At a new manufacturing plant in Tewkesbury that is dedicated to the production of Airbus landing-gear kits, Bowmill Engineering Ltd (
www.bowmill.co.uk) has installed a Jones & Shipman Suprema Easy cylindrical grinder (
www.jonesshipman.com) as part of a multi-million-pound investment programme that also includes eight new machining centres and high levels of automation throughout.
The factory in Tewkesbury is similar to a bespoke facility at Bowmill’s headquarters in Poole, Dorset, dedicated to the production of Airbus landing-gear kits (Bowmill has been manufacturing kits for A320s and A330s since 2002, along with complex components and assemblies for other OEMs).
Both sites operate as full manufacturing operations producing Class 1 critical components, with the emphasis on the A320 and A320neo aircraft, which are currently the subject of intense build schedules.
Kits from Tewkesbury, which are delivered to a tight Kanban schedule, are despatched to customers based in nearby Gloucester, as well as in Canada and Mexico.
Initially, Bowmill’s new Tewkesbury plant is concentrating on A320 kits; components for other Airbus aircraft and aircraft builders will come on-line later in the year.
Nick Epps, managing director of Bowmill, says that when it came to specifying the grinding machine, he had a particular affinity with Jones & Shipman. “I’m a time-served tool maker by trade, and a good deal of my apprenticeship was undertaken using J&S manual machines.
Here at Bowmill, we operate three J&Ss in Poole, while a sister company of ours — Taymar Precision Grinding — also operates a number of J&S machines.
“The Suprema Easy is a multi-purpose machine that has established a reputation as a true ‘all-rounder’, being equally adept at processing high-volume production grinding work or fulfilling high-precision small-batch quantities and one off work — as encountered at Bowmill.”
The company has identified nine critical Class 1 kit components that require grinding-tolerance finishes — retaining pins, uplock pins and spacers.
Some are chrome-plated, which Mr Epps says presents a grinding challenge in itself, but all grinding programmes are stored in the memory of the machine’s Easy graphical software, which is said to offer a real advantage in terms of speed of set-up for dressing and grinding cycles using touch-screen technology.
Bowmill’s machine has a 650mm between-centres capacity (capacities of 1,000mm and 1,500mm are available); it is also the external wheel-head version, which is designed to combine ease of use with high levels of productivity.
In addition to a new colour touch-screen interface, the latest Fanuc control can store thousands of dressing and grinding programs. It also offers increased processing speeds and enhanced connectivity via a USB port.
Other features of the Suprema include the latest Fanuc digital drives and motors, Heidenhain 12.5nm scales on both the vertical and cross-feed axes, and increased diameters on both the left- and right-hand external wheels on the universal wheel-head.
This gives longer wheel life and improved productivity by reducing the number of times wheels need dressing during grinding cycles.
Mr Epps said: “We identified specific processes in the Tewkesbury factory that require grinding, so we needed a machine with proven production capability plus consistently high levels of tolerance and repeatability — a brief that the Suprema has met.
Moreover, keeping grinding in-house gives us much more control and manufacturing flexibility. All components are NDT checked as part of our quality regime, so full transparency is all important. With regard to cost reduction, we have cut machining times by 21%, defects by 17% and raw-material usage by 28%.”
Unusually for the aerospace sector, Bowmill is the single-source global supplier of the type of A320 kits that it supplies, but contract obligations require the company to have two distinct manufacturing centres — hence the investment in the new Tewkesbury plant.
All kits are produced in left- and right-side versions, as well as in standard- and heavy-duty versions.
The A320 kit has 82 items, whereas the A330 has 221; each kit comprises sub-assemblies and individual items with component ratings from Class 1 (critical part) to Class 3 component ratings.