Overview of

Additive Manufacturing and

Potential Occupational Hazards

Gary Roth, MS, PhDNIOSH Health Scientist

DOE Office of Worker Safety and Health Policy, and IH/OS SIG Webinar8 January 2019

The findings and conclusions in this presentation have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

The National Institute for Occupational Safety and Health

The U.S. Federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness.

Mission: To develop new knowledge in the field of occupational safety and health and to transfer that knowledge into practice.

Market Impact of AM

Consumer Electronics Aerospace Automotive Medical

Comparative Advantages

Attribute Traditional Manufacturing

Additive Manufacturing

Materials Options Vast Small, but growing

Quality Control High Varies

Throughput High Low

Scalability High Low (parallelization)

Tool requirements Multiple Single

Maximum Complexity Low High

Process Modification Difficult Easy

Waste material generation High Low

Power consumption Low High

Labor Pool Existing Training

Benefits of AM/3DP

•Computer-Aided Design (CAD)

•Rapid iteration & prototyping

•More innovation spaceDevelopment

•Novel geometries

•More complex parts

•Efficiently use high-cost materials

•Customization

Products

•Lower material use

•Fewer tools

• Just-in-Time fulfillment

•Distributed manufacturing

Logistics

PROCESSES

The Basics

Computer-Aided Design (CAD)

Feedstock material

Selective x-/y-axis binding

Stepwise vertical (z-axis) build

Post-Processing

Materials & Feedstocks

Liquid Resin Solid Plastic Metal Powder

… or any permutation thereof.… or something else entirely.

Binding/Joining Mechanisms

Curing Heat/Cooling Cementing

TaxonomyA

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Liquid Feedstock

Vat Polymerization

Stereolithography

Digital Light Processing

Material Jetting

Solid Feedstock

Material Extrusion Fused-Filament Fabrication

Sheet Lamination

Powdered Feedstock

Directed Energy Deposition

Powder-Bed Fusion

Selective Laser Melting

Electron Beam Melting

Selective Heat SinteringBinder Jetting

Material Extrusion

• Thermoplastic

Build Material

• Solid filament

Feedstock Form

• Deposition nozzle

Selector

• Melting

Binding Mechanism

Powder Bed Fusion

• Metal/Plastic/Ceramic

Build Material

• Powdered

Feedstock Form

• Laser

Selector

• Sintering / Melting

Binding Mechanism

Vat Polymerization

• Photopolymer resin

Build Material

• Liquid

Feedstock Form

• UV Laser/Projector

Selector

• Curing

Binding Mechanism

Binder Jetting

• Metal/Plastic/Ceramic

Build Material

• Powdered

Feedstock Form

• Printer Head

Selector

• Adhesion/cementing

Binding Mechanism

Post-Processing

Removing material

• Wet-chemistry

• Powder evacuation

• Manual removal

Retreating• Annealing

• Curing

Finishing

• Sanding/Polishing

• Texturing

• Coating

POTENTIAL HAZARDS

AM requires a Holistic Approach to Risk Management

Materials

•Toxicity

•Safety

•Formulation

Environment

•Transport/Storage

•Contamination

•Organization

Process

•Energy/Mechanism

•Consumables

•Support Processes

Process, Post-Process, and Support Process Hazards

Process

• UV Light, Lasers, Radiation

• Fire/explosion

• Cutting injuries

• Compressed gases

Support Processes

• Ergonomic concerns

• Falls & falling objects

• Crushing injuries

• Burns

Post-Processing

• Ergonomic concerns

• Cutting & grinding injuries

• Chemical exposures

• Burns

Machine

• Electrical shock

• Noise generation

• Heat generation

• Crushing injuries

Materials & HazardsPolymers Acrylonitrile-butadiene-styrene

Polylactic acid

Propylene fumarate

Poly(vinyl alcohol)

Polystyrene

Solvents Dimethyl fumarate

Isopropanol

Acetone

Methyl Ethyl Ketone

2-Butanone

Metals Aluminum

Titanium

Steel

Superalloys

Nanomaterials nFe (steel sintering)

nAg (sintering, conductivity)

nCB, CNT (conductivity, stiffness, tensile strength)

nSiOx (polymer strength)

Particle Emissions

Outgassing/VOC Emissions

Dermal Toxicity

Reactivity

Flammability

Combustibility

Specific formulation

Process-induced changes

Environment

Transport & Storage

Waste Management

Workspace Ventilation & Airflow

Area Contamination

Robotics & Automated Systems

Scheduling

Psychosocial Stresses

Example Hazards

Thermoplastic Extrusion

• Burns

• Particulate emissions

• VOC emissions

• Post-process chemical use

Stereolithography

• Chemical dermal contact

• VOC emissions

• Post-process exposure

• Ergonomic hazards

Aluminum Laser Sintering

• Fire/explosion

• Powder inhalation

• Powder dermal contact

• Ergonomic hazards

Plastic Binder Jetting

• Fire/explosion

• Powder inhalation

• VOC Emissions

• Post-processing

AM users and knowledge will vary

Large Enterprises Small-to-Medium Enterprise

Service Locations

Hospitals Schools Libraries

• Budget for OSH activities (controls)

• Expertise (in both OSH and additive manufacturing)

• Synergistic exposures

• Demographics

• Communication preferences

• Decision-making structure

• Safety culture

Users may differ in terms of …

Safe AM requires Communication

Safety Officers

• Hazard identification

• Risk assessment

• Safety controls

Operators

• Build operations

• Support operations

• Practicalities

Designers

• Product application

• Material properties

• Process principles

SUMMARY

Additive Manufacturing …

Is substantially impacting multiple market sectors

Includes many materials and processes

Hazards will vary significantly based on particulars

Requires rapid and responsible development

NIOSH Performs On-Site Research

• Over 100 visits (65 sites)

• Uses existing methods

• Evaluate processes & personal exposures

• Provide Guidance and recommendations

• Seeking more partnerships and collaborations!

References & Image Sources

• Bloomington Public Schools (2014) Poplar Bridge Elementary to incorporate 3D printing. URL: https://www.bloomington.k12.mn.us/node/3121478 (accessed 20-Nov-2017).

• Florida Public Library (2017) Our 3D Printer. http://www.floridapubliclibrary.org/news/our-3d-printer/ (accessed 20-Nov-2017).

• GE Additive (2017a) GE Additive takes bold moves in aerospace industry. https://www.ge.com/additive/press-releases/ge-additive-takes-bold-moves-aerospace-industry (accessed 20-Nov-2017).

• GE Additive (2017b) GE Additive to certify new production partners. https://www.ge.com/additive/press-releases/ge-additive-certify-new-production-partners (accessed 20-Nov-2017).

• Hewitt, Cooper (2014). Design Dictionary: Powder Bed 3D Printing. Youtube. URL: https://youtu.be/kBHsfNDsbCs (accessed 8-Feb-2017).

• McCue, TJ (2018). Wohlers Report 2018: 3D Printer Industry Rises 21 Percent To Over $7 Billion. Forbes. URL: https://www.forbes.com/sites/tjmccue/2018/06/04/wohlers-report-2018-3d-printer-industry-rises-21-percent-to-over-7-billion/#4875d8092d1a (accessed 14-Jun-2018)

• O’Conner, Daniel (2013). Formlabs launch new Resin and win CES award. TCT Magazine. URL: https://www.tctmagazine.com/tct-events/formlabs-launch-new-resin-and-win-ces-award/ (accessed 13 Feb 2017).

• Open Biomedical Initiative (2016) Japanese medical insurance to cover cost of 3D printed organ models. URL: http://www.openbiomedical.org/japanese-medical-insurance-to-cover-cost-of-3d-printed-organ-models/(accessed 20-Nov-2017).

• Pesce, Mauizio (2015). 3D Printing Materials. Wikimedia Commons. URL: https://commons.wikimedia.org/wiki/File:3D_Printing_Materials_(16837486456).jpg (accessed 13 Feb 2017).

• Sęk, Matylda (2011). Crosslinker, UV Stratalinker 2400. Wikimedia Commons. URL: https://commons.wikimedia.org/wiki/File:Crosslinker_UV_Stratalinker_2400-1.jpg (accessed 13 Feb 2017).

• Sols Systems (2016) Mapp3D. http://www.sols.com/mapp3d/ (accessed 20-Nov-2017).• Vít, Tomáš (2017). Selective Laser Sintering (or LaserCUSING) cycle. Youtube. URL: https://youtu.be/5-y8iep7jTk

(accessed 8-Feb-2017).

Acknowledgments

• Charles Geraci

• Laura Hodson

• Kevin L. Dunn

• Eric Glassford

• Kevin H. Dunn

• Duane Hammond

• Aleksandr Stefaniak

groth@cdc.gov