Thinking about getting into 3d printing lego.

[Mechbuilds]

Hi guys! 

I'll be getting my tax returns on august and was thinking about purchasing a 3d printer. I would mainly 3d print custom lego pieces that lego doesn't have to offer. (Or rare discontinued parts) 
Currently i'd like to custom print front and rear axles for my 4x4 lego truck. The problem with original lego pieces are massive bending and studs loosening to the weight of the model. 
I'd rather 3d print a custom axle and let that bend instead of harming real lego parts. (Currently i have my model on a stand to save any lego parts from bending.) 

So, what 3d printer should i go for? What filament is best for technic based creations? 
I want the 3d printer to be small and cheap but still a good enough buy to invest in. (2-300 euro range) 
(I can also buy and assemble a kit)

Any tips and tricks would be great too!

[splatman]

If you have not already, ask on a 3D printing forum. You will probably get better answers there.

[jimmynick]

Frantisek Hajdekr over on Flick designs and prints custom parts quite frequently - he might be a good person to get in touch with.

[dr_spock]

Sounds like you're putting a large load on the axles.  3D printed parts may not perform any better for your particular application.  Perhaps 3rd party metal axles? 

A strong plastic is nylon but can be difficult to 3D print. PLA is an easy plastic for beginners to use.  It is stiff and doesn't have same flex as ABS.

If you like tinkering and troubleshooting, then a kit printer can be fun.

[MAB]

^ This. If you are bending official LEGO axles in your design, then don't both making your own from plastics used in 3D printers. Go for something metal. There are some supplied of lego compatible axles, although not cheap.

[ShaydDeGrai]

If your designs are really stressing official (injection molded or extruded) pieces, I'm skeptical that most 3D printed plastics would offer any better performance.  Like dr_spock and MAB, I recommend looking into metal alternatives (either find a third party stock item or make friends with someone at a university with a mechanical engineering department - a CNC or milling machine could easily turn an aluminum or steel rod into a suitable replacement for a technic axle in just a few minutes).

If, on the other hand, you want to explore the more general question of designing and creating Lego compatible parts with a 3D printer, you might want to see if any schools, youth clubs or libraries in your area have "maker spaces."   Where I live, this is the latest trend in keeping libraries relevant in the age of Kindle downloads and these maker spaces often have computers with design software, 3D printers, and people to help you get started.  One place near me has a free sign-up (with a max time usage per session if there's a queue) and only charges (by weight) when you actually print something out.   I've been using this as a way to check out different machines, software and materials before I commit to buying my own device.

Also, my procrastination/indecision when it comes to buying my own printer has turned out to be a good thing.  The machines keep getting better, smaller and more affordable, so taking your time finding the solution that works for you is not a bad thing.

 

[corasaur]

Most 3d printers aren't gonna match the tolerances of standard legos. I'm curious how 3d printed studs will compare to regular lego clutch power. will it be indistinguishable to human eyes? feel like when megabloks got stuffed into a lego bin as a kid?

And if you want an axle more rigid than lego out of 3d printed plastic you'd probably need to get a high-end printer with proprietary plastic. you might be able to find metal rods of a diameter close enough to work so they wouldn't need turned down, and then would only have to find a way to chop them to length. Or you could just be prepared to view your 3d printed axles as consumable.

a relative does own a 3d printer that was in the 200USD price range and is having fun with it. i'll figure out what model it was and post it here later.

Source: using 3d printers at work. researching purchases for home use.

[BubbaFit45531]

From my limited experience having someone else 3D print a few simple things, there are problems with warping and shrinking upon cooling that could hinder precise fit. 3D designing a part can be difficult enough. Probably needs a bit of trial and error.