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slimleeroy

3d printed gears

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Has anyone ever used any 3d printed gears in their cars?  I am restoring an optima mid and could only find a 3d printed part for the center gear.  Not sure how strong it will be.  It will only get a light running. Any experience?  Thanks

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I am just testing some different materials for 3D printet spur gears, some are real strange and expensive materials. I am not through now with testing but I am afraid its just testing and would not replace a industrial machined gear.

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My own 2 cents, I would not use 3D printed gears. I've built  several gearboxes from scratch and have always used machined steel gears or Tamiya gears. If you get the distance between the gears wrong by as little as 0.1mm (That's 0.05mm error on each gear) the transmission will bind. So you've got to ask what the absolute of the 3d print is going be especially with regards to the centre hole. If the gear is eccentric by as little as 0.05mm it's probably going to be scrap. Then you've got to look at surface finish. Steel gears have a very smooth finish, I've never seen any 3D printed part that can come close to that, so when the gears are under load a rough surface finish is going to generate a lot more friction.

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5 minutes ago, slimleeroy said:

Seen that but postage to UK is about £30!!!  Unless someone can post one to me and I can pay them 

HPC gears in the UK (www.hpc.com) will make custom gears to order. A standard 0.8 or 1.0 module gear of about that size in steel that is going to set you back around £10 plus £8 for postage (Last time I ordered from them about 4 years ago), but then it looks like you'd have to get them to machine it for bearings, so that will cost as well. But the good news is that will be the last part  to wear out on the car.

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That sounds really promising. However I am a bit of a technical dinosaur so how would they know the sizes etc of what I would require?  Thanks

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Posted (edited)

@Madinventor: You provided the incorrect URL. This is the correct one: https://www.hpcgears.com

Thank you the link. I've added HPC Gears to my favorite. Might come in handy.

Edited by GreatDane
Added some more text
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12 hours ago, slimleeroy said:

That sounds really promising. However I am a bit of a technical dinosaur so how would they know the sizes etc of what I would require?  Thanks

If you have a bottomless wallet you can just send them a sample and they can measure it from that. However, most cars use one of a few standard sizes, it looks most likely to be 0.8 module. You can work it out by measuring the diameter of the gear and counting the number of teeth. From this you can work out the pitch of the gears.

 

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hi, if you add a picture of the gear you need, i might have a used one you can have, and im in the uk. 

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Unless you’ve access to aerospace (or top end automotive) 3D rigs you’ll end up with an explosive mess - that will likely do more damage than swapping what’s left of the gear ?

Layering complex polymers (that have tensile + multi directional strength) is currently too expensive for most mainstream 3D part producers

 @MadInventor is also spot on re the tolerances of most consumer machines being approximate if stressed - to rob an aero mantra ... its bling not wing 👍

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11 hours ago, catman79 said:

hi, if you add a picture of the gear you need, i might have a used one you can have, and im in the uk. 

Hi mate. Thanks for this

Screenshot_20200704_002050_com.android.chrome.jpg

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11 hours ago, catman79 said:

hi, if you add a picture of the gear you need, i might have a used one you can have, and im in the uk. 

Need this one aswell.  I already have the yellow part.  Thanks

kyosho-ot-86-ot86-counter-gear-optima_1_202915d8f1a84d3f422a877b33d88eb5.jpg

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3 hours ago, SuperChamp82 said:

Unless you’ve access to aerospace (or top end automotive) 3D rigs you’ll end up with an explosive mess - that will likely do more damage than swapping what’s left of the gear ?

Layering complex polymers (that have tensile + multi directional strength) is currently too expensive for most mainstream 3D part producers

 @MadInventor is also spot on re the tolerances of most consumer machines being approximate if stressed - to rob an aero mantra ... its bling not wing 👍

Was thinking about the ones from shapeways

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I have 3D printed a gear for my Kyosho Rocky and it has held up fine, though I'm not too rough on it.  I created it in Blender and printed it at Shapeways using multijet fusion plastic.   The multijet fusion plastic is quite strong and durable.  The 3D printed gear is perfectly round with no distortion in the teeth.  I made sure to orient the part so that the gear laid flat on the X-Y plane so the teeth were built up on the Z-axis.

The hardest part was getting the dimensions correct.  I used software called eMachineShop to create a 2D mesh of a 32p gear with the proper tooth shape (curved; not just straight sides on the teeth), then imported it into Blender and made it 3D.

While the mesh in Blender showed perfect dimensions that matched the original Kyosho gear I used as a template, when I printed it at Shapeways the 3D printer wasn't perfect in how it produced the part.  I totally expected this, so was not surprised at all.  I was curious how close the gear would be to the original .  The gear I created ended up being too small, both in total X-Y dimensions (due to the teeth being in this plane) and in tooth size and shape.  This is partly because the 3D printer is only accurate to within 0.1mm and mostly because the plastic shrinks slightly after cooling off from the laser sintering process.  So many small protrusions (teeth) around the outside of the 3D printed object results in a lot of shrinkage.

Messing around in Blender and spending more $$$ getting multiple gears printed with different dimensions that increased by 0.1mm (!) each in various ways (total X-Y-Z dimensions and also tooth shape/thickness), I was able to finally get a perfect (as much as 0.1mm resolution can muster) 3D reproduction of the Rocky front gear.   While the mesh in Blender looks like the gear needs to go on a diet, the resulting 3D printed gear is a perfect fit.  It took a LOT of work to get it right, so it really only makes sense for me to create gears that absolutely cannot be bought any longer.

image.png.8e37d9e1a8c32b232436525c9b277c45.png

Due to my personal experience in creating and testing a gear made by Shapeways, I don't know if I would buy someone else's gear that they put into their Shapeways shop unless I knew they had done proper testing of their design.   I say this because if they have never personally printed and tested fitment of their creation, then the gear you receive may be totally wrong in size and a waste of money.  So unless these guys that have gears for sale in their shops know a secret (or software/process) that can account for the 3D printer shrinkage, or have spent money on test fittings, I wouldn't trust them.   No offense, but how do I know if the gear for sale is actually EXACTLY the right size?  All of the sellers of gears that I've seen on Shapeways make absolutely no mention of how they test-fitted their design to ensure it is exactly the right size.

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1 hour ago, Champ85 said:

I have 3D printed a gear for my Kyosho Rocky and it has held up fine, though I'm not too rough on it.  I created it in Blender and printed it at Shapeways using multijet fusion plastic.   The multijet fusion plastic is quite strong and durable.  The 3D printed gear is perfectly round with no distortion in the teeth.  I made sure to orient the part so that the gear laid flat on the X-Y plane so the teeth were built up on the Z-axis.

The hardest part was getting the dimensions correct.  I used software called eMachineShop to create a 2D mesh of a 32p gear with the proper tooth shape (curved; not just straight sides on the teeth), then imported it into Blender and made it 3D.

While the mesh in Blender showed perfect dimensions that matched the original Kyosho gear I used as a template, when I printed it at Shapeways the 3D printer wasn't perfect in how it produced the part.  I totally expected this, so was not surprised at all.  I was curious how close the gear would be to the original .  The gear I created ended up being too small, both in total X-Y dimensions (due to the teeth being in this plane) and in tooth size and shape.  This is partly because the 3D printer is only accurate to within 0.1mm and mostly because the plastic shrinks slightly after cooling off from the laser sintering process.  So many small protrusions (teeth) around the outside of the 3D printed object results in a lot of shrinkage.

Messing around in Blender and spending more $$$ getting multiple gears printed with different dimensions that increased by 0.1mm (!) each in various ways (total X-Y-Z dimensions and also tooth shape/thickness), I was able to finally get a perfect (as much as 0.1mm resolution can muster) 3D reproduction of the Rocky front gear.   While the mesh in Blender looks like the gear needs to go on a diet, the resulting 3D printed gear is a perfect fit.  It took a LOT of work to get it right, so it really only makes sense for me to create gears that absolutely cannot be bought any longer.

image.png.8e37d9e1a8c32b232436525c9b277c45.png

Due to my personal experience in creating and testing a gear made by Shapeways, I don't know if I would buy someone else's gear that they put into their Shapeways shop unless I knew they had done proper testing of their design.   I say this because if they have never personally printed and tested fitment of their creation, then the gear you receive may be totally wrong in size and a waste of money.  So unless these guys that have gears for sale in their shops know a secret (or software/process) that can account for the 3D printer shrinkage, or have spent money on test fittings, I wouldn't trust them.   No offense, but how do I know if the gear for sale is actually EXACTLY the right size?  All of the sellers of gears that I've seen on Shapeways make absolutely no mention of how they test-fitted their design to ensure it is exactly the right size.

Strictly speaking you should be adding shrinkage in the software when 3D printing to fit existing parts = just the same when you design injection mould tools.

When I design a injection mould tool the first step is add shrinkage to parts so you actually machine bigger. Same goes when I have had 3D printed parts that needed a decent fit, shrinkage was added before we sent it to our printers.

You would expect Shapeways to add shrinkage or ask if you want shrinkage adding but who knows, I have never used them.

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23 hours ago, catman79 said:

hi, if you add a picture of the gear you need, i might have a used one you can have, and im in the uk.

Catman79 any joy?  Thanks

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Hi not yet, I’ve found the box with the gearbox casings and a few other bits, but not the box with the diffs and gears yet

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On 7/3/2020 at 12:29 PM, catman79 said:

hi, if you add a picture of the gear you need, i might have a used one you can have, and im in the uk. 

Hi again mate. Did you get the pics

 

Thanks

 

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18 hours ago, catman79 said:

Hi not yet, I’ve found the box with the gearbox casings and a few other bits, but not the box with the diffs and gears yet

Thanks for looking catman79. My fingers and toes are crossed that you find the box. 🤞🤞🤞

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Interesting thread guys 

For me, unless you know the chemical (so directional / torsional) strength of the material / polymers you’re layering, design maths will only take things so far 

Otherwise it’s Formula 1 Lego made of jelly 

To be fair, the tolerances may not matter to most at our scale but I’d suggest none should expect things not to go bang 😇

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Right now, I'm testing 3D printed gear in my MF01X, printed from PET-G on FDM printer with 0.2 nozzle. I had time to run only 1 pack, but it survived so far.

It seems that 0.8 gears can be printed with reasonable detail on FDM, they mesh properly with original gears. I plan to test 0.6 and also printed-to-printed in future.

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If you have a really big wallet burning to spend money you could go for direct metal laser sintering. It's not cheap, on a rare occasions I have used them on injection mould tool designs. It's down to 0.02mm layers these days but the price goes through the roof at fine layers.

Believe it or not back between 1997 to 1999 (can't remember the exact year) I was working for a company which I designed the BMW mini headlight prototype injection mould tools. We got made tiny inserts in the tool using direct metal laser sintering - over 20 years ago!

https://www.protolabs.co.uk/services/3d-printing/direct-metal-laser-sintering/

 

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