Janz mk I
This is my first take at designing a 3d printer .
This design is based in the Lautr3K http://www.openbuilds.com/builds/lautr3k-reprap.379/
I had to redraw some of the parts because I couldn’t find the leadscrews used in the original build, so I ordered the 10x25 fast leadscrew from Igus for th x/y/z motion axis.
When I’m done I’ll post the sources at openbuilds.
IMHO this is a very bad delta design.
To be serious why don’t you use belts? A leadscrew is an overkill for a printer where the forces are negligible compared to a CNC machine.
because it will make some light mill too, why do you say its a very bad delta design? I’m interested in your input!
Are you really planning to rest the z-axis on the motor bearings? This might be acceptable for very lightweight printer constructions, but the motor bearings really are only good for radial forces. Especially if you plan for milling you should put a radial and axial bearing at the top of the construction so the weight of the whole X assembly is hanging from it. The motors should not carry any axial load. The same goes actually for the Y axis, you should at least use a belt to drive the y thread.
You will also find that just having two extrusions for all of the Z frame is not enough to stabilize the setup. You will need either much wider pillars that can take the angular forces, or use a double A frame like the original Mendel.
thank you for your input, this is WIP, but still take a look at the link I posted, the lautrek printer. I’m only redesigning the bearing holders to fit the IGUS nuts the rest is all the same except the T union of the base to the Z witch is in metal and have some metal cast 90º brackets , the z thread is 10x2 (http://www.igus.com/wpck/6135/DryLin_Trapezgewindespindel?C=US&L=en) won’t put any weight at the motors, like the traditional prusa z rod.
I understand your point about the load on the motors, but it might get more sense to invert the motors and place the bearings in the base right?
Have you tried the IGUS threads yet? I only have a small sample of that here and the nut is VERY tight on it. You will need a lot of motor power to turn it. Also the spindle will weigh just as much as any other threaded rod, only the nut is a bit lighter, due to it being made of a nylon variant. The 20mm extrusion is borderline for any kind of milling, it is just not stable enough for that.
Placing the bearings at the base will put pressure on the threaded rods. This is ok if the rods are fairly thick and the force small. If however you use small rods (or soft material) and a heavy load they will bend over time and introduce some serious z-wobble. By hanging them you avoid the problem from the beginning.
I do have some samples here too, the nut for the z rod does have backlash so its very light and smooth on the rod, the x/y nut haves anti-backlash spring but its also very light and smooth, not as smooth with backlash http://www.igus.de/wpck/11091/N14_13_1_dryspin_ZeroBacklash_Gewindemutter?C=LB&L=en.
I really don´t understand how to properly hang the rod, can you post a quick scketch?
Check this album https://plus.google.com/u/0/photos/106179733123702088243/albums/6096353473103392001 i just added a couple of shots of the setup from my latest build
I would make a suggestion: when displaying your design, in the program, use perspective view mod (rather than parrallel).
I don’t know what command you would use for that – but you get a clearer view of your model, where everything looks squared-up (and not distorted, as it currently does).
Looks like FreeCAD… Cool! To set the 3D view in perspective mode, just press “P”. “O” will set it back to orthographic mode. Or you can go to the View menu. And if your graphics card is up to it, you can activate anti-aliasing in Edit --> Preferences / Display / 3D View. I use MSAA 8x myself.
But contrary to what William wrote, perspective view is not “squared-up”, it’s actually quite the reverse. Orthographic projection is quite valid and is how most designers work all the time because the view is not distorted.
@Normand_Chamberland I wan’t talking about perspective vs orthographic.
I was talking about a parallel view.
In Autocad(2013) you have orbit view (which can be parallel or perspective) and if the view is in parallel mode – then the model can be slightly distorted when moving around the orbit.
And the picture of the model, would look like that, in Autocad’s parallel view.
Man, read again your comment, you wrote “perspective view mode”. I have no idea what parallel view is. I haven’t used AutoCAD in years. This screenshot is from FreeCAD and it is clearly an orthographic projection.
Orthographic view is a special case of parallel view. Both keep the length of edges regardless the camera distance, different to perspective view. Don’t get to hung up over such technicalities, any kind of paarallel view is ok for technical modelling, for presentation purposes i would prefer perspective.
@Bjorn_Marl Yeah, that’s what I was trying to get at…(for presentation)
It is freecad, I’m still learning how to use it. I did the assembly wit Assembly2 module, but most of the positioning was done by hand !!!
