AEROSPACE SUPPLEMENT
CNC PROGRAMMING & MATERIALS MANAGEMENT
Metal &
composite bene ts
A UK aerospace fi rm praises Alphacam for its CNC machine programming
capabilities; US fi rm opts for Jetcam products to support composite
material management and cutting
Sussex-based Drallim Aerospace used
helicopter cargo hook in just ve months.
18
Alphacam CADCAM to help it develop
a family of 45 high-spec parts for a
February 2020 www.machinery.co.uk @MachineryTweets
The Hawk 8000 cargo hook has been
selected for the next-generation Bell 525
Relentless helicopter, which is currently being
developed – the hook must handle an 8,000 lb
payload. Drallim Aerospace, located in St
Leonards-on-sea, approached one of its
established suppliers, Leemark, to help out in
the manufacture of casings, solenoid covers,
heavy duty linkages, levers and pins for the
assembly.
Leemark is run by three brothers, Mark,
Kevin and Neil Stockwell, having been set up
by their father over 50 years ago. Principally
supplying precision components to Tier 1
aerospace companies, aircraft such as the
Lockheed Martin F35 Lightning fth-generation
stealth plane, the Saab Gripen E ghter jet and
various military, police and civilian helicopters,
along with ejector seats and satellites, can be
counted amongst its end use applications.
Most components are complex,
manufactured on 12 CNC machine tools at the
company’s factory in Middlesex. Director and
production manager Neil Stockwell explains
that 11 of those machines are programmed
with Alphacam (https://is.gd/neligi). “It drives
all our 3- and 5-axis Matsuura
machining centres, CMZ Y-axis and
2-axis lathes and Agie wire eroder.
The only one it doesn’t drive is the spark
eroder, which has conversational software.”
He says Alphacam was an essential piece
of the equation when it came to producing the
Hawk 8000 cargo hook components, mainly
from aerospace aluminiums and billets of
hardened AMS 5643 American spec stainless
steels, along with a small amount of plastic.
“We were tasked with not only
manufacturing them from scratch but producing
them as if we were making them in large
volumes, so we needed tight cycle times. Being
aerospace, there were AS9102 reports with
every component, and it meant that the
processes were sealed, so that when they did
go into full production there were no more
quali cation periods to go through. We
achieved all that within ve months, thanks to
Alphacam’s built-in machining strategies, which
helped us to optimise our high-end machines
and cutting tools.”
Leemark manufactures every machinable
part for the Cargo Hook; the most complex, in
terms of 5-axis machining, being the cover and
solenoid case. But the most accurate is the
steel lever, which carries out several actions
inside the body of the hook. “A high percentage
of the milled components have bores on them
with an 18 micron tolerance,” says Neil
Stockwell. “The majority of the turned
components have even tighter
tolerances.”
Engineering director Kevin
Stockwell says programming
time varies from around half an
hour for simple parts, to
between 15 and 20 hours for
the most complex components, with machining
cycle times taking up to two hours. “We use
waveform and trochoidal milling strategies,
which give us signi cant savings on cycle times
and extend tool life.”
His programming process begins with
importing STEP models, working out the best
way of machining the part, and how much
excess material is required to hold it during
The Hawk 8000
lever part has
demanding
tolerances
/www.machinery.co.uk
/neligi)