TPT November 2011

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72 November 2011 ›
Technology Update
the angled end pieces for an elbow pipe
and then assembling them – a task that
previously took about 15 minutes in total
– can now be accomplished in around
4 minutes.
The tube being cut is mounted in
the machine with its top end held in
a rotating pneumatically driven clutch
assembly. The plasma cutting torch is
moved up and down as the tube rotates,
at a rate that determines the severance
angle or the size and shape of the hole
being cut. Both the main rotational
axis and the plasma torch height axis
are powered by Baldor BSM series
AC brushless servomotors driven by
Baldor MicroFlex digital servo drives,
and employ interpolation to secure a
constant cutting rate regardless of the
profile of the cut or diameter of the tube.
The machine can handle a wide range
of tube diameters, from 90 to 350mm,
with wall thicknesses up to 1.5mm.
The tube cutter also uses three
Baldor stepper motor driven axes.
Two of these control the position of a
pair of guide rollers, which support the
tube during the cutting process and are
driven closer together or further apart
A NEW plasma cutting machine for flue
pipes has been developed by Techserv
Cutting Systems, a manufacturer of
CNC profile cutting systems. Advanced
interpolated motion of the cutting
system is used to increase production
throughput, using an economic real-time
machine control module from Baldor.
Capable of cutting aluminium and
stainless steel flue pipes at any angle,
as well as holes of any shape or size,
the plasma tube cutter completely
automates this aspect of manufacturing.
For example, elbow pipes have
traditionally been produced by cutting
complex shapes from flat metal sheet,
which are then rolled and welded before
assembly. This time-consuming multi-
stage fabrication process requires
considerable movement of work pieces
around the factory.
The new cutter dispenses with
the need to pre-cut complex shapes.
Instead, the flat metal sheet is rolled
into a tube and seam welded, then each
tube is successively loaded into the
machine. The entire cutting operation is
handled autonomously; a simple angled
cut takes a matter of seconds. Cutting
depending on the diameter of the tube.
They also move aside automatically
during the tube reload phase to
facilitate operator access. The third
stepper-driven axis dynamically varies
the distance between the plasma torch
head and the wall of the tube during
the cutting process, to provide optimum
performance.
All five electrical axes are controlled
by a Baldor NextMove ESB-2, a compact
real-time machine control module
that receives commands direct from
an on-board PC-based CNC system
developed by Techserv specifically
for tube profile cutting applications.
The CNC system software runs
under Windows XP, with all operator
information presented on a large, touch-
sensitive, full colour HMI.
Baldor’s NextMove controller
provides all the control functions for the
machine’s five servo and stepper motion
control axes, with even the base model
capable of accommodating a further
two axes if required for future machine
variants. The controller also features
extensive built-in I/O capabilities, again
with expansion options.
According to Techserv’s technical
director, Mike Cowley, “Baldor’s high-
level Mint programming language
helps us to develop motion control
programs for custom applications
like this very quickly. Integrating the
NextMove controller with our front-end
CNC system was also straightforward
because it uses the same API naming
conventions as ActiveX commands.”
Baldor Electric – USA
Fax: +1 479 648 5792
Website:
Baldor UK Ltd – UK
Fax: +44 1454 859002
Email:
Website:
Techserv Cutting Systems – UK
Fax: +44 1924 458630
Website:
All-in-one machine controller simplifies
development of plasma tube cutter
Baldor’s NextMove ESB-2 real-time
controller provides control functions for
the tube cutter’s motion axes