machining
Heller H series tool
magazine takes the
shortest rout to deliver the
tool; changeover is under 2
seconds.
Miyano turning
centres cope with a
diversifying workload at
Macro CNC
accurate to two decimal places. Commonly, by
amortising the tool change times across the workpieces
on the fixture, minutes of non-cutting time can be saved.
‘The advantage the Hellers have in this respect is that
the machines have a high speed, very accurate B-axis
rather than an indexing table. This enables the part to
be rotated very quickly, even more quickly than a tool
can be exchanged and with good repeatability. This is
fundamental for tool amortisation to be fully effective,’
says Lloyd.
A quick acting toolchanger on the Heller machines
gives a tool change time of less than 2 seconds, with 2.2
seconds chip-to-chip time (including tool exchange
time, spindle deceleration and acceleration) measured
to the VDI standard. However, tool change times can be
deceptive, says Lloyd. Critical is tool administration ie
the time taken by the tool magazine to bring the tool to
position. Heller has a bi-directional tool magazine so
the tool magazine takes the shortest route to deliver the
tool to the tool waiting position. A tool fracture sensing
device checks the tool on its return to the tool magazine
so it does not impinge on cutting time. Tools are
cleaned and dried by the air purge mechanism during
the tool change cycle, so does not incur a time penalty.
Heller treats acceleration times as crucial to overall
cycle times. Heller machines achieve fast spindle rampup
time of 1.68 seconds due to new motor and spindle
technology.
With competitive advantage absolutely vital to winning
contracts in a fiercely combative marketplace, it comes as
no surprise to find a plethora of new machines offering
features aimed at attacking non-cutting time. These
include the new 5-axis Deckel Maho DMC 75V ‘linear’
vertical machining centre, which has the advantage of
short positioning times through the use of linear drive
systems in each of its three main axes capable of
accelerations of 2G up to the 90m/min rapid traverse rate.
While among the latest developments incorporated into the
latest Fanuc Alpha F Series vertical machining centre from
600 Centre is a 35% increase in torque for the new
10,000rev/min spindle that enables larger holes in steel to
be drilled from solid. A patent pending high speed
toolchange mechanism now enables a chip-to-chip time of
just 1.6 seconds to be achieved across the machine range.
Elsewhere, having one of the fastest rapid traverse
42 MWP january 2008
rates of 96m/min currently available on a vertical
machining centre attained with an acceleration of 2G, a
high speed spindle option of 20,000rev/min, tool-totool
change time of 0.7 seconds and a twin-pallet 180°
index time of 1.5 seconds, the new Dugard agency for
Akira-Seiki vertical machining centres is hoping to set
new benchmarks for short cycle production sequences.
Of course eliminating idle times is equally critical
when applied to turning machines. For instance, on the
new Tornado slant bed range from Colchester, a new
bar feed system option is able to save 25% of the time
normally taken on the feeding-out process, while turret
indexing time on the latest machine versions is also
reduced by a quarter.
At sliding head turn-mill centre manufacturer, Citizen,
the latest R07 Type VI CNC features six-axes, a main and
sub-spindle and up to 13 tools available, of which three are
driven and two tools can be brought into action
simultaneously. Available in the UK from NC
Engineering, an important development with the R07 that
significantly increases machine utilisation is the ability to
open and close the collet at normal machining revolutions
without adding to the cycle time by slowing the spindle.
They say the proof of the pudding is in the eating,
which is why whenever Machined Component Systems
(MCS) takes on a new contract or needs a machine tool
that can considerably improve productivity, the
company always makes a point of considering turning
centres from Macro CNC. The Redditch-based
subcontractor has seen its workload diversify
considerably in recent years and now, working across the
automotive industry for BMW, Jaguar and Ford as well
as supplying major medical technology OEMs, this
diversification has led to a change in machine tool
philosophy, prompting the company to acquire 4
Miyano turning centres from Macro CNC in the past 3
years, including a new ABX-64TH2 10-axis turning
centre to produce a complex environmental component.
Using its existing machines MCS couldn’t hang enough
tooling on the turrets to machine the 51mm diameter
component in a single set-up. However the Miyano ABX
64TH mill-turn machine with 64mm bar capacity, twin
spindle, three turrets and the potential for 36 driven
tools allows the most complex of components to be
manufactured completely in one operation.
Like EMO in September, MACH at the Birmingham
NEC (21-25 April) is certain to feature a high
population of machine tools boasting the latest idle
time reduction features. Like the machines, you’ll need
to be quick to get the best vantage point.
www.mazak.com www.heller.co.uk
www.gildemeister.com www.600centre.com
www.dugard.com www.colchester.co.uk
www.ncengineering.co.uk www.macrocnc.co.uk
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