Bending plastics for a small robot

[strombom]

I found the datasheet for Lexan 9030, which is what I have !

http://bildz.altronix.se/mekpro/9030.pdf

In page 4 different methods of forming it are described. I will try drape forming around a piece of sheet aluminum in the bottom of my oven at 140 degrees. If that fails I will try to bend it by force.

[greybeard]

Geof - thanks for the identification. I was beginning to feel embarrased by all those bubbles. I've not had any experience with polycarbonate so the overheating before bending is a useful tip.
John

[strombom]

Woho, it worked!!

http://bildz.altronix.se/mekpro/robot5.jpg
http://bildz.altronix.se/mekpro/robot6.jpg

We put the part in a screw vice (is this the correct word in english? swedish=skruvstäd). Then we preheated slowly with a hot air gun and finally bent the pieces with help from a small piece of wood. very simple and efficient.

Thanks for all your help.

Now it looks like our drawing: http://bildz.altronix.se/mekpro/robot.jpg

/Johan

[jahl69]

I lay a hot piece of metal between to bigger chuncks and let the heat rise into the plastic slowly. Works great for Acrilic and other plastics.. Form over another piece of steel shaped with what ever angle you want!! I have used this method to form .062 to .250 inch thick plastics.

[leberen]

I saw this post too late I have had experience with polycarbonate and boiled it with results successful! Greybeard is correct with boiling, though we now know that a hot air gun will work as well! Nice bot!!!

[jxdxwx]

[B] Ok, Very cool!
I like to see robots and intricate projects. Really think they are cool.


(I can understand your motivation more clearly now on the selection of drive mechanisms)

[strombom]

jxdxwx:

First off, I dont know what a swivel idler is (I am not a native english speaker).

The robot is finished and worked well, actually my group won the competition at the end of the course (10 robots w. 4 students each).

Here is a movie of the final round:
http://www.tfd.chalmers.se/~strombom/video/robot_3.avi

The competition was to find objets in a previously unknown environment.

Here is our design report (in swedish, the mathematical model is language independent i guess):
http://www.tfd.chalmers.se/~strombom/video/robot_3.pdf

We thought it was a good idea to use three encoders, we used them booth for dead-reckoning and for the robot-control-model. The model is based on x- and y-coordinates and the robot angle.

To be honest i did not really understand your question

Maybe some of the above information made things more clear?

/Johan

[mxtras]

Very nice thread!

Congratulations on your sucess, Johan. Impressive work.

Scott