Unanswered Robo Calibration for tight part fitment!

Hello everyone! I need help with my Robo, I started working on putting together a little laser engraver which uses DVD drive mechanisms to move object and laser around. Very cool project!http://www.thingiverse.com/thing:902826 . After printing all parts out it turns out that none of the parts fit together. But that's only in my case, it works great for everyone else. I've read up on it a little bit and it has something to do with the shell thickness and XY ratio or whatever. I spent hours filing the parts to get them to fit and I thought that instead of dealing with the problem it's time to solve it! Did anyone of you encounter such problem? It looks like everything relating to Z the axis is alright, but the wall thickness is larger that I want it to be. Distances between holes and etc. are alright, only the walls are too thick. They're nice and smooth after z rod upgrade and extruder calibration.

 

Until now I thought that my printer was calibrated. I mean, I successfully printed the 20x20x10 cube with spot on measurements +\- 0.05mm, calibrated the extruder, got the right temperature for the filament and I got rid of the z ribbing.

Speaking of the slic3r, where is this feature located? I'm using cura for the last few months, I don't know if there is any way to change that setting in cura. Neither is using other slicer than cura's in cura software, is it?


Sent from my iPhone using Tapatalk

 

They were all PLA, same manufacturer but different colors


Sent from my iPhone using Tapatalk

 

Approximately 0.35mm too tight on most of the parts.


Sent from my iPhone using Tapatalk

 

don't get me wrong, I love my Robo and I'm very happy with how it prints, it just seems that for whatever reason the walls are thicker than what they're supposed to be. I'm looking for rather a software solution that would help me loose that 0.175mm on each wall, given a light error on both parts and the tolerance that was counted for by the designer is lost. The sides of the prints are very smooth and consistent. Probably if I owned the software I'd be able to increase the tolerances but I don't have any CAD software that would allow me to edit the project.

 

for the last few months I was using Cura, I'm not really familiar with any other software. I used matter control for a day or two but it didn't work for me.

 

I use Cura (15.04.4), could never get MatterControl 1.4 to even launch without crashing and wasn't that happy with Slic3r 1.2.9 when I tried it (lots more controls, but couldn't get the quality as good a Cura was with much less tweaking).

WIth my R1+Plus I found the outer dimensions were dead-on, X Y and Z (I printed a 100x100x100 calibration axis from Thingiverse and every axis was within 0.1mm on my calipers). However inside dimensions are an issue, so things like making a peg to fit in a hole was tricky. My experimentation has shown that with the 0.4mm nozzle at least, I basically have to subtract 0.4mm from the diameter of a peg (or add 0.4mm to the hole diameter) to get it to fit. This goes for any shape peg I tried, circular, square and triangular. Same for screw holes as well (I used the "polyhole" concept in OpenSCAD, but still had to do an extra 0.4mm adjustment to get the holes to be the proper size). With the combination of polyhole and a 0.4mm adjustment I was able to print every hole size from 5/64" to 3/8" and fit my entire drill bit set perfectly into each hole. My test print was able to be oriented with the holes vertical, horizontal and at a 45° angle and the fit was right in every case.

I'm assuming the 0.4mm adjustment on the 0.4mm filament width isn't a coincidence, and if I printed with a different nozzle size I'd have to adjust the peg/hole size adjustment the same amount, though I haven't tried changing nozzles yet. It seems that Cura just doesn't make the adjustment for inside dimensions vs. outside dimensions on its own, where it sounds like other slicers can. But the amount it was off by appeared to be the width of the nozzle at least in all of my testing. Or perhaps more specifically half the nozzle width on each side, so assuming the opening is a full surround it's a full nozzle width expansion from wall-to-wall.

 

I think that 0.4mm is just a coincidence, but I don't undermine your opinion, maybe there's some connection between these. Perhaps the software generates an extra perimeter or something that is the width of the nozzle. I wish I was able to edit the files to change the tolerances, but files were generated used some advanced CAD software. I will try running repetier host with slic3r. If I remember right, last time I tried it, I couldn't get the slic3r to slice the file, maybe I didn't set it up right in Repetier Host.


Sent from my iPhone using Tapatalk