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#1
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Re: VEXPro - After the season
Our experience with the Vexpro products:
Ball shifter gearboxes Pros: Compact, light, and in our experience they shift more quickly than dog clutch shifters. They were also easier to mount than the AM Shifters we used last year. Cons: The output shaft came out! Please fix this. We had to pin our shafts (through a hardened steel shaft housing, mind you) to prevent this from happening. It would be great if IFI could implement a mechanical connection between the steel housing and the hex shaft that would be removable so we could swap out shafts of different lengths. One of our steel shaft housings also had a hairline fracture on it, but this seems to be an anomaly. The encoder gear press fit is not very good, and eventually it was so slippy in the shaft that we couldn't use it without supergluing it in. Finally, it would be nice if we could have different spreads that outputted at appropriate speeds. The way they are now, the output speed is only appropriate for direct-driving very small wheels, without a third stage. Motors Mini-CIMs are awesome. BAG motors work pretty well (we didn't have failures with ours like some other teams did), but I wish they were a bit more powerful, perhaps on par with a 550. Side note: if you stall a BAG motor for a really long time, as we did in Madera, it'll burn out and smell as bad as anything you've ever smelled in your life. Sort of a sickly sweet fruity vomit smell. VersaPlanetaries Pros: Very easy to adapt motors of all types, even CIMs and Mini-CIMs if you need to. Swapping out gear ratios is very easy, as is swapping output shafts. We're never going back to BaneBots planetaries. Cons: It's so hard to get 550s concentric! I know there's some play in the face plate mounting holes, but it doesn't work amazingly well. It shouldn't be that hard for IFI to include a plastic or aluminum centering ring with the gearboxes, like some teams have made themselves. Also, it would be nice to be able to put a CIM or Mini-CIM on a planetary without butchering it. Gears, Bearings, and Shaft Collars Flipping fantastic. Shafts Pros: They work well, when they work. Cons: They're so bent, all the time. Out of five 3/8" shafts we received today, only two were within a straightness tolerance that we could use. This is fairly representative of all the shafts we bought during build season. The 1/2" shafts are better, but not too much better -- one of three shafts we received today was bowed noticeably. We would happily buy 18" long shafts (12" might be too short for many purposes) if they were straighter. Pneumatics Can you also supply single-ended solenoid valves, please? Everything else is great, and easy to purchase. VersaWheels (Disclaimer: we didn't use these on our robot; only bought 1 with hubs for testing, so take this with a grain of salt. I also can't speak to durability over a season.) Pros: Very cheap, easy to put together, and grips very well... Cons: In one direction. When pushed from the side, the wheel slides without much resistance. Given that when we play defense, we often block with the side of our robot, this is an issue. Perhaps this could be helped by offsetting the W pattern like so: ---~~--- ~~---~~ ---~~--- ~~---~~ Of course, this would probably make the wheel more expensive. |
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#2
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Re: VEXPro - After the season
We were pleasantly surprised by the offerings from Vex Pro. This was a good year for all FIRST teams by their addition.
Ball Shifter - We had several failures mostly self induced. The fitting on the solenoids are just too fragile and I would like to see them (or even the whole solenoid) changed. We also lost our chance at Boilermaker when the C-clip sheared off the end of the sifting shaft costing us two matches. I'll be perfectly honest, with FIRST allowing so many good powerful motors to choose from, I doubt we will ever shift again unless the game screams for it. Six or even eight motor non-shifting drives may become the norm for us. Bag Motor - This motor caused us many headaches this year. We started with four on our robot and ended with zero. I really hope the problems with this motor are solved, it's a nice package and has huge potential VersaPlanetaries - A real game changer. Easy to use, easy to change and modify, by far the most significant new part to come to us in a long time. These little things took every thing we could throw at them. We used six on our bot from 1:1 to 1:300 with various motors. We abused them and they never let us down. Gears - These low cost high quality gears enabled us to finally have our dream of a robot without chains. Our completely gear driven drive never gave us a second of trouble. The gears on our practice chassis still look almost brand new after many hours of use. |
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#3
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Re: VEXPro - After the season
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#4
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Re: VEXPro - After the season
Sorry I'm a bit late with this reply, been a bit busy competing...
Here's a picture showing the difference in tread profile between a well-worn versawheel and a brand new one. The wheel on the left has ~40 'official' matches on it, ~10 practice matches and some build season run time on it. It's noticeably slicker than a new wheel, almost as if the tread has glazed over. Last edited by thefro526 : 05-04-2013 at 23:40. Reason: Resized Image |
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