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ASME Y14.46-2017 — Product Definition for Additive Manufacturing
🔬 ASME Y14.46-2017 is the ASME Y14-series standard dedicated to product definition for additive manufacturing (AM). Issued as a Draft Standard for Trial Use, it establishes uniform requirements for the specification of AM product definition data sets and related documents, capturing relevant detail from design, manufacturing, and quality engineering. Additively manufactured parts or assemblies are referred to simply as “parts” throughout the Standard; unless otherwise specified, any reference to features, parts, or processes is interpreted as applying to parts manufactured using an AM process.
⚠️ Important: ASME Y14.46-2017 is a Draft Standard for Trial Use. It has not been approved by an ASME consensus process and is not an American National Standard. Its content will be reviewed and revised by a Consensus Committee or Project Team following the one-year trial and comment period, and a public review under ANSI procedures is required before it can be submitted for approval as an American National Standard.
1. Background and Scope 📌
On October 10, 2014, the Y14 Standards Committee approved the charter of the Y14.46 Subcommittee, tasking it with developing requirements in geometric dimensioning and tolerancing (GD&T) for additive manufacturing. The goal was to create a broadly accepted standard that incorporates, expands, or refines international practices and symbology so that AM product definition data sets can be created, interpreted, and consumed on a global basis. After roughly two years of work, the Y14 Standards Committee approved this Draft Standard for Trial Use on June 19, 2017, and it was issued on November 15, 2017.
The main body is organized into five sections: Section 1 (General) covers scope and Y14-series conventions; Section 2 (Definitions) defines AM product definition terminology; Section 3 (Supplemental Geometry) specifies coordinate systems and orientation information; Section 4 (Product and Process Definition Requirements) is the core, defining how AM-specific geometry and process information is expressed; and Section 5 (Product Data Packages) defines the content of the various data packages. Three nonmandatory appendices provide example AM notes, methods for defining transition regions, and reference documents for conformance testing.
Following the Y14-series convention, “shall” states a requirement, “will” a declaration of purpose by the design activity, “should” a recommended practice, “may” an allowed practice, and “unless otherwise specified” (UOS) indicates a default requirement that may be overridden by another document.
2. Supplemental Geometry: Coordinate Systems and Build Direction 🧭
Because the physical properties of AM parts — anisotropy, surface quality, residual stress — are closely tied to spatial orientation during printing, Y14.46 requires that build-related geometric information be explicitly captured in the product definition. These are collectively termed “supplemental geometry”:
- Single coordinate system: the entire model uses one unified coordinate system to avoid conflicts among data sources.
- Multiple coordinate systems: where parts are nested or multiple components must be located within a build envelope, additional coordinate systems may be established with their transformation relationships clearly defined.
- Build direction unit vector: a unit vector that explicitly indicates the layer-stacking direction during printing — a critical parameter for mechanical performance.
- Gravity direction unit vector: identifies the gravity direction, used for support-structure design and residual-stress analysis.
- Build surface: planar or nonplanar, defines how the part is located on the build platform.
💡 The engineering adage “print direction determines performance” is formalized here: the design team must record the build direction in the data set; otherwise, downstream process engineers can only guess, and design intent is easily lost.
3. Product and Process Definition Requirements 🔧
Section 4 is the heart of the Standard, specifying how AM-specific geometry and process information that is difficult or impossible to express with traditional manufacturing notation is conveyed:
| Definition Element | Description | Typical Example |
|---|---|---|
| Theoretical supplemental surface | Imaginary surface bounding lattice or void regions; planar or nonplanar | Supplemental surface in a rectangular lattice cuboid |
| Bounded volume region (VOL) | Indicator for internal or external volume regions, can carry a profile tolerance | VOL1 with a profile-of-a-surface tolerance |
| Bounded surface region (SURF) | Indicator for surface regions, can couple with a feature control frame | SURF1 + feature control frame |
| Lattice structures and unit cells | Unit-cell geometry and dimensions for lattice/infill | Unit-cell geometries, lattice fill, multiple bounded volume regions |
| Material gradients and transitions | Gradual allocation between materials (MAT1, MAT2) or between material and void | Local notes + material gradient values table |
| Topology-optimized geometry | Organic surfaces from topology optimization, with explicit tolerances and verification | Complex topology-optimized geometry |
| Free zone | Open region around the part with limits on support, defined by offset dimension or bounding box | Offset dimension, free-zone bounding box |
| Layer thickness and track paths | Layer thickness, track-path specification (including Follow Boundary, FB, modifier), paths across layers | Layer thickness 0.05 mm; three-contour track path |
| Infill and unit cells | Infill ratio and unit-cell geometry definition | Infill examples, unit-cell structures |
| Support structures | SEA (structure exclusion area), SLA (structure limiting area, e.g., 20%), SRA (structure required area) | SURF1 annotated SEA/SLA/SRA |
| Test coupons | Location, quantity, and material-property verification of coupons | Local notes identifying test coupons |
Material gradient allocation is a capability unique to AM. The Standard uses a combination of bounded-volume-region local notes and material gradient value tables to write the material mix, void fraction, and allowable material fractions of each region explicitly into the product definition, conveying “one part, many materials/porosities” design intent. For transition regions, Nonmandatory Appendix B offers definition methods and tolerance specifications.
🚨 Improper support-structure treatment is a common cause of AM part failure. The Standard requires SEA (Structure Exclusion Area) for regions where supports are prohibited, SLA (Structure Limiting Area) to cap support density (e.g., ≤ 20%), and SRA (Structure Required Area) to mandate supports. Design and process teams must jointly review these regions to avoid sagging overhangs or difficult-to-remove supports.
4. Product Data Packages (PDP) 🗂️
Section 5 divides the data packages for AM products into four types, each with Required and Optional elements:
| Data Package Type | Stage | Main Content Elements |
|---|---|---|
| AM Design DP | At design completion | Model geometry, GD&T, material requirements, surface requirements, supplemental geometry |
| AM Build DP | At process preparation | Build direction, support scheme, layer thickness, track paths, nesting layout |
| AM Processed DP | At build/post-processing | Process parameters, heat treatment, support removal, machining datums |
| End Product DP | At acceptance/delivery | Inspection results, test-coupon data, conformance statements |
The Standard also gives AM use cases based on the codes of ASME Y14.41.1 and specifies metadata requirements for model-based definition (MBD) data sets (Table 5-7), ensuring the data packages can be exchanged reliably across CAD/PLM systems and archived long-term.
5. Engineering Practice Essentials 🛠️
- 🔍 Data-set completeness: in addition to the 3D model, the delivery must include supplemental geometry (build direction, gravity direction) and material gradient information; absence makes the definition incomplete.
- 🔧 Tolerance expression: prefer profile-of-a-surface tolerances with bounded region indicators for natural surfaces such as lattices and topology-optimized geometry, instead of forcing traditional linear dimensions.
- 📊 Coupon management: define coupon locations and quantities in the data set; coupons should be built in the same run, batch, and orientation as the part, and their test results serve as the basis for material-property acceptance.
- 📋 Data-package flow: Design DP → Build DP → Processed DP → End Product DP forms a complete traceability chain; each responsible party should sign off on data consistency.
6. Frequently Asked Questions ❓
❓ Q: Is Y14.46 a formal standard? Can it be cited directly in contracts?
A: No. It is a Draft Standard for Trial Use and comment — not approved by ASME consensus and not an ANSI-approved national standard. Contractual citations should wait until it becomes final, or explicitly state “per draft Y14.46-2017, accepting the associated risk.”
A: No. It is a Draft Standard for Trial Use and comment — not approved by ASME consensus and not an ANSI-approved national standard. Contractual citations should wait until it becomes final, or explicitly state “per draft Y14.46-2017, accepting the associated risk.”
❓ Q: Why does additive manufacturing need its own product definition standard?
A: Traditional tolerancing assumes homogeneous, isotropic material. AM part properties depend strongly on build direction, layer thickness, track paths, and porosity, and features like lattices, material gradients, and topology-optimized surfaces cannot be expressed with conventional drawing language — hence new mechanisms such as supplemental geometry and region indicators.
A: Traditional tolerancing assumes homogeneous, isotropic material. AM part properties depend strongly on build direction, layer thickness, track paths, and porosity, and features like lattices, material gradients, and topology-optimized surfaces cannot be expressed with conventional drawing language — hence new mechanisms such as supplemental geometry and region indicators.
🔍 Q: Where is the build direction recorded?
A: Section 3 requires directional unit vectors in the model for build and gravity directions, allows multiple build directions for a single part (e.g., split builds or flip-and-reprint), and, in the build data package, permits coordinate systems to locate parts within the build envelope.
A: Section 3 requires directional unit vectors in the model for build and gravity directions, allows multiple build directions for a single part (e.g., split builds or flip-and-reprint), and, in the build data package, permits coordinate systems to locate parts within the build envelope.
❓ Q: How are SEA, SLA, and SRA chosen?
A: SEA (Structure Exclusion Area) prohibits supports — used for surfaces needing smooth appearance or post-machining; SLA (Structure Limiting Area) caps support density (e.g., 20%); SRA (Structure Required Area) mandates supports, such as large overhang bottoms. All three can be annotated on different regions of the same part.
A: SEA (Structure Exclusion Area) prohibits supports — used for surfaces needing smooth appearance or post-machining; SLA (Structure Limiting Area) caps support density (e.g., 20%); SRA (Structure Required Area) mandates supports, such as large overhang bottoms. All three can be annotated on different regions of the same part.
