of it.”

Efficiency levels

Reporting and the visibility of information have dramatically improved, with full efficiency stats immediately available. Previously Aircelle was reliant on operators manually logging information, which was time consuming and prone to errors.

Since going live Aircelle has had little reason to contact Jetcam for support as most processes run automatically without user intervention. Jetcam and Aircelle have an ongoing development partnership and after using the laser identification system for several months Aircelle has identified enhancements that could further streamline the ply picking process. These are being worked on collaboratively by the two companies.

The company is in the process of purchasing a third cutter, and is also implementing a new MRP system which will ultimately be used to completely automate the nesting process through automatic loading of orders. With no major support issues since installation, Aircelle is confident that Jetcam will play a major part in its expansion plans. “For us the integration between the laser and the nesting was essential,” says Mr Hudson. “Operators used to be reliant on the programmer being available if a nest had to be remade, but now nests can be ‘tweaked' directly on the shop floor.”

He concludes: “I didn't believe that we'd actually get the increase of efficiency that we did with Jetcam. The improvement in nesting efficiency and the quality of information that the system is providing has given us visibility of other issues such as the fluctuating material width. We believe we are still in the infancy of making the most out of Jetcam but based on our projected savings over the year it has paid for itself in 50 days of use.”

Jetcam
www.jetcam.com