Aermet Annulus Gears

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Annulus Gears
Annulus Gears

One of our specialties at American Precision Gear Co., Inc. is our work with high-tech industries; our portfolio of clients includes a number of high altitude UAV manufacturers. The nature of this industry stretches the limits of material science and precision machining. In the project highlighted here, we worked with one of these clients to develop a very small diameter annulus gear. This gear would be composed of a relatively new alloy called Aermet 100; though patented in 2010, it has gained popularity for its high strength and fracture resistance, as well as resistance to stress corrosion, cracking, and fatigue. Though difficult to machine, these characteristics make it ideal for high-value applications such as UAVs.

Since this began as an R&D project, we conducted a number of engineering reviews with the customer before the first prototype was fabricated. This process was repeated a number of times with each cycle, resulting in 50 gear sets for each four prototype iterations. For each of the four runs during this process, the gear sets were checked for tooth to tooth error (TTE) and total composite error (TCE). Our extensive research effort not only identified an optimal design and manufacturing method, but it impressed this customer enough to award us the contract.

Ultimately we used a multi-step machining process to produce these gear sets; this included CNC turning, milling, and gear shaping. Additional processes included high precision honing, grinding, and deburring, followed by heat treating and nitriding. The finished product had a 64 RMS finish, 102 teeth, 64 pitch, a 20° pressure angle; it is 1.831" (±.005") in length, with an O.D. of 1.740" (+.000"/-.005") and an I.D. of 0.502"/0.501". Throughout the prototyping and manufacturing process, our comprehensive quality program ensured zero defects. Testing included various types of dimensional testing including the use of our CMM, as well as run out, center distance, and roll testing, all in full conformance with AGMA 12 standards. The precision machining of unique materials such as Aermet 100 is only one reason why so many customers count on us to produce high precision gears, both economically and within tight time constraints.

To learn more about this project, or the processes used to manufacture it, see the table below or contact us directly.

Annulus Gear Details

Project/Product Name
Aermet Annulus Gear
Project/Product Description
End use is in high altitude UAV
Capabilities Applied/Processes
CNC Turning
CNC Milling
CNC Gear Shaping
CNC gear Shaping
Heat Treating / Niriding
Equipment Used to Manufacture Part
Doosan Lynx LM 200
Fadal VMC-15xt CNC 4 axis mill
Lorenze 152 CNC Shaper (alternate to broach)
Monnier Zahner CNC hob machine w/ auto loading
Studer S30 Universal OD/ID Grinder
Sunnen MBB-1290D Hone
Profile Engineering Gear Analyzer 4FPRL w/ PC Software
Overall Part Dimensions
102 Teeth, 64 Pitch, 20° Pressure Angle
OD: Ø 1.740" + 0.000 / - 0.005
ID: Ø 0.502"/0.501"
Length: 1.831" ± 0.005
Tightest Tolerances
Ø 0.502" / Ø 0.501"
Material Used
Aermet 100 Alloy
Material Finish
63 RMS Max
In process testing/inspection performed
Dimensional Testing
AGMA Quality Testing – Run Out, Center Distance/Roll Testing
Certificate of Conformance Reports
Industry for Use
Aerospace / UAV's/ Drones
Prototype: 10, Then Annual Contract(s)
Delivery/Turnaround Time
Prototype: 10 weeks
Production: 8 weeks
Delivery Location
Standards Met
Customer Specifications, 2D CAD Drawing

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