Improved X ends for Prusa with clamped rods
Derived from
Description
Prusa's snap in LM8UU holders have one huge problem: motor- and idler-mount are supported via those holders, so the whole holder can twist unevenly and warp the bearings agains each other. This is avoided with my design.
The rods are fixed using one screw for each, tightening the built in clamps. Their screw heads are easily accessible from below and there are nut traps at the top. I made open end rod holes, to be able to push the rods all through. The system achieves a rock solid fit AND easy adjustability - what else you should need?
The leadscrew nut trap uses two bridges inside instead of a circular hole, so there's no "post-print-processing" (i.e. drilling) necessary in this point.
The design is entirely parametric, so you can even use professional leadscrews like trapezoidal ones with bigger nuts. I additionally attached STLs for use with metric trapezoidal leadscrews TR8x1.5 and nuts of 17mm wrench size (15mm height). For standard Prusa requirements use the "threaded rod" files.
Instructions
The STLs are generated for 0.25mm layer height - change the parameter in OpenSCAD for your needs.
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Hi, great job, but how i can print that, with or wihout support material? abs, pla? fan? regards!
Fantastic! Both X ends and Jonas's X carriage printed. Everything fits like a glove. Many thanks Jonas!
Can you explain how the leadscrew nut is retained? Is it simply friction or is there a mechanical component. Does the design require multiple leadscrew nuts or a single nut on each side. Thanks for a nice design.
Jonas, Thanks!just printed those, any idea as to the distance between x-ends on a prusa i2? Thanks again!
I'm still printing this, but these very thin bits in one part of the idler... I'd say they're a minor bug. They don't print cleanly and aren't structurally useful.
Would it be a huge job to allow for 12mm x and z smoot bars?
In these and yours x Carraige?
How would I go about it?
Thanks.
Just a short update of my notes concerning those spindle nuts:
They do still sell hexagonal TR8x1.5 nuts with 17mm wrench size as I wrote in the thing description. Only their square nuts have changed to 18mm, but you an still get the nuts I made the STLs for!
Great parts Jonas. Where did you get the spindles? Was it in Europe? All I have found is quite expensive.
Is anyone using this with 32mm OD GT2.5 Pulleys? I don't think they work with this motor end...
I found you have to sand down the edges of the pulleys a wee bit, or else do the same to the interior of the motor holder arm.
I tried to, but found the same thing.
I haven't had much luck in general with any x-ends that have the motor hanging off the back.
Using the idler end though and I like it a lot so far.
Do you only use one screw at the bottom with these or do you use a second one with springs on the top? Im concerned about that the springs will have problems with only the bridges inside the nut trap.
I use two spindle nuts for each x-end with springs and put an additional washer on top of the bridges before applying the springs. The necessity of a washer depends on the spring diameter - if the spring is only little wider than the spindles, a washer might be beneficial.
Hi Jonas, Like your improvements but would it be dificult to adding an end stop like greg's then they would be perfect :-) Thanks.
Hi Typhoon, thanks for your compliment! So sorry, I'm quite buisy at the moment working on several projects that eat all my development resources :-) Btw. I heavily recommend switching to hall-o endstop for z homing and really comfortable endstop finetuning via potentiometer! No more complicated mechanical/optical endstop adjustment, all you need to do is glueing the little magnet underneath one of your xends and you're ready to go... See http://ikmaak.nl/eenblog/2011/...
Looks great! I am getting the following errors, which is preventing a successful render in OpenSCAD.
WARNING: Ignoring unknown module 'roundcorner_tear'.
WARNING: Ignoring unknown module 'teardropcentering_half'.
WARNING: Ignoring unknown module 'roundcorner_tear'.
WARNING: Ignoring unknown module 'teardropcentering_half'.
WARNING: Ignoring unknown module 'roundcorner_tear'.
Am I missing some de
pendencies? I have all the .scad files you provided here in the same folder.
Jonas, could you please elaborate (or point me in the proper direction) for what you mean by "a properly calibrated machine". I'm very interested in these parts as well as the
&
lt;50mm bridge prospects. Thanks for these awesome upgrades.
I totally switched to slic3r since it was released as version 0.5.7 (it's at 0.7.0 at the moment) and achieved brilliant results. Calibration and adjustment is REALLY simple, compared with skeinforge etc.
If you'd like to give it a try, I explicitly recommend RichRap's trilogy "Slic3r is nicer" which you can find here: http://richrap.blogspot.com/20...
Follow his guide for your first steps with slic3r and I'm sure you will earn awesome results within days
..
If your printer works as intended and extrudes as intended, even long bridges come out easily. At least you will have a good starting point for further tweaking to even get the best quality possible out of your machine :-)
you've really done them with Slic3r? How did you get the clamps printed - wouldn't you need Support material for it?
I currently got a 0,5mm nozzle only and PLA but i'd like to give it a try. Just wondering if could really do that with slic3r cuz i didn't see any support structure for the top of the motor mount and the clamps. Would be a bit too far distance for bridging wouldn't it (still rather a newbie :))
Good -and much needed - job!
The only part that might be missing is moving the X axis motor center of mass back where it belongs, in line with the X axis instead of cantilevered.
The other background question: with a properly squared machine and well calibrated prints, one shouldn't be in need of so many springy parts. Any particular reasons?
I sticked to the x-motor position since overall stiffiness of the x ends was more important to me than balance of weight. The x motor itself doesn't perform fast movements despite of little z elevation and possibly retract-lifting via slic3r..
The previous position inline with the x axis gives less opportunities to support the mount beefy enough, I found. There ain't too many possibilities for the motor mount at all at least if one would like to stick to the prusa belt lineup, tried out various on my way :)
(Might be time for vertical x axis....)
I didn't get the point you asked with springy parts, could you please specify your question? Thanks in advance ;-)
Thank you i really hate zippy ties
you must be really patient ,,ie wot kind of print time are you getting.
and how much fill ?
Print time should be comparable with standard Prusa v2 x ends.. I use 25% rectangular infill (slic3r) for ABS and I have pretty rigid results. The rod clamp design doesn't depend much on a special infill level and all parts that should come out strong but flexing are rather thin, so most infill values lead to nearly solid infill in these parts anyway (rod clamp, lm8uu clamp). 25% is good and strong, you shouldn't need much more than this.
Oh and I use a 0.35mm nozzle, 0.25mm layer height, 3 solid layers and 3 perimeters.
These look really good. I think I may have to make a set of these for my Prusa :) Nice design
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