Titanum

[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?

[Cory]

Expensive, hard to work with, not as easy to weld as aluminum, greater density than aluminum, which requires you to use less material to achieve same strength. This sounds good, but it means if you want to maximize your strength to weight ratio you need to change how you design your parts, which may require more analysis than it's worth.

It has plenty of advantages, just not so much in FRC. Since most power transmission components are steel off the shelf, shafts are the one place you could apply Ti. Since you could easily substitute 7075/7068, with infinitely better machinability, it would be hard to justify the use of Ti.

[MattC9]

I'm pretty sure 103 used Ti for thier frame this year. Can any one from 103 confirm or debunk this?

[Akash Rastogi]

Originally Posted by MattC9

I'm pretty sure 103 used Ti for thier frame this year. Can any one from 103 confirm or debunk this?

103 has used Titanium tubing for the past few years now for their base frame. Not sure of what grade or size.

2009 and onward http://www.cybersonics.org/cybersonics/robots.html

[JamesCH95]

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?

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.

[AlexH]

i have experience with using grade 5 ti as armor for a battlebot. it's a pain in the a** to drill with a cordless drill, throws awesome sparks when you cut it with a cutoff disk, cuts nicely with a good bandsaw, pain to weld because it sometimes warps and is near impossible to bend unless you heat it up. oh and it's really expensive. but it's tough as anything.

best place to buy it is titanium joe

[GilaMonsterAlex]

I like having this conversation with my students every year. It's not so much that it couldn't work, but like James said, we can't take advantage of the real benefits of titanium.

It would be awesome to make one though, the nice blue color of the welds would be sweet looking.

[PAR_WIG1350]

Originally Posted by GilaMonsterAlex

I like having this conversation with my students every year. It's not so much that it couldn't work, but like James said, we can't take advantage of the real benefits of titanium.

It would be awesome to make one though, the nice blue color of the welds would be sweet looking.

Speaking of colors, imagine how much attention you could get for an anodized titanium frame. I think Wildstang should give it a try.

[Brandon Holley]

One cool feature of Titanium is you can anodize at home using just a battery and Coca-Cola (or Pepsi): http://www.popsci.com/diy/article/20...um-technicolor

-Brando

[DonRotolo]

Originally Posted by PAR_WIG1350

Speaking of colors, imagine how much attention you could get for an anodized titanium frame. I think Wildstang should give it a try.

Like Brandon wrote, you can 'anodize' Titanium yourself with relatively benign chemicals, the color dependent upon the applied voltage (!).

[JamesCH95]

Just some food for thought:

Anodizing might look pretty, but it can substantially reduce the fatigue life of the component because the anodized layer is considerably less ductile than the base titanium and will start cracks. Maybe not a big deal, but it depends on the application.

Same goes for welding... blue titanium welds indicates that the weld was contaminated, generally by oxygen and nitrogen. It is acceptable in some welding specifications, and unacceptable in others. Again, application dependent, but this contamination embrittles titanium, making it less ductile and more likely to crack.

[PAR_WIG1350]

Originally Posted by JamesCH95

Just some food for thought:

Anodizing might look pretty, but it can substantially reduce the fatigue life of the component because the anodized layer is considerably less ductile than the base titanium and will start cracks. Maybe not a big deal, but it depends on the application.

Same goes for welding... blue titanium welds indicates that the weld was contaminated, generally by oxygen and nitrogen. It is acceptable in some welding specifications, and unacceptable in others. Again, application dependent, but this contamination embrittles titanium, making it less ductile and more likely to crack.

True, but the same would also apply to anodized aluminum which has been widely used for years without causing significant issues.

[jspatz1]

Our team has found that while titanium is a bit expensive and hard to work with, it can be fashioned into an excellent team name.

[Garrett.d.w]

Originally Posted by jspatz1

Our team has found that while titanium is a bit expensive and hard to work with, it can be fashioned into an excellent team name.

Agreed

We have discussed the use of Ti as part of our frame, but the expense to reward ratio is a little low. We have limited our use of Ti to some shafts, which we get material for from Boeing's rem buckets (no more than three/ four inches in length though).

[PhantomPhyxer]

Titanium is a very good material for Ballistic Armor, high temperature applications or other applications. But the weight alone is a penality in FRC.
The weight per cubic in goes ike this: Steel(ST) .283, Titanium (TI) .163 and Aluminum(AL) is .1 some grades are a little less but not weldable. Aluminum is easiest to work, then Steel and then Titanium. TI machines like 4130 Steel. Cost campare like this: A-36 and Alloy Steel -- cheapest, Although some alloy steels approach the cost when considering heat treatment of Steel. Aluminum is next cheapest. Gr. 6061-T6 is most common. Titanium is very expensive. So, unless you have a source of free Titanium I do not think it is worth the cost or additional effort to machine it.