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-   -   Sheet Metal Fabrication vs. Using Channel (http://www.chiefdelphi.com/forums/showthread.php?t=137105)

carpedav000 03-05-2015 17:06

Sheet Metal Fabrication vs. Using Channel
 
I have seen both used before, I just want to know if one is in any way better than the other. Or just the benefits of using one over the other.

asid61 03-05-2015 17:09

Re: Sheet Metal Fabrication vs. Using Channel
 
We've used sheet metal for a couple small parts.
It lets you cheesehole like crazy to get rid of material that doesn't really help strength anyway if a sponsor does it. Channel is faster to source though.

Chris Endres 03-05-2015 17:25

Re: Sheet Metal Fabrication vs. Using Channel
 
It really is dependent on many factors: resources, time, designing capabilities, experience, etc. WildStang has recently worked with two sheet metal manufactures to make parts for our robots. This year, our bot was almost entirely sheet metal, apart from most parts on our lift. Channel is useful for many things, you just need to use it right. I'm not going to get into much detail about this, or start a war. You may want to look at older threads that explain pros and cons of both.

artdutra04 03-05-2015 17:48

Re: Sheet Metal Fabrication vs. Using Channel
 
The best way is using the resources at your disposal. Both require different design methodology, but both will get the job done.

Dominick Ferone 03-05-2015 17:54

Re: Sheet Metal Fabrication vs. Using Channel
 
For the last 6 years our drive train was c-channel. We have done one and two level chassises for complex designs.
The channel is quick to put together snap together, easy to mount to(just need to make spacers for the inside so it clod rant get pinched), and not all to heavy.(can always still wide holes to take out weight)

We may switch to sheet metal or tube design chassis next year if we can get access to the cnc machine.

Joe G. 03-05-2015 18:08

Re: Sheet Metal Fabrication vs. Using Channel
 
The biggest difference is that most teams using C-channel or other extrusions are typically doing most of the individual part fabrication inhouse, where most teams that do primarily sheet metal construction have their parts produced in partnership with an external sponsor. This is a very different approach to fabrication, and it works very well with certain resource sets (and not well at all with others). I wrote at length about the process, and why our team uses it, here.

Mike Marandola 03-05-2015 20:00

Re: Sheet Metal Fabrication vs. Using Channel
 
Quote:

Originally Posted by Joe G. (Post 1479678)
The biggest difference is that most teams using C-channel or other extrusions are typically doing most of the individual part fabrication inhouse, where most teams that do primarily sheet metal construction have their parts produced in partnership with an external sponsor. This is a very different approach to fabrication, and it works very well with certain resource sets (and not well at all with others). I wrote at length about the process, and why our team uses it, here.

Your post that you linked is really great. On a similar note, how do you get your students interested in CAD? It's one thing that I think could help us greatly but no one wants to implement it.

Qbot2640 04-05-2015 11:37

Re: Sheet Metal Fabrication vs. Using Channel
 
Quote:

Originally Posted by Mike Marandola (Post 1479693)
Your post that you linked is really great. On a similar note, how do you get your students interested in CAD? It's one thing that I think could help us greatly but no one wants to implement it.

A 3D printer really helps here. There is just something about drawing something in CAD, then holding it in your hand a short time later.

Chinske4296 04-05-2015 22:12

Do you do large scale 3-D printing? Or just small stuff? I know of a team that 3-D printed a whole chassis with carbon fiber and fiberglass infused filament on an 8 foot by 8 foot printer platform.

MStump 04-05-2015 22:42

Re: Sheet Metal Fabrication vs. Using Channel
 
Quote:

Originally Posted by Chinske4296 (Post 1480036)
Do you do large scale 3-D printing? Or just small stuff? I know of a team that 3-D printed a whole chassis with carbon fiber and fiberglass infused filament on an 8 foot by 8 foot printer platform.

Do you know what team that was? Because that sounds awesome and I want to figure out how they managed to get the resources for that haha.

Mike Marandola 04-05-2015 23:37

Re: Sheet Metal Fabrication vs. Using Channel
 
Quote:

Originally Posted by MStump (Post 1480043)
Do you know what team that was? Because that sounds awesome and I want to figure out how they managed to get the resources for that haha.

The team is 3824. They discuss the process in this thread. Here are their robots from 2012 and 2013. They are really awesome.

TheModMaster8 05-05-2015 01:31

Re: Sheet Metal Fabrication vs. Using Channel
 
Sheet metal frames allow you have a much lighter but equally strong chassy/robot compared to slotted tube, however sheet metal is harder to fabricate (bending it correctly) and can be dented easer, though i would definitely use sheet metal if i ever get the chance.

also note that by making the base out of sheet metal you have also move the robot/s center of mass much higher, thus making it more flip prone.

asid61 05-05-2015 01:34

Re: Sheet Metal Fabrication vs. Using Channel
 
Quote:

Originally Posted by TheModMaster8 (Post 1480093)
Sheet metal frames allow you have a much lighter but equally strong chassy/robot compared to slotted tube, however sheet metal is harder to fabricate (bending it correctly) and can be dented easer, though i would definitely use sheet metal if i ever get the chance.

also note that by making the base out of sheet metal you have also move the robot/s center of mass much higher, thus making it more flip prone.

Why would you have to move the COM higher?

TheModMaster8 05-05-2015 02:14

Re: Sheet Metal Fabrication vs. Using Channel
 
Quote:

Originally Posted by asid61 (Post 1480094)
Why would you have to move the COM higher?

when reducing weight of your foundation you cause it's COM to be to a heavier side, so if i take weight off the bottom and add it to the top i now have a pendulum

it's due to that fact that your weight lemit is 120 so by reduce your chassie weight by 20 pound and now you added it to the top of the robot, you will be more likely to have more mass at the top of the robot and is more likely to tip/flip

if this needs further explanation I'll reply when it's not 2:14 AM lol :)

carpedav000 05-05-2015 08:04

Re: Sheet Metal Fabrication vs. Using Channel
 
Quote:

Originally Posted by TheModMaster8 (Post 1480097)
when reducing weight of your foundation you cause it's COM to be to a heavier side, so if i take weight off the bottom and add it to the top i now have a pendulum

it's due to that fact that your weight lemit is 120 so by reduce your chassie weight by 20 pound and now you added it to the top of the robot, you will be more likely to have more mass at the top of the robot and is more likely to tip/flip

if this needs further explanation I'll reply when it's not 2:14 AM lol :)

I can only see this being a problem if you have a tall robot (above 60" or so)


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