tooling
Recording year-on-year turnover growth of over 30%, and having the foresight to recruit an
apprentice every second year, toolmaker TBM has invested in a sophisticated portfolio of
CNC technology, with a 5-axis tool grinder at the heart of its operations.
Meteoric growth
– but no burnout
STARTING with a clutch of secondhand
machines, TBM Precision Engineering has
enjoyed meteoric growth as a specialist designer
and manufacturer of solid carbide, HSS, HSSCo
ASP CBN, brazed carbide tipped and indexable
carbide insert cutting tools. These are supplied
(uncoated or coated in TiN, TiALN or TiCAN) in
various styles and sizes to the nuclear, automotive,
aerospace, marine, oil and gas and medical sectors.
The company, which started five years ago as a
one-man band producing special-purpose tooling
for a handful of local customers, now employs
eight people to meet growing demand from an
intenational customer base.
Previously part of the management of a tooling
manufacturer’s production operations, timeserved
toolmaker Tom Mackie established TBM
in a small village near Chorley in 2002. Armed
with an assortment of pre-owned machines, he
set about building the company producing
special-purpose tooling and toolholders. ‘CNC
tool grinding has been paramount to the
company’s success,’ he says, and the investment in
CNC started with a Walter NC45 - purchased,
unseen, via the Internet for £18k. ‘The machine
gave me the ability to produce fluted carbide
without burning out grinding wheels; and that
was a tremendous advance on the manual optical
grinding methods I started with.’
CNC tool grinding was an essential step, he
says, since the company’s reputation for bespoke
complex carbide tooling and accompanying
toolholders, and therefore supplying turnkey
solutions, was gathering momentum. Today, the
shopfloor also includes CNC turning and milling
as well as AutoCAD software, for designing and
manufacturing not only tooling but also bespoke
jigs, fixtures, gauges and assembly tools.
Installation of a Walter Helitronic Power is
regarded as a significant milestone in the
company’s progress - in much the same way as its
Walter Helitronic Power Regrinder, which
enabled previously sub-contracted work to be
brought back in-house. Offering 11.5 kW of
power and rapid traverse rates of 15m/min in all
linear axes plus 120˚/sec on the rotational axes, the
Helitronic Power can accommodate tools up to
350mm long (300mm for face grinding) and
320mm diameter. And, like the regrinder, it is
attracting work by itself.
‘The machine’s reputation is such that
customers contact us’ says Mackie. ‘Not only is its
quality of output consistently superb - the
machine accounts for 80% of production - but its
A new PCD milling system combines simplified tool pre-setting with the highest levels of precision to deliver
exceptional levels of performance when finish milling aluminium components.
Precision: it’s all about attitude
AS PCD cutting edges are relatively expensive, users are required to regrind
them in order to reduce the average cost of use. This brings its own problems
in that service costs - for regrinding, insert adjustment in the cutter body, and
related logistics (spare inserts) etc - can be high. To overcome this, the inserts
used in WNT’s HPC12 cutters do not require regrinding, and adjustment is
carried out by a much simplified system that features only two elements to
clamp and adjust the PCD cutting edge. The simplified tool pre-setting of the
HPC 12 system ensures that the inserts are all set to the correct height,
ensures that the minimum amount of time is spent to achieve the both
optimum performance and the highest levels of surface finish.
The tool design sees the insert seat become part of the adjustable wedge
that, using a standard Torx key can be adjusted to an accuracy of less than
five microns. The design of the insert seat and wedge system, which uses
mechanical forces to overcome the centrifugal effect, combined with the
novel screw design provides the user with increased process security, which
is fundamental when operating at surface speeds up to 5000m/min and feed
50 MWP january 2008
reliability is undisputed and the level of back up,
when needed, is excellent.’ He says he has fully
tested the level of technical support offered on the
Helitronic Power by Körber Schleifring UK,
since the complexity of some of the tooling so far
produced has ‘stretched the machine’s
programming cycles to the limit’ by demanding
‘what some may describe as ridiculous tolerances’
while using the extensive ability of ‘Package 27’
flexible programming to allow the machine to be
used for the production of complex components.
‘We are continually asking more and more of
the machine and its control technology - and so
far, it has responded.’ Another indispensable asset
in the company’s ability ‘to produce the
seemingly impossible’ is the role played by TBM’s
manager Brian Pendlebury who, at 63 is enjoying
a new lease of life with the Walter CNC
technology and its complementary Walter Cyber
Grind simulation software package. This allows
the tool grinding process to be simulated onscreen
- for verification and optimised design,
grinding result, operation sequence and grinding
wheel paths - and so provides savings in cutting
tool design and production by allowing nonstandard
new tools to be created off-line.
www.walter-machines.com
rates up to 0.3mm/tooth. The tangential insert
seat also presents a high positive rake angle to
the workpiece. This 25° approach assists in reducing cutting forces, which in
turn reduces the deformation of the component being cut, and ensures a
high level of parallelism on the surface of the component.
A further cost saving is achieved through the use of lightweight steel
cutter body that is resistant to the abrasion experienced during high speed
machining. Cutters greater than 160mm are of a bi-metal construction, with
the outer diameter/ring being steel and the inner ‘core’ aluminium. This helps
to reduce the weight of the cutter, and at the same time the forces being
placed on the machine spindle.
Typical cutting data for the HPC 12 are 1000-5000m/min and 0.1 -
0.3mm/tooth feed when cutting aluminium with a silicon content of 4-8%.
The surface speed drops to 700-3000m/min when the silicon content is 9-
12%, and a further reduction to 400-900m/min when this goes above 12%.
www.wnt.com
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