A move to horizontal
machining centres has
eliminated swarf build-up
and associated downtime
at CTPE
Inset: the high volumes
of swarf generated in
machining multiples of
these parts was an issue
Pump up
the volume
A move to horizontal machining centre technology for CTPE; Mazak
turning centre delivers boost at GW Martin; a cobot fi rst and vertical
machining upgrades keep NPI Solutions on top form
Mildenhall subcontractor CTPE
focuses on medium to large
volume production of high precision
components for the scienti c, medical,
electronics and defence sectors, using 3- to
5-axis vertical machining centres (VMCs), as
well as xed- and sliding-head CNC lathes.
To expand its prismatic machining
capacity, in July 2020 the company invested
in its rst ever horizontal machining centre
(HMC), a 4-axis Averex HS-450i (640, 610,
680 mm; X, Y, Z) with nominal half-metre
cube working volume from Whitehouse
Machine Tools ( www.is.gd/bupuju ). Maximum
workpiece size is 750 mm diameter by one
metre high and control is by a FANUC 31i
Nano CNC
Investment in the twin-pallet, 40-taper
machine was prompted by an increase from
150 to 350 per week of a particular 6061
aluminium, two-part enclosure needed by
CTPE's largest customer, a medical sector
OEM, for the production of critical care
diagnostic equipment.
SUBCONTRACTING PROGRESSIVE FIRMS PLOUGH AHEAD
There is no problem completely machining
the required quantity of covers three at a time
in two hits on a Japanese-built Brother
Speedio S1000X1 30-taper VMC installed in
Mildenhall last April by Whitehouse Machine
Tools. Neither is there an issue completing
Op2 on the matching housing using the same
machine, which has now been tted with an
angle head to make the cycle even faster.
However, Op1 on the housing was proving
too time-consuming on a 3-axis VMC to meet
the increased order level and was causing a
permanent bottleneck, despite the running
hours having been extended from 10 to 14
per day.
Alex Taylor, a director of CTPE and son of
the founder, Chris, decided that an HMC
would best suit the higher production volume.
The second pallet allows the next parts to be
xtured while the previous parts are being
machined and automatic pallet change takes
just ve seconds. Dual augers ef ciently
remove chips that have fallen from a cube
xture, so there is no manual intervention,
except to empty the swarf bin after every
couple of pallet changes.
In contrast, the spindle on the xed-table
VMC was idle for 25 minutes after each cycle
for accumulated swarf to be cleared and the
next parts clamped for machining. A further
problem was recutting of the swarf chips that
collected within the component, which risked
damaging the solid carbide tools.
An HMC eliminates that dif culty and is
more robustly built than a VMC, so vibration
is lower, meaning that cutters last longer. The
most signi cant bene t, however, is that four
aluminium billets can be xtured on a cube
for Op1, so 24 housings are machined in a
cycle time of 160 minutes. Formerly on the
VMC, only two billets could be xtured for
machining a total of 12 components and the
program ran for 135 minutes. The gures
equate to a production time saving of 40%,
considerably reducing manufacturing cost per
part for this operation, particularly as there is
now minimal operator intervention.
The Averex machine won out against two
www.machinery.co.uk | MachineryMagazine | @MachineryTweets | October 2020 25
/bupuju
/www.machinery.co.uk