Manufacturing Machinery World - June 2020

NEWS NEWS NEWS
SET-UP TIMES
CUT, THEN
REDUCED AGAIN
US-manufactured CHICK System 5
workholding equipment, supplied in the UK
through sole agent 1st Machine Tool
Accessories, Salisbury, (www.1mta.com) is
helping to increase productivity and
efficiency in the machine shop of Axminster
Tools & Machinery (www.axminster.co.uk),
located in Axminster, Devon.
The company is an on-line and high street
retailer of tools and machinery that it imports
from global suppliers. However it chooses to
manufacture some machine accessories,
notably jigs and chucks, including the
popular Clubman SK80 woodturning chuck,
in-house to ensure consistently high quality.
Historically, standard wind-up vices were
used to fixture components for machining on
CNC mills and machining centres, but as
production levels rose they became too
inefficient. Several years ago a new, still ongoing
job came along that required
particularly accurate clamping of multiple
small parts, namely steel jaws for chucks.
Conventional vices were not suitable, as it
was impossible to present a sufficiently large
number of parts to the spindle. An initial
workholding solution was to use a steel
fixture plate machined to retain the parts by
bolting them individually into position. The
problem with that was the two hours it took
to change over to produce the next batch.
To provide a solution, 1st MTA proposed
its CHICK Qwik-Lok system. It significantly
reduced set-up times, as the jaws secure
components quickly and to high repeatability
for milling and drilling. One large part can be
clamped between two jaws but to allow more
parts to be loaded at a time, more usually a
pair of components, or multiples, are held in
two stations. Aluminium jaws machined
with the profile of the parts to be held ensure
they are retained firmly during machining.
Turning a single handle advances the two
movable Qwik-Lok jaws simultaneously
towards a fixed central jaw to clamp the
parts, which also has the effect of cancelling
the opposing forces and creating a reliable
reference point for machining. A beneficial
side effect of clamping more parts faster was
a rise in walk-away time, allowing operators
to be more productive in other parts of the
factory.
Once Axminster Tools & Machinery
adopted this procedure, clamping several
steel mounting jaws in each Qwik-Lok
station, productivity was dramatically
increased. The machine operator is able to
change over up to six Qwik-Loks on a
vertical machining centre (VMC) table in half
an hour, four times faster than when
previously using the bespoke steel fixture
plate. Moreover, the latter had the drawback
of potentially causing damage to the cutter in
the event of a programming error, whereas
this is not the case with aluminium jaws.
The machinable soft jaws were soon
found to be a versatile solution to other
clamping problems, such as how to retain
chuck bodies without the risk of the
cylindrical components rotating during
machining. Again these parts were
previously bolted to a fixture plate,
necessitating a half-hour set-up time,
whereas now the bodies are swapped in the
line of Qwik-Lok jaws in a couple of minutes.
Axminster Tools & Machinery initially
decided to mount the units directly onto the
machining centre table, but it meant that
when a clamp was removed it was timeconsuming
to realign the unit for a new job.
To avoid this, two years ago Jake Knight,
head engineer at the Innovation and
Manufacturing Department in Axminster,
decided to invest in a CHICK foundation
plate for two 3-axis VMCs on-site, a Mazak
VCN-530C and one of a pair of VTC-200Ms.
Manufactured to suit the size of the
machining centre table, the cast iron plates
have a grid of accurately drilled holes at 50
mm centres with hardened bushings and
threads at each location that allow Qwik-
Loks to be positioned anywhere over the
surface rapidly and repeatably to an accuracy
within 10 microns. The use of round and
diamond pins at two positions allows the
Qwik-Loks to be located and mounted
quickly and easily.
Alpha-numeric labelling of the grid
enables unerring relocation of each base and
jaw set so that the same program can be used
every time a job repeats. All unused holes in
the plate are sealed with plugs to prevent the
ingress of swarf, which could compromise
location accuracy.
Mr Knight confirmed, “Overall, we use
about 20 Qwik-Lok bases and have three
times as many soft jaw sets machined to hold
a multitude of components that we machine
from stainless and other steels through to
aluminium and plastics.
“We have chosen CHICK’s 1040 base size,
with a jaw width of 100 mm and an overall
length of 400 mm, as this supports a majority
of the components and accessories we
produce for the products in our catalogue.
“In another project, 1st MTA also
regularly supplies us with machinable steel
chuck jaws for our four Mazak turning
centres. They are especially useful for
clamping various rotational parts to a high
degree of concentricity for turning, such as
chuck bodies for our woodturning lathes.”
www.1mta.com
8 Manufacturing Machinery World, June 2020