What to calibrate next?

Hey all,

I have an original Mendel with a .40 mm extruder. The past few days I have been tuning and tuning trying to get a really good print quality. At this point I have so many parameters in my head I think I may be getting lost. Here is what I have:

Repetier Host 1.5.3
Cura slicer

X Axis steps calibrated
Y Axis steps calibrated
Z Axis steps calibrated

Infill shell 1.2 mm
Top and Bottom layers 1.2 mm
Infill overlap 0%

PLA at 205 degrees

I've mainly been playing with Temperature and Extruder Steps to try and make this better. I'm hoping someone can take a look at these pics and let me know which direction to go. The three main problems I see are:

1. Squishy corners


2. Bulges in the shell where the infill meets the shell


3. General uneven layers


Many thanks!

I think you are over extruding, and the temperature is too high. Calibrate the extruder steps/mm the standard way, then either adjust the extrusion factor in your slicing program, or use the extrusion factor control in the user interface (or the M221 command if there isn't one) to adjust the extrusion to suit the filament you are using. Reducing the temperature to about 195C should reduce the stringing.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Thanks for the reply.

I've actually gone back through the whole machine both hardware and software and rechecked everything. I was quite a bit more scientific this time around. I have also switched over from Cura to Slic3r. I have performed 17 test runs so far to try and dial the machine in. There is one persistent problem throughout that I can't seem to get rid of no matter how hard I try.

The test subject is this simple square. 20 mm on the outside, 10 mm on the inside, 5 mm high



The results of my testing are depicted below:



Perhaps you all can spot the common theme? No matter what I change the infill refuses to connect solidly with the inner walls of the object.

If a kind soul could take a look at my spreadsheet and review what I have changed throughout the testing I would greatly appreciate it. I feel like I'm so close but I can't get over the last hurdle.

Mendel_Test.ods
Mendel_Test.xlsx

I've printed in temperature ranges from 195 to 160. This kind of makes me scratch my head as well as the lower limit for my filament is supposed to be 190. Maybe my thermistor is off? At 190 I definitely get stringing between features so I took that as a cue to go lower.

The only relevant (I think) settings I haven't messed with yet are:

Changing my nozzle diameter to something other than what it is supposed to be (.40 mm)
Changing the Extrusion multiplier

I suppose I could just keep increasing Infill/perimeters overlap until I force the infill to connect, but that doesn't seem like the right solution. I'm afraid it would start negatively affecting the outer walls where the infill is already connecting. Maybe I'm wrong.

Perhaps now that I have things dialed in a bit better I'll give Cura another shot as well.

Thanks in advance for anyone willing to dive into my test documents.

Just for kicks I went over to the Slic3r area to see if anyone was having the same problem as me. It seems people are struggling quite a bit with 1.2.9 stable. I went ahead and switched over to 1.2.7 and loaded all of the same settings. Sadly this was not the magic fix I was hoping for. The issue remains.



Edited 1 time(s). Last edit at 07/23/2015 03:30AM by icius.

I've noticed you've set infill overlap to 0% in cura, it should be 15%. If you did the same in slic3r then that's probably causing it. It's the overlap between infill and perimeters. Slic3r can be a bit troublesome to get the perimeters the way you want them. Play with the advanced settings extrusion width to avoid gaps in perimeters.