One of the killer apps of 3D printers is the ability to make custom gears, transmissions, and mechanisms. But there’s a learning curve. If you haven’t 3D printed your own gearbox or automaton, here’s a great reason to take the plunge. This morning Hackaday launched the 3D Printed Gears, Pulleys, and Cams contest, a challenge to make stuff move using 3D-printed mechanisms.
Adding movement to a project brings it to life. Often times we see projects where moving parts are connected directly to a servo or other motor, but you can do a lot more interesting things by adding some mechanical advantage between the source of the work, and the moving parts. We don’t care if it’s motorized or hand cranked, water powered or driven by the wind, we just want to see what neat things you can accomplish by 3D printing some gears, pulleys, or cams!
No mechanism is too small — if you have never printed gears before and manage to get just two meshing with each other, we want to see it! (And of course no gear is literally too small either — who can print the smallest gearbox as their entry?) Automatons, toys, drive trains, string plotters, useless machines, clockworks, and baubles are all fair game. We want to be inspired by the story of how you design your entry, and what it took to get from filament to functional prototype.
Prizes and How to Enter
Head over to Hackaday.io and publish a project page that shows off your gears, pulleys, and/or cams — enter using the “Submit Project To:” dropdown on the left sidebar of your project page.
There are no strict requirements for what information you share but here’s some advice on wooing the judges: We want to see what you went through during the project. Show off your planning, the method you used to fabricate it, share design files/drawings/schematics if you can. Tell the story like you would if standing around the workshop with your best friend.
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Three Exceptional Entries will each win a $275 cash prize
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Seven Runners-up will each win a $100 Tindie gift certificate
Full contest rules are available on the contest page.
What Kind of Mechanism Should I Print?
Mechanical advantage is used everywhere. Once you start looking you won’t be able to stop seeing examples of it. You could change the gear ratio in a consumer item, animate the inanimate by building an automaton, or build your own machine tool. Those examples are shown here, but there are more on the contest page, along with some recommended design tools to get you started.
Do you have a favorite software for designing gears, pulleys, or cams? We’d love to hear your recommendations in the comments below. Warm up your creativity and get designing!
Oh man. This reminds me that I need to design/print a new gear for my chainsaw. Worx branded 15 amp thing tore through a gear in less than two months of use. It’s an odd gear, though – the inside is splined, and the teeth face inward. I’ve been slowly learning Fusion 360 with the intent of modelling a new gear, but I haven’t quite gotten that far into it. If anyone does have an easier way of generating such an odd gear, I’m all ears.
https://hackaday.io/project/20082 files section using OpenSCAD.
An inside gear is just an involute gear, subtracted from a solid, with negative backlash and clearance.
I’ll second OpenSCAD. Precise positioning of each surface to get every tooth the correct size and in the correct place is a math problem easily solvable in code. I can’t imagine designing such a thing by clicking a mouse around to each point manually.
Fusion has parametric gear generators, can also import from supplier catalogs, like McMaster Carr. Creating a gear like OP defines wouldn’t take more than a couple steps.
You say “just”, but for someone picking up a CAD package for the first time, it’s still a little daunting. :P
I suspect the original gear didn’t really even have properly shaped teeth. The metal teeth directly on the motor shaft seemed well shaped, but from what I could tell of the shredded remnants of the plastic gear’s teeth, I think they have have just been triangular in shape.
What really annoyed me about the whole experience was that they _had_ a replacement part in their catalog, but they stopped making it. For a model that was less than a year old, I couldn’t find the replacement part anywhere in stock from any other supplier. Nothing quite like having a $100+ tool reduced to being useless because a $2 part failed.
I figured rather than getting mad about it, I’d rather get even and create a proper model of it and shove it up on thingiverse (or any similar site) for anyone else to replicate.
Proper inside involute spur gears with negative backlash and clearance *are* surprisingly triangular. I thought exactly the same thing the first time I generated them. :)
If you are feeling adventurous and need a hand getting started on this the OpenSCAD way, ping me [daren] in hackaday.io chat. Provided it’s not a ton of work, I’ll generate the basic shape for you and then you can play with the numbers until it’s right.
I personally found doing this in OpenSCAD far easier than any other method, but having a basic programming background and the ability to think in 3D primitives is kind of required.
One of the best things about using OpenSCAD is the Customizer–both in the program itself and on Thingiverse; you don’t need to understand the programming end of things, just know what values are needed to be input. to get the desired output.
I’m going to write up an intro-to-gears article for OpenSCAD. Custom gears was the first real “killer app” for me with 3D printing.
I’ll be looking forward to it!
Did my first custom ring bearing/spur gear drive a couple months back. Worked, first try. I was like… damn.. I may actually know what I’m doing here now. :)
I mocked up a 3D printed drivetrain for my latest project, but I copped out and went with chain. 400W static load, probably 10 times that in shock loading (pushing a human), and dirty so no lube. If I had enough nylon filament to burn perhaps, but my ‘precious’ is looking a little anemic. To keep it from delaminating under that kind of load I would need to anneal it. I’ve never, ever gotten the shrinkage right the first time on annealed nylon gears.
My ‘precious’ was a sample roll of a prototype nylon filament. My god was that stuff was awesome.. and currently irreplaceable.
If you just want to get going quickly without learning all the math, I highly recommend the gear generator from Matthias Wandel – http://woodgears.ca/gear_cutting/index.html – With the downloaded version you can export DXFs and import them into your modelling program of choice. It does internal and extenal gears, racks, pin drives and chains
At some point, will you have a contest about lasercutting?
The gears (and most of the rest) of the examples shown on the contest page can be more easily made using a lasercutter instead of a 3d printer.
Yeah, you’re right about the popularity of laser-cut gears. We should totally have a laser-cutting contest… any suggestion for the challenge of the contest?
Laser cut robot
Laser-cut laser cutter?
Im pretty sure Id be blacklisted, but Id love to see a laser-cut-into-the-3rd-dimension contest where projects have some sort of depth to them besides just a single panel.
Just because you’re not eligible to win doesn’t mean you shouldn’t enter! (Josh is a Hackaday contributor. Hi, Josh!)
“Laser-cutting into the 3rd Dimension” is an awesome idea. I think you’ve just brainstormed up our next mechanical contest!
What’s the current state of laser-cutter slicing modelling software? Are people still writing their own?
https://hackaday.com/2015/12/06/laser-cut-and-weld-makes-3d-objects/
https://hackaday.com/2015/11/01/are-you-telling-me-you-built-a-lexus-out-of-cardboard/
https://hackaday.com/2015/04/30/3d-printering-laser-cutting-3d-objects/
There was an awesome (art) piece from fiveish(?) years back where the guy made über-rococo columns and arches from cardboard (?) laser-cut. If anyone knows the link, I’ve been dying to revisit that article.
You mean this one?
http://www.michael-hansmeyer.com/subdivided-columns
Like, make a 2-axis laser cutter into a 5-axis laser cutter?
????
Puzzles perhaps?
I’ve seen a lot of elaborate puzzles with moving parts in a flat-ish idiom, such as built into the leaves of books.
Adding the 3rd dimension to laser cutting. Jointery, layering, engraving.
I’d better get started on my Antikythera mechanism!
I was thinking about getting started on a model of a synchromesh transmission using herringbone gears, so it doesn’t have much thrust component like typical helical gear transmissions have.
Well I’ll make a Kythera mechanism to annihilate your chances.
I like Blender as the multi-tool of 3D modeling. Its not the best at anything necessarily, but it can do just about anything.
And if I understand it correctly, Python plugins can be written for it, so you have a path to parametric part creation.
Impetus.
And only a month to put that long nagging idea to flesh…
Better get to work!
That’s the spirit!
Please change the terms of the contest to make it about fabricated gears, because it should be about the gears themselves, not how they are made. If [This Old Tony] milled a Ravigneaux Planetary Gear Set or [Peter Brown] cast a working Geneva Mechanism out of resin filled with CAT5 wire and pencil crayons, should they be disqualified?
Well, yes, resin filled with CAT5 wire should be disqualified from everything. But opening up to any fabricated gears lets gears made in a CNC machining center in the door, and we just don’t want their kind around here.
Too right, mate! Making should *cost* money, not *earn* it! :grin:
Completely agree, my shed is smaller than a VMC but only the printing requirement is stopping me from submitting my amazing project.
Well, the 3D printed aspect does present itself with its own challenges. Generating functional parts where layer separation is not an issue I think is issue number one, and sectioning the parts so everything can be printed flat being number two.
Laser cutting them is just cheating.. :)
Yes, the majority of mostly 2D gears would be better fabricated using a laser cutter or traditional machining.
Depends on the point here..
I’m already a fan of [This Old Tony]. You are making me look up [Peter Brown] now…
Most straight gears are better purchased from gear vendor. Cheaper, cleaner, stronger.
Only specialized and unobtanium ones requires 3d printing. And in most case FDM is not the best choice.
Gears like 14 Diametral Pitch with 14.5 degree Pressure Angle or Module 2.75 – which is >thisclose< to 14DP 14.5 PA, would be ideal candidates for 3D printing.
Why? Because not long after WW2 the entire gear making and using industry decided *nobody* was going to use 14DP gears anymore, especially not 14.5PA. There is ONE place in the UK that claims to have stock 14DP gears but only in 20 degree PA. One place on Earth, and they don't have that pitch in the PA most old 14 pitch using machinery needs. Which is why a 13" LeBlond 'trainer model' metal lathe with headstock gear damage is a Do Not Buy item, unless you really want to get into making your own gears.
Flash forward to the 1980's and to India. At least one company must have been pining for 14 DP gears. A company named Takang used 2.75 Module metric gears in the drive to the quick change gearbox on some models of their metal lathes. Missing one? It will cost you *a lot* of money to get a gear custom made, much more than a similar 14 DP. What's worse is despite being given the measurements that prove its a 2.75 Mod gear, the machine shop insists there's no such thing and makes it in 2 Mod. Unfortunately the two are different enough they don't mesh properly.
Takang quit making manual machine tools some time ago. They only do CNC now and don't acknowledge the older machines – and despite being very popular in India and for export, manuals for manual Takang machines don;t seem to exist, not in any electronic form at least.
By the 90's the entire gear making and using industry booted 2.75 mod out of the playground like they's done to 14 DP.
Same thing with 35mm diameter single key shafts on 3 HP motors for split sheave variable speed belt drives. In the 90's that's what was used on things like clones of Bridgeport knee mills. Then at some point the whole variable speed belt drive industry went to splined shafts for 3HP drives and parts for the older single keyed shafts are 195% unobtanium. I had to use a lathe to cut new plastic bushings for the motor pulley on my 1990 Acra knee mill.
I'm certain there are other mechanical things in various industries that were once very common, then overnight declared to be obsolete and essentially forbidden for anyone to manufacture.
I don’t know if maybe the cultural norms of machine shops vs every other business transaction are different or what. I would think that if I ordered an X and some business tried to give me a Y that business would not be getting paid until I had a nice shiny X in my hand!
If I already paid I would register a dispute through the credit card company that I used to do so.
A spline is the profile of a gear with a stub of of 50% on its addendum with a pressure angle of 30 degrees typically. There is a forum topic on the forum at gearotic.com that goes into more detail. Splines are typically denoted by two DP’s, such as a 16/32 spline. ( normal DP of 16 profile with an addendum 50% its normal). The 30 degrees tends to make the pinion look
triangular toothed.
Thank you. This is actually useful.
OMG. There is a website called “gearotic.com”…. Surprisingly, entirely SFW as far as I can tell. Depending on your work, of course.