SAE competitions look a little different this year with the COVID19 pandemic. All in-person competitions were cancelled and some were moved to an online platform. With state restrictions and lock-downs, Universities across the country had to cancel classes and students were prevented from continuing work on their vehicles. However, before the lock-downs, some teams were able to start the machining and building process. Perry Cheney from Chico SAE Baja’s team, Wildcat Racing, explains the process of machining the titanium and how they were able to get valuable practice before working on and completing their own parts.
“Titanium is not as hard to machine as we once thought and the strength to weight ratio is just about unbeatable. We have done both turning and milling operations to create many parts on the car such as our gearbox shafts and spindles. The biggest things we have found with general turning and milling is just to ensure that your tools are sharp and the feeds and speeds are correct. Fortunately, we have a wonderful endmill sponsor, Xceliron. With good endmills it is quite easy to cut small keyways, deep pockets, and hold very tight tolerances.
This being our second year working with titanium, we took on a more challenging task of further reducing weight and inertia by drilling out the material in the center of the shafts. Our FEA calculations had always shown this material could be removed without issue, but we were previously unwilling to risk the time and material on an operation that could scrap the part. Because of PTG’s generous donations we were able to practice drilling on small test pieces. Using our donated license of HSM advisor, we were able to find the feeds and speeds that worked best for drilling in our ST10 lathe with HSS CO bits, that we did not have the ability to run through with spindle coolant on. We found that by drilling with a slow surface speed, but pretty heavy chip load, that we could drill about 3/8” holes up to 2.5″ deep. This allowed us to hollow out the majority of our rotating shafts and cut over 1 lb of material off the car as compared to the non-drilled shafts.
We can’t thank PTG enough for their support in allowing us to learn how to design and build parts out of their high-quality titanium. We hope this helps for anyone out there who may be considering titanium for their applications!”
We know that this valuable practice and experience will help the team as they get back into competition and apply what they learned for next year’s build!
For more information on the team and SAE competitions you can visit the links below: