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-   -   Failure of FUEL game piece (http://www.chiefdelphi.com/forums/showthread.php?t=153622)

pilleya 14-01-2017 02:30

Failure of FUEL game piece
 
Today while testing our 2017 robot with competition spec bumpers around our wooden practice field we had a failure of a few balls.

This occurred when the balls were squashed between the fabric covered noodle of the bumper and a wooden field perimeter while driving at a low speed.



The balls are broken, with cracks occurring between many holes. The failures are not along the welded seam but spread from the edge of the holes, or crack the bridge between holes. That occurred after a limited impact with the balls. A similar occurrence to the same ball a second time would most likely cause the ball to be in several separate pieces.

It seems like the cracks would be quite difficult to notice when field reset is dealing with 600 balls at the end of the match unless they are physically picking up each ball, and squeezing it to check.

Is this an issue others teams have had occur in testing?

NinjaMunkeeNao 14-01-2017 02:52

Re: Failure of FUEL game piece
 
Wiffle balls (or fuel) can take a lot of pushing around but once pressure is applied to them they tend to crack kinda easily. One thing is that the balls you purchased aren't (I'm assuming anyway) official FIRST game pieces, so there's a possibility the actual fuel pieces aren't as frail? There are a lot of knockoffs that break easily.

But don't feel bad about it! Like I said, Wiffle balls tend to crack if pressurized enough so I think everyone, even refs and rest crews are expecting to see a lot of cracked pieces throughout the day and probably won't point any fingers about it.

pilleya 14-01-2017 03:02

Re: Failure of FUEL game piece
 
Quote:

Originally Posted by NinjaMunkeeNao (Post 1630975)
One thing is that the balls you purchased aren't (I'm assuming anyway) official FIRST game pieces, so there's a possibility the actual fuel pieces aren't as frail? :o There are a lot of knockoffs that break easily.

All game pieces we possess are those distributed in the KOP.

Quote:

Originally Posted by NinjaMunkeeNao (Post 1630975)
But don't feel bad about it! Like I said, Wiffle balls tend to crack if pressurized enough so I think everyone, even refs and rest crews are expecting to see a lot of cracked pieces throughout the day and probably won't point any fingers about it.

Although we will do everything we can to avoid damaging gamepieces, we are more concerned with the broken fuel particles impacting our own game play and that of other teams. A ball which is effectively in two pieces tends to not go through a intake and shooting mechanism very effectively.

I think that the conditions which caused the breakage( ball against wall) are going to be very common with robots crushing balls when placing gears, shooting, intaking and feeding from hoppers/chutes.

ShIfTiNgBoT 14-01-2017 03:45

Re: Failure of FUEL game piece
 
Quote:

But don't feel bad about it! Like I said, Wiffle balls tend to crack if pressurized enough
That's very odd. From our testing, after some relatively light use, they become VERY flexible. Like you can cave in half of it and pop it back out.

Green Potato 14-01-2017 06:41

Re: Failure of FUEL game piece
 
We actually noticed the same thing. We were testing a shooting prototype, but the balls wern't really compressed that much... yet I noticed that a few of them, not many, but a few, had developed small cracks like this.

arichman1257 14-01-2017 08:39

Re: Failure of FUEL game piece
 
A) I'm pretty sure that they are identical to the real ones.

B) Like in previous years, imperfect GAME PIECES are to be expected during regulation play. They get damaged over time and FIRST expects teams to be able to handle the damaged ones. Such as in 2016 with the boulders having small chunks missing or being not quite round or in 2011 (throwback, I know :D) when the tubes would not be fully inflated causing many intakes and grabbers not to function properly.

TL;DR The damage to GAME PIECES in real competition is to be expected.

Jaleelmoore34 14-01-2017 10:01

Re: Failure of FUEL game piece
 
Hi Im jaleel from team 4592 and I have a quick question about compression on the wiffle ball, do you know what compression is best to shoot and pick up the wife ball.

Ether 14-01-2017 10:39

Re: Failure of FUEL game piece
 

Some plastics (like polyethylene) are more flexible than others (like polystyrene).

And most plastics are far more flexible when they're warm than when they're cold.




Ari423 14-01-2017 19:16

Re: Failure of FUEL game piece
 
Quote:

Originally Posted by Jaleelmoore34 (Post 1631025)
Hi Im jaleel from team 4592 and I have a quick question about compression on the wiffle ball, do you know what compression is best to shoot and pick up the wife ball.

I saw you asked this in another thread too. While some teams will give away that information, most teams prefer not to just give away the results of days of prototyping and testing. I suggest if your team hasn't started prototyping shooters (if you plan on building one), you should start very soon testing different wheel sizes, types, configurations, and compression levels to see which works best for you. Good luck!

MARS_James 14-01-2017 21:18

Re: Failure of FUEL game piece
 
Huh, we tested the fuel alot, and they handle abuse really well. I actually jumped on one and it bent out of shape then slowly reformed, and i am around 200lbs

Hitchhiker 42 14-01-2017 21:28

Re: Failure of FUEL game piece
 
We noticed the same thing (cracks) on one of our fuel when we were testing a shooter prototype.

Mr V 14-01-2017 21:46

Re: Failure of FUEL game piece
 
As Ether noted the flexibility of some plastics can vary greatly depending on temperature. Personally I squashed a ball by stepping on it and thought it would certainly be damaged but I watched it pop out on its own. Granted I did realize that I was stepping on something and didn't put my full weight on it. That took place in a warehouse with the thermostat sat at 60 degrees and the balls had been in their long enough that they should been close to room temp.

Since we have several reports of cracking, yet others report that they have survived serious deformation, I have to wonder what the temp was in the location where they were being testing and stored in each case.

Tom Ore 14-01-2017 21:57

Re: Failure of FUEL game piece
 
We have one cracked ball so far - it may have arrived with the crack.

pilleya 14-01-2017 22:02

Re: Failure of FUEL game piece
 
Quote:

Originally Posted by Mr V (Post 1631335)
Since we have several reports of cracking, yet others report that they have survived serious deformation, I have to wonder what the temp was in the location where they were being testing and stored in each case.

It's been around 100 F in Sydney lately, but our build/practice space is air conditioned to probably about 70-75 F. So the balls being cold is most likely not the main issue.

MARS_James 14-01-2017 22:03

Re: Failure of FUEL game piece
 
Quote:

Originally Posted by Mr V (Post 1631335)
As Ether noted the flexibility of some plastics can vary greatly depending on temperature. Personally I squashed a ball by stepping on it and thought it would certainly be damaged but I watched it pop out on its own. Granted I did realize that I was stepping on something and didn't put my full weight on it. That took place in a warehouse with the thermostat sat at 60 degrees and the balls had been in their long enough that they should been close to room temp.

Since we have several reports of cracking, yet others report that they have survived serious deformation, I have to wonder what the temp was in the location where they were being testing and stored in each case.

So we have jumped on them at a range of about 47 to 83 degrees idk if anyone is doing it in temperatures outside this range


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