[step-manufacturing] Minutes of March 18th conference call

[Martin Hardwick]

Attendees
--------------
Martin Hardwick, STEP Tools, USA
David Loffredo, STEP Tools, USA
Julie Huang, Sandvik Sweden
Bengt Olsson, Sandvik, Sweden
Charles Gilman, GE, USA
William Carter, GE, USA
Robert Erickson, Pratt & Whitney, USA
Vincent Marchetti, Ameritech, USA
Dan Finke, Penn State, USA
Tom Raun, Iscar, USA
Larry Maggiano, Mitutoyo, USA
Than Huynh, Okuma, USA
Shogo Nakashima, Makino, USA
Zhigang Wang, Makino, USA
Alain Brail, Airbus (retired), France
Ian Stroud, EPFL, Switzerland

We discussed the representation of additive process data in STEP-NC.
ftp://www.steptools.com/private/additive/CLI_to_STEP-NC.pptx
ftp://www.steptools.com/private/additive/CLI_to_STEP-NC.wmv

Additive manufacturing shares many issues with subtractive 
manufacturing. There is a requirement to "lock down" a process when it 
has been completed by fixing the toolpaths. There is a requirement to 
spatially optimize the process so that different materials and 
temperatures can be applied at different locations. There is a need to 
know if a wall or floor is thin so that the process is not too 
aggressive at that location. There are issues if a path is too short or 
too long because this can lead to cavities for additive manufacturing, 
and surface issues in subtractive manufacturing. There is a requirement 
to be able to compensate for worn tooling or lenses that are losing focus.

In addition additive manufacturing has the special quality of being very 
time consuming so there is a desire to have multiple lenses operating 
concurrently and machines with two or four independently operated lenses 
are coming on line.

New formats are being designed to help optimize additive processes. The 
input is STL or AMF but within the process there is a desire to 
represent each layer as a solid model, and then divide the layer into 
different sections that can be given different properties.

STEP-NC uses STEP as its input. This has the advantage of allowing exact 
geometry to be used as the input. With the latest enhancements the 
geometry can be annotated with the design requirements as geometric 
dimensions and tolerances (GD&T) and other product manufacturing 
information (PMI). As well as GD&T, the latest edition of STEP has a 
very powerful and concise format for tessellated geometry.

STEP-NC allows each layer to have its own model and with its own PMI and 
GD&T if necessary. STEP-NC supports multiple parallel processes and 
other advanced control structures, and it already allows a process to 
vary spatially. We agreed that the synergy between STEP-NC and the new 
additive manufacturing requirements deserves further investigation, and 
we will arrange further meetings after the kickoff of the new America 
Makes projects that are looking into the new formats.

A recording of this conference calls is on the web site at the address 
below:
ftp://www.steptools.com/private/CAM_exchange/Cycle_6/stepmanuf_telecon_20150318.wmv

The next conference call is planned for Wednesday April 1st. The times 
for Europe and the USA will be synchronized again.

Martin Hardwick
Team Leader ISO STEP-Manufacturing