Fundamental Measurement Science for Additive Processes Project

Additive manufacturing (AM) processes have great potential for making high-value, complex, individually-customized parts, but several technical barriers must be overcome to achieve widespread use of additive processes for direct part production. Measurement science is lacking to evaluate fundamental AM process characteristics, improve the performance of AM equipment, and improve the accuracy of AM parts. This project will establish new standardized test methods to overcome key barriers for metal-additive processes.

Objective:

Develop first-ever standard test methods by 2016 that allow industry to evaluate and improve the performance of AM systems to make better parts more quickly and more economically.

What is the new technical idea?

The new technical idea is to improve the performance of AM systems and facilitate innovations throughout the AM community by establishing new standardized test methods for evaluating and controlling fundamental process characteristics for metal-based AM processes.

What is the research plan?

The research plan is organized into four task areas as defined below.

1. NIST Metal-Additive System

• Conduct hazard review, prepare safety procedures, and implement safety controls (including personal protective equipment, laser system, compressed gas, powder management, part handling, build platform preparation, system and facility maintenance)
• Bring the NIST-purchased AM system (EOS Corporation, Model M270) and its auxiliary equipment online (including shot peen station, heat treat oven, cleaning system)
• Implement the commercial software systems obtained with the NIST AM system purchase for 3D product data interface, support structure generation, and system monitoring and control
• Extensive training will be required: onsite vendor training; supervised hands-on experience at FBI research center; variety of test parts will be built
• Develop a standard guide that documents the process and recommended best practices for implementing an AM system, from receiving the equipment to its operational state
  

2. Methods to Improve AM System Performance

• Develop test methods to evaluate and improve the performance of AM equipment
  
• • e.g., geometric and thermal errors of the machine, positioning accuracy of build platform, accuracy of laser motion, repeatability of build platform set-up, repeatability of powder delivery for varying layer thicknesses
    
• Develop test methods to evaluate fundamental process characteristics within the build chamber
  
• • e.g., powder deposition and distribution, powder melting and solidification, melt pool temperatures, laser power, gas flow
    
• Develop standard test artifact in collaboration with customers and stakeholders
• Complete investigation of the potential for process-intermittent, in-situ measurement of AM parts
  

3. Standards Development

• Contribute to standards committee ASTM F42 on Additive Manufacturing Technologies, specifically:
  
• •  F42.01 on Test Methods – focused on test specimen design, test parameters, test reporting, etc.
    
  • F42.04 on Design – focused on file formats and data interfaces, design process guidelines, etc.
  • F42.05 on Processes and Materials – focused on metrics for initial conditioning of machines, machine performance metrics, comparison standards, material traceability, material qualification, etc.
  • F42.91 on Terminology – focused on definition of terms for the AM industry
    
• Contribute to standards committee ISO TC261 on Additive Manufacturing, primarily through the U.S. Technical Advisory Group
• Submit technical results to improve existing draft standards or as proposals for new standards
  
• • Standard test methods to evaluate fundamental process characteristics
    
  • Standard test methods to evaluate system performance
    
  • Standard performance metrics and test artifacts
• Leverage the substantial NIST experience with existing manufacturing standards to accelerate progress in AM standards.
  

4. Stakeholder Outreach

• Organize and conduct roadmapping workshop with industry to further define measurement science needs and priorities –
• Continue participation with the Additive Manufacturing Consortium (AMC)
• Establish relationship with the Additive Manufacturing Branding Initiative (AMBI), a new trade association of AM system vendors
  
• Contribute technical results to key industry events, e.g.,
• •  RAPID Conference (Society of Manufacturing Engineers)
  • Solid Freeform Fabrication Symposium (UT-Austin)
    
• Interact with other federal agencies to determine their AM measurement science needs and priorities: e.g., NASA, Army, Navy, Air Force, FBI, DARPA

Recent Results:

1. Output: Completed extensive literature review of AM technology and research; documented as internal project report 

2. Output: Completed exploratory efforts on methods to assess AM system performance; focused on test parts and system error mapping; investigation of process-intermittent, in-situ measurement of AM parts; presented as conference paper at Solid Freeform Fabrication Symposium (Austin, TX, August, 2010) 

3. Outcome: Purchased and received a metal-additive system (EOS Model M270); awaiting facility modifications and installation (expected Aug/Sept 2011)

4. Outcome: Contributed to AM standards development through ASTM F42 on Additive Manufacturing Technologies; standards issued to-date address terminology and data formats 

5. Outcome: Participated as member of the Additive Manufacturing Consortium, initially focused on metal-additive solutions for aerospace 

6. Outcome: Contributed to development of the 2009 Roadmap for Additive Manufacturing that defined technology barriers and identified research opportunities through 2020

Standards and Codes:

Project staff serve as members of the ASTM F42 committee on Additive Manufacturing Technologies, with technical contributions to standards developed by subcommittees on Test Methods (F42.01), Design (F42.04), Processes and Materials (F42.05), and Terminology (F42.91).

As outlined above in Task Area 3 of the Research Plan, NIST technical results will be submitted to the ASTM F42 committee to improve existing draft standards or as proposals for new standards. In addition, NIST experience with existing manufacturing standards will accelerate progress in development of new AM standards.

Project staff will interact with the newly-formed ISO TC261 standards committee on Additive Manufacturing, primarily through participation with the U.S. Technical Advisory Group (TAG). The U.S. TAG for ISO TC261 has been instituted as a special subcommittee within ASTM F42 (F42.95) open only to U.S. participants. The ISO TC261 and ASTM F42 committees have established liaison and collaboration to ensure consistent standards.