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<u>Attendees</u><br>
Martin Hardwick, STEP Tools, USA
<br>
David Loffredo, STEP Tools, USA
<br>
Fred Proctor, NIST, USA
<br>
Leon Xu, Boeing, USA
<br>
Mikael Hedlind, KTH, Sweden<br>
Magnus Lundgren, KTH, Sweden<br>
Chris Pfeifer CCAT, USA<br>
Fiona Zhao, NIST,/New Zealand<br>
Larry Maggiano, Mitutoyo, USA<br>
Bob Erickson, Pratt & Whitney, USA<br>
Sid Venkatesh, Boeing, USA<br>
David Odendahl, Boeing, USA
<br>
Anna Valente, ITIA-CNR, Italy<br>
<br>
<u>Apologies for Absence</u><br>
Aydin Nassehi, U.Bath, UK<br>
Stephen Newman, U.Bath, UK<br>
Alain Brail, AlBavis, France
<br>
Ian Stroud, Switzerland<br>
Bengt Olsson, Sandvik, Sweden
<small><br>
</small>
<br>
We reviewed the results of the dry run testing at NIST.<br>
<br>
<a class="moz-txt-link-freetext" href="ftp://ftp.steptools.com/private/NIST/NIST_boxy-setups.ppt">ftp://ftp.steptools.com/private/NIST/NIST_boxy-setups.ppt</a><br>
<br>
Some concern was expressed by a third party on the desirability of
placing the part at the edge of the fixture instead of the center
because this will result in an uneven distribution of forces.<br>
<br>
KTH explained that this fixturing method was chosen for simplicity and
to reduce the number of setups. The T square is only necessary for the
third setup when a surface that has yet to be machined is at the bottom
of the part. In the other setups the square is used a a quick method to
position the part and it can be replaced by a probe or other measuring
device.<br>
<br>
<a class="moz-txt-link-freetext" href="ftp://ftp.steptools.com/private/NIST/8_Setup_Fixture_Assembly.pdf">ftp://ftp.steptools.com/private/NIST/8_Setup_Fixture_Assembly.pdf</a><br>
<br>
We discussed the required attributes of the tool. It was observed that
the tooling data in V7 of Boxy is unfinished because the number of
flutes is not set, and that the information is incomplete because it
does not include a "stick out" (gauge) length, a flute (cutting)
length, and a shank diameter. For Boxy the shank diameter must be less
than the flute diameter to avoid rubbing the shank during machining.
Several diagrams were made showing the required tool attributes and
these have been put into the following ftp directory:<br>
<br>
<a class="moz-txt-link-freetext" href="ftp://ftp.steptools.com/private/NIST/tools/">ftp://ftp.steptools.com/private/NIST/tools/</a><br>
<br>
We would like to add the missing information by importing ISO 13399
files into the STEP-NC Explorer. We would also like to create better
geometry models for the tools showing the reduced shank dimensions and
other key attributes. We would like for presentation information to be
included with the geometry models because many slightly different terms
are used to describe these parameters by industry. We would like to use
the standard terms defined by ISO 13399 and then show where those terms
apply on the geometry models to avoid any ambiguity.<br>
<br>
We reviewed the information model developed by Fiona Zhao for her Ph.D
thesis at the University of Auckland which she recently completed
(congratulations to Dr. Zhao). The model is an extension of the HiPP
model developed by Tom Kramer at NIST. HiPP is an extension of STEP-NC
for High level inspection Process Planning. Fiona implemented much of
this model while testing her thesis and we would like to use her
results where applicable in Edtiion 2 of AP-238. <br>
<br>
<a class="moz-txt-link-freetext" href="ftp://ftp.steptools.com/private/NIST/HiPP_cover_letter.doc">ftp://ftp.steptools.com/private/NIST/HiPP_cover_letter.doc</a><br>
<br>
The model adds an its_tolerances attribute to manufacturing features.
There were questions about the value of this attribute because as was
shown during the Scania demonstration the tolerances that apply to a
feature can be deduced from the STEP geometry. <br>
<br>
<a class="moz-txt-link-freetext" href="http://www.steptools.com/library/stepnc/2008_sweden/closedloop/index.html">http://www.steptools.com/library/stepnc/2008_sweden/closedloop/index.html</a><br>
<br>
However, Fiona's model also includes attributes for required machine
accuracy so that an end user can determine if the tolerance needs to be
measured during machining. If the machine is above the required upper
level of accuracy then no measurement is necessary. If the machine is
below the required minimum level of accuracy then the part cannot be
made on this machine and again no measurement is necessary. If the
machine is between the upper and lower levels then a dm_workingstep (dm
= dimensional measurement) is created to make the necessary
measurements and confirm or deny the satisfaction of the tolerance. (We
might want to make the dm_workingstep a dm_workplan so that there can
be a setup and alternate measurement plans for different types of
equipment).<br>
<br>
It was suggested that the its_tolerances attribute of the model might
be renamed its_critical_tolerances because these are the ones that must
be met for machining to continue. It was further suggested that the
accuracy upper and lower requirements might be defined for each
critical tolerance to allow for finer grain decision making.<br>
<br>
Questions were also asked about the dm_features in the model. These
featured describe lines, planes, cylinders and other geometric items
that are already in the geometry model. In her thesis work Fiona
measured the underlying geometry in the geometry models and did not use
these features.<br>
<br>
The HiPP model will be further discussed at the NIST
meeting.<br>
<br>
Martin Hardwick briefly showed that the STEP-NC Explorer now supports
http addresses. We will revisit the use of STRL links for navigation
between program models in the next conference call.<br>
<br>
The next call will be at the regular times on Wednesday April 28.
No video was made of this call because of an error by the team leader.<br>
<br>
Martin Hardwick<br>
Team Leader STEP-Manufacturing<br>
<br>
Action Items<br>
----------------<br>
Sandvik to make ISO 13399 models for the cutting tools.<br>
Boeing to make AP-203 e2 presentation models for the cutting tools.<br>
STEP Tools to integrate the ISO 13399 and AP-203 e2 models into the
AP-238 for Boxy.<br>
NIST, Boeing and CCAT to machine Boxy in Wax.
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