BAe is relying on lean manufacturing to meet cost goals for the Eurofighter

Ian Sheppard/Samlesbury


Recession and restructuring can have their benefits, as is the case for British Aerospace's Samlesbury site in the north of England. With the closure in the early 1990s of the nearby Preston plant, then the heart of BAe's manufacturing activities, Samlesbury is now the flagship manufacturing site.

The aim was to start almost from scratch at what had been Preston's "satellite", says John Duxbury, formerly Salmesbury's head of operations development and now chief of airframe operations on the Joint Strike Fighter (JSF) programme. Pressure from Airbus Industrie to reduce costs was "one of the keys to change", says Duxbury, who adds that "-we borrowed everything we could" from the car industry, primarily through its ownership of Rover.

The Samlesbury plant is now gearing up for its share of Eurofighter EF2000 production work, with many new machines going into the assembly engineering building opened in September 1997. BAe estimates that £100 million ($160 million) will have been spent by the end of 1999. Samlesbury also produces subassemblies for the BAe Hawk and Boeing/BAe Harrier II, and supplies major wing subassemblies for the Airbus A320 family.

One of the key changes has been to avoid making a distinction between civil and military work. Synergy results from the fact that civil work drives "commercial best practice" into the plant, while the military work drives "engineering best practice", says Duxbury. Military manufacturing projects have all been for different export customers and in batches of 50 or less, which has forced a flexible approach. "It is a chaotic environment," he says.

The military area of the plant, for example, produces around four sets of 24 leading edge ribs a week for A320 wing assembly. Flexibility has also allowed three extra EF2000 centre fuselage frames to be taken on from Germany, for example, after the workshare shifted.

One cost-cutting measure has been to decide what processes to keep in-house. A six-month strategic "make or buy" process led to a product cost model, and not the traditional cost-recovery model which is based on input (man hours plus an overhead rate). Conventional machining - less value-added and less critical work - was farmed out. Comparing in-house with subcontractor costs for machined parts based on quotes for two-year deals, there were "some clear winners and losers, and some surprises", says Duxbury. Samlesbury retained detailed manufacturing of critical parts. "You have to understand and control them," he says.

Today, the Samlesbury site takes in raw material and turns out fully equipped and tested aerostructures. The pressure now is to re-examine costs, cut down on inventory capital value, optimise flow and implement or fine-tune lean manufacturing concepts centred around team working and empowerment.

Improvements should make the 50th production EF2000 the "target learning aircraft" rather than the 150th with the Panavia Tornado, and allow for an 18-month, rather than a 40-month target production span. Interchangeability of parts will be achieved from the first production aircraft, rather than "as and when" with the Tornado. For example, the entire skin of the EF2000 front fuselage is load-bearing, but some panels, known as interchangeability panels, have to be removable and therefore require close-tolerance fasteners. "It's not a plastic Tornado," says a BAe cell manager.


The UK Ministry of Defence is funding half the new machine tools required for the EF2000, which is "-the first time ever they've funded tools", says BAe. Some 18% of the EF2000 work is deemed "critical" and will be kept on-site, the company says. The first forward fuselage frames and the spigot housing for the foreplane, items with the longest lead-time, were produced in May on MoD-funded, and therefore Eurofighter-dedicated, machines. "If they're good, they'll fly," says BAe, reflecting the right-first-time approach.

Also in May, the Advanced Tooling Facility (ATF) opened at Samlesbury, which is now busy producing tooling and jigs to tight tolerances for the military airframe centre. The frames and jigs have to be positioned so precisely, to within 80 microns using a laser tracker, that the building will be kept at between 18¼C and 20¼C at all times.

In the ATF, BAe is developing a "virtual reality shop floor" so that all processes can be simulated before any metal is cut, thus "designing out the risk".

Electronic product definition has been a "major challenge", says BAe - not with the industry-standard IBM/Dassault Systèmes CATIA design environment, but with linking this directly to the physical processes.

Part definitions go straight from CATIA to numerically controlled machining avoiding physical prototypes. This is why the laser-based measuring techniques used to position jigs are essential. "It's not easy turning a craft-based industry into a measurement-based one", says strategic development manager Jon Rogan. The result must be that the part is there "-when you said it would be", and that it "will be right", he says.

The "hard metal" shop added Makino machines in 1995, which BAe says are "still the most advanced in Europe". The shop is now producing parts for the Airbus wing "-with a view to Eurofighter coming on stream". Four BAe-funded advanced contour machines, produced by Germany's DS Technologies, will be installed from early 1999 for cutting EF2000 centre frames and "-could make JSF parts".

Steve Mills, "soft metal" cell manager, says cells are treated as "-mini-factories with well defined inputs and outputs", although they "-vary enormously" in size and nature. "There is no identikit for what a cell is," he says.

Gluing all the machining cells together is the difficult part, says BAe, which believes its drive to make cells more flexible is "-leading edge-you'll not see it anywhere else". Statistical process control allows visibility of performance for both managers and workers, who are given ownership of work and approve it themselves. "What we have is a particularly difficult application of lean manufacturing," says BAe. Employees are also involved in Total Productive Manufacturing, a programme pioneered in the USA where cells take responsibility for maintaining their own machine tools.

Direct-to-line feed of small parts such as fasteners is now taken for granted, although it took two years to get the first pilot project to work in the early 1990s. Other lean operations include the just-in time delivery of materials, with 80-90% of the semi-prepared billets being ordered direct from cells as required, with no stores anywhere. Ultimately, manufacturing will all be pulled along by the final assembly line, as the "engine", with regulators between the different stages providing "bufferage". "Just-in-time to the second is nonsense," BAe believes.

Enterprise re-engineering has been central to the effort, resulting in a flatter structure of cell managers under around 60 executives. Gone is Preston's multi-layered command and control type structure. In the Samlesbury assembly hall, the line is reconfigurable with all the jigs mobile and all services routed under a suspended floor, showing how BAe is thinking well ahead.

Source: Flight International