18-11-2008 03:26

AdamHeard

Re: pic: re-modified 6wd

I don't recall the specific reasons people told you to add a bottom pan, but I assume it was mainly to make the frame more rigid, and to provide a structure to mount electronics to.

I think if you added a larger piece on the bottom, and made the gusseting thinner, you would like the results. You increase the rigidity of the frame substantially, and would get a light piece to mount components to.

18-11-2008 09:38

spc295

Re: pic: re-modified 6wd

we have always advoided mounting electronics to the chassis we always mount to lexan and then mount the lexan to the frame. we could not make the plate go any farther back because of the shifters, and i wanted to keep the plate centered

18-11-2008 11:44

sdcantrell56

Re: pic: re-modified 6wd

If the plate in the middle is the most you can do then it probably is not worth it to make it a plate. Instead just go back to a 2x1 tube. I think the best thing for this frame would be adding flanges on the side plates which would increase the stiffness dramatically. Overall though it is very nice.

I would caution you to carefully examine the upcoming game and to make your decision to use this chassis based on the way you want to play the game. Don't lock yourself into this design just because you have prototyped it.

18-11-2008 14:21

Andy Baker

Re: pic: re-modified 6wd

Neat design

Since we are discussing the bottom plate and electronics mount... why not combine the two? You could make your plate bigger, and get rid of the polycarbonate sheet at the same time. If you make that bottom plate out of 3/32 - 1/8" thick perforated aluminum, then you have a rigid bottom plate that doubles as an electronics mount panel.

Andy

18-11-2008 15:44

spc295

Re: pic: re-modified 6wd

what do you mean by perforated aluminum.

18-11-2008 16:20

Cory

Re: pic: re-modified 6wd

http://www.mechanicalmetals.com/perforatedmetals.html

18-11-2008 16:21

AdamHeard

Re: pic: re-modified 6wd

Perforated Aluminum is a sheet of aluminum with a standard pattern of holes, hexagons, squares, etc. already cut into it. Search "Perforated Aluminum" on Mcmaster; however, I would advise against buying from them as I can only see very expensive sheets available.

Another option, since it appears you have your own waterjet/sponsor with one, is to cut your own bedpan similar to how 233 does it.

18-11-2008 21:19

spc295

Re: pic: re-modified 6wd

since we cant start cutting until kickoff I will arange the electronics on 3/32 aluminum plate then mark what we can waterjet out, and then draw the plans for the bellypan.

18-11-2008 22:35

Jim E

Re: pic: re-modified 6wd

I would make the bottom plate out of 1/4"hardwood plywood. It's not only lightweight but also strong. Mounting electronics to it is a breeze too. Once you paint it, nobody can tell the difference,

19-11-2008 10:25

spc295

Re: pic: re-modified 6wd

yes but how would you mount it.

19-11-2008 10:40

EricH

Re: pic: re-modified 6wd

Flange the lower side of the inner plate, or weld on a small plate that you can put a bolt through.

Plywood is pretty strong, and the thicker versions have a lot of weight loss potential. In 2007, 330 had a very interesting pattern on the underside of its 1/2" plywood base. One of the mentors took a router to the bottom of the robot. He left a support structure for screws and bolts and took the rest down to half thickness or thinner. We had no problems that year with the base.

19-11-2008 10:53

sdcantrell56

Re: pic: re-modified 6wd

You could also do the mentioned 1/4" thick plywood or even go down to 1/8" thick and then laminate it with some fiberglass cloth and epoxy, which would make a very strong, stiff, and light board plus it would be very cheap and give you the opportunity to work with composites. Be sure to use a good plywood though like baltic birch or even better, 1088 meranti or okoume plywood.

19-11-2008 13:18

Tom Line

Re: pic: re-modified 6wd

Laminating 1/8 won't increase the stiffness that much.

You want the skins on a lamination as far apart as possible to increase rigidity. If you're going to laminate, better to buy the 1 inch thick insulation styrofoam (blue or pink). Cut out (cheese hole) the styrofoam.

Lay your glass on an old doorwall window (get it for free off craigslist or the garbage) in whatever size you need, then use epoxy to glue it to the top and bottom of your lightened styrofoam.

You'll get essentially a honeycombed panel for far less cost.

19-11-2008 15:04

spc295

Re: pic: re-modified 6wd

you guys keep mentioning flanging as a way to mount things, I dont think we have a tool available to us that would do that, (i dont think we have ever done that) what would that tool be called?

19-11-2008 15:14

sdcantrell56

Re: pic: re-modified 6wd

You would need a sheet metal break. You could probably find a local machine shop that would be able to do it for you. It would be a very quick process and if you're nice they'd probably even do it for free. You would just have to design in the extra material that will get bent out to make the flange