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Juggular

3D printed gears?

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I just saw gears for Tamiya cars on Shapeways.  

Are they strong enough?  Has anybody used them? 

 

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6 minutes ago, Juggular said:

I just saw Blackfoot gears on Shapeways.  

Are 3D printed gears strong enough?  Has anybody used them? 

 

I got a set for a Marui Hunter,/Galaxy (the idle gear is  becoming really difficult to find for those) but I did not tried them yet, as the cars are in parts waiting me to built them. It probably depend the printing process and the material as well...

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ignoring the obvious point of whether the tooth profile is correct or not it really depends on the material it's printed in. Acrylic tends to be too soft, nylon 12 is pretty tough and then the filled versions are even stronger.

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5 hours ago, jonboy1 said:

ignoring the obvious point of whether the tooth profile is correct or not it really depends on the material it's printed in. Acrylic tends to be too soft, nylon 12 is pretty tough and then the filled versions are even stronger.

This . Some of the 3d printed materials are much stronger and harder than any original. Just make sure you know what your buying 👍

James.

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14 hours ago, jonboy1 said:

filled versions

What are filled versions? Are there empty versions? 

What are natural versatile plastic?  What are multi jet fusion plastic?  

(Never mind, I found a blog on Shapeways. Multi jet fusion is a bit stronger, it seems.  Still not sure if it's better or worse than Tamiya stock gears, though.)

https://www.shapeways.com/blog/archives/39641-nylon-plastics-material-guide-pa11-pa12-pa12gb-sls-mjf.html

 

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34 minutes ago, BuggyGuy said:

Very few 3D printed gears will be as strong as moulded or machined gears

That's what I suspected. I'm wondering if nylon could be that very few. So if Shapeways print in nylon, I might give them a try.  They aren't offering stuff made with nylon...  Is it harder to print with nylon?  But some articles say that PLA is stronger, so I'm more confused. 

Resin 23, ABS 38, Nylon 48, PETG 50, PLA 64 MPa...

wait... Shapeways says "versatile plastic" is nylon

https://www.shapeways.com/materials/versatile-plastic

As long as it's not the pinion gear, I might give it a try.  

And... I find this...

I wonder if printed metal strong enough? 

kJDOV7S.jpg

https://www.shapeways.com/materials/steel

Shapeways says that it's 60% steel, 40% bronze. Not recommended for load bearing applications. I wouldn't use this unless it's for a shelf queen.  

 

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Nylon filiments tend to require printing at a higher temperatures and can be harder to print (though I'm sure shapeways are great at dealing with this!)

The main issue with printed parts is that the parts are printed in layers - which can make them weaker in some dimensions than others, the multijet fusion stuff is meant to help get round this weakness I believe - but I've not got a printer that can do that so haven't go experience with those parts. I've tried printing gears in various materials for the old Tenth Technology Predator cars (so bevel gears) - but have not yet found a material I can print that's durable enough (either too stiff so teeth sheer, or so soft that stuff melts, or in between where the wear rate is excessive) - though this has been with very powerful modified motors, something using a silvercan could well be fine.

I'm currently trying to get the bits together to machine the parts from Delrin - but it's a rather expensive project to resurrect a car from the mid 90's so haven't put much time into it (building a machine to do it well has been a touch expensive...)

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9 hours ago, BuggyGuy said:

Very few (if any!) 3D printed gears will be as strong as moulded or machined gears

Not entirely correct. If we are talking about metal gears, then absolutely, as a forged gear will be much stronger than a machined one due to the grain structure. 

With plastics it's a bit different as plastics don't have grains, they have chains, which act differently. 3D printed parts are another ball game entirely, as it's as much down to the material as it is the method of printing. As you say, when printing in layers the direction can make a difference, but with SLS and multijet these constraints don't apply. 

10 hours ago, Juggular said:

What are filled versions? Are there empty versions? 

"Filled" means instead of being just nylon material it has glass fibres in the mix too (think of it a bit like fibreglass matting or reinforced concrete) which gives the material a lot more structural rigidity. 

A complete guide to Shapeways materials is here: https://www.shapeways.com/materials

9 hours ago, Juggular said:

That's what I suspected. I'm wondering if nylon could be that very few. So if Shapeways print in nylon, I might give them a try.  They aren't offering stuff made with nylon...  Is it harder to print with nylon?  But some articles say that PLA is stronger, so I'm more confused. 

Resin 23, ABS 38, Nylon 48, PETG 50, PLA 64 MPa...

wait... Shapeways says "versatile plastic" is nylon

https://www.shapeways.com/materials/versatile-plastic

As long as it's not the pinion gear, I might give it a try.  

And... I find this...

I wonder if printed metal strong enough? 

kJDOV7S.jpg

https://www.shapeways.com/materials/steel

Shapeways says that it's 60% steel, 40% bronze. Not recommended for load bearing applications. I wouldn't use this unless it's for a shelf queen.  

 

Printed metal is strong. You have to apply common sense to their claims of "not for load bearing applications" so they don't get people suing them every week when their 3D printed, poorly designed brake caliper adaptor broke. At work we have 3D printed titanium parts that survive incredible abuse (I work in the oil industry, so this is not low impact stuff.) But again, the design and application of the part is a big factor in how long it will last, it's not just material. 

Also, remember that there are nylons and nylons. As I mentioned in my original reply, Nylon 12 is tough, but there's nylon 6 which isn't as tough, so you can't just say "don't use nylon," or "you must use titanium" because there are so many different variants of all materials. For example, using just 2 materials in different ratios we can print a range of materials that go from rock solid to floppy rubber, so one part can be tough at the ends and bendy in the middle - so you can't classify it as being one or the other.

So going back to that Blackfoot driveshaft, imagine taking a metal coat hanger and cut a 2-3" section out of it. Weld a standard Tamiya drive pin across each end and then try to twist the coat hanger by hand. Now consider that this driveshaft is thicker and made from a stronger material than the coat hanger, and compare your strength to what force you can get from a little 540. The material strength is way in excess of anything purely suitable for a shelf queen - if you just want it to look good on a shelf, make it from tooth picks and wrap it in tin foil! But again, the design is just as important. If there are sharp corners you get stress risers and this can make a huge part crack and fail, so you need to look at the whole thing as a whole, not just the material in isolation etc.

Hope this helps.

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Printed gears seem to hold up surprisingly well in my limited experience.  They don't seem to be as vulnerable to damage as printed arms etc even though I suspected the teeth would break off easily. 

I have run a WR02 chassis with some printed gears in for a few packs with no issues. They were only printed in PETG on an FDM printer, too.

I don't own my own printer though, so sending them off can be hit or miss because firstly, some people out there charging for it really shouldn't be because they produce terrible prints:

received_249775956386996.thumb.jpeg.e7f6782a6ef02f429c636580a5419648.jpeg

And secondly, even if you find someone who's getting nice results from their printer or have your own, you still have potential issues such as shrinkage which can be an issue for stuff like gears but they can come out pretty well:

received_230936081659732.thumb.jpeg.25e4c3feaef7534cbc029459d583af42.jpeg

If you have your own FDM type printer and it's well honed, it could be worth a try IMO or if you know someone reliable.

If you don't, the laser sintered style from places like shapeways will generally be much more dimensionally accurate and right the first time and the nylon is pretty tough too.

Long story short: If FDM petg gears can work when done right, then I'm certain shapeways gears can work as the printers they use tend to more easily produce high quality, accurate and consistent results.

 

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My Fox originally came with 3D printed gears. I probably blew up the original gears more often than the 3D printed ones, but the originals were a touch smoother.

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