I hope they kept the core the same! How long ago was that btw? Think it will be out for Christmas?
I emailed the about 2-3 months ago, i hope they keep same core also !
@longhairedboy What are the pulleys from shapeways made of? Are they 3D printed?
Any chance of 40t versions?
Yes, they are 3D printed by Shapeways. I’m not sure exactly what plastic it is, but its tough. After some googling i found this datasheet hosted by Shapeways for thier Strong & Flexible Plastic which they claim is structural and can be used for anything from iphone cases to drone bodies and even stuff like this. Here’s the datasheet, its something called PA 2200: https://www.shapeways.com/rrstatic/material_docs/mds-strongflex.pdf
Testing these things had very good results. I’ve been riding around on them for a while now and they’re tough. I dug a few tiny sharp rocks out of the teeth and discovered that they hadn’t pitted the pulley, just the belt. Crushed plant matter had no affect on them. Belt rubbing on the wheel is a complete non issue because of the flange, and the flange seems to handle belt misalignment rather well as the belt doesn’t seem to wear the flange much at all when misaligned.
Then I went one step further and loosened my motor mount a little so that it would do that thing where it starts to creep over towards the pulley so that i could test how well they handle the scraping against the motor plate bolts. Nylon pulleys handle this very well, they just kind of start to smear and melt a little but no real damage, so i was wondering how well these would handle it. I discovered that the pulley would actually start to shave when rubbing against the plate bolts, so the result was kind of like peeling, but the peeling made a noise that let you know what was up, but didn’t provide the kind of rolling resistance that the injection molded variants produce when the injection points start to hammer against the bolt heads. Once the mounting clamp was put back where it belongs the shaving stopped and after tearing off the shavings i rode around a lot more to see if that damage would trigger more peeling after more heavy use. It did not continue.
As a result of that i also discovered that shapeways prints everything in white plastic then dyes the part to the color ordered. They don’t actually use colored plastic. They mention that on their site also apparently.
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Yes. The per unit cost after the mold fee is shockingly low, but the tooling/mold fee… well lets just say i’ve made lower down payments on cars. I’ll have to move a lot of these to justify it, which is why i’m starting with the one that i feel the community would want the most. The only option right now for insert pulleys on kegels is to buy one from Evolve and chop it. Also the Evolve pulleys require a removal of a shocking 18mm of aluminum form the hanger which in my opinion is a bit much. I’ve got two boards out there like that, and the hangers are doing fine, but i’d much rather remove 8mm than 18mm. And without chopping the belt surface town to 10mm from 16mm using a chop saw.
These are made of a special grade of Nylon specifically designed for 3D printing. Linked is the full data sheet from EOS sourced by a local company that does this stuff near me.
It’s printed using an SLS (Selective Laser Sintering) 3D printing process that yields incredibly strong parts both physically in nature as well as in properties. There is no “layers” once the part is printed. It is in the literal sense on the word, one part. Because of this, the material acts uniformly in all directions resulting in no one weak plain or direction in the print. Meaning you have a solid and incredibly tough print. This is not your desktop 3D printer you have at home, it’s commercial grade and meant for serious abuse and forces.
PETG and ABS last a couple hundred miles if not more under FDM (Fused Deposition Modelling) which is what all home printers use, unless you have one with a resin tank which uses a laser to print in fine detail (SLA or Stereolithography) but these tend to be more for models that require extreme detail and not so much physical strengths). The thing with FDM is that here you do have layers visibly present and the material acts like it. Your material properties will not be constant in all directions, you will have weak shear plains in between the layers which is why it’s important to print at or as close to 100% so maximize those areas of contact.
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Did you ever produce these?
Not via injection molding, not yet. Still gathering funds for that. ITs probably going to take me a while. I do have them on a shapeways store though.
I’m also in the process of uploading more kegal pulleys. I’ve had them for a while but i keep getting sidetracked.
“Strong and flexible” is the filament you’ve been using?
What material is that?
sintered nylon. So far they’ve been very, very tough. I’ve only had one break while it was on a board and it was clearly defective, and i’ve tested and used dozens of them. I’ve deliberately broken others to see how they break. they’re not the typical 3D prints for sure.
Hey!! Did you get a chance to injection mold these???
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