How Feasible is it to use 3D Printing to Maintain Military Assault Rifles?

In ‘Additive manufacturing for field repair and maintenance of the assault rifle AK5C – a feasibility study,’ Master’s student Emmelie Simic of Uppsala Universitet (Sweden) explores the feasibility for using such technology in connection with Swedish forces who might be stationed in areas such as Mali or Afghanistan.

Simic points out that the Swedish Defense Materiel Administration (FMV) is responsible for supplying their armed forces with material, and 3D printing could very possibly be in their best interest. She also considers that the European Defence Agency sees potential in using 3D printing and additive manufacturing to ‘improve the defense capabilities’ due to the chance for greater:

  • Mobility
  • Sustainability
  • Power
  • Protection

All the above are relevant to both field maintenance and repair, especially if they bring about a ‘reduced logistic burden.’ With the ease in creating on-demand spare parts offered by 3D printing, the Swedish armed forces could benefit greatly for maintenance of so many different military aspects – from boats and planes to ammunitions.

“When equipment is used over time it tends to break,” states Simic. “This is why the Swedish armed forces is severely impaired without spare parts in field.”

Many systems in the military may be so old also, that spare parts have become obsolete—and this is a topic we have touched on numerous times regarding why 3D printing is so critical to maintenance endeavors; in fact, along with following projects where obsolete 3D printed parts have been created to finish projects such as returning older vehicles to new condition, we have also noted militaries for numerous countries using the technology to fabricate parts such as the Dutch Army and Taiwanese defense forces.

Simic has chosen the assault rifle of choice for the Swedes, the AK5C, as a prime example of how 3D printing could be used to benefit the military. This weapon has both semi-automatic and automatic modes, and each setting affects the rifle differently, according to Simic:

“For semi-automatic fire, the hammer is released and thrown against the rear part of the spark plug, the spark plug is pushed forward and the cartridge fires. After that the hammer is brought back to the tightened position where it is hooked up by the hammer latch. Automatic fire has almost the same principle, except that the hammer of the rifle is against the rear of the spark plug during the whole time when firing until the trigger is released. Then the hammer is brought back to the tightened position the same way as for semi-automatic firing.”

“Since the hammer-axis works as an axis for the hammer to rotate around, it is more affected during semi-automatic than automatic firing. This is because for every round that is fired in semiautomatic, the hammer goes back and forth around its axis, causing friction and wear, whereas for automatic fire, it only goes up every time the trigger is pressed.”

The AK5C rifle, the Swedish soldiers’ primary field arm.

Another problem area for added wear and tear is the hammer axis, subjected to enormous amounts of movement, exposing it to friction and causing so much wear that it may break. The gas cylinder is a part that also takes a lot of the heat too, literally, along with large amounts of pressure—causing the material to break down eventually. The magazine follower in the plastic magazine is another area that breaks down easily due to repetitive use.

The hammer axis

The gas cylinder

The magazine follower from two different angles.

Simic outlines the different modes of 3D printing and additive manufacturing, adding that all the parts were made by Lasertech LSH AB in Karlskoga. DLMS processes (using the EOS M 290) were chosen for printing the metal parts, while SLS (using the EOS P 395) was used for polymers. A minor amount of post-processing and assembly was required.

The testing area.

Test results in firing the weapons showed that the 3D printing processes were successful, with some minor adjustments required to the gas cylinder, and added recommendations for materials, along with explaining difficulty in that area:

“Because of ethical reasons, since the components are part of a rifle, it was hard to find a company that offered to print the components. This caused limitations to which type of material that could be used for the parts manufactured in AM, and to the type of method.”

“To use additive manufacturing as a manufacturing process in the future for field repair and maintenance is very promising. In this case, it gave almost the same dimensions as the conventional methods, the components were of high quality and didn’t break during functional evaluation. To use AM in Mali or Afghanistan is probably possible with the method that were chosen here for the parts, but more evaluation and testing are needed,” states Simic.

For the future, Simic also suggests further evaluations regarding temperature issues during military use of the rifles and how parts might be affected, along with considering different materials and economic factors.

“In conclusion, additive manufacturing does allow for fabrication of functional spare parts – at least the ones evaluated here,” says Simic.

We would be curious to see how DED processes performed in such a role. Perhaps these would outperform DMLS (powder bed fusion, LPBF) in cost if they could handle the accuracy. The AK5C is a variant of the widespread FN FMC rifle so the study has broader implications than just Sweden. Maintenance, especially overseas, restricts modern militaries as does ageing equipment generally. This indicates that 3D Printing May have a broad role to play in maintenance and repair.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

Source / Images: ‘Additive manufacturing for field repair and maintenance of the assault rifle AK5C – a feasibility study‘]

US Army Learning About and Using 3D Printing to Improve Military Readiness

The REF Ex Lab at Bagram Airfield produced these items after Ex Lab engineers worked with Soldiers to develop solutions to problems they encountered.

The US Army has long been putting 3D printing to good use. In an article published in the latest edition of Army AL&T Magazine, senior editor Steve Stark takes a deep dive into just how this branch of the military is using 3D printing, and what barriers stand in its way.

Stark wrote that 3D printing “is a natural fit for the Army” as the military branch works to upgrade its manufacturing technologies. Dr. Philip Perconti, director of the US Army Research Laboratory (ARL), says the technology “is at a pivotal stage in development.”

At the opening of the new Advanced Manufacturing, Materials and Processes (AMMP) manufacturing innovation center in Maryland this fall, Dr. Perconti said, “The Army wants to be at the forefront of this advancement in technology.”

Dr. Perconti believes that mobile production of various replacement parts and components is on the horizon, and he’s not wrong: the Navy, the Air Force, and the Marines are already taking advantage of this application.

3D printing can be used to improve readiness, which is a fairly wide-ranging category that covers everything from buildings and repairs to logistics and sustainment. The overarching goal is to send units out with just the right amount of equipment to establish a mobile unit for on-demand 3D printing.

Mike Nikodinovski, a mechanical engineer and additive expert with the Army’s Tank Automotive Research, Development and Engineering Center (TARDEC), explained that various places around the Army, like its Research, Development and Engineering Command (RDECOM) and the Aviation and Missile Research, Development and Engineering Center (AMRDEC), are currently enhancing readiness, and speeding up the sustainment process, by experimenting with the 3D printing of plastic and metal parts.

“We’ve been repairing parts for the M1 Abrams. … We’ve done projects cross-Army and with the Marine Corps where we printed things like impeller fans. A lot of the things we’ve been doing are just basic one-for-one replacement,” Nikodinovski said. “What can you do with additive for a part that’s traditionally manufactured? A lot of that gets at sustainment, and that’s what we’re trying to stand up at Rock Island—give them the capabilities so they can print metal parts, especially if you want … long-term procurement for parts where you only need a couple, vendors are no longer in business and it doesn’t make a lot of sense to spend a lot of money to set up tooling. Can additive be used to supplement the sustainment process, where I can just, say, print three parts and save all the time it would take to find vendors or set up the tooling?”

A 3D printed 90° strain relief offset connector, which was designed and fabricated by REF engineers at Bagram Airfield, Afghanistan to prevent cables from breaking when attached to a piece of equipment.

Additive manufacturing is very different from subtractive manufacturing, which means that critical training is involved.

“That’s a huge undertaking. We need to not only train the people who are going to touch and run the machines, but train the troops and the engineers on the capabilities of and how to design for AM,” explained Edward Flinn, the Director of Advanced Manufacturing at Rock Island Arsenal.

“You’ve got to train the Soldier on the capabilities of the technology along with how to actually use the machine. Then there’s how to teach the design community themselves the benefits of additive so they can start designing for it.”

Ryan Muzii, REF support engineer, cuts metal for a project.

Megan Krieger, a mechanical engineer at the Army’s Engineer Research and Development Center (ERDC), explained that the use of makerspaces in the MWRs (morale, welfare, and recreation facilities) at libraries is a helpful way to get military personnel more familiar with 3D printing. She explained that this way, “if people are passionate about making things, they’ll learn it a lot better than if they’re just thrown into it.”

Outside of actually learning how to use the technology, the Army is also working to develop new materials and design tools for 3D printing.

Dr. William Benard, senior campaign scientist in materials development with ARL in Maryland, said, “The Army’s near-term efforts are looking at readiness, and in research, one of the simpler things is to just design new materials that are easier to print with, more reliable to print with, [the] properties are well understood—that kind of thing as a substitute, sort of a more direct approach to support of existing parts.

“One of the areas of investment that ARL is making to support this, and I know others in the RDECOM community are looking at it as well, is, really, new design tools for additive.”

The Army also needs to determine the specific economics of adopting 3D printing. While cost is less of a factor when you’re up against a tight deadline, this reverses when manufacturing reproducibility and cost are more important in a project. Additional factors include how critical the need for the part is, how quickly developments are being made, what else depends on the particular project, and where exactly the Army is spending money.

Tim Phillis, expeditionary additive manufacturing project officer for RDECOM’s Armament Research, Development Engineering Center’s Rapid Fabrication via Additive Manufacturing on the Battlefield (R-FAB), explained, “We as scientists and engineers can talk about material properties and print bed temperatures and print heads and all this kind of stuff, but the senior leadership is looking at, ‘So what? How does this technology improve readiness? How can I keep systems and Soldiers ready to go?’ And that’s what we’re learning.”

Soldiers used R-FAB during a Pacific Pathways exercise in 2017 to print a camera lens cover for a Stryker vehicle in four hours. [US Army photo]

Stark wrote that the Army is mostly “focusing its efforts on its modernization priorities,” and leaving further development up to academia and industry. If our military wants to use 3D printing for real-world applications, this development needs to speed up – these parts must stand up under plenty of stress.

Dr. Aura Gimm, who was managing the Army’s MIT-affiliated research center program at the Institute for Soldier Nanotechnologies at the time of her interview, said, “It’s one thing to create decorative parts, but it’s something else if you’re trying to create a loadbearing or actuating parts that could fail.

“The standardization and making sure that we have metrology or the metrics to test and evaluate these parts is going to be quite critical, for [items made with additive] to be actually deployable in the field. Because one thing that we don’t want is to have these parts … not work as expected.”

Dr. Perconti concurred:

“Ultimately, the goal for us is to enable qualified components that are indistinguishable from those they replace. Remember, when you take a part out of a weapon system and replace it with an additive manufactured part, you’re putting lives on the line if that part is not fully capable. So we have to be very sure that whatever we do, we understand the science, we understand the manufacturing, and we understand that we are delivering qualified parts for our warfighters.”

UH-60A/L Black Hawk Helicopter [Image: Military.com]

For example, AMRDEC has been working with General Electric Co. to 3D print parts for the T700 motor, which powers both the Apache and Black Hawk helicopters. However, these motor parts are not in use, as they have not yet been tested and and qualified at the Army’s standards. Kathy Olson, additive manufacturing lead in the Manufacturing Science and Technology Division of the Army’s Manufacturing Technology program at Redstone Arsenal, Alabama, said this project is “more of a knowledge transition” to show that it’s possible to 3D print the parts with laser powder bed fusion.

In order to qualify 3D printed parts for Army use, the materials must first be qualified.

“Then you have to qualify your machine and make sure it’s producing repeatable parts, and then qualify the process for the part that you’re building, because you’ll have likely different parameter sets for your different geometries for the different parts [that] you’re going to build,” Olson explained.

“It’s not like you can just press a button and go. There’s a lot of engineering involved on both sides of it. Even the design of your build-layout is going to involve some iteration of getting your layout just such that the part prints correctly.”

One solid application for Army 3D printing is tooling, as changes in this process don’t need any engineering changes.

Dr. Patrick Fowler, right, former lead engineer of the Ex Lab in Afghanistan, works with a Soldier on an idea for a materiel solution.

“You can get quick turnaround on tooling,” Flinn explained. “The design process takes place, but the manufacturing can take place in days instead of weeks…For prototyping or for mainstream manufacturing, I can have a tool made [additively] and up and running in 24 hours.”

If applied correctly, 3D printing will allow soldiers deployed all over the world to make almost anything they need in the field.

“What missions can we solve? We’re finding all kinds of things,” said Phillis. “Humvees are being dead-lined because they don’t have gas caps. Or the gas cap breaks. When they order it, they’ve got to sit there for 30 days or 45 days or however long it takes to get that through the supply system.

“If we can produce it in a couple of hours, now we’ve got a truck that’s ready for use while we’re waiting for the supply system to catch up.”

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[Images: US Army photos by Jon Micheal Connor, Army Public Affairs, unless otherwise noted]