7 Things That Are Highly Illegal To 3D Print. Avoid prison.

In the US there are few things that are illegal to 3D print due to the legality of owning the item while at the same time there are thousands of things that are illegal to 3D print due to the design being owned or trademarked. Although you may have special approval to make certain items, for the average person all of the items on this list are punishable by time in prison.

It is illegal to 3D print anything that is trademark, copyrighted, or patented. It is also illegal to 3D print counterfeit money as well as multiple attachments for firearms, such as; bump stock, drop in auto sear, suppressor (without proper approval), lightning link, and shoulder stocks for pistols. 

Anything that is trademark, copyrighted, or patented.

It is illegal to 3D print anything that is trademarked, copyrighted, or patented. If you 3D print something that is patented there is a possibility that the person that holds the patent could sue you or pursue you for any damages or losses to their brand.

A patent is a protection of a design meaning that any reproduction of said design is illegal. If you have the rights to the design then obviously you can create the object to your hearts desire but if you do not have the rights to the design you will need permission from the owner to use the design. 

Websites like thingiverse, cults3d and grabcad have free 3D models that you are allowed to print through their terms of service as well as user agreements. This means that unless you are selling the object you may use these free designs in any capacity that you desire. You will have to obtain the rights from the owner of the design for any design that you plan to monetize.

Prison time – Up to 10 years depending on severity.

Counterfeit Currency.

It is illegal to produce or own any form of 3D printed counterfeit currency. While it may seem silly to 3D print a paper bill it is plausible to produce a passable 3D printed coin with an SLA printer. Do not do this though because crimes involving counterfeit currency are punishable up to $5,000 or imprisonment for up to 15 years, or both. 

Basically it is just a really bad idea for the prospect of gaining a few extra cents, not to mention the filament, time, and electricity you are spending to counterfeit the money will probably be close to equal to the actual value of the money. 


Prison time – Up to 15 years depending on severity.

Bump stock.

As of March 26, 2019 it is illegal to own a bump stock and therefore illegal to 3D print bump stocks in the U.S. Per the ATF a bump stock allows a semi-automatic firearm to shoot more than one bullet per trigger pull making it a fully automatic AKA machine gun.

Without a FFL (Federal Firearms License) it is illegal to own a fully automatic firearm in the United States. The process of obtaining an FFL is not too complicated as long as time is not an issue and you have a clean criminal background.


Prison time – Up to 10 years.

Drop In Auto Sear.

A drop in auto sear is an attachment for a firearm that converts a semi-automatic firearm to be fully automatic therefore classifying it as a machine gun. There are drop in auto sear that work with rifles as well as pistols and it is a great way to get raided by the ATF if you are interested in them dropping in for a visit. Owning a drop in auto sear is a felony offense and could result in prison time as well as fines.

Per the national firearms act you must obtain a tax stamp and register all NFA (National Firearms Act) guns with the ATF to possess a single NFA firearm. For an additional NFA firearm the buyer must obtain additional approval as well as an additional tax stamp.


Prison time – Up to 10 years.

If you don’t believe me that this carries a potential for prison ask this guy who was recently sentenced to 5 years in prison for making and distributing auto sears. https://gizmodo.com/west-virginia-man-arrested-for-making-a-wall-hook-that-1845636765

Suppressor (without a tax stamp).

It is legal to 3D print your own suppressor if you have the correct approval as well as a tax stamp for the suppressor, however you are only permitted to obtain one NFA suppressor with a single tax stamp. 

There have been a lot of advancements in the metal 3D printing industry and perhaps there would be no difference in quality from a metal 3D printed suppressor and a CNC manufactured suppressor but I think If I could choose between one or the other I would choose the tried and tested CNC manufactured suppressors.

Prison time – Up to 10 years.

Lightning Link.

A lightning link is a device that converts an AR-15 from semi-automatic to fully automatic which then technically makes it a machine gun. The lightning link is a small assembly of two pieces of sheet metal that by itself those two small pieces of metal are actually considered a machine gun which is registered with the ATF and is serialized. Only 900 lightning links were registered with the ATF and as of May 1986 the production of lightning links is illegal including production through 3D printing.

Prison time – Up to 10 years.

Shoulder Stock For Pistol.

It is illegal for a pistol to have a stock attached to it unless the barrel of the firearm is more than 16 inches and the overall length of the firearm with the stock attached is at least 26 inches long.

3D printing a stock does not necessarily make it illegal but attaching the stock to a pistol that has a barrel less than 16 inches technically makes it a short barrel rifle (SBR) which is illegal without the proper tax stamp.


Prison time – Up to 10 years.

100% Plastic Gun.

Per the ATF it is illegal to manufacture a gun that can not be detected by metal detectors or X-Ray, therefore a 100% 3D printed gun would be illegal. However, it is legal to manufacture firearms solely for personal use so long as you have some metal components in the firearm, such as the barrell, the trigger, and the firing pin (which will be necessary anyways for proper functioning of the firearm).


A gun is constructed of many pieces, most of which you are able to purchase off the shelf or have shipped straight to your door. So as long as you are legally able to own a firearm, you are able to manufacture a firearm for your own personal use. 

There is a pretty interesting video by vice that goes into the world of 3D printed firearms and the legality, I have linked it below.

“Are we cool yet” is an online group that is dedicated to artistic and second amendment freedoms. Although their videos are a little creepy it is very interesting to see how 3D printed guns have evolved and grown into their own corner of the web.

Prison time – Up to 10 years.


If you are interested in printing any of these things the files are not hard to find but I would advise against it. Obviously I am not your boss or your mom so I cant stop you but trust me you dont want to get caught 3D printing any of these things.

Please follow your local laws. This article is intended for American readers and it is the responsibility of each person to know their own local country/state/provinces laws. This is not legal advice in any sense and should not be treated as such.

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