In a story on the Army.mil website, Picatinny Arsenal Public Affairs specialist Cassandra Mainiero discusses work on durable solid lubricant or DSL, which is a dry surface treatment applied during manufacturing. The motivation here is to make weapon maintenance simpler for Soldiers. Currently, they plan to transition the technology to PM Soldier Weapons by 2017.
(US Army photo by Erin Usawicz)
PICATINNY ARSENAL, N.J. — Although weapon maintenance may seem tedious to the unencumbered civilian, Picatinny Arsenal engineers know a clean weapon could save the warfighter’s life.
That’s why they are developing an advanced surface treatment for armament components that not only mitigates weapon maintenance but also provides increased reliability and durability.
Currently, when cleaning a weapon, warfighters use a conventional wet lubricant known as CLP (cleaner, lubricant, and preservative) that is continuously reapplied.
CLEANING METHODS ARE CRITICAL
As early as 2003, the Army was experiencing problems with weapon stoppages in sand and dust environments if proper lubrication procedures and cleaning methods were not followed.
Army engineers recognized the importance of weapon maintenance in these extreme environments.
Thus, they set out to identify a materiel solution, which resulted in a Durable Solid Lubricant.
“The new technology eliminates CLP and uses a dry surface treatment known as durable solid lubricant, or DSL, that is applied during armament component manufacturing,” said Adam Foltz, an experimental engineer at the U.S. Armament Research, Development and Engineering Center, or ARDEC.
“So far the DSL has been applied to small and medium caliber weapons, such as rifles, like the M4A1 Carbine, and machine guns like the M240 to demonstrate the technology capability,” Foltz continued.
As a result of using the durable solid lubricant, weapons function properly, require less maintenance, and the war-fighter has more peace of mind regarding possible weapon malfunctions.
Foltz is part of a team of ARDEC engineers who set out to perform a rigorous program of material screening experiments for an improved lubricant. The team was established with a cross-functional team of subject matter experts.
Aside from Foltz, who is with the Individual Weapons Branch, other team members are Christopher Mulligan, research engineer (specializing in surface technologies) from Benét Laboratories, and Doug Witkowski, a project officer at the Weapon Software and Engineering Center.
The team was challenged by its sponsor, the Joint Service Small Arms Program, to mature and transition the DSL technology to Project Manager Soldier Weapons by FY17.
“The Soldier knew that something had to be done,” said Witkowski.
“These extreme environments necessitated rigid adherence to weapon maintenance schedules and had a tendency to degrade weapon performance if scheduled maintenance lapsed.
“The Soldier knew that if this problem continued that operational availability would be compromised and that the warfighter’s mission readiness would be impacted.”
Witkowski added that the warfighter was experiencing similar problems with machine guns. “Army engineers understood the importance of maximizing weapon reliability and reducing the sensitivity of system performance in adverse environments,” Witkowski said.
The program, a science and technology funded project, began as a response to the U.S. military’s Global War on Terrorism campaign to counter terrorist attacks on the United States.
Yet, Picatinny was not the first group to experiment with developing new surface treatments. A number of commercial and congressional programs also attempted to improve surface treatments for armaments over the past 15 years but were unsuccessful in finding a materiel solution.
The challenge of a development effort like this is finding a solution that can do all the things that CLP does, and do them better, said Foltz.
MULTIPLE BENEFITS
The DSL solution achieves three ideal outputs: a lower friction coefficient, better wear resistance, and improved corrosion protection. “Friction coefficient” describes how a weapon slides; a low coefficient means the weapon slides easily, a high coefficient suggests sliding resistance.
“With typical wet lubricants, Soldiers need to reapply in order for the weapon system to function properly. Soldiers also have to regularly clean off carbon residue that builds up from firing and it can be tough to clean,” explained Foltz.
“Our DSL has a high wear resistance and a low friction coefficient, so it’s easy to clean off anything that builds up. You can use a steel brush to knock off any residue, and you don’t even have to worry about reapplying anything.”
Additionally, the current industry standards for preventing corrosion on armament components involves treating steel parts with phosphate and oil while aluminum parts are anodized (coated with an oxide layer.)
DSL uses a benign material that eliminates the need for a phosphate/oil coating process, making it an environmentally friendly solution.
DEVELOPMENT STRATEGY
To accomplish these goals, the team broke the project into three testing stages, progressing from lab scale experiments to live fire testing in order to rapidly and effectively evaluate solutions.
The first stage involved tribiological testing of 27 different coating combinations in a rapid “ball-on-three-disk” test. During this test, a ball–coated with the different candidate coatings– is brought into rotating, sliding contact at a specified load against three pads, which are also coated with the various candidate coatings.
Then, the friction coefficient is recorded and wear on the pads is measured. The samples were tested in various environments including with and without sand, as well as at ambient and elevated temperatures (up to 480 ?F) to evaluate overall stability.
In stage two, the 27 combinations were down-selected to six material combinations and placed in the team’s slide-rail simulator.
The team created the slide-rail simulator to glean a more accurate representation of the unique geometry, motion, and contact stresses typical in the gun.
The simulator included two pieces of metal (denoted a slide and a rail) coated with the materials of interest that slide against each other in a manner meant to simulate specific weapon actions.
In stage three, the team down-selected to four different promising material combinations and did a small-scale live fire test at the Armament Technology Facility. Testing included ambient endurance firing, hot and cold, sand/dust, and salt/fog.
In the ambient environment, the project team shot 15,000 rounds per weapon. The baseline weapons with the CLP showed wear and complete loss of the phosphate on approximately 75 percent of the bolt carrier sliding surfaces and 90 percent of the bolt.
Meanwhile, the DSL material showed less than 5 percent wear on both the bolt carrier and bolt.
In every instance, the DSL material showed either an improved or an equivalent performance to the CLP baseline. Results demonstrated increased wear resistance, increased reliability, and improved maintainability.
Although this project is ongoing, the payoff for the warfighter continues to rise. According the team, the DSL material has potential application to numerous other armament systems, manufacturing machinery, and advanced oil-free turbomachinery.
For now, though, the next stage for the DSL project is a repeat of stage three, but on a larger scale.
If testing is successful, the project will be transitioned to Project Manager Soldier Weapons, which will eventually field it to its ultimate customer, the warfighter.
“I know that it [weapon maintenance] is not a glamorous topic and when you’re briefing, there are higher profile technologies being briefed,” said Witkowski. “But this is a high-tech innovation and they [the warfighters] will love it, when they get it.”
