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Wednesday, 2018-06-20

LOTAR 3D CAD with PMI Workgroup

Goals and Objectives

The specific goal of the 3D Mechanical & PMI Technical Working Group is focused on the preservation of the explicit 3D Geometric shape representation and associated Product and Manufacturing Information. The results will be documented as NAS/EN 9300-1xx parts. ( See table below )

Mechanical Domain: Parts 100, 110, 115

Goals and Objectives

The 3D Mechanic Domain covers the definition of the physical shape of a component, the positioning of components within an assembly, and the information about shape, such as tolerances or surface finish, which constrains the results of a manufacturing process, but does not specify the process itself.

The Domain also covers the ‘explicit representation’ which refers to the mathematical representation of the final result of the CAD model. From the designer's point of view, it corresponds to the 3D shape (points, curves, surfaces, solids etc.). Explicit 3D shape may be associated with non-geometric data including design management meta-data such as layer, color or group or user defined properties. These non-geometric data are optional, and are added by users and checked and validated by specific tools.

The 3D Mechanical Domain finally describes the requirements, and particularly the information required, for the long term archiving and retrieval of a mechanical CAD explicit assembly structure.  This will allow the retrieval of the assembly structure including the placement information.

PMI Domain: Parts 120, 121, 122, 125

Goals and Objectives

The objective of the Product and Manufacturing Information (PMI) Domain, is to define the requirements for the long term digital preservation of the presentation of Product and Manufacturing Information (PMI) with their associativity to the 3D explicit shape and geometry of CAD parts. 

The specific Goal of the PMI Working Group is focused on the preservation of the explicit 3D Geometric shape representation and associated Product and Manufacturing Information.

There are different levels of information that can be exchanged in that context, which are listed below:

 Figure 1: PMI Definitions 

 

The 3D Mechanical PMI team in support of Industry's requirements to have an explicit 3D Geometric Shape Representation with associative 3D Product & Manufacturing Information presented in an ISO 10303 AP 203, AP 214, or AP242 file format in a timely manner. Options were to use current enabling technology to support this requirement and to develop the geometric based parts P100, 110 and 115 and phase in the PMI aspects as technology matured as described below.

  • Phase I: The PMI would be represented graphically with cross-highlighting capability. The PMI would be initially presented as non-semantic Polylines and documented in EN/NAS 9300-120e1. Edition 2 illustrates the tesselated representation of PMI..

  • Phase II: The PMI would be represented as semantic STEP entities that are fully associative to the Geometric Shape Topology. This would be documented in EN/NAS 9300-121 aligned with AP242.

  • Phase III: Will include explicit 3D Geometric Shape Representation with associative 3D PMI applied to Machining and Mfg Form Features that includes Holes and Fasteners. This would be documented in parts EN/NAS 9300-130-132.

Figure 2 describes a generic process for the development of 3D CAD parts with PMI and illustrates  the main categories of essential information created in the Aerospace and Defense industry. The associated tasks for developing, manufacturing and supporting 3D CAD parts with PMI are also illustrated.  The current priorities of development of the LOTAR 1XX standards are also shown.

Figure 2: Generic Pracess Flow for 3D CAD developement PMI Definitions

The LOTAR Family of Standards for 3D CAD PMI

The planned NAS / EN 9300-1XX standards for the Long Term Preservation of 3D CAD Geometry with Product & Manufacturing Information (PMI) include the following:

Part Title Status
100ed1 Common concepts for L-T Archiving and retrieval of CAD 3D mechanical information Rel 2012
110ed1 L-T Archiving and Retrieval of CAD mechanical 3D Explicit geometry information Rel 2012
110ed2 L-T Archiving and Retrieval of CAD mechanical 3D Explicit geometry information Rel 2016
115ed1 L-T Archiving of Explicit CAD assembly structure Rel 2012
120ed1 L-T Archiving & Retrieval of CAD 3D Explicit Geometry with Graphic PMI Presentation Rel 2012
120ed2 LT Archiving & Retrieval of CAD 3D Explicit Geometry with Tessellated PMI Presentation Rel 2017
121ed1 LT Archiving & Retrieval of CAD 3D Explicit Geometry with Semantic PMI Representation Rel2018

Associated ISO 10303 Information Models

  • The LOTAR standards do not define specific information models for Long Term preservation of CAD and PDM information models. They rely closely on the ISO 10303 STEP Application Protocols. The STEP modular architecture ensures the consistency of the information models subsets common to several ISO 10303 standards.

  • The LOTAR P1XX family is based on:  
    • ISO 10303-203 “Configuration-controlled design”
    • ISO 10303 -214 “Automotive Design”
    • ISO 10303-42 “Product data representation and exchange”
    • ISO 10303-47 “Shape Variation Tolerances”
    • ISO 10303-59 “Quality of Product Shape Data”
    • ISO 10303-519 “Geometric Tolerance” this AIC describes the PMI model used in P120
    • ISO 10303-242 “Managed Model Based 3D Engineering”

Meetings

  • The 3D Mechanical PMI Working Group holds weekly WebEx/Teleconf meetings on Tuesdays from 08:00am – 09:00am (PST)

  • The 3D Mechanical PMI Working Group also holds weekly WebEx/Teleconf meetings to work AP242e3 actions  on Fridays from 08:00am – 09:00am (PST)

Accomplishments for 2017

  • Parts 121e1 Sematic PMI Representation and Part 125e1 Assembly Graphic PMI were completed for initial draft and ready for ballot to AIA and ASD-STAN.

  • The Holes and Fastener WG prepared “Recommended Practices for the Representation and Presentation of Hole and Fastener Information” and draft is planned to be completed by the end of the year.

  • Worked with AP242ed2 PMI Working Group to complete all CR_PMI_2 deliverables to support DIS release in December 2017.