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Originally Posted by Kevin Selavko
Does anyone have any experience with grade 5 Titanium? It seems like it should be very strong and light, very useful for building robots, right? Or are there any big downsides?
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It machines and welds similar to stainless steel. Make sure to use carbide tooling when machining it, and setup a back-purge when welding it. Nothing is really special, difficult, or magical about working with it though.
Titanium 'likes' heavy feeds and slow speeds when machining. This is counterintuitive compared to most metals, which is why many people think it's so difficult to work with. It'll machine just fine, though not nearly at the rate of material removal as aluminum. Thus it is important to not design high material loss parts (none of this machine a 3oz part from a 20lb billet nonsense
).
The biggest downside is cost, it can be $30+/lb for plate stock, and considerably more than that for thin sheet/bar/extrusion/tubing stock.
Unfortunately, some of the biggest advantages of titanium cannot be utilized in FRC; namely high-temperature strength, fatigue strength, and corrosion resistance.
I've found that many robot parts are stiffness constrained, not strength constrained. There are plenty of robot systems (arms, chassis, manipulators, etc) that never actually broke, but were too flexible to be effective. Aluminum, steel, and titanium all have about the same stiffness-to-weight ratio, so titanium has no advantage.