Why California’s 3D Printer Software Legislation Will Fail

By: Kyle Huang

In many hobbyist communities, 3D printers are becoming increasingly common tools. From electronics projects to cosplay, the convenience of being able to fabricate objects from digital models makes them an appealing choice for independent creatives. Model-sharing websites and social media have led to these machines becoming popular with the general public. Notably, they have also been used in the illegal creation of untraceable “ghost guns.” In response, AB 2047 has been introduced. Its goal: to implement mandatory firearm detection and blocking technology in 3D printers sold in California. The bill was presented to Governor Gavin Newsom on September 14th, and was signed into law by the Governor on September 26th. It will take effect on January 1st, 2027. However, due to the specific language used by AB 2047, it is almost guaranteed that no such software will be installed on future printers.

AB 2047 requires that the Department of Justice – beginning no later than July 1st of 2027 and continuing quarterly until July 1st of 2029 – must check for published industry-standard methods of firearm-blocking technology from ASTM International. ASTM International, formerly known as American Society for Testing and Materials, is notable in the 3D printing community for standards like ISO/ASTM 52900, a document-defining basic vocabulary used in additive manufacturing (a general term for building objects layer-by-layer). If ASTM publishes such a standard by July 2029 (and the standard shows the technology is feasible), the DOJ will have two years to write minimum specifications that must be met by 3D printers in order to be lawfully sold in California. On the other hand, if ASTM does not do so, the DOJ is released of its responsibility and the mandate may never take effect.

On the technological side of things, such a specification is nearly impossible to create. With similarity-based algorithms, there’s always concern over balancing false positives and false negatives. Although supporters argue that such algorithms don’t have to be perfect and that they’d be effective just by cutting off a large source of illicit firearms, the nature of 3D printing resists effective detection. For example, once tech-savvy individuals obfuscate models by adding detachable geometry, they can share these files with numerous people, and it would be no less convenient for an end user to print out. Furthermore, any system that effectively blocks firearms must resist simply being overwritten. This means that an effective performance standard would likely include mandatory locking of hardware, preventing users from using open-source firmware. In effect, giving 3D printer manufacturers the power to control what their tools can and can’t print raises the possibility for locking users into their product ecosystem. In other words, it potentially restricts the user to just that manufacturer’s products and protocols.

Fortunately, ASTM released a statement near the end of August stating that they take no position on the legislation. The statement clarifies that their purpose is focused on gathering data and developing methods, not developing standards for implementation. Combined with the technical difficulties of creating the vaguely described industry standard, it is exceedingly unlikely that ASTM will publish anything of the sort in the foreseeable future. If this holds true until July 2029, as the bill states, these measures will not make it inside 3D printers.

AB 2047 faces backlash due to the threat it poses to open, consumer-friendly technology. Additionally, its dependence on an organization which has stated neutrality makes its firearm-blocking plans difficult to bring to fruition. Nevertheless, this bill may be only the start of a larger debate. The balance between public safety and privacy has a long history, and as future technologies emerge, there will inevitably be more disagreements. As for now, Governor Newsom’s decision will set a precedent for the further discussion of consumer manufacturing technologies.