US Navy engineers build 3D-printed clip to stop unexploded submunition blasts
The mechanical locking prototype secures firing pins inside Gulf War remnants without relying on slow-curing epoxy or plaster.
By Giovanni Sapere
2 min readHuman-Edited, AI-Assisted
Two engineers at Naval Surface Warfare Center Corona Division have designed a mechanical clip that blocks the arming components of unexploded submunitions. The invention, developed for explosive ordnance disposal teams, replaces slow-setting plaster mixtures with an on-demand component produced using 3D printing.
Mechanical locks replace unstable chemical binders
Clearing unexploded ordnance often forces technicians to improvise stabilization tools in the field. For decades, explosive ordnance disposal specialists neutralized loose submunitions by pouring epoxy or plaster around the firing pin to freeze it in place. That technique requires technicians to carry heavy mixing supplies, wait for the compounds to cure, and risk handling a device that might not be fully immobilized. According to reporting by Interesting Engineering, technician Samuel Larter and engineer Darren Mansour from the Close Combat Engineering Team at NSWC Corona built the Submunition Clip to mechanically grip internal arming parts instead. By physically clamping the trigger parts of M42 and M46 submunitions, the tool halts unexpected shifts during handling and transport.
“We could just have them print it themselves and they’d have plenty”
— Darren Mansour, Engineer at NSWC Corona
“I just want to see this get out there so people can use it to save lives”
— Samuel Larter, Engineering Technician at NSWC Corona
From Gulf War minefields to additive manufacturing
The threat addressed by the tool stems from cluster weapons dropped decades ago. During the 1991 Gulf War, American forces deployed Dual Purpose Improved Conventional Munitions across combat zones. Thousands of those submunitions, equipped with shaped charges and fragmentation casings, failed to detonate upon impact and remain buried in Kuwait and Iraq. Larter encountered thousands of unexploded bomblets while serving in the Middle East with the 15th Marine Expeditionary Unit. To make clearing them faster, Mansour translated Larter's physical locking concept into digital files intended for local 3D printing. Instead of waiting for central military supply shipments, disposal units can fabricate the plastic parts on standard additive manufacturing machines wherever they deploy.
Provisional filing points toward commercial licensing
The project received the Naval Sea Systems Command Excellence in Safety Award for fiscal year 2025. To secure the rights to the mechanical design, NSWC Corona filed a provisional patent application with the United States Patent and Trademark Office. The legal protection gives the Navy a framework to negotiate production agreements with industrial manufacturers. While the initial prototype targets two specific submunition models, the engineers plan to adapt the mechanical gripping geometry to stabilize other unexploded weapons.
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