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-   -   Best of: Polycarbonate (http://www.chiefdelphi.com/forums/showthread.php?t=95753)

Molten 24-06-2011 01:07
Re: Best of: Polycarbonate
 
Quote:
Originally Posted by Laaba 80 (Post 1066635)
We dont use metal for structural parts, the frame is entirely polycarb. If we have an option to make a piece out of plastic, or even better, clear plastic, we do it.
www.chiefdelphi.com/media/photos/34998
If you look closely, you'll notice we even made clear wheels.
Aside from our great resources to work with plastics, we also do it because it is cool. It has always been a goal to be as clear as possible, and our robots have become clearer every year. If you ever get a chance to visit our pits, you will also see the clear isnt limited to the robot, we have clear toolboxes, as well as an awesome clear battery charging station
It is nice to see some transparency in a group for once. Seriously though, thanks for explaining it to me. I've heard arguments by teams that argue for all wood robots and thought motives might be similar. Turns out they are completely different.

Sorry if the pun was too bad, I couldn't resist.

Jason

Mike Wittman 24-06-2011 10:06
Re: Best of: Polycarbonate
 
Quote:
Originally Posted by Laaba 80 (Post 1066635)
We dont use metal for structural parts, the frame is entirely polycarb. If we have an option to make a piece out of plastic, or even better, clear plastic, we do it.
www.chiefdelphi.com/media/photos/34998
If you look closely, you'll notice we even made clear wheels.
Aside from our great resources to work with plastics, we also do it because it is cool. It has always been a goal to be as clear as possible, and our robots have become clearer every year. If you ever get a chance to visit our pits, you will also see the clear isnt limited to the robot, we have clear toolboxes, as well as an awesome clear battery charging station
On this robot we also made clear sprockets and a clear ratchet gear for the kicker. One day I would like to see us try to make a clear transmission, gears and all. We took the first step with this robot. We used an AndyMark 2 speed transmission, removed the metal side plates and made clear ones.

Nuttyman54 25-06-2011 23:52
Re: Best of: Polycarbonate
 
Quote:
Originally Posted by jwfoss (Post 1066465)
Seems as though 190 has a long history of using polycarb...
That we do, polycarbonate is used for major features on almost every one of our robots. The 2003 robot deserves to be added to the list of cool polycarbonate features.

As does 2007 (some of you may be very confused at this mention). By far the most recognizable feature of the Goat-Dactyl were the giant sheet-metal ramps, but one of the most important features on them were the almost invisible anti-rollback devices. You can see one just above the painted numbers, and they served to keep our partners above 4" in the event that the ramps didn't lift properly or in time. We relied on the toughness of the material to survive repeated robot impacts and the many many cycles of use.

We also used the insulating properties of the material to house the custom high-power slip ring at the base of the turret in 2008.

2011 used polycarbonate wings as an alignment device for the tower base. Because they extended well beyond the frame perimeter when deployed, not only were they designed to align the robot in a full-speed (12fps) collision with the tower, but they also had to withstand the force of a worst-case collision with another robot. Polycarbonate was the only material both light enough and tough enough for the job.

It's a wonderful engineering material for it's toughness and machinability. Unlike aluminum or steel, polycarbonate will deflect elastically to absorb the energy, which means it will return to it's original shape. This is great in applications that are likely to see high impact forces, since it will not dent or kink permanently under forces that would do the same to aluminum.

Stephi Rae 26-06-2011 00:31
Re: Best of: Polycarbonate
 
Quote:
Originally Posted by Nuttyman54 (Post 1066816)

2011 used polycarbonate wings as an alignment device for the tower base. Because they extended well beyond the frame perimeter when deployed, not only were they designed to align the robot in a full-speed (12fps) collision with the tower, but they also had to withstand the force of a worst-case collision with another robot. Polycarbonate was the only material both light enough and tough enough for the job.
Additionally 190's 2011 robot had a polycarbonate claw, both the structure/sides and the pulleys for the pulleys for the polycord. The minibot was also entirely polycarb. But both of these uses were pretty common this year.

2k7 had a polycarb claw, also.

Chris is me 26-06-2011 12:53
Re: Best of: Polycarbonate
 
Quote:
Originally Posted by Nuttyman54 (Post 1066816)
It's a wonderful engineering material for it's toughness and machinability. Unlike aluminum or steel, polycarbonate will deflect elastically to absorb the energy, which means it will return to it's original shape. This is great in applications that are likely to see high impact forces, since it will not dent or kink permanently under forces that would do the same to aluminum.
It's certainly a cool material. I've considered using it in many places that teams use sheet metal now, since you can get it thicker for the same weight and it deflects under load (elasticity). If you need it to be more solid you just add a flange.

I've been meaning to CAD a polycarbonate drivetrain lately. You might see it in a few days.

Andrew Schreiber 26-06-2011 13:23
Re: Best of: Polycarbonate
 
Quote:
Originally Posted by Chris is me (Post 1066849)
It's certainly a cool material. I've considered using it in many places that teams use sheet metal now, since you can get it thicker for the same weight and it deflects under load (elasticity). If you need it to be more solid you just add a flange.

I've been meaning to CAD a polycarbonate drivetrain lately. You might see it in a few days.
Take a look at 703. I know their 2007 DT has some good pictures up here. They use a polycarb DT every year it seems. It is pretty but it is really thick stuff.

EricH 26-06-2011 13:52
Re: Best of: Polycarbonate
 
Quote:
Originally Posted by Chris is me (Post 1066849)
I've been meaning to CAD a polycarbonate drivetrain lately. You might see it in a few days.
Wait. See a polycarbonate drivetrain? :D (Highlight the blank.)



Actually, one of the best uses of polycarb has to be this little gem. Even though it isn't used on a robot necessarily...

Nuttyman54 27-06-2011 18:59
Re: Best of: Polycarbonate
 
Quote:
Originally Posted by Chris is me (Post 1066849)
It's certainly a cool material. I've considered using it in many places that teams use sheet metal now, since you can get it thicker for the same weight and it deflects under load (elasticity). If you need it to be more solid you just add a flange.

I've been meaning to CAD a polycarbonate drivetrain lately. You might see it in a few days.
One word of warning on the PC drivetrain is that because of the elastic deflection, large hits have a tendency to throw the chain if you're not careful with your construction. This was a serious problem on our 2003 and 2006 robots (mentioned above). Our 2006 drive team considered it a miracle if the robot made it through a match with all the chains still on.

Chris is me 27-06-2011 20:10
Re: Best of: Polycarbonate
 
Quote:
Originally Posted by Nuttyman54 (Post 1066972)
One word of warning on the PC drivetrain is that because of the elastic deflection, large hits have a tendency to throw the chain if you're not careful with your construction. This was a serious problem on our 2003 and 2006 robots (mentioned above). Our 2006 drive team considered it a miracle if the robot made it through a match with all the chains still on.
Always a big problem. You really have to overbuild a polycarbonate chassis to make it take those hits effectively.

Though in the advent of bumpers, this has been less of an issue.

Molten 05-07-2011 01:23
Re: Best of: Polycarbonate
 
Reported.


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