Chief Delphi - Plexiglass

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- - Plexiglass (http://www.chiefdelphi.com/forums/showthread.php?t=62058)

Quote:

Originally Posted by Protronie (Post 681791)

Question; Would not starting your hole with the smallest drill bit you have and working your way up to the hole size you want by redrilling with with the next size bit up also lessen the chance of cracking the Plexiglass ?

Good question. Although that definitely makes sense, I'll defer to someone with more practical experience with that technique for a definitive answer. (Edit: Literal translation of that sentence = "Duh... I dunno?")

And yes... to a previous comment... you really don't have to worry about Lexan cracking unless it has been exposed to UV for many years, in contact with nasty chemicals (never thought about loctite being one, but thanks to the poster above who mentioned it), or you are working in extremely cold temperatures.

We don't use plexiglass on our robots... not that it can't be done or is bad practice to use it... its just that lexan is SO much tougher.

Jason

Quote:

Originally Posted by Rinaldi 427 (Post 681597)

we've used both lexan and plexi in the past and we found its brittal and heavy last year we used 1/8" ply wood its light and easy!

Quote:

Originally Posted by AdamC (Post 681672)

I would use 1/4" plywood if I were you. It's cheap and easy to work with. Plexiglass, while tough and cool, has a tendency to crack when you're working on it. We also tried using sheet polycarbonate, and the stuff just cracked and shredded like no other. However, because it was cheap, we just got huge sheets of the stuff.

Real polycarbonate should never just crack and shatter, unless it made contact with Loctite or acetone. (Both of these cause a chemical reaction that eats away at the material).

In 2006, Team 190 literally built their entire robot using polycarbonate, including the chassis, ball hopper, and shooter super-structure.

Besides the cost, it's great stuff to work with. I've personally spent a lot of time milling parts out of Lexan on a milling machine, and it's really easy to machine. I've never had problems with cracking, chipping or shattering, even when working with very small and thin parts.

If cost is an issue, then plywood is a sensible choice. But if you have more financial freedom with your robot, then polycarbonate is my preferred building material.

Quote:

Originally Posted by Drwurm (Post 681840)

Probably, but unless you really need the flexibility of plexi, I'd go for lexan.

Polycarbonate is a lot more flexible than acrylic.

Whereas acrylic will shatter if you bend or hit it, you can gratuitously bend polycarbonate without worrying about it breaking.