October 29, 2018
Servando Cuellar, a senior engineering manager with Lockheed Martin, wanted to see if additive manufacturing could be used to produce more than prototypes and replacement parts. Could the company use 3D printing technology to design and produce satellite parts faster and still fly safely?
A necessary question as designing for additive manufacturing is very different from conventional manufacturing processes. It requires a complete re-evaluation of the production process — from part design to product launch, each step needs to be evaluated and tested to determine if it was feasible.
Additive manufacturing also demands a clear understanding of the safety risks unique to the technology's materials, processes and planned end-use. Printing for space application requires alloys — aluminum, titanium and nickel — to meet the very specific requirements for the space environment.
However, these alloys are also highly reactive in their powder form, susceptible to flammability under certain conditions. If handled incorrectly, the superfine material can ignite or explode.
Certifying facility safety
To completely harness additive manufacturing's full potential, Lockheed Martin needed a large facility to house three distinct groups—engineering, production and quality assurance—plus the two 3D-printers needed to print the redesigned parts.
The company found the perfect option in its Sunnyvale, California campus. At over 6000 square feet, the building was large enough to meet its needs. However, before the work could start, Lockheed Martin needed to submit a facility plan to determine if their design conformed to local building and fire codes.
They reached out to their local authority having jurisdiction (AHJ), which was, in this case, Sunnyvale’s fire marshal. The adopted state fire code and local municipal code, though, lacked clear direction and provided little reference in the treatment of metal powder additive manufacturing systems.
“Because of the newness of the technology and the reactive nature of materials, the fire marshal wanted the facility’s design and safeguards to be evaluated by a third-party,” said Cuellar.
Lockheed Martin engaged UL to conduct a site assessment, perform a process hazard analysis, develop a safety management system, train the workforce and provide a final evaluation report.
Fortunately, UL had published UL 3400, Outline of Investigation for Additive Manufacturing Facility Safety Management, in 2017 followed shortly by the launch of a formal certification program for additive manufacturing facilities.
The UL Standard covered the reactivity of the materials in the facility, as well as, the health risks involved with exposure to metal dust. Strict procedures and safeguards must be in place, along with comprehensive training, to create and maintain a safe workspace.
Multi-layered concerns with technology
“Exposure to metal powder dust can result in respiratory and intestinal infections and can even lead to life-threatening conditions such as cancer, neurological disorders, etc.,” said Balu V. Nair, global development engineer for additive manufacturing facility safety for UL.
“Besides, the release of toxic waste into the environment can contaminate underground water sources with possible adverse effects on plants and animals.”
UL 3400 references applicable standards from the Occupational Safety and Health Administration, The National Fire Protection Association, UL, and ASTM International Standards, among others.
“We address additive manufacturing safety in terms of three layers of protection: the materials; the equipment; and the overall operation of the facility,” said Melissa Albrecht, additive manufacturing global program manager for UL.
“Many jurisdictions find it difficult to keep up with emerging technology and are not fully aware of the inherent risks associated with metal and metal alloy powders. UL 3400 provided the necessary safety guidance in the development of the Sunnyvale facility.”
Lockheed Martin became the first organization to be certified to UL 3400 in September 2018.
According to Cuellar, the certification of the facility was a collaboration between Lockheed, the fire marshal and UL, a team effort resulting in fire and life safety controls that addressed the unique hazards presented by combustible metal additive manufacturing.
“With the large variations in how jurisdictions implement and apply the fire codes and building codes, cities could start using UL 3400 to serve as a guide when working with companies looking to utilize additive manufacturing technology,” said Albrecht.