Flight Refuelling - state of the art manufacturing

Flight Refuelling is now using advanced CNC machine tools, the EdgeCAM off-line programming systeme, and an effective and reliable DNC network serving the shop floor
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When it comes to optimising manufacturing performance, Flight Refuelling in Dorset, a member of Cobham plc, now has all the pieces of the jig-saw in place. Advanced CNC machine tools, for which many are capable of extensive single set-up working, together with the flexibility and power of EdgeCAM off-line programming system by Pathtrace, and an effective and reliable DNC network serving the shop floor via Seiki Systems are all fully operational.

As a result lead times are reduced by up to 75 per cent and programming times cut by half. FR-HiTEMP (a division of Flight Refuelling) has progressively moved toward one-hit machining with the phased installation of eight HiCELL multi-axis turning centres from Hitachi Seiki UK. This has transformed production efficiency at the Wimborne-based company which manufactures fuel-related components and systems for the aerospace industry.

Many of these intricate parts are now produced under a 'one-hit' machining philosophy which has cut both cycle and lead times and improved accuracy, particularly in terms of relational features. However, the part programs required for such multi-axis work are far more complex than for previous production methods involving separate CNC machine tools, so efficient programming, data management and control became a key issue. This aspect of the manufacturing process has been addressed with the installation of an EdgeCAM off-line programming system, from Pathtrace of Reading and, DNC software and terminals from Seiki Systems of Brighton. While both companies maintain independent operations, they have formed a distribution agreement that provides customers with a single source supply of the leading CAM and factory communications software. It was this single source deal that bought these two systems to service some 18 CNC machines installed for civilian aerospace work.

A prime example which highlights the benefits of the FR-HiTEMP 'one-hit' machining and advanced programming concept involves a family of end connectors machined from 100 mm diameter by 63 mm long aluminium alloy billets. Production involves: turning, recessed profiling, milling, drilling, spherical boring and facing as well as the machining of 'O' ring grooves.

These components were originally produced on four separate CNC machines with a total programming time of over 30 hours. Now, these parts are produced in a 'one-hit' cycle on Hitachi Seiki HiCELL turning centres reducing lead times by some 75 per cent and the more complex programs generated in under 20 hours on EdgeCAM."The move toward advanced C- and Y-axis machining meant we had to upgrade our previous CAM system," says CNC programmer Steve Clarke.

He explains: "With around 80 per cent of components being produced on the HiCELLs, we needed a programming system which could readily handle complex multi-axis 3D work. It also had to accept IGES and DXF file-type CAD data while being a flexible and easy to use system which was equally at home on simple 2D profiles."

The company finally specified EdgeCAM on the grounds of performance, price, capability and all-round versatility. It was also impressed with such features as Code Wizard, which enables post processors to be readily tailored for individual machines by the company's own programming engineers. FR-HiTEMP now has 12 EdgeCAM seats to program a wide variety of components which are often very complex and include families of valve housings, spherical plugs, end connections and fuel-related pump parts along with a range of other fluid handling units.

Machined from either S130 aluminium alloy or stainless steel bar, in sizes between 38 mm and 152 mm diameter, these parts are produced to tolerances as tight as 0.02 mm and in typical batch sizes of 20. A high proportion of production involves machining spherical features and the introduction of single operation machining with advanced programming, has also enabled some sub-assemblies to be re-engineered in order to reduce the number of separate parts required.

Certain fuel related products are now manufactured from two more complex instead of three individual components and this has obviously improved lead times as well as manufacturing economics in general. This means the programs required are obviously much more complicated than before. But even where the number of sub-assembly elements has not been reduced, most products are now manufactured in a single set-up on the HiCELLs which further compounds the programming task.
Here, the power of EdgeCAM has come into its own, enabling rapid and very cost-effective part program instructions involving turning, surface and multi-axis milling, C- and Y- axis machining."Viewed in general terms, we can operate EdgeCAM up to 50 per cent faster than the previous CAM system," says Steve Clarke.

He follows on to explain how the Seiki DNC system has also enabled the EdgeCAM programs to be effectively and speedily distributed to the CNC machines on the shop floor. Terminals are spread around the shop floor to enable operators to have immediate access to production schedules, tooling list and other key manufacturing data - as well as the programs themselves. This has created the immediate effect that management of all program transfer functions and issue changes is now optimised and, with well over 10,000 part programs stored on the file server, such control is vital. Machining operations on aluminium valve bodies measuring 38 mm diameter by 76 mm long have also been streamlined. These components require: turning, face grooving, boring, threading, milling and facing, drilling, tapping and boring. Previously, two separate CNC machines were used and the programming time was some 32 hours. Today, these parts are machined in a single set-up on a HiCELL and EdgeCAM has cut the programming time by half to just 16 hours.

Both EdgeCAM and the Seiki Systems DNC system are also used by programmers involved on the military side of Flight Refuelling's business at Wimborne.

Working in the same department, these engineers program a wide range of CNC machine tools for the manufacture of components including drones and tanks for in-flight refuelling and weapons release systems. These projects often require the machining of some quite intricate steel castings - a task easily handled by EdgeCAM. The off-line programming system has made a big difference to operating efficiency at FR-HiTEMP as Steve Clarke concluded: "As well as enabling us to program more complex machine moves in less time, EdgeCAM readily accepts electronic CAD data from our design office and is easy to use.
The Code Wizard feature, in particular, has been a real boon allowing us to write specific machine post processors in about a day and a half instead of the five days or so before."