Additive manufacturing is proving its place amongst the U.S. Air Force (USAF). When aging aircraft need repairs, it is often becoming difficult to find replacement parts and cost-prohibitive to manufacture parts using traditional fabrication methods. Unfortunately, until recently, these were the only options.
Thankfully, new advanced manufacturing methods are opening the door to the efficiency and inexpensive fabrication of replacement parts. Additive manufacturing and 3D printing of parts are keeping the mission of the USAF moving forward and our troops prepared and safe.
The thousands of parts in a typical aircraft are subject to tremendous pressure and wear-and-tear. This causes parts to wear out quickly. The stress of missions strains metal components which, in turn, develop weakness and failure in manufactured pieces over time. USAF technical crew and engineers constantly face the battle of keeping aircraft airworthy against strong odds, tight timeframes, and strict budgets.
The GovDesignHub recently sat down with the USAF Tech. Sergeant Ryan McBride who saw the need to introduce additive manufacturing practices to solve a common bracket failure – saving almost $4,000 per part. Through a partnership with the University of Dayton Research Institute (UDRI), which performed the engineering, a 3D printed aluminum replacement bracket was designed, tested, and implemented.
Here is what Tech. Sgt. McBride had to say about this project:
GovDesignHub (GDH): To start, can you tell us a bit about yourself? How long have you been in the Air Force, how did you get into working with metals technology, and what does that mean for your daily duties?
Tech. Sgt. McBride: I entered the Air Force in 2007. I originally entered the service as an engine troop on C130 Gunships out of Hurlburt Field, Florida. I did 6 years in that role until cross-training to a Metals Technology unit in 2013. I currently hold the rank of Technical Sergeant E6 (TSgt) and I am the Metals Technology Section Chief here at Little Rock AFB – in charge of 16 personnel.
Daily duties for myself consists of training our Airmen, accomplishing the mission, and doing what no other Air Force career field can accomplish. Training our Airmen is my top priority. We are responsible for training our next generation of Air Force machinists. Ensuring that my work center has the skills needed to fix aircraft and ground equipment is critical.
This section accomplishes the mission by keeping our aircraft safe and airworthy. We do this by welding cracked parts, fabricating parts that are no longer available, and repairing ground equipment such as generators and maintenance stands.
We can do what no other career field can do. When other career fields cannot remove stuck or damaged hardware, they call us. When a hangar door main gear cracks in half, we can machine a new gear within the same day. We are the Swiss Army Knives of the Air Force.
GDH: How often did you have to fabricate replacement hydraulic pump brackets before you began 3D printing them?
Tech. Sgt. McBride: On average, we fabricated about 8 to 10 brackets per year – machined from a block of solid aluminum. That is just here at Little Rock AFB. There are several bases with C130 aircraft that struggle with the same bracket failing. Each bracket requires about 16 hours of work to machine and fabricate start to finish.
GDH: Walk us through how you decided to try 3D printing the bracket. Why did this seem like a logical step forward?
Tech. Sgt. McBride: In the summer of 2019, I received an email from the Air Force Life Cycle Management Center or AFLCMC. The email was entitled, “Additive Manufacturing Maintenance Advisory.” Basically, the memo was asking if anyone knew of parts that could possibly be 3D printed from metal. I immediately thought of the hydraulic hand pump bracket.
Moving forward, I created a PowerPoint explaining the difficulties of machining the bracket and the possibility of re-enforcing or re-designing the part to minimize future cracking. A short while later, I received an email from 1st LT. Jesse Montgomery. In his response, he stated his team would like to move forward with 3D printing out of aluminum. This was a logical move forward not only for cost savings but also for proving additive manufacturing has its place in the active-duty military.
The cost savings per part is about $3,800 per part to print over purchasing or machining. That’s pretty good! The re-design was done with AFLCMC teaming with engineers at the University of Dayton Research Institute (UDRI).
GDH: What role did design software play in making this possible? Were there challenges in creating the 3D model of the part?
Tech. Sgt. McBride: The UDRI team was able to increase the overall strength of this part by close to 33%. That’s a huge improvement over original designs.
We did run into some challenges. The UDRI team did not have access to a C130J model. So, they could not test fit the part onto the aircraft. The UDRI team printed a prototype bracket from ABS plastic and sent it to me for test fitment. I was able to recommend slight changes to the bracket to ensure a proper fitment was guaranteed. The UDRI team made the changes and finally 3D printed it out of aluminum.
GDH: We’ve heard that 3D printing metal parts can be far more difficult than when you’re printing with polymers. Were there any challenges specific to the materials that you encountered?
Tech. Sgt. McBride: Although we do not have a 3D printer here on Little Rock AFB, I’m no stranger to additive manufacturing. In 2016, I was able to 3D print the first parts installed onto an E3 AWACS aircraft at Tinker AFB. These parts were printed from a plastic called Ultem 9085.
Printing parts from metal or polymer plastics is always going to be tricky. Having a good machine is key. Metal printing requires a 100% argon gas inert atmosphere and extra clean aluminum media. Any grains of other metals or debris could possibly cause contaminants and weak points within the printed part. That is the difficult part.
Getting engineers to have trust in the printing team – that they have printed each part to the best strength possible – compared to traditionally milling from a solid block of aluminum where we know the block of material meets a specific spec or hardness throughout the entire block.
GDH: Give us a sense of how you think your team—and the Air Force at large—will be using metal 3D printing going forward. Are there certain types of parts that you think will be fabricated at scale?
Tech. Sgt. McBride: I would hope other career fields, or metals technicians, can realize that each of them has the power to create or improve processes and parts within the Air Force. You don’t even need to have a printer. You just need to know the steps to take in order to get the process moving.
Before the maintenance advisory email, I didn’t know something like this was possible. The use of 3D printing in the Air Force will bridge the gap between aircraft sustainment, cost, and part availability. These planes are not getting any younger and parts are already becoming hard to find. Little victories such as this bracket, prove there is a place for additive manufacturing within the military. And, it’s individuals such as LT. Montgomery and I that are working hard to prove this.
*Featured image courtesy of USAF, Airman 1st Class Jayden Ford