[step-manufacturing] Minutes of 11th conference call

[Martin Hardwick]

Attendees
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Martin Hardwick, STEP Tools
Mikael Hedlind, KTH
Magnus Lundgren, KTH
Bengt Olsson, Sandvik
Alain Brail, AlBavis
Fred Proctor, NIST
Sid Venkatesh, Boeing
Patrick Marchand, CEITM
David Loffredo, STEP Tools
Aydin Nassehi, University of Bath
Stephen Newman, University of Bath
Matthew Lloyd, CCAT


Apologies for absence
--------------------------------
Gary Hargreaves, Mastercam
Xun Xu, University of Auckland
David Odendahl, Boeing
Ian Stroud, EPFL
Leon Xu, Boeing

Boeing has machined the five axis version of the part and plans to 
machine the three axis version in the next week. Boeing has offered 
to prepare stock for all of the machining participants. They are 
making 12 pieces so that each participant can have two. Currently the 
participants are CCAT, NIST, KTH and University of Bath. Sandvik may 
also participate.

We discussed the tool compensation presentation. The goal is to 
enable automatic process adjustments on the machine tool when errors 
are found in any of the tolerances or required properties of the 
part. The adjustments include changes to the tool path, the feeds and 
speeds and the selection of alternate workplans.

ftp://ftp.steptools.com/private/Vancouver/meeting/stepnc_compensations.ppt

The presentation shows how tolerances can be measured and the errors 
found can be used to change the tool paths, feeds and speeds or 
select an alternate workplan. A number of options were presented and 
clarifications were suggested. At the current stage we are seeking to 
determine if there is value in the approach. If so then the proposal 
will be further discussed at the upcoming T24 and SC4 meetings.

The feedback was mixed. There was a strong recommendation to 
continue, but also words of caution about whether the proposal really 
belonged in AP-238. Some are not sure if new program control 
structures should be added to AP-238 when several of the existing 
ones have not yet been tested. Others want to enable conditional 
programming in AP-238 and do not think it is possible to do so using 
the existing control structures because they are too hard to use.

There is also concern that any compensation strategies developed for 
one machine are unlikely to be applicable to other machines. In 
general there seems to be an independence hierarchy where machining 
strategies are the most portable, measurement strategies are the next 
most portable and compensation strategies are the least portable.

The Goto meeting video for the conference call is at:
ftp://ftp.steptools.com/private/Vancouver/stepmanuf_telecon_20090318.wmv

The next conference call will be held on Wednesday April 1st. This 
call will be at the usual times for Europe and the USA because both 
continents will have moved to summer time.

Action items
------------------
1.   Boeing to deliver stock to participants.
2.   Boeing to test three axis machining.