So often, I am asked: “Why must we annotate or tolerance a 3D printed part?” The answer always is “INSPECTION.” Regardless of quality verification for First Article Inspection (FAI) or lot inspection for most organizations evaluating conformance to requirements is needed.
I recently co-authored “Towards Annotations and Product Definitions for Additive Manufacturing” with Dr. Paul Witherell and Dr. Gaurav Ameta. The title sounds official, as it should for a published paper, but perhaps, between you and me, we could give it a lighter name: All About That Communication. Cue Meghan Trainor. Forms of the word “communicate” appear 43 times in the paper! Yes, I counted.
Here's a few examples:
“…AM is compelling us to rethink how we package and communicate design requirements.”
“…Model-Based Definition (MBD), a technique of communicating a product using the 3D model geometry and 3D annotations, is ideally suited for parts and assemblies built with AM methods.”
“…GD&T is…a means for specifying dimensions on geometry and communicating allowable dimensional and geometric variations (tolerances) for which manufacturing can be planned and inspections can be made.”
“In MBE practices, product definitions have become the standard means for communicating requirements.”
“With AM products, comprehensive product definitions are needed to facilitate (a) clarity in the communication, (b) efficiency in the as-built versus as-designed comparison, and (c) increased product quality.”
“…the challenges associated with communicating GD&T in AM are just beginning to emerge. As the technology matures, new methods will be necessary to communicate design intent, and these methods must rely heavily on PMI and representation techniques.”
As additive manufacturing is viewed more and more as a production-capable technology, data and information needs have made the costs of AM complexity increasingly apparent. Techniques available in current GD&T practices do not fully support product definitions needs in additive manufacturing. The fully model-driven process introduces new intricacies and complexities that must be addressed to facilitate the reproducibility of AM parts. Machine-readability needs must trump human interpretation requirements. In this paper, we discuss the future directions of GD&T and semantic annotations as they relate to satisfying AM product definition requirements.
The 3D model should be the master source of information for products produced with 3D printing. To this end, properly communicating necessary model requirements – geometry, annotations, and attributes – is essential to data reusability.
Annotation
We want the annotations to be semantic, that is, for software consumption (not only for readability by humans) and digitally associated to the feature (see definition of feature from ASME Y14.41) they represent, to get maximum reusability out of the product definition. AM will require us to do this. Semantic annotations are easing their way into GD&T practices through the ASME Y14 standards. The paper by Witherell, Herron, and Ameta discusses annotation challenges created by AM and the future of 3D product definitions and semantic annotations as they relate to overcoming these challenges. In the end, it’s all about that communication. Read the full paper here.
Here is a summary of the ASME Y14 series standards underway today.
ASME Y14 Engineering Drawing and Related Documentation Practices
- Home to 25 active subcommittees
- Upholds 24 published standards
- Maintains 1 GD&T Certification Exam
- Holds the U.S. TAG to ISO TC 10 on Technical Product Documentation
- Part of the U.S. TAG to ISO TC 213 on Dimensional and Geometrical Product Specifications and Verification
ASME Y14.46 Product Definition for AM is a subset of the Y14 Series
Y14 series standards provide comprehensive criteria for implementing GD&T effectively across the manufacturing supply chain:
- Geometric Dimensioning & Tolerancing (GD&T) – 3 standards (Y14.5, Y14.5.1, Y14.41)
- Drafting Practices – 11 standards (e.g., Orthographic and Pictorial Views, Drawing Sheet Size and Format)
- Mechanism and Devices – 5 standards (e.g., Screw Thread Representation, Mechanical Spring Representation, Gears)
- Symbols & Abbreviations – 5 standards (e.g., Y14.36 Surface Texture Symbols, Y14.38 Abbreviations, Y32.7 & Y32.18 Graphic and Diagram Symbols)
- Certification – 1 GD&T Certification Exam (Y14.5.2)
- Model Schema – 1 standard (Y14.47, not yet released)
- Product Definition for AM – 1 standard (Y14.46, not yet released)
The approved charter for ASME Y14.46 is:
- Develop and standardize systems and indications to promote uniform practices for product definition for additive manufacturing.
- Create a broadly accepted standard that incorporates, expands, or refines international practices and symbology to enable AM product definition data sets to be created, interpreted, and consumed on a global basis.
- This standard shall ensure that component parts and component assemblies, produced from such AM product definition data sets, are subject to a single interpretation of engineering specifications and requirements for the purpose of conformance verification.
- This standard shall supplement the requirements of the Y14 series.
ASME Y14.46 consists of four areas:
- Product Definition, led by John Schmelzle, NAVAIR
- Process Specification Definition, led by Dr. Paul Witherell, NIST
- Conformance to Specifications, led by Katharine Losoncy, Aerospace Corp.
- Data Package (DP) Requirements, led by Jennifer Herron, Action Engineering
The America Makes & ANSI Additive Manufacturing Standardization Collaborative (AMSC) is a cross-sector coordinating body whose objective is to accelerate the development of industry-wide additive manufacturing standards and specifications consistent with stakeholder needs and thereby facilitate the growth of the additive manufacturing industry.
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