New text for USA #2

[Martin Hardwick]

Dear All,

Thank you for a very productive meeting last week.

The enclosed file contains a new description for USA comment #2.
To remind everybody: we agreed to accept this comment if its
description was expanded to describe how in-process geometry
can be used to validate a STEP-NC file by making sure that the
CAM system and CNC agree on the material volume to be
removed by a working step.

Martin Hardwick
-------------- next part --------------
Issue: USA 14649-10 DIS - #2 
Author: Honeywell 
Clause: 4.6.2.1 and 4.6.4.1 
Classification: Major Technical 
Description: The STEP-NC standard should allow the CAM
application to include in-process geometry in a STEP-NC
file for the following reasons:

1. To enable easy visualization of the process when neither a CAM
   system or a CNC system is available.
2. To enable checking of the STEP-NC data by the CNC system
   which can compare the removal volumes it is calculating
   for each working step/work plan with volumes previously
   calculated by the CAM system.

Proposed Solution: 
Define a new entity to represent in-process geometry

ENTITY in_process_geometry; 
as_is : OPTIONAL advanced_boundary_representation; 
to_be : OPTIONAL advanced_boundary_representation; 
removal : OPTIONAL advanced_boundary_representation; 
WHERE 
WR1: EXISTS (as_is) OR EXISTS (to_be) OR EXISTS (removal); 
END_ENTITY;

Make this entity an OPTIONAL attribute of machining_workingstep 
AND workplan

ENTITY machining_workingstep 
SUBTYPE OF (workingstep); 
its_feature: OPTIONAL manufacturing_feature; 
its_operation: machining_operation;
its_effect: OPTIONAL in_process_geometry;
WHERE 
WR1: (NOT EXISTS (its_feature) AND EXISTS 
(its_operation\operation.its_toolpath)) OR (EXISTS (its_feature) AND 
(its_operation IN its_feature.its_operations)); 
END_ENTITY;

ENTITY workplan 
SUBTYPE OF (program_structure); 
its_elements: LIST[0:?] OF executable; 
its_channel: OPTIONAL channel; 
its_setup: OPTIONAL setup;
its_effect:OPTIONAL in_process_geometry;
WHERE 
WR1: SIZEOF(QUERY(it <* its_elements | it = SELF)) = 0; 
END_ENTITY;