20-05-2014 23:48

Arpan

Re: pic: One piece sheet metal chassis concept

I'm curious as to how this would be bent into shape. Would it not intersect the brake?

21-05-2014 00:06

highlander

Re: pic: One piece sheet metal chassis concept

You do realize that this has to be manually bent. That's why most teams have to use multiple pieces, just so that you can physically bend it like arpan said.

21-05-2014 01:30

T^2

Re: pic: One piece sheet metal chassis concept

I'm not sure how one would even bend this manually... unless it were made of paper.

21-05-2014 01:37

wasayanwer97

Re: pic: One piece sheet metal chassis concept

Well, there's always 3D printing

Haha, anyways OP, the design effort and practice is great. Keep it up.
Just remember though- one of the most important parts of design is keeping in mind the fact that you have to actually be able to make it. (At least if you want the design to actually be of use...)

21-05-2014 01:47

Chief Hedgehog

Re: pic: One piece sheet metal chassis concept

I am not sure how feasible a one part assembly would be for most schools or teams - but I do like where you are going with this.

Even if it was a 3 part assembly, it would provide for great learning opportunities for the students.

It would be cost-effective, light-weight, and offer many other advantages.

Keep us up to date on your advances - and great work!

21-05-2014 08:32

cxcad

Re: pic: One piece sheet metal chassis concept

I think a can modify this design to make it possible to be bent from one piece.

21-05-2014 08:35

pwnageNick

Re: pic: One piece sheet metal chassis concept

What would be the benefit? The improvement in overall strength would be negligible, and it would make putting the robot together much more difficult. Using rivets to attach pieces of sheet metal works well, it is fairly easy and quick to do, and it allows you to assemble modules of parts together before bringing it all together.

-Nick

21-05-2014 08:50

cxcad

Re: pic: One piece sheet metal chassis concept

there's no real benefit; I just thought it was an interesting proof of concept.

21-05-2014 11:33

Monochron

Re: pic: One piece sheet metal chassis concept

This would actually be a really interesting project to learn what must be taken into account by the designer before handing off to the fabricator. I worked in a production plant briefly where Mechanical Engineers made CAD models to be fabricated by the in house shop. The first couple things they designed would often not take into account the fabrication nuances of the shop and thus, the shop could not make them.

Most college courses that I know of don't bother to teach the necessity of designing something that is both reliable and fabricate. The best designs come from a close relationship between engineer and technician.

21-05-2014 11:48

Carolyn_Grace

Re: pic: One piece sheet metal chassis concept

As a non-CADer and non-engineer, I found it interesting to think about. I agree that it's probably not the ideal way to create a chassis, but it looked like a fun challenge. Do you have an image of the metal CADed before bended?

21-05-2014 13:23

jman4747

Re: pic: One piece sheet metal chassis concept

Harder than how you will machine something in my opinion is assimilability. Making sure you can get your hand into something or the space in front of a bolt is accessible by whatever tool is needed for it. That can be one of the worst time wasters when building something and is one of the easiest things to miss.

21-05-2014 13:36

hrench

Re: pic: One piece sheet metal chassis concept

Actually, there may be no or small benefit from a robot-standpoint (I haven't seen your one-piece design) but there is benefit from an engineering standpoint.

As a working ME that designs products, I've been trained that you nearly alway save money-- in total part cost, in assembly time and in ordering and handling cost--if you can reduce parts-count. This is a normal part of DFMA training. (design for manufacture and assembly) Granted, unlike the above image the part Does have to be able to be made with regular equipment. Occassionally multi-part versions are more cost effective, but not usually.

Further, another 'trick' when bending sheetmetal--if the bend line doesn't require as much strength, you can perforate it to remove metal and then hand-bends really are possible even if not 'easy.'

Part of why we're here in First is to teach future engineers--so I say if you can do it in one piece, i say "name that tune".

21-05-2014 21:18

cxcad

Re: pic: One piece sheet metal chassis concept

I'm not quite sure what you are asking. This is the CAD.

If the modification below is made, I think this part can be bent much more easily.
https://drive.google.com/file/d/0B3b...it?usp=sharing

21-05-2014 21:20

Andrew Schreiber

Re: pic: One piece sheet metal chassis concept

Do you have the version without the bends on it, ie the flat part.

21-05-2014 21:33

cxcad

Re: pic: One piece sheet metal chassis concept

I see. It is here
By the way is there a direct way to upload pictures?

21-05-2014 22:43

EricH

Re: pic: One piece sheet metal chassis concept

You can use attachments, at least if the thread isn't in one of the image-gallery discussion threads (where they're disabled, and which this thread is). Sometimes it's easiest to just upload the new one and reference the current thread in the description.


On another note... I think it's entirely feasible to do this as a 3-piece chassis, using largely the existing geometry, with a few rivets to hold the pieces together. How I think it's possible to do that I leave as an exercise to the reader.

21-05-2014 22:52

asid61

Re: pic: One piece sheet metal chassis concept

I'm not sure it would bend right. Get a sheet metal guy to look at it.
Definitely interesting though. 3-piece would be good enough and strong enough IMO, but if this works it could be valuable later.

22-05-2014 09:37

Bennett548

Re: pic: One piece sheet metal chassis concept

The complete tubes down the sides will still be non-possible with any normal brake (finger or press). If you lose the bottom of the side tubes and have them bend up from the belly pan, it may be possible on a finger brake, and easy on a press brake. Add spacers and dead axles to make up for the loss of stiffness.

Alternatively, take a look at industrial origami. With that you can bend by hand and not have to worry about machine access. I'm not sure how the bends would hold up to fatigue in aluminum, but it might work.

22-05-2014 09:57

pfreivald

Re: pic: One piece sheet metal chassis concept

It's a neat idea, but part of the "hard" part of good design is taking into account fabrication and assembly methods (as mentioned above, bolt holes you can't get a wrench anywhere near are bad...bends you can't make on a break are bad...)

So it's neat, and I'm sure it's a fun exercise...but a true test would be to make a chassis you like just as much, but that is easy to fabricate, assemble, and maintain!

22-05-2014 10:36

Taylor

Re: pic: One piece sheet metal chassis concept

..

23-05-2014 00:39

cadandcookies

Re: pic: One piece sheet metal chassis concept

It depends on what one is trying to test. From what I've read here, the one piece chassis here was essentially presented as a tested though experiment-- "can I make a one piece chassis work?" Was the test and the answer appears to be "in CAD? Yes, In reality? No." I'd argue that if that was the intended test, this was a good one of CADD skill.

In terms of being an engineering/DFMA test, it falls short, but that doesn't appear to be the intent. Anyhow, I digress; it's not worth ruminating over.

cxcad: Good job, keep up the good work. I hope to see more designs from you! It's always nice to see new designs and ideas around here to shake things up a bit. I'll have to take a closer look when I get a chance.

23-05-2014 07:16

pfreivald

Re: pic: One piece sheet metal chassis concept

That's what I meant when I said it was neat!

23-05-2014 07:45

Gdeaver

Re: pic: One piece sheet metal chassis concept

After walking the pits and observing a great number of broken robots this year. Watching the frustration teams went thru, I believe that teams need to put more effort in repair ability of their designs. Teams need to think about this more. Modules are one method to accomplish this. How easy is going to be to repair the drive train in that chassis?

23-05-2014 11:51

cxcad

Re: pic: One piece sheet metal chassis concept

it probably is going to be a nightmare, but that's the price for innovation... In all seriousness, this is something I wouldn't build, but I'm going to keep on iterating this concept or something similar until it becomes work able.

23-05-2014 17:30

roystur44

Re: pic: One piece sheet metal chassis concept

Here is a little video of what a modern press brake looks like. If the chassis was made out of 1 piece you could not make the final bend to close the box. You would have to make the box and weld up the flange to make it appear like one piece

https://www.youtube.com/watch?v=c1GkvsruJ8g

23-05-2014 20:04

caboosev11

Re: pic: One piece sheet metal chassis concept

In my opinion, it'd be difficult and time consuming to bend the sheet metal into place. It'd be much easier and more convenient to just use multiple pieces. It's a good idea though.