Acrylic Sheets
 

Hi,

My team was wondering whether we could use Acrylite Acylic sheets on the robot. I found that Lexan and Acrylite were both thermoplastic sheets, but I was just posting here just to be sure.

Re: Acrylic Sheets
 

I would never use acrylic on my robots. It's impact resistance is just not up to the abuse. I don't even allow it in the lab so it isn't mistakenly used on the robot.


Stick with polycarbonate (lexan.)

Re: Acrylic Sheets
 

Seconded. Lexan can defiantly take much more abuse than the acrylic sheets. Lexan can take a full bore robot collision with minor damage while acrylic can be easily cracked if you even try to drill into it.

Re: Acrylic Sheets
 

Are you asking about FTC or FRC?

Re: Acrylic Sheets
 

Stick with Lexan as everyone has suggested. Just a note in forming it. If you "heat soak" it for a while at below thermoform temp, you force out trapped vapor, and eliminate bubbling in the sheet that occurs if it is heated too fast. Experiment and it's appearance will be maintained.:) ::safety::

Re: Acrylic Sheets
 

I vote for polycarb, over acrylic. No matter where it's used.

-Nick

Re: Acrylic Sheets
 

FRC rules do not allow acrylic (Plexiglass (tm)). Stick with polycarbonate (Lexan (tm)) as it is impact resistant.

Re: Acrylic Sheets
 

What rule (from last year) forbids it?)

Also, he isn't in FRC, he is in FTC. Different rules.

Re: Acrylic Sheets
 

Fixed.

For either program, acrylic should never be used, except for some really obscure exception or something. Always always use polycarbonate.

Re: Acrylic Sheets
 

in FRC you could almost build your whole robot from polycarbonate...right? :)

Re: Acrylic Sheets
 

I can think of more than a few roles where acrylic would be suitably strong, such as concealed ball hoppers/dividers or decal backing. Just never use it for anything structural or might otherwise take any shock loads.

Re: Acrylic Sheets
 

They're really close in price though, if I remember correctly, so wouldn't you go for polycarbonate just because it won't shatter on you?

Re: Acrylic Sheets
 

We have had decal backing shattered by another robot. Shards of plastic in your robot can be bad.

Polycarb is generally twice as expensive as acrylic.

Re: Acrylic Sheets
 

Funny that you say that, especially since you built a crab drive structure out of the stuff.

Re: Acrylic Sheets
 

That's just for prototyping a few plates that need to be milled out of poly that are harder to machine. The piece of acrylic is being used as a place holder.

Any "real" crab module will have zero acrylic in it, and I'm hoping my team's replacing the temporarily acrylic parts of the prototype rather than waiting for competition to build one that's strength testable...

Re: Acrylic Sheets
 

Chris, why would we replace the acrylic, It was a prototype, we are done with it now, we are moving on.

BTW It is possible to build a robot completely out of Polycarbonate, thats what our team does.

Iv seen a few teams use bits of acrylic. Sometimes it works, other times... it shatters with disasterus results.

My advice, use Polycarb, It machines similar to wood or aluminum. You can router it like wood... or cold bend it like aluminum.

Also, if you use polycarbonate, heat bending is very difficult. We almost never heat bend ours just because there is such a small window between bending and melting, or (molecular decomposition). I recomend Cold bending but then you need a large brake.

Re: Acrylic Sheets
 

I meant on a "real" module, if we build one for build season some year.

Re: Acrylic Sheets
 

And here I thought it was totally polycarb... :rolleyes:

Re: Acrylic Sheets
 

Actually, I think Acrylic is twice as clear as Polycarbonate or something like that. :)

I also would never use Acrylic anywhere on a robot. Drilling holes in the stuff results in cracking and you have to be really precise about bolting it. Polycarb just takes the slack. I do this demo where I clamp identical pieces of polycarbonate and acrylic to a table and whack each with a large hammer.

Re: Acrylic Sheets
 

we use acrylic all the time for prototyping (only when they are directly on an aluminum plate of course). Acrylic can be laser cut, which makes it really quick to put an idea together. No matter what plastic you use, make sure you have extras of your plastic parts at the competition and an easy swap out to boot. We must have gone through 3 polycarbonate motor mounts last year