February 5, 2002 -- Arrive at the entrance of Greene, Tweed in Nottingham and you are immediately confronted with a modern, science park-style building, which gives the impression of being home to a high-tech software development business. It certainly does not look like your average engineering company.
Yet this is the European manufacturing centre of Greene, Tweed & Co Inc.,
of North America, which designs and manufactures a comprehensive range of
speciality seals and plastics components for a wide range of industry
sectors. At the site it also produces its own PTFE materials, using a large
isostatic press in the mould shop.
First impressions count and, in reality, this advanced manufacturing
business knows exactly where it is and where it's going! The
Ruddington-based company has invested heavily in advanced CNC machine
tools, including nine multi-axis CNC lathes and four vertical machining
centres, of which two have a full five-axis capability as well as 3-D
co-ordinate measuring machines.
In order to optimise its programming routines, Greene, Tweed has also
invested in EdgeCAM offline programming software supplied by Pathtrace of
Reading and, as manufacturing manager Barry Williams comments: "The
software has made a big impact on production efficiency."
He describes how on a number of thermoplastic seals, programming time has
been reduced from around 30 minutes to just 30 seconds. Meanwhile, on
complex profile milling operations used on composite type materials,
program preparation times are now on average some 250 per cent faster than
the previous shopfloor programming methods. "Combined with ease of use,
flexibility and direct links to our SolidWorks CAD system, EdgeCAM has also
contributed to the trimming of product lead times by upwards of 10 per cent
and is enabling us to be even more responsive to customer demands."
When the company decided to move away from on-machine programming and
invest in a CAM system for both lathes and machining centres, it
investigated the benefits of a number of different packages. From initial
market research, a shortlist of three systems was drawn up which were then
subjected to further detailed analysis.
Barry Williams recalls: "We finally selected EdgeCAM because it best met
our ease of use, flexibility, speed and simulation demands. It would also
enable us to automate certain elements of our programming cycle. The
software dovetailed neatly with our CAD system without the need for data
translators and we could see how easily it would reduce programming times
which was particularly important on some of our small batch runs."
Established in the UK in 1982, Greene, Tweed & Co currently employs 106
people and it moved into its modern 35,000 (square feet) facility on the
Ruddington Fields Business Park some two years ago. Specialists in the
design and manufacture of sealing elements and systems it also produces,
custom designed bearings and precision components from specially formulated
elastomers and thermoplastics.
Its customer base is spread across aerospace, fluid handling, motor sport,
oil field, medical and semi-conductor industries with approximately
one-fifth exported. Aerospace accounts for a significant part of the
business, involving production of sealing assemblies for landing gear,
flight control, fuel systems and a whole range of sub-systems. In
addition, high strength thermoplastic aerospace components used in engines,
suspension units and landing gear are produced at the Nottingham facility.
For the future, the medical sector is a rapidly developing business area
for which Greene, Tweed is using its expertise in design and materials to
replace metal components with special thermoplastics. It is also utilising
its engineering and production to good effect particularly for in-vitro
diagnostics, haematology systems and other extremely demanding
The company also produces components out of Orthtek (trademark), an
advanced polymer composite, for a range of surgical instruments. With
stiffness properties exceeding those of aluminium and almost half the
weight, these structures are gradually replacing traditional metals in
fixators, guides and robotic surgery devices. As well as strength and
weight advantages, this material is also inherently radiolucent, which
enhances the X-ray visibility of critical areas without interference from
the surgical tools.
It is here that EdgeCAM has played a key role by streamlining the
production of these highly complex surgical tools. For example, a series of
surgical fixtures used in hip joint replacement are required in batches of
just 20 and are machined directly out of solid plates of Orthtek using the
company's latest Mazak five-axis vertical machining centres.
Polycrystalline diamond tooling is utilised to carry out typical operations
of profile milling, slotting and drilling of interlocking elements which
then make up the surgical tool.
One such part, which acts as a drilling fixture, is machined from a 203 mm
by 101 mm by 25 mm thick composite block. Prior to EdgeCAM, it took some
four hours to program but this can now be achieved inside 90 minutes
through EdgeCAM working directly from a solid CAD model. A 25 mm by 101 mm
femoral fixator is now also programmed in just 45 minutes compared to 112
minutes and it is much the same story on a number of other composite parts
where, on average, programming time savings are averaging around 250 per
Depending on customer demands, Greene, Tweed can be called upon to produce
20 new programs a week. Most of these are now handled by EdgeCAM which is
DNC linked to the CNC machines. With average batch sizes ranging between 10
and 50, the company needs to be able to program quickly and accurately
which, as Barry Williams concludes: "Is exactly the capability that EdgeCAM
He maintains that the new software speeds up programming routines, enables
modifications to be more readily incorporated and provides the graphical
simulation which ensures that part programs are right first time. "Without
doubt, EdgeCAM has helped us to optimise our investment in CNC machine
tools and is a key element in expanding our business into more complex
plastics machining projects," he says.
For more information, please visit
www.edgecam.com or email