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Unread 08-01-2009, 15:42
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skimoose skimoose is offline
Parent/Mentor/Engineer
AKA: Arthur Dutra
FRC #0228 (GUS)
Team Role: Electrical
 
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Location: Meriden, Connecticut
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Re: paper: HOW TO: Make Homemade Orbit Balls

You can churn out non-fabric covered balls fairly rapidly. Simply cut 0.062" Lexan into strips and pop rivet. The two longest parts of this operation would be cutting the Lexan and deburring it so it would be safe for human player practice, and then the weaving process. It takes a little practice to learn the correct weave pattern. We've tried two different ways.

Weaving all six strips simultaneously. You'll need two to three people two to weave and one to drill and pop rivet.

Weaving one strip at a time. Our preferred method, it takes two people one to weave and one to drill and pop rivet.

We estimated 2 man hours per covered ball in our initial tests, but I'm sure we can knock that time down if we set up more of an assembly line for production. That's cutting Lexan, cutting fabric, cutting batting, gluing batting to Lexan, sewing fabric into covers, sliding the covers on, then assembling the balls. The extra steps from cutting, gluing, sewing the batting and covers, and installing the covers doesn't add much time. Plus you can save a little time on deburring the Lexan since the fabric and batting will cover any sharp corners. The only other time consuming step is stitching the Spandex closed on the assembled Gus Balls. Its pretty hard to squeeze your hands into the ball to stitch the inside of the seam closed. I'm no tailor so it was taking me about twenty minutes to stitch all six strips closed.

After pondering this lengthy part of process, I'm now considering using gaffers tape to hold the spandex closed and hiding the seam behind another strip in the weave. Anyone want to try this right now, since we're waiting for more 0.062" Lexan to arrive.

We paid $14/ yard for Spandex at a local fabric retailer, you might find it cheaper online. We estimate that you should be able to cover six balls per yard of fabric, therefore adding fabric adds about $2.50 per ball.

So our revised price per ball is closer to $8.00 USD.

If anyone finds a good source for inexpensive Spandex, please let the FIRST community know.

Go Teams!
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