Castings in FRC

[HumblePie]

In 2011, we overmolded performance wheels with a urethane tread. Performed well, but we've also had good luck with the Hi-Grip wheel that came out in 2012. Here's some pics of our setup..

https://plus.google.com/photos/10248...CK2p1N3ssbWSRQ

[tsaksa]

Originally Posted by JamesBrown

Interesting, there is a guy on there who has a furnace that burns waste oil, it appears to be made out of a keg (undoubtedly lined with some sort of ceramic) and an old vaccum cleaner. Pretty cool.

A friend of mine has built one of these waste oil furnaces. It gets hot enough to cast iron, (which he has done). There are only a few hobbyists who ever attempt casting iron. This is an order of magnitude more difficult and dangerous than casting aluminum. For aluminum casting a propane furnace is clean, convenient, and not overly expensive unless you plan to do a lot of casting. Some folks use a charcoal furnace, which is easier to build from scratch, but does have additional drawbacks. The waste oil furnace is relatively expensive to build, quite large to store, and requires a fairly large, open, and dry yet fire-safe area to operate. A location suitable for casting with a propane furnace is generally easier to locate. You might try checking the cost of just a used stainless steel keg sometime to see how quickly the parts start to add up.

[Seth Mallory]

Our art department casts both aluminum and brass. Some of the other schools in our area have the same capabilities in their art departments. Artists are a good source of experienced people and equipment that can help with casting.

[ahecht]

Originally Posted by DampRobot

I'm not sure if this was what you had in mind, but in 2006 one team cast (out of plastic) meccanum rollers. I forget what team it was, but they were featured in the 2006 "Behind the Design" book. With the rise of 3D printing, even printing metal through sintering, I doubt many teams will use casting in the future.

In 2005, Team 190 cast custom urethane rollers for their mecanum wheels. Team 357 did one better in 2006 by not only casting the urethane rollers, but casting the aluminum hub as well. Their hubs were cast using a 3D-printed mold, if I remember correctly.

[George]

Hi All
Last year we needed 2” x 7” dia. aluminum material for wheels
We had lots of scrap from robots over the years and I have an electric kiln,
I had not done any casting with aluminum for years, (like others I learned foundry at high school) with no green sand we used plaster for a mold (after it was baked to remove the moisture) it worked well enough to get us the billet material at a reasonable cost.
It was a great experience in Up-Cycling and I have hopes that we can explore more options this year,
To that goal I have invested in a set of foundry tools and built a molding bench.
I should say “made” a set of tools and a bench as most of the tooling was outrageously priced for as simple as it is.
I went with petro-bond sand instead of mixing my own “home brew” a little more expensive but better results too.
Altogether total cost was about $400.00 including the kiln + time and brain power
I have found many books on the subject on amazon
If there is an interest I will list materials resources and supplies as I did with 15c machine shop.
Have Fun
Geo.

[Tristan Lall]

Originally Posted by George

Hi All
Last year we needed 2” x 7” dia. aluminum material for wheels
We had lots of scrap from robots over the years and I have an electric kiln,
I had not done any casting with aluminum for years, (like others I learned foundry at high school) with no green sand we used plaster for a mold (after it was baked to remove the moisture) it worked well enough to get us the billet material at a reasonable cost.
It was a great experience in Up-Cycling and I have hopes that we can explore more options this year,
To that goal I have invested in a set of foundry tools and built a molding bench.
I should say “made” a set of tools and a bench as most of the tooling was outrageously priced for as simple as it is.
I went with petro-bond sand instead of mixing my own “home brew” a little more expensive but better results too.
Altogether total cost was about $400.00 including the kiln + time and brain power
I have found many books on the subject on amazon
If there is an interest I will list materials resources and supplies as I did with 15c machine shop.
Have Fun
Geo.

Did you need to adjust the alloy for better casting properties? (I assume you started with mostly wrought Al-Mg-Si alloys like 6061.)

Did you attempt any heat treatment afterward? (If so, what was the process, and how did it go?)

[tsaksa]

Originally Posted by Tristan Lall

Did you need to adjust the alloy for better casting properties? (I assume you started with mostly wrought Al-Mg-Si alloys like 6061.)

Did you attempt any heat treatment afterward? (If so, what was the process, and how did it go?)

If you plan to do some casting, it is best to get your raw metal from scrap castings. That way you know the specific alloy was appropriate for casting in the first place, and not stamping, extruding, machining, etc. There is a lot of scrap metal out there, so if you hook up with the right source it is usually easy to get enough of the correct raw material at modest or even zero cost for casting projects. The real issue with casting is having a safe location and the right tools and experience to do the work in a safe manner.

[JohnSchneider]

Ive seen teams use casting of metals - but have any of these teams tried using this process to create stronger metals.

For instance: say you were making a wheel shaft out of steel. You could add just a trace ammount of beryllium to the steel and close to double your strength. Without adding any weight.

It's sort of a bad example but I'm curious if any teams with a material sciences mentor has experimented with alloying their own metals.

[George]

Originally Posted by Tristan Lall

Did you need to adjust the alloy for better casting properties? (I assume you started with mostly wrought Al-Mg-Si alloys like 6061.)

Did you attempt any heat treatment afterward? (If so, what was the process, and how did it go?)

As our final product was to be wheels other than flux and de-gassing we did not adjust the alloy, nor attempt artificial aging or annealing, this was a spur of the moment measure, the cast billet worked fine and machined well, with no flaws and no failures.
We did not send any of our cast samples out for analyses, so I can’t comment on the alloy content, other than you are correct as most of the material we used was 6061 with a good helping of 6063
If we decide to cast gears, high strength components or wear parts it would be a different story, in this case a bit of zinc would go well,

fyi Blast from the past; http://www.youtube.com/watch?v=fJyD8...eature=related

Have Fun
Geo.