California Signs 3D Printer Gun-Blocking Bill Into Law – 3DPrint.com

California’s 3D printer firearm-blocking bill is now law. But the version signed by Governor Gavin Newsom is quite different from the bill introduced earlier this year.

Newsom signed Assembly Bill 2047, the California Firearm Printing Prevention Act, on September 26 as part of a larger package of gun legislation. The law aims to prevent 3D printers from producing firearms and machine gun conversion devices by eventually requiring printers sold in California to include technology that can identify and block certain print files.

But nothing changes for printer manufacturers today. Instead, California has created a process that could lead to a future requirement, and that process depends first on ASTM International.

So, what happens now?

Here’s how it will work:

• September 26, 2026: Governor Newsom signs AB 2047 into law.
• By July 1, 2027: California’s Department of Justice (DOJ) must begin checking every three months to see whether ASTM International has published an industry standard for firearm-blocking technology on 3D printers.
• If ASTM develops a standard, California DOJ must determine whether it shows this type of blocking technology is technologically feasible for 3D printers.
• Within 24 months of that determination, DOJ must publish guidance or regulations, including minimum performance requirements.
• One year later: The sales restriction would take effect.
• At that point: Manufacturers selling covered 3D printers in California would have to ensure the machines include compliant firearm-blocking technology.

There is also an important deadline. If ASTM has not published a qualifying standard by July 1, 2029, California DOJ no longer has a legal obligation to keep checking. For now, AB 2047 is law, but its central requirement is not yet active and may never take effect if the necessary industry standard does not emerge.

What exactly would the printer have to do?

This is where the law gets more specific. AB 2047 defines “firearm blocking technology” as “hardware, firmware, or other integrated technological measures” designed to stop a 3D printer from proceeding with a print job until the underlying file has been evaluated by a firearm blueprint detection algorithm and determined not to produce a firearm or machine gun conversion device. If the requirement takes effect, a printer would block a print job if the file is determined to produce a firearm or machine gun conversion device.

If the requirements take effect, manufacturers of covered printers would have to add technology that screens files and blocks certain print jobs. Exactly how that technology would work, and what standard it would have to meet, has yet to be determined.

The bill changed along the way

When 3DPrint.com covered AB 2047 earlier this year, the proposal included many more requirements. Earlier versions required manufacturers to submit an “attestation form” for each make and model of 3D printer, confirming that the machine met the proposal’s requirements. DOJ would then maintain a public list of printers with a valid attestation. The proposal also included civil penalties of up to $25,000 per violation.

Many of those requirements were later removed. The final law instead waits for ASTM to establish an industry standard. California DOJ must then determine that the standard shows firearm-blocking technology is technically possible before moving ahead.

The law says DOJ “may provide for a self-attestation or self-certification process” for manufacturers, meaning such a system is possible but no longer required.

The industrial exemption disappeared

Another major change involves industrial 3D printers. Earlier versions of AB 2047 specifically exempted printers manufactured for and sold exclusively to aerospace, biomedical, automotive, chemical or mechanical engineering companies and government contractors, provided those machines were not also sold into the consumer market.

That industrial exemption is gone. The firearm-blocking requirement would not apply to 3D printers used only to make props for the entertainment industry. DOJ could exempt other types of printers later.

California’s existing legal definition of a 3D printer, which AB 2047 uses, defines one as a “computer-aided manufacturing device” that produces a 3D object from a digital model by layering cross sections made from “a resin or similar material.” The definition does not clearly separate desktop printers from professional or industrial machines, leaving questions about exactly which industrial AM systems would be covered.

What it could mean for manufacturers

If the requirements eventually take effect, manufacturers could have to add file-screening and blocking technology to 3D printers sold in California. Industrial companies could also face questions about how files are screened and whether their printers are covered by the rules at all. Those details are still unclear.

California banner about Assembly Bill 2047. Image courtesy of California State Portal.

Supporters say the law could help stop illegal firearms before they are printed. Assemblymember Rebecca Bauer-Kahan, who authored AB 2047, has called blocking technology an “upstream” approach to 3D printed firearms. After Newsom signed the bill, she said the goal was to stop these weapons “at the source.”

The proposal has also faced criticism from parts of the 3D printing industry. In a June interview with 3DPrint.com, industry consultant David Tobin questioned whether the technology could accurately identify firearm files and raised concerns about printers screening users’ designs.

California is not the first state to pass this type of law. New York passed its own 3D printer blocking law earlier in 2026, but manufacturers are not yet required to include the blocking technology. A state working group must first study the technology and determine whether it can work.

The next step for AB 2047 comes by July 1, 2027, when California DOJ must begin checking whether ASTM has developed an industry standard. If a standard is developed and DOJ determines the technology is feasible, California can then begin setting the requirements manufacturers would have to follow.

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