3D Printed Winch - Team 2359
 

Team 2359 created a winch mechanism for our shooter that consists primarily of 3D Printed parts. The only pieces not printed are the lead screw and lead screw nut, some bearings and other misc. hardware. There are 6 parts.
Green Motor Mount and Green Tensioner. Blue take up pulley. Green Ratchet Hub, Red Hub Mount and the Blue Pawls (2 of these one not visible) that hold the ratchet hub in place.

A video of the winch in action is here:
http://www.youtube.com/watch?v=yDsW9tcMrRo

We think it sounds like an old wooden roller coaster.

I hope to have the parts posted on thingiverse later.
***edit*** they are now posted: http://www.thingiverse.com/thing:271463

Re: 3D Printed Winch - Team 2359
 

This looks great.

Re: 3D Printed Winch - Team 2359
 

How much load is your winch taking, i.e, how many lbs does it take to pull back your catapult?

Re: 3D Printed Winch - Team 2359
 

We had a 3D printed cRIO case. Due to all of the heavy impacts this season, it snapped it multiple places. I don't mean to say yours won't work, but be really careful.

Re: 3D Printed Winch - Team 2359
 

Looking forward to seeing this in person at OKC. Keep up the good work guys!

Re: 3D Printed Winch - Team 2359
 

I understand the durability of the plastic can be questionable, but so far we have survived. We have already competed at the Arkansas regional with no problems with the winch. Most of the parts were done with 15% fill and 4 layers. The ratchet hub which probably takes the most load was done with 5 layers, I can't remember if we increased the fill rate on that part. We did have a small part on another part of our robot break fortunately we took the 3D printer with us, and it was a part that only took about 30 minutes to print.

The winch is pulling in a web strap, and the launching force of the catapult arm is created by two of the 25 pound constant force springs from Vulcan. We can make a successful shot if we are around 10 feet or so from the wall. I think the amount of torque provided by the springs is about 650in-lbs, and due the angle that we are pulling, I think the maximum force exerted on the webbing is around 72 pounds when we initially start pulling but decreases from there as we pull it in.

With respect to the winch, the only part that broke during practice was the lead screw nut sheared off the head. This wasn't even a part we had printed. But it happened because we overdrove the lead screw. Since then we have had a couple of limit switches in place to keep that from happening again.

The parts have been uploaded to thingiverse:
http://www.thingiverse.com/thing:271463

Re: 3D Printed Winch - Team 2359
 

That's really cool! I never thought to 3D print a winch system. The durability worries me a bit, but if you design it correctly then I guess it should hold up fine. And on the plus side, if parts start wearing down or failing after too many shots you can easily 3D print spare parts! :)

Out of curiosity, what 3D printer did you use and what plastic?

Re: 3D Printed Winch - Team 2359
 

We are using a MakerBot Replicator 2, we were fortunate enough to get one from the promotion last November by MakerBot and DonorsChoose to get a 3D printer in their short lived "3D printer in every school" campaign.
The Replicator 2 can only do PLA. You need a heated plate to do ABS and the "2" model doesn't have one.

We did have to print one part that broke, fortunately it was on another motor assembly and was a small part. Except for the pawl that we have, the parts on the winch take at least 4 or 5 hours to print (the largest parts I believe took over 20 hours but those are not really high load bearing). So we would be in a world of hurt if we had to rely on that. We do have some spares, and will probably have a few more by the next regional.

Re: 3D Printed Winch - Team 2359
 

That's awesome. Our team started leveraging 3D printing this year as well and I totally feel for you when you say 20 hours to print a part haha

Best of luck to you guys!

Re: 3D Printed Winch - Team 2359
 

Wow thats amazing, great to see you guys pushing this to the limit! as for plastics i hear that you can print in nylon (on the Rep2) which i hear is considerably stronger. check out some discussion about it here.
http://www.reddit.com/r/3Dprinting/c..._replicator_2/

can you guys upload your CAD Assembly? id love to see it!

did you guys have any revision to your design due to parts that failed? how did you insure the durability of your parts?

Re: 3D Printed Winch - Team 2359
 

Thanks for the link about Nylon. I'll have to look into that. I don't currently have a CAD Assembly. However if you want to look at the individual plastic pieces, you can download the stl files from thingiverse. I will try to see if our designer has one, but it may be a while as we are starting spring break.

As far as revision, we revised the motor mount from our original design not because of failure, but to make it vertical to take up less real estate. The only other part that was revised was the piece we call the ratchet hub. But not because it broke, but because the lead screw nut that it was attached to broke, and we didn't have another. So a groove was cut in the lead screw nut and an associated key was put on the new ratchet hub. We beefed the ratchet up quite a bit for fear it might shear off, so the fill I believe was 20% and the layers was set at 5.

Re: 3D Printed Winch - Team 2359
 

hey you guys had a really good looking robot, what elastic material is that on you shooter it looks great and it looks like it wont come loose and fray in our gears.

Thanks

Re: 3D Printed Winch - Team 2359
 

The winch design sounds really cool! I hope it stays together for you guys. We've had enough issues with 3D printed parts deforming permanently when under load (Spacers, ect) that none of them made it onto the final robot this year (replaced with metal).

Regardless, I'm interested to see how this gearbox holds up

Re: 3D Printed Winch - Team 2359
 

Team 801 has been using Taulman 618 Nylon for the past few months on our Replicator 2. I must say it's wonderful stuff! By adjusting layer thickness and printing temperature you can adjust the softness of the material making anything from CIM motor mounts to soft, squishy bumpers (used for preventing our gatherer assembly from hitting and damaging our frame). As far as durability goes, we have broken probably half of all 3D printed parts we've made with PLA but have yet to break a single Nylon part (most people seem to think the yeild strength is about 3-4 times that of PLA).

The only drawback of using the Nylon is that it requires modification to the printer in order to get it to stick to the build plate. We bonded 1/16" Garolite LE plating (http://www.mcmaster.com/#garolite/=r3k3b4) to our build plate and sprayed on Aqua Net (specifically this brand) hairspray on our printing surface. It also needs to be stored in a sealed bag with desiccants, as it rapidly absorbs moisture if left out, which can cause printing problems.

We really love the Garolite and hairspray combination, and it works great for PLA as well, allowing us to print complicated objects, and even supports, without using a raft (dramatically reducing print time for small parts). It also allows us to reduce the frequency of re-leveling the build plate to about once every 25+ prints, as a loose leveling job allows the printer head to cut lightly into the layer of hairspray rather than the build plate.

Overall the Taulman Nylon and Garolite are definitely worth a look, and we plan to make many more parts with them in the future!

Re: 3D Printed Winch - Team 2359
 

thats awesome, wanted my team to move into nylon and hope to get at it soon, do you have some picture of parts printed in nylon?

How does the Nylon 618 compared to the nylon used in AndyMark Toughboxes from the kit?