[FTC]: Wear on Polyurethane Roller

[atwang]

Thank you both for the input!

Originally Posted by cadandcookies

I'd agree that it looks like a materials issue.

When you see polyurethane used for intakes in FRC, it's much more often in this form (McMaster #9697K138 or similar). Yours is a bit softer than the softest tubing, which also likely has something to do with it (in general, softer polyurethane/rubber/tread material wears faster). If you go down the polyurethane tubing route, I'd probably suggest the 1/2" ID tubing for Tetrix tubing, but it will be tight. Best of luck!

We haven't really had the funds to test a bunch of different materials or hardnesses (and our tournament is this weekend, so time doesn't present us with a lot of options), so more out of curiosity…do you think that the hardness of the polyurethane would affect the intaking ability significantly, specifically for the debris in this year's game? I assumed that increased compression of the roller would be beneficial, and so picking a durometer would be a balance between this and the rate of wear, but I haven't really had the resources to test this theory. Also, in order to better understand how we can improve this if we continue down this route, do you think buying it in tube form makes a significant difference, or is hardness more likely the culprit, and a full tube would just help it to hold together better? Also, would you recommend attaching it to the tube using something like rivets or an adhesive, or does it usually rotate with the tube just by friction?

Originally Posted by DavisDad

A design we've had success with for a "harvester" is to use "fingers":

1. drill hole along shaft normal to axis
2. press fit or glue flexible extension springs into the holes
3. push soft latex tubing over springs

You can adjust the length and stiffness of the spring, and length of rubber "fingers" to achieve varying performance. We used this to collect the wiffle balls last year. It's like what a lot of team do with zip ties, but the rubber grabs much better.

We have considered a surgical tubing intake as well. From what I've seen and tested, I personally like the roller because of the "control" aspect—at least in theory, once the intake makes contact with the game element, it immediately pulls it in—whereas a surgical tubing intake may have to spin several times to actually collect debris and is pushing the debris more than grabbing it (plus some other quirks about the two). That said, it may come down more to implementation and driving than the fine differences, and both can be executed well.