Above: Mill-turn machines present
challenges in collision avoidance,
now solved with VERICUT
Inset: simulating probing
forward, so everyone has to be open to
new ideas and new methods.”
The machine shop runs on a
continental ve-shift system, but the CAM
programmers are available for the day
shift, which is when prove-out occurs.
If the prove out is not completed within
one shift, then the following two shifts
can’t progress or make parts. This was
one of the key reasons for investing in
VERICUT and the software has helped
signi cantly, as noted above.
Moving onto speci c machine-related
issues, speci cally two turning centres
with B-axis and milling, Hass recalls:
“For the rst few years, the new machines
were operated just for turning. No one
could handle the programming
complexities of the milling and drilling
capabilities, as they are very dif cult to
program safely. There are many
opportunities for collisions between the
tools, xturing, machine structure and the
workpiece.”
It’s a point that Lee Fowkes, Country
Sales Manager for CGTech, emphasises:
“We see many customers investing
signi cant sums in large mill-turn centres
and they simply do not achieve the
expected productivity levels, because they
do not have either the skills or the
mindset to unlock the full potential of
these machines. I call it the ‘myth of millturn
productivity’.”
Now, VERICUT is used to verify the
post-processed CAM program to ensure it
will run safely without crashing. The staff
to run these machines have been
The aim is for VERICUT prove-out time to
be a factor of cycle time. For a one-hour
cycle, a 2.5-hour prove-out is targeted
specially selected, not by skilled capability
but by attitude and willingness to adopt
new concepts.
Prior to using VERICUT, machine tool
crashes were seen as part of the
operational risk, these were not usually
identi ed during the prove-out, as all the
parameters are backed off and the
process is being monitored very closely.
However, when the parts went to
production, errors that didn’t arise during
the early stages were often highlighted.
Part of the justi cation and ROI for
investing in VERICUT software came from
the expected saving of one spindle per
year. “We have had several virtual
crashes in VERICUT, but nothing on the
physical machines,” Hass con rms,
adding: “However, the real savings come
from the prove-out time achieved.”
Another key part of VERICUT software
that is supporting MAN ES is the Auto-Diff
module. It enables the programmers to
compare a CAD design model to a
VERICUT simulation to automatically
detect differences. Using this module in
the production process can identify
incorrectly machined areas.
Hass again: “The process is to turn
the blank to size and then mill the
prismatic features, and so on, with
following sequential operations. Some of
this will be removed by the increased millturn
capacity where we probe the part on
the machine, but for some families of
parts it is still the most effective route.
Previously, if the parts required, say, four
turning operations and two milling
operation and an error was made at any
stage, then it would not be detected until
the part had been nished. This wasted
time and effort, effectively making scrap.
“Now we are updating our
manufacturing documents in NX and
using Auto-Diff in VERICUT to check the
part stock for each stage of the
manufacturing process. It is a great tool
to provide con dence in the process and
eliminate the risk of bad parts being
unnecessarily progressed. If you make
scrap, you have to make the part again,
but it is better to catch the error as early
on as possible to save your resources.
Many of our parts are similar, with just
small detail changes and these can easily
go unnoticed, which is why Auto-Diff is
important.”
Advanced machining centres from
Heckert and Heller are also modelled in
VERICUT and now they will not run any
program without it being veri ed rst in
the software. A total of 10 of the
advanced machine tools on the shop oor
at MAN-ES are accurately modelled in
VERICUT today. One of the latest being a
DMG-Mori NTX 1000 multi-function turning
machine with B-axis. “Space is tight on
these machines, so you have to check
toolholders and so on, we had to buy
special holders, due to the lack of space.
And, we can get our part production
programs ready prior to the machine
installation. It avoids the protracted
installation sequence that is too often
followed when a complex new machine is
installed,” concludes Hass.
www.machinery.co.uk @MachineryTweets February 2020 9
/www.machinery.co.uk