Manufacturing Machinery World April 2024

CASE STUDY
Working area of the Cincom L20, showing the gang tooling and sub spindle on the left
opposing the sliding-headstock unit.
A batch of heritage railway carriage brass fixing pins.
Mr Davies commented, "Although all the
parts are relatively simple, some tolerances
are tight. The bore on one of the components
for industrial gases has to be held to 0.05 mm
total and the engine shaft OD must be within
0.04 mm.
"Despite the Cincom being 20 years old,
provided we run it at sensible feeds and
speeds we achieve this level of accuracy
easily.
"Not only that, but we have confidence
leaving the machine running unattended to
get on with other tasks, as all dimensions
repeat from part to part to within 15
microns."
He went on to mention that although
the purchase price of the lathe was only
about one quarter of the investment
needed for a modern 20 mm capacity
Cincom in the manufacturer's L-series, he
was treated by all Citizen Machinery UK
staff as though he were purchasing a new
L20. "They went above and beyond what
would normally be expected for the sale of
a used machine and the delivery,
commissioning and training were
exemplary," he said. "I cannot sing their
praises highly enough."
TAS Engineering is currently undergoing
a metamorphosis whereby, while
fabrications will continue to play a part in the
business, in the future it will only be if they
undergo prismatic machining or contain
turned parts. Already this policy has seen the
contribution of chip removal, mostly metal
and but also plastic, in the factory rise from
10% to 90% of turnover. It is a progression
that was accelerated by the Covid pandemic,
when on-site visits to provide customers
with fabrication services were forbidden.
Another insight offered by Mr Davies is
the formidable financial advantage of
purchasing a good quality used machine
tool, provided that one can be sourced, which
is not always easy. His L20 had only 40,000
hours on the clock when it arrived,
equivalent to having run for a single shift
every weekday. It is notable that, for the jobs
completed so far, repayments on finance for
a new Cincom would not have been viable.
On the other hand, paying back only onequarter
of the amount puts TAS Engineering
in a strong position to quote for work very
competitively, especially if it is not especially
complex. Moreover, small quantities are also
practicable, provided that the machine can be
set up quickly. Mr Davies often uses Citizen's
Alkart Wizard software running on his
laptop to speed programming and
downloads the code to the control.
Applications engineers at Citizen
Machinery UK are always on hand to assist
when needed. A recent instance was when
Mr Davies was worried about possible
damage to the steel engine shaft as it was
ejected from the sub spindle. Within an hour,
a response was received advising him to omit
an M-code at the end of the cycle and replace
it with a specific line of alternative code that
worked perfectly as soon as it was
implemented. "Such after-sales engineering
back-up is invaluable, especially if you are
new to sliding-head turning," he concluded.
www.citizenmachinery.co.uk
The components produced so far by TAS Engineering on the Cincom L20. The fabrication
including the turned magnet holder is pictured centre, with a separate magnet holder
inverted nearby.
A batch of machined steel engine
components.
Manufacturing Machinery World, April 2024 51