cuting plexi

[Mike Betts]

Originally Posted by morganh2550

what is the most efficient way to cut plexi-glass

Although it has been hinted at in this thread, I wanted to be sure that you knew that Plexiglas is different than polycarbonate.

I know that the difference may appear to be semantic to us electrical types but it is important. If you hit Plexiglass with a hammer it will violently shatter whereas polycarbonate is so resilient that it is used in most saftey glasses you and your team wear in the pits...

The impact resistance of polycarbonate extends to tooling as well. Polycarbonate can be cut in a sheet metal shear, bent on a brake and drilled or machined easily. Plexiglas is not nearly as machinable.

My team always uses polycarbonate on our robots and we never use Plexiglass. This not only gives us a more robust robot but also increases the safety margin for the students working on the robot.

JMHO

Mike

[Dick Linn]

And a tip on drilling - you can break the leading edges on the bit to prevent them from digging in and grabbing. See http://www.hawkfish.org/snailman/acrdrill.htm If you can find the untwisted drill bits that are used in the Yankee type push drills, they serve a similar purpose. This also works for brass.

A few drops of water with liquid dishwashing detergent in it will help as well.

[IndySam]

Originally Posted by Mike Betts

Although it has been hinted at in this thread, I wanted to be sure that you knew that Plexiglas is different than polycarbonate.

I know that the difference may appear to be semantic to us electrical types but it is important. If you hit Plexiglass with a hammer it will violently shatter whereas polycarbonate is so resilient that it is used in most saftey glasses you and your team wear in the pits...

The impact resistance of polycarbonate extends to tooling as well. Polycarbonate can be cut in a sheet metal shear, bent on a brake and drilled or machined easily. Plexiglas is not nearly as machinable.

My team always uses polycarbonate on our robots and we never use Plexiglass. This not only gives us a more robust robot but also increases the safety margin for the students working on the robot.

JMHO

Mike

Mike I totally agree. I would never use plexiglas anywhere in my robot. I can get all I want for free but we still chose to purchase polycarbonate instead.

My company sells supplies for sign making. The reason I can get plexi free is because it is easily damaged in shipping and we always have the damaged pieces saved in our damaged goods rack. You won't find any polycarbonate in that rack.

[Dick Linn]

In a bind, Team 975 once used some of the "high strength" Acrylic. It was only moderately more durable than the regular stuff. No comparison to polycarbonate.

[VEI Dude]

Other than the table saw type stuff, we use a dremel with a spiral cutting bit (actually a Roto-Zip bit), with a straight-edge clamped to the material as a guide. Works very well.

BTW, don't inhale the fumes! Ventilate!

Cheers,
-Neil.

[CPUgirl]

We always use polycarbonate and always use our bansaw when cutting it. Anything else is much more of a pain the only thing are the little shreds that you have to deal with but if you make sure to keep your mouth closed and of course your safety glasses on (probably semi-long sleeves too) and you should be fine. You grow used to it. Good luck.

[ZInventor]

I've found that using a dremmel with a high speed plastic cutting bit works really well, as long as you have a steady hand.

it's also nice since it lets you carve complex shapes.

be careful though, the fragments sent off from the dremmel are EXTREMELY HOT, and if you aren't careful, your arms get covered in little red dots from the burning plastic.

also, WEAR SAFETY GLASSES, they will save your eyes.

-Z

[millerm277]

What we do: Big/straight cuts-Table Saw
Not possible to cut on a table saw-Band Saw
Too technical for either-Dremel, very slowly.

[NC GEARS]

As everyone has said, leave the film on it. Our team uses a band saw and a table saw to do it. Any detailing, such as rounding corners etc, are done with a dremel. Be sure not to overheat it so it doesn't melt. If at all possible, get some Lexan. If your using the plexi I am thinking of, then its an acrylic material. Lexan is a polycarbonate material that doesnt break very easily. We learned not to use acrylic the hard way. Good luck to you though!

[Carlee10]

Whatever you choose to do, do it very carefully!!!! I was working and unfortunately destroying plexiglass just the other day. You have to be very careful and gentle or it will break easily. I tried drilling a piece and cracked it, then was cutting another and managed to crack it,too. I was embarassed, and felt bad about ruining it. I won't be working with it anytime soon..... Good luck, though.

[artdutra04]

Originally Posted by Water Bandit23

Whatever you choose to do, do it very carefully!!!! I was working and unfortunately destroying plexiglass just the other day. You have to be very careful and gentle or it will break easily. I tried drilling a piece and cracked it, then was cutting another and managed to crack it,too. I was embarassed, and felt bad about ruining it. I won't be working with it anytime soon..... Good luck, though.

Next time use polycarbonate (Lexan). It won't crack unless you spill Loctite or acetone on it.

[Carlee10]

I'm not sure what kind it was, but i didn't know it was so breakable. I tried to drill it without a guide hole, and it cracked. so we got more, and i was finishing the cut, and somehow managed to crack it again, even though I was being really careful. and the covering was on it.

[Dave Morris]

Just use a jig saw and stay proud of your final cut line. Then use a hand held router with a bottom mounted bearing and clamp the plexi/polycarb to a straight edged countertop and trim it to final size. This easily works up to 1/2 inch thick if your router bit is large enough in diameter. We do this all day at work.

[colin340]

Originally Posted by IndySam

Mike I totally agree. I would never use plexiglas anywhere in my robot. I can get all I want for free but we still chose to purchase polycarbonate instead.

My company sells supplies for sign making. The reason I can get plexi free is because it is easily damaged in shipping and we always have the damaged pieces saved in our damaged goods rack. You won't find any polycarbonate in that rack.

this is the first thing a tell any rookie team

[Team 135]

Fast moving, fine tooth blade. Band saw is what we have used, we have also had luck with a circular saw.