polyurethane tubing

[HighLife]

We've had a few teams come to us and say that they've tried the lighter method and had belts break on them.

Pay a few bucks for the barbs and you'll save yourself time in the build process and stress later.

[EgROS]

Originally Posted by HighLife

We've had a few teams come to us and say that they've tried the lighter method and had belts break on them.

Pay a few bucks for the barbs and you'll save yourself time in the build process and stress later.

We used a simple fusing technique and have never had any belts break on us despite attempting very hard to do so. We created a simple mold by drilling a hole through a delrin block then cutting it into two halfves down the center of the hole. We then heated the two ends of the cord with either a lighter or soldering iron, placed it in the mold and applied presurre for about a minute.

[artdutra04]

Welding the solid core takes a little practice to perfect, but once you get it down it will not break. We've found that once you melt the ends together and wait five minutes, if you pull on the joint really hard and it doesn't break, it won't break on your robot.

[big1boom]

We welded the solid orange polychord with a standard propane torch.

Just melt both ends that you want to connect
Place them in a piece of Angle Aluminum, with the two ends in contact.
Hold for 5-10 minutes till cool.

This resulted in a weld that was strong enough that two people doing tug-of-war could not rip it.

The welds might not be the prettiest, but they work amazingly, and don't jump off of our pulley's

If I remember correctly, the polychord on our bot had a tension of somewhere more than 30%. (I think I remember it being 35%, but I might be wrong.)

[Phyrxes]

We used the orange solid core from McMaster, heated both ends up with and clamped it with an old ribbon cable crimper that had some small angle added to it. to keep things lined up.

[JesseK]

Here are some intersting tables on Rounthane. Notice that you can see the extra load the stretching will put on your motor, which guided us into our new conveyor motor setup for Atlanta. Previously, we just guestimated everything with conjectures that a motor would or would not work. This data, PINK's recommendation, and the lack of necessity to weld the belting are all of the reasons we're redoing our conveyor with it for Atlanta.

Quick question though -- is the polyurethane cord on McMaster the same as the Rounthane? Usually mcmaster mentions the brand name, if there is one, in the product details.

[AlexD744]

If you are attending nationals, you can find 744 SHark Attack. We used a lot of belting this year and Ralph, our electrical lead, is an expert belter. He does almost all the belting at him company. Feel free to stop by, we melt them simply and they have not broken for us yet.

[Johnny]

My team used the 1/4 inch clear polyurethane tubing from mcmaster. I constructed a welder out of these parts listed:

Materials:
-one 6-inch piece of KOP C-Channel(cut out notches on each side where the holes are lined up so that the belt can be taken out once it is welded)
-squirt bottle WITH WATER!
-Heat gun
-pair of nice channel locks
-piece of flat bar(used for rolling the belting to create smooth weld)

Process:
1: cut an access whole on each side of the c-channel so that each end of the belting can touch and be pulled out with ease(when it is connected).
2:Have one person hold each side of the belting slightly spaced apart while another uses the heat gun to start a slight melt on each side of the belting(person holding the belts might need some gloves if you have sensitive hands )
3: As the belts start to look "melty", push them together and continue to heat to the point when the ends of the belt reach its melting point, then remove the heat.
4: Use channel locks to squeeze the belting smooth and squirt with water to cool it down so it can retain its shape.
5: Place belting on flat surface and roll it with the flatbar(works nicely if it's cold), I usually rolled in once forward, and once back.
6; Now, brag (graciously) about how successful a weld you have without spending 300-400$ on a belt welder

We were able to weld 30 belts in about 45 minutes(including a snack break). It might take a few tries to master, but the welds will turn out really nice, almost as if you bought a welder to do it for you.

[anyheck]

I have no experience with this material. Does its texture allow some slip on the balls, to avoid jamming them together when they are 'queued' in your conveyor systems.

We used rubber surgical tube and it had nothing but grip, so we had to keep the balls spaced out well to avoid jams.

I wanted to find a semi-slippery material to re-work the belt system just for the experience.

[dtengineering]

we found that the 1/4" hollow core worked quite nicely and could be asssembled in place. that might be my choice for quick fixes and retrofits.

Jason

my first post from a cell phone... isn't technology coool?

[Blue_Mist]

This stuff is excellent as semi-slip material. It isn't grippy like rubber surgical tubing, but the problem is that it may not pick up as quickly (in my experience-we put tread on our bottom rollers to aid pick up). You can pretty much jam balls down our hopper and then pull them out just as easily.

Going back to the welding discussion, 766 used the yellow hollow cord this year, and we just welded it together with a heat gun. We held the ends in the heat until they melted slightly and put them together when melted, waited for cooling and dremeled (with that sanding attachment) the surrounding blobs off. In two regionals we've never had any loop break.

Technology is cool!