32 AEROSPACEMANUFACTURING | MARCh 2010
and three-shot drilling, which involves Payling notes that while the UK
cutting a small diameter hole first and supply chain’s thirst for composite
then gradually opening it out to finished manufacturing technologies continues
size. Unfortunately this multiplies the unabated, some suppliers are struggling
amount of tools that can wear out. to keep pace with its rapid evolution.
Payling says another business reason
for Dormer establishing its RTC Working hand in hand
concerns skills development and training: Dormer’s roadmap will involve the
“A huge task for the RTC is to research continuous development of products and
these products and then train our processes, not only for the design of tools,
technical sales engineers to ensure they but for the machining strategies too.
have the competencies to demonstrate “New composite products present
The art of holemaking: A big focus for Dormer
their knowledge and win this business. a challenge for any manufacturing
Dormer is working towards offering a process, so the RTC must work hand
and reamers. The joining of composite total package which involves hand held, in hand with the manufacturing
structures is a black art itself and is semi automatic drilling techniques, as industry, disseminate this information
still very much based on riveting. The well as different assembly processes too. to its employees and customers and
present capabilities of adhesive joining However, many aerospace companies help provide everyone with a core
technology would seem to indicate are now looking at the latest trends in competence,” he concludes.
that this is unlikely to change for the automation by using robotics to try and “Research into the structure and
foreseeable future.” improve accuracy and production.” machining characteristics of composites
The composition of carbon fibre is gathering pace and as such, the RTC
Keep them separated reinforced plastics presents issues of places Dormer and its partners on a fast
The other issue vexing manufacturers is concern for the holemaking process. track to understanding these materials
the problem associated with aluminium And as new material technologies evolve and most importantly, providing
and composite materials sandwiched rapidly, Dormer is investigating the customers with tooling solutions that
together in close proximity. Here, an classification of carbon composites. offer increased productivity, improved
adverse chemical reaction occurs and is “This would make it easier to cross quality and reduced costs.” ❙
the main reason why composite materials reference and categorise materials – as we www.dormertools.com
need coating so that they aren’t directly do already with, for example, steel; the
in contact with the aluminium. problem is that we still cannot classify
“This is why aircraft OEMs tend to composite materials very easily,” he
favour titanium because it’s lighter and notes. “There are so many variations and
stronger and can be used in harmony structures in terms of the way that fibres
with composite materials,” Payling are laid up in different directions – plus
continues. “However, the problem here is the use of different resins too. If we could
that titanium is much harder to machine classify each one, then we’d know which
and when used with composites, will type of drill suits each grade of composite
often need to be machined ‘dry’. This in material and apply a set of speed and
turn creates increased heat, which can feed parameters based on its behavioural
damage the composite material. characteristics under machining
“Everyone is looking for the optimum conditions. New and very different
solution for drilling composite and materials are developing, so material
titanium stack material in one hit, technologies are challenging, which places
problem free. Drilling the composite part demands on us to find solutions.”
of the sandwich is fine; the problems
begin once you reach the titanium
“The Research Technology Centre is designed
because you cannot drill it at the same
speed and feed. Swarf can be problematic
to help us to gain more knowledge and insight
and has abrasive properties that score
about composite materials.”
and damage the composite material.
One solution would be to perform two- Ricky Payling, key account manager, Dormer
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