(1st print) Issues with overhangs
Hello everyone,
I had another Prusa i3 before (Rework), but it was so inconsistent and I didn't want to loose 90% of the time to re-calibrate it. No I got my Original MK2 and just did my first print. It didn't come out quite as good as I would like it to be.
Printer: Original Prusa i3 MK2 (from this week)
Firmware: Firmware 3.0.6-RC2 (July 27, 2016)
Print mode: silent
Filament: Blue PLA from Prusa (recomended 190-210°C)
Nozzle temp: 210°C
Bed Temp: 55°C
Model: Marvin gcode on SD card (seems to be from 10th June)
Layer resolution: 100µA
Print time: 45min
I did the X/Y calibration (great job on the software btw!) and the Z-Calibration. As the P.I.N.D.A. was in the middle of all circles I then printed the V2calibration.gcode and adapted the Z-value.
I'm not sure, what the problem is for this one. As the parts without overhang are looking really nicely, I would think, that the cooling is the problem, but the fan was on the whole time (after the first layer). (how can I upload the .gcode? It always says "invalid file extension"?)
Re: (1st print) Issues with overhangs
Hi Steven
To upload GCode (and some other files) you have to zip them up first, then drag the zip file to the message box.
To me, it looks like there are 2 issues with your print, namely over-extrusion and temperature.
There is also a third issue that you may experience when slicing your own models. You also say that the fan was on from the first layer. Is it running backwards?
All printers are different and being used in different environments with different filament, so ideally you need to calibrate the extrusion.
Load some filament and mark the filament 110mm above the entry to the extruder. Using Pronterface (or similar) extrude 100mm of filament and measure from the top of the extruder to your mark. If it is calibrated correctly, there will be exactly 10mm between extruder and your mark.
You can then calculate the required steps/mm (default is 161.3) and set using GCodes.
Many people are experiencing a hot summer at the moment, if you are one of them, it may be affecting your prints, and you may want to lower extrusion temps by maybe 10 degrees.
Currently, 3.0.6 RC2 has a MIN_Z value of 0.2mm and the pre-sliced files have a first layer of 0.15mm; this causes over-extrusion in the second layer but if you calibrate to them and then slice your own models with a first layer of 0.2mm, you will then have over-extrusion on the first layer.
Hope this helps.
Peter.
P.S. Google will assist with things I have not fully explained.
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: (1st print) Issues with overhangs
Arg. Okay, I was wrong, my print-fan was not enabled. The cable was not properly connected.
(Perhaps something that could be included in the self-test? Like power the fan and ask "is the front-fan turning?", same for the extruder-fan)
Temperature wise I will test lower temperatures on sunday.
For the extrusion: The problem seems to be over-extrusion, but infact I have under-extrusion. 9cm extrusion command only extrudes 7,35cm. I will adjust the feed-rate in the config accordingly.
Could the problem be (apart from the fan, that was my pretty stupid mistake ^^) that the model has an extrusion width of 0.45mm? I added the model I used as an attachment.
/Edit: Tried again: with print fan on, 200°C and 200% print Speed, came out beautifully! Didn't think that the fan can change this much!
Re: (1st print) Issues with overhangs
Steven
OK, great. Now forget everything else I mentioned, and get on with the printing. Do not make any adjustments to the printer.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…