Below:- A simple tool offset optimisation
Offset optimisation
Metrology and CMM expert Aberlink has originated new software for the well-established process of
generating tool and workpiece offset update information, whether it be for manual or automated input.
And in typical Aberlink style, it demonstrates an innovative approach to improve established practices.
Andrew Allcock has the details
In Machinery’s November issue (p16 –
www.is.gd/nudago ), we revealed details of
Aberlink’s latest CMM developments,
Horizon and Extol. The latter was driven by
the favour that its predecessor, Xtreme, had
found on the shop oor, although it was not
speci cally designed for that. The origination
of tool offset software for incorporation within
the company’s associated metrology
software was similarly driven to complement
Extol’s shop oor use, with that software
used to create offset data that can then be
transferred automatically to the machine
tool, or simply entered manually. (Loading/
unloading of parts can also be automated via
the existing automation interface available
with Aberlink metrology hardware, too.)
Marcus Eales, technical director at
Aberlink ( www.is.gd/oP2kjx ), explains why the
company developed its own and chose not
use an existing package: “When we looked
at other software, while you could obviously
get it to do all the updates, it wasn’t very
tightly integrated. It required the sort of
effort that wouldn’t have been a problem if
you’ve got a couple of production engineers
spending several months getting a robot cell
up and running, because the hour getting the
tool offset program running is neither here
nor there. But because our market is in
smaller companies that typically run a
different job in the morning and afternoon,
we really did want something that was very
simple and fully integrated into our system.”
The company could have integrated an
existing system, but for the fact that the
established tool offset update process is a
one-dimension-one-offset approach that has
its roots in the past. Eales again:
“Historically, machine tools are updated
from measurements taken from hard
gauging tted with multiple measurement
transducers and you obviously get one
measurement for one dimension, so one
measurement will update one offset. That’s
ne for long runs, of course, but today there
are more exible gauges, such as
Renishaw’s Equator, that can replace hard
gauging and which can be easily and quickly
programmed to suit different parts. Yet the
same approach to offset update has been
maintained, because it is kind of what
people expect and never really question.”
He says that he was very surprised to nd
in standard tool offset software that he
couldn’t, for example, update a tool offset
and work coordinate offset at the same time
via a simple calculation, although it is
possible with the Equator and via metrology
software such as PCDMIS, he adds. But such
calculations can quickly become complex. So,
as far as integrating such a capability within
its own software goes, this summing
capability could be added to Aberlink’s
existing software, but the choice was to go
further and do something more generic.
Eales again: “Okay, well I’ve got all these
equations that are basically giving me
dimensions but all I really want to do is to
minimise the errors on a dimension, or
minimise all the errors on the dimensions,
or prioritise the more important dimensions,
or get everything in tolerance, or everything
closest to nominal, or whatever. It’s
basically a big optimisation exercise, with
the user able to de ne the preferred
approach.
“It really doesn’t matter whether it is for
two dimensions created on a single machine
or for 100 dimensions created on three
different machining centres, the algorithm is
28 December 2020 | www.machinery.co.uk | MachineryMagazine | @MachineryTweets
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/oP2kjx
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