(fair warning: I work for a 3D printer company [Type A Machines])
I thought this cross-posting up on the RepRap forum would be useful here.
Summarizing that post:
It is possible to 3D print LEGO-compatible parts on desktop 3D printers, but with caveats:
The fit will likely never be as tight as real LEGOs. Those are tough tolerances to match. LEGO Corp ...
I found CAD files for LEGO technic axles here: https://grabcad.com/library/lego-technic-axles-1
and some gears which have holes for technic axles here: https://grabcad.com/library/lego-technic-gears-1
Using their online viewer I found the following dimensions (Which are a little inaccurate due to the limits of their online viewers tools. For more accurate ...
LDview can directly export LDraw files to .STL. But the problem is that the mesh obtained may not be suitable for 3D printing, many of LDraw parts are not "watertight", or contain surfaces inside the part volume (eg. studs are simply lain on flat top surface).
Depends on your tolerance. :)
In the manufacture of LEGO bricks the machine tolerance is as small as
10 my (0.01 mm).
Source: Company Profile. An introduction to the LEGO Group (2010)
For me, 3D printing resolution would need to be pretty close to that.
According to WikiPedia:
The moulds are permitted a tolerance of up to two micrometres, to ensure the bricks remain connected.
But, as I noted in a comment, that is in an industrial environment, where great care is taken to ensure that not just a one-off piece is right, but that the entire batch of pieces is right. They probably take a six sigma approach ...
First, some notes:
LEGO Digital Designer cannot do 3D printing.
LDD won't get any new features any time soon, as it is no longer being updated.
LXF files contain no part meshes. They only contain information on how to assemble the parts. The actual part data is stored in binary files inside the various LIF files.
LDraw files are similarly structured like ...
You can't directly export from MLCad to the .STL format that the Makerbots require, but there are workflows you could probably set up.
MLCad doesn't really have many export options, so you're better off using something like LeoCAD which can read .ldr files from MLCad, and export as other formats.
Using LeoCAD, add the part you want to print to the scene.
The canonical location for 3D models of LEGO bricks would be LDraw, with its huge catalogue of official parts.
Another resource specifically catered to the 3D printing community is PrintABrick. Their library is not as big as LDraw's, but they offer ready-to-print STL files.
The tolerance of a LEGO brick is 10 micrometers, while most customer-grade 3D printers are orders of magnitude worse than this, according to this site. The best I see there is 25 micrometers, which is still 2.5 times.
I'm in no way a 3D printing specialist and haven't used any tricks to enhance my print quality as I haven't printed any bricks ever, but I've ...
There have been various questions asked here previously regarding 3D printing, with very mixed results. Here is a link if you are interested in the responses to those questions.
The experience you are looking for to answer your question is slightly out of the scope of what we ...
I have actually tried 3d printing lego on a prusa i3 printer at I think 5 microns using PLA. I found that they worked fine initially but they quickly started to lose their grip. I think the issue was the layers grind against each other which wears them down rather than the brick walls flexing to grip. You certainly won't be getting anything close to the ...
Look here: http://www.thingiverse.com/tag:LEGO
But be aware- as a single person manufacturing a LEGO compatible item, you might be open to litigation. You would probably win, but winning very frequently bankrupts people either way. Do you really require a unique piece that LEGO does not make? There are many custom sets around that are a kit of LEGO ...