If you are using a flexible material IE polycarbonate cut out concentric circles, think doughnut shape, then cut one side from the center out in a straight line, and pull the ends apart. Try your methods out on paper, it behaves well like a material such as polycarbonate.
To be more specific, we’re aiming at a helical magazine similar to the ones that teams 66 and 121 made in 2006. Our prototype was made out of 1/32" polycarbonate cut into a doughnut and wrapped around a cardboard tube. When we tried to wrap it around the tube, we were unable to get it to fit right and it buckled when forced into position. Our cuts weren’t of the highest quality, but the problems we were experiancing went beyond what I would attribute to our circles not being perfectly round.
I would suggest trying to build one like 469 did in 2006 (picture here). It would probably be easier to build and tweek. If you go to a Lowes or Home Depot you can buy some sprinkler hose, which comes in various widths and lengths and is made of a hard and somewhat flexible plastic. The best part is that it already comes rolled up, so you don’t have to deform it much to make a helix.
We just bought 100 feet of 1/2" hose for $14. The hole role weighs only a couple of pounds! (Not like we’re thinking of something similar… :rolleyes:)
there is a book out that has a lot of good 06 bots that use this system use utube it also may help you ( team 694) they have a nice simple one that would not B too hard to build u may wish to ask one of them.
Our cutting itself isn’t too bad (ok, well it wasn’t great, but we were rushing). The big problem with cutting appears to be putting an accurate trace on the polycarb for the cutter to follow. Any ideas for making a accurate circle that 20+ inches in diameter?
We just prototyped a helix system today with the center drum powered and it worked wonderfully. We used PEX tube which comes in 25 foot rolls and supported it with a wood frame. we used to separate runs, one under the ball and one on the outside of the ball to keep it in.
My team is doing the same thing. There is a ton of math that we had to do with our loader considering dimensions because the ball must sit in a certain confined space given your “lead” height and the spinning mechanism’s diameter. Draw a picture and just start drawing triangles (don’t put in numbers until you have an equation :ahh: ). We were somewhat able to build a prototype but it was really shotty. ALSO remember, if you decide to cut out donuts and connect them, remember that their diameters will decrease the more your pull it out to “uncoil” it. Have fun and good luck wiht your design!