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incorporate this flexible forming (“Flexforming”)
process into their operations. Cost reductions
(compared to conventional mechanical pressing)
can be achieved through the pressing of multiple
parts per cycle with little or no rework, precise
forming to tighter tolerances, much lower tool
costs, shorter part lead times, improved levels of
quality, and the ability to design and produce complex
shapes that would be prohibitively expensive
with conventional presses. Compared to rubber
pad presses, Flexforming generates two to four
times more forming pressure more uniformly over
the tool, creating deeper, more intricate shapes
with higher accuracy and part definition.
There is little question that, despite the recent economic downturn, the projected
growth for commercial, private, and military aircraft will continue well into the
future. Sales of new commercial aircraft have slowed, but a large backlog of prior
orders remains. The global air cargo business has already stabilized and is set to
resume expanding activity as global economic conditions improve. Aging fleets
need replacing, emerging nations have growing needs for modern aviation, and
there is increasing demand for affordable light jets for corporate and private
travel.
With these opportunities come new challenges for airframe manufacturers: new
and intensifying global competition, extreme pressure to control costs at all levels,
the need for advanced technology to expand capacity and productivity, reduction
of labor-intensive processes, and the ever-growing demand for lighter, more fuel
efficient, and environmentally compliant aircraft.
Abstract:
Changing dynamics in the aerospace industry
-1-
As with most major manufacturers in industrialized nations, many aerospace companies
are concentrating on core competencies. They are becoming aircraft integrators
and outsourcing an increasing share of their production, most notably the fabrication
of sheet metal components. In some cases, strategic “manufacturing offset” agreements
are negotiated with vendors in countries with the potential to purchase aircraft.
Similarly, many of the original tier 1 suppliers have shifted to more value-added
assembly and integration activities, and are contracting parts production to
smaller tier 2 and 3 sources. While some of these sources are still using older, lower
pressure rubber pad presses, others have made the switch to fluid cell technology to
meet the stepped-up quality and delivery demands of the airframe producers.
To be successful, aerospace OEMs and their first tier subcontractors must be assured
of low-cost, high-quality, on-time components. By the same token, tier 2 and 3 suppliers
must ensure their reliability in these areas to be competitive. The answer to both
concerns may well be the recent availability of mid-size, supplier-focused fluid cell
presses and advancements in Flexforming processes and tooling technology.
Flexforming is basically a simple process. Unlike mechanical and hydraulic presses
which use upper and lower forming dies, (often in three pieces), Flexforming uses a
single, rigid, shape-defining tool half (also known as a hydroblock or die). A sheet
metal blank is placed over this tool and is pressed into shape by a flexible rubber
diaphragm under uniform hydrostatic pressures as high as 20,000 psi (140 MPa, an
equivalent pressing force of up to 150,000 tons). Multiple tools and blanks are placed
freely in large forming trays at each end of the press which shuttle in and out of the
central frame containing the pressurized diaphragm. Multiple part sizes, shapes and
gauges can be formed in a single one- to three-minute cycle.
Flexforming’s key advantage over mechanical and rubber pad forming methods is the
uniform application of very high pressure, forcing the metal evenly into intricate
shapes, including undercuts. In some cases, forming, trimming and hole punching can
be performed in the same cycle.
-2-
Supply chain opportunities
The fluid cell concept
A “rebirth” of fluid cell processing has taken place over the past three years. A
great deal has been learned through testing and research about predicting and
controlling the behaviour of aerospace aluminium alloys and other metals under
very high forming pressures. Much of this recent work has been done in Europe,
funded and carried out by Agon Consultancy.
Studies centered on several materials and a variety of processing characteristics:
stretching and elongation under varying pressures, draw ratios, bending radius,
strain hardening, elasticity modulus, etc. The result has been a much
greater practical understanding of the elastic/plastic thresholds and
　
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