First printed in TCT magazine, September 2011
Part of the remit for the ASTM F42 Committee (specifically Subcommittee F42.04 Design Task Group on File Formats) has been to conceive and develop a replacement for STL that is better suited to the current, and future, abilities of AM machines. The standard aims to answer the growing need within the industry for a standard interchange file format that can work with the myriad of technologies and abilities in today’s marketplace.
The new file format will be fully standardised through the ASTM process, and will get the technical name of ASTM F2915, Specification for Additive Manufacturing File Format. For most, it will simply be known as AMF.
The F42.04 Subcommittee is chaired by Professor Hod Lipson of Cornell University, who explained: “This standard describes a file format that allows CAD programs, scanners and 3D graphical editors to communicate with 3D printers and AM equipment. The standard is non-proprietary and was developed by an open discussion between all stakeholders.
“For the last three decades, the STL file format has been the industry standard for transferring information between design programs and AM equipment. An STL file contains information only about a surface mesh, and had no provisions for representing colour, texture, material, substructure, and other properties of the fabricated target object. As AM technology is quickly evolving from producing primarily single-material, homogenous shapes to producing multi-material geometries in full colour with functionally graded materials and microstructures, there is a growing need for a standard interchange file format that can support these features. The new AMF standard is XML-based and covers these new capabilities, and allows for future expansion.
“The new standard will provide engineers, architects, artists and anyone involved in 3D design 3D printing to seamlessly transition from design to a physical printed object, independently of the specific software or printer hardware being used. This is similar to PDF file format that allow any document to be viewed and printed regardless of the display and printer being used. The availability of such a standard is key to growth of the industry and proliferation of new applications.
“Geometric design software vendors and 3D printer manufacturers would be the primary users of the standard. However, anyone in the growing ecosystem of businesses involved in the design, aggregation, fabrication and consumption of 3D objects using new additive manufacturing technologies would benefit from adoption of this standard.
“Just like any standard, the real test is that of adoption by the community. While all major equipment manufacturers and CAD software vendors have signed on, we anticipate that continued community involvement is required to continuously revise and adapt the standard as new needs emerge, if implementation problems surface, and as new technologies become available.
“The most immediate form of participation from the community that we’re hoping for is in developing viewers and slicers for the new file format. I hope that interested parties will be willing to contribute open-source code to catalyse the adoption and testing of this standard.”
A website with files, documentation and forums for ASTM F2915 is located at www.stl2.com
The full Standard Specification is available to purchase from the ASTM by visiting http://www.astm.org/Standards/F2915.htm