Time for RP Standards

By Pamela J. Waterman

The lack of standards for rapid prototyping (RP) is a perennial barrierto launching it on the fast track to wide acceptance. A time and moneysaver when compared to traditional subtractive machining, RP can alsoproduce parts otherwise not physically buildable, but there are stillno official methods for evaluating its benefits and limitations. WhileRP equipment and materials suppliers provide their own specifications,users are seeking objective information.
Every year at the Society of Manufacturing Engineers (SME) RapidPrototyping and Manufacturing Conference, roundtable forumsinevitably turn to the need for national or international standards.Despite the apparent demise of several government-led projects, thereare pockets of activity addressing this subject around the world. DEcaught up with some of the activists involved to get a status report.

Stepping Up to the Plate

Wondering if a given material will behave consistently from batch tobatch? Can you predict how behavioral properties may or may not varybetween traditional and RP parts? Where can you go for answers?
The SME, continuing its efforts to meet the needs of professionals,companies, and industry, recently launched the Rapid Technologies andAdditive Manufacturing Community (RTAM) to address such questions. Itevolved from the Rapid Prototyping Association of SME (RPA/SME), agroup that had been active since 1993. Within the RTAM, the Materialsand Process Standards committee is working to research and collect justthis kind of data, and eventually determine a path that could bring theresults together as universally accepted standards.

Image of cowling Courtesy of Stratasys, Inc.

View the RP Providers Chart

Carl Dekker, last year's Chairman of the RTAM Steering Committee andPresident of Met-L-Flo, an RP service bureau located in Geneva,Illinois, notes that one drawback to developing standards is that mostpeople don't want to fund something if the end result only applies toprototyping, rather than large-scale manufacturing. "The groupacknowledges that material and process standards are critical toevolving rapid prototyping into true 3D digital manufacturing," headds, "but what's needed are definitions."In the mid-1990s, both the NationalInstitute of Standards andTechnology (NIST) and ASTM International (originally known as theAmerican Society for Testing and Materials), supported independent workin this area. The former generated a flurry of articles andpresentations by its Manufacturing Systems Integration Division, butthat work does not appear to have stimulated action toward eitherformal standards—possibly defined by the American National StandardsInstitute—or de facto standards, such as an improved or replaced STLfile format. And while ASTM's website still lists an RP subcommittee aspart of its mechanical testing group, activity on the subcommitteeended sometime prior to 1998. So, the search continues.

Z Corp's Spectrum Z510 System prints prototypes like this running shoe sole inhigh-definition color to reflect original design data and to make sure modelsaccurately communicate thedesign intent.

Academic Research Digs Deep

Of the several dozen universities spread around the world that areheavily involved in a range of RP material and process research, manyhave projects that tackle bits of the standards puzzle.