Thread: Printing a YoYo: A Step by Step Look into the Design Process

Hey all,

My curiosity got the better of me, and I decided to try and see if it was possible to get a good yoyo out of a 3D printer. My school has one, and I'm good friends with the teacher who runs it, so I got the OK to give it a shot.

First of all, for those of you who don't know how it works, I will explain 3D printing to the best of my limited capability. It is, like you can imagine, a printer. Instead of ink and paper, however, it uses plastic powder and binder. The printhead can move in the x and y directions, and the platform on which the printing occurs moves up and down for the z axis. The design that you send to the printer is split into layers, about .004" thick, and each layer is printed one at a time. After each layer, the build platform lowers so that another layer can begin.

My school's printer is a ZCorp 450. Google can tell you more about it than I ever could.

Research on the Internet gave me an idea of the weight of the plastic powder, and the tolerances the machine was capable of. I made a design in Autodesk Inventor (free for students!), converted it to a .stl file, and printed it up.

Printing the yoyo takes about 50 minutes. There is an additional drying time of an hour and a half as well. The optional last step, which I chose to do, dips the part in an infiltrant for extra strength. It's pretty much like soaking the part in super glue.

My first design:



A LOT of things went wrong with this build. First of all, in the file conversion process, the dimensions of the part were lost. The slot for the bearing spacer was the wrong size, and the hex slot for the axle was off too. I made a small sleeve so that a Duncan spacer could sit in the slot, which is the black wring on the left. A Duncan spacer can hold a D sized bearing, so that was what was going on. The hex slot, originally made to be for an M4 .70 pitch bolt, ended up using a 4-40 nut/bolt. When tightening the yoyo, the parts were under too much stress from not fitting perfectly, and the hub sheared off the side. Back to the drawing board....

Design 2:



I converted the Inventor file using a different method, and I was able to keep my dimensions during the print. I put in an ORing slot underneath the spacer slot, thinking that I could remove some of the stress on the half from overtightening. The response groove, designed to be the same size as a YYJ ORing, was too small due to a bad reverse engineering job with my calipers. When I was working on getting the bolt in the hex slot, the core of the yoyo came out. It's hard to describe, but the bolt sort of "drilled" through the core of the yoyo. This was fine, because I had been careless in my design about the width, so the yoyo would have been over 45mm wide when finished. Time to revise....

Design 3:



This design was made to really beef up the hub area of the yoyo, because that was where all of my problems had occured. The yoyo isn't solid like it appears though; there is a hollow channel inside. For this print, we also soaked the part in the infiltrant for extra time, to make sure it reached the core of the yoyo. This worked, and I never had a hub blowout. However, the issue with this design was the weight. It was pushing 90 grams when assembled. I didn't have any good data on the density of the plastic/glue combo, so I was guessing it to be similar to ABS plastic, at 1.060 g/cm^3. I was wrong. It is actually over 1.6 g/cm^3, which is more than even Delrin. I had to redesign again to compensate for the weight.

Final Design:







This design made the holes in the yoyo larger in diameter and more numerous. The diameter was taken down from 55mm to 51mm. The width came down from 40mm to 37mm. I also tried a color print. The printer just mixes regular printer ink with the powder to make the color.

I dropped the ORing groove under the spacer, and modified the response ring to fit a YYJ ORing. The hub of the yoyo was kept beefy for strength.

This design is a winner! Its smoothness is on par with an injection molded plastic. The spin times are not exceptional because of the weight being in the center, but I like regens anyhow. The color scheme was based off of the Bapesit look; I always liked the blue-silver combo.

Final Specs:
Diameter: 51mm
Width: 37mm
Weight: ~68g (I need to go weigh it, but the scale is at school )

I'm happy with the way it turned out. There are definitely pros and cons in this method of making a yoyo. For example, you can do a lot of interesting features in the body of the yoyo that would be hard to do on a lathe, like the holes. The tolerances on the machine aren't airtight though. They are right around .01". The yoyo isn't dead smooth as a result. Also, the printer does not print with a uniform density. The outside of the part has more binder than the inside. The inside has a scaffolding type structure. I might see about changing the settings around to eliminate this. Also, the part comes out rough. It chews strings. I'd say it probably has the texture of 200 grit sandpaper. Smoothing it with sandpaper isn't hard though. Another issue is the strength/weight of the material. This stuff isn't very strong, so thick walls are needed. This limits your weight distribution options. More experience with it would probably help this though.

I had fun working with the printer and design software. What I like best about the yoyo is that the holes make a breeze when they spin. The yoyo whooshes when you play with it. I think next design I might try to make an impeller type design in the hub.

Congrats if you read that all the way through! I know I was getting impatient when writing it... :)

Charlie

Nice job Humphrey! I really found this interesting. I had never even heard of a 3d printer.

Very cool!

you could always try making a mold of that one, doing an injection mold with plastic, then from there do some minor modifications to the finish, mold it again, and have that be the final mold..... and then release it so we can all share the joy of the awesome look of that yoyo.

Originally Posted by J_scap

you could always try making a mold of that one, doing an injection mold with plastic, then from there do some minor modifications to the finish, mold it again, and have that be the final mold..... and then release it so we can all share the joy of the awesome look of that yoyo.

Do you have any idea how much injection molds cost? A LOT! Thousands....

Nice work. I'm sure you learned a bit from all of that.

I certainly did. Id never used one of these machines before, so it was neat to give it a try.

that is awesome dude, as far as i know most attempts to make a working yoyo from a 3d printer have been too light to actually function well.

Good job!

Awesome job! Landon did a 3d print of the Omni x long before he started production, but it was just one half, so it wasn't usable.

That's cool that you were able to use the machine so much to mess around with it!

You should post a video. Wait! I think I hear something, sounds like a chant....

video!, VIDEO!, VIDEO!, VIDEO!,

Yes, definitely a chant...
VIDEO!, VIDEO!, VIDEO!,VIDEO!


Hmm, they seem to want a video. Maybe you should post a video on how it plays?

I can work on that. I don't have any cool tricks, and I can't do them right now (sliced my thumb with a knife, so I have stitches in).

I will see if I can make a video showing the vibe/catching the noise of the whoosh. My camera is pretty bad though, so no promises.

I think he was asking for a video of the process which is awesome by the way.

The process is WAY too long to make a video. It's kind of like watching paint dry.

I could probably get a short clip of it printing though. The total time to make one yoyo, excluding creating it on the computer, is about 5 to 6 hours.

Printing takes about an hour, drying after printing takes an hour and a half, dipping the parts in infiltrant takes about 20 minutes, and the drying after that takes about 3 hours.

These times change depending on the design/size of the part you print.

EDIT:

Someone else's video....



EDIT EDIT:

I think the final product, excluding time and previous attempts, cost about $5.

Originally Posted by J_scap

you could always try making a mold of that one, doing an injection mold with plastic, then from there do some minor modifications to the finish, mold it again, and have that be the final mold..... and then release it so we can all share the joy of the awesome look of that yoyo.

While I do agree with what was said earlier about injection molds costing a lot, I am guessing that non-factory quality and single use molds are much cheaper. I bet that 3D printing could be useful for designing prototype designs.

I only heard of 3D printing recently, but I love the concept and can't wait to see where it gets in 50 years. I hope to see a day when tolerances are extremely high, density is balanced, and the medium used can vary with the application. Imagine being able to buy an iPod (I'm not going to lie, my first example was going to be a book and I realized we have printers that can print books already :P).

EDIT: 3D printer that can print out a 3d printer. On that day I will have seen all that there is to see in this world.

Originally Posted by Mr J

I think he was asking for a video of the process which is awesome by the way.

Actually I was asking for a vid on how it plays. A vid with timelapse then play would be cool...

Cool! I had just seen a video for a 3d printer, and the guy made 'impossible' bearings, where the bearings were attached to one another(like linked rings)

The video said something about different resins making it different strengths.

Heres the impossible bearings



Makes me think it might be possible to make a ONE PIECE ball bearing yoyo.. Only thing I can see(unless the video is being missleading) is that it might be hard to get extra powder out of the bearing? I wonder if putting holes around the outer race would allow for that..

Originally Posted by icthus

Do you have any idea how much injection molds cost? A LOT! Thousands....

awww.... oh well you learn something new every day, well... how's about putting the design up on rapid share so those with access to a 3d printer get the chance to try this thing out?

Design your own!

I am not trying to be selfish, but I don't want to share my design. It took a lot of work. If you have access to a printer, make a better one.

Find a different solution to the problem. That is the only way progress is made.

Gotta say I am impressed. I really didn't think you'd be able to make much of a yoyo with a 3d printer, but Humph proved this wrong.
Has definitely proved there is some potential there at least.
I wonder if there might be higher strength plastics available to work with ?
Thanks for sharing, quite the feat of engineering there.

Originally Posted by Graiskye

I wonder if there might be higher strength plastics available to work with

I know ZCorp has different kinds of powder available.

I was also thinking about trying to make the print with uniform density, which I think would be stronger. It would use more binder in the print, which should increase strength.

I posted this on another board, but figured I'd copy it here to show what 'can' be done with this type of thing.

____

I don't recommend trying to do something like this, but it can be done.. and with tolerances held as well.. and a decent surface finish :)

I never really gave many details as to how this was done, so I will now since it's been a couple years :)

The model was created in SolidWorks after somewhere around 350 hours of modeling and design work. The design is extremely complicated, modeled after the "Bird's Nest" stadium in China that was built for the Olympics. The problem of course is not only the intricate modeling work, but actually keeping it actually balanced and spinning true as well.

The body is 3d printed on a fairly specialized machine that holds better tolerance than your typical printer. The body was printed with tolerances in mind, and was 'over-sized' very slightly.

It was then machine down to spec on a lathe, by hand.

Then, you can 'polish' certain 3d printing plastics by essentially melting the surface. You can do this with a yoyo by spinning it with a lathe and polishing it with a cloth soaked in a solvent like acetone. You have to be -very- careful to not screw it up, and you obviously want to wear chemical resistant gloves and probably a respirator in a WELL ventilated area.

Then, a steel hub was machined along with steel weight rings. The plastic body is actually 2 parts on each half.. one is the body, one is the rim.. that's how the steel rings are 'captured' inside the yoyo.

The yoyo uses a nut/bolt system.. the ends of which are captured under a 3rd body piece that snaps over the ends of the nut/bolt.









All the benefits of a 3d printer, and as few of the downfalls as possible.

Hope some of this can help you in your projects.

Kyle