McMaster Alum Perforated/Expanded Bellypan

[Jibsy]

I've been working on designing a WCD style drive in Solidworks, and deciding what to use for the bellypan. I've read many of the previous discussions about the pros and cons of custom aluminum sheet bellypans. My goal is for minimal machining, without compromising performance.

I was just browsing McMaster-Carr and tripped across perforated and expanded aluminum sheets. The perforated comes in a few different thicknesses, the expanded only at 0.032".

The perforated sheets come 36" x 46" for from $45-65. The expanded sheets cost a little more.

http://www.mcmaster.com/#perforated-aluminum/=k3tbg0

http://www.mcmaster.com/#aluminum-expanded-metal/=k3tc8z


Any thoughts/experience relating to these? More resource efficient than a custom one, but still has the cool-factor of an aluminum bellypan.

[sanddrag]

Personally, I don't like either one. You have nowhere to drill and tap any holes and no flat surfaces of any significant area to attach things. I'd say you're better off with a sheet of ABS or something of the sort.

[Jibsy]

Personally, I don't like either one. You have nowhere to drill and tap any holes and no flat surfaces of any significant area to attach things. I'd say you're better off with a sheet of ABS or something of the sort.

An easy alternative to tapping is putting a nut on the other side. For most of our electronics (cRio obviously excluded) we typically secure them with zip ties anyway.

I'm also not quite sure what you mean by no significant area to attach things?The perforated sheets have an average of around %40 cut out.

[DampRobot]

Personally, I don't like either one. You have nowhere to drill and tap any holes and no flat surfaces of any significant area to attach things. I'd say you're better off with a sheet of ABS or something of the sort.

I'd second this. A lot of the purpose of a custom (or not) sheetmetal bellypans are for mounting electronics. However, as you said, you could put screws through with nuts and washers, or even zip ties to hold the electronics down. A more typical (ie, 254/973 style) bellypan is custom waterjeted, with pilot holes which are then drilled out and then tapped to hold the electronics down. Overall, it's less about the strength of the fastener than about it's ease of assembly. We've had success with velcro, for example.

Those sheets look like a reasonable choice, but they obviously don't have many of the advantages of a custom bellypan. You also might look at AndyMark, I believe they stock a bellypan type plate pre-lightened for use with the kitbot chassis.

Finally, custom bellypans all include a border around the outside (where it is mounted to the frame, for example) which is solid metal. Yours would have the lightening pattern all the way up to your cut, which would compromise strength.

[Al Skierkiewicz]

We use perf stock and have been for many years. We don't use hardware. Tie wraps are secure enough for everything including the PD. You only need one tool to change parts out and you don't have to worry about dropping something that is conductive into a bad place on the robot.

[Clinton Bolinger]

In 2011 we used 9232T191 (http://www.mcmaster.com/nav/enter.asp?partnum=9232T191). Most electronic parts can be held down with zip ties (speed controllers, digital side car, wires, etc). The .1875" hole diameter it allows for a #8 to pass through with lots of room, #10 with a very tight fit, and 1/4" if you drill out the hole. I think we even tapped it with a 1/4-20 but you get like 1 thread. Also 3/16" pop rivets work great to attach it to you chassis or to use the material as a gusset.

The only down side to the material is that once you cut it the edges are really sharp because of all the holes. Also I would not recommend that you try to make a lot of bends in it because it will eventually fatigue and break.

-Clinton-

[BrendanB]

Those sheets look like a reasonable choice, but they obviously don't have many of the advantages of a custom bellypan. You also might look at AndyMark, I believe they stock a bellypan type plate pre-lightened for use with the kitbot chassis.

We have used the AM perforated sheets on our past two robots but I wouldn't recommend using it if you need a bellypan that adds structural integrity. They are great for easily securing electronics but it is extremely flimsy.