Parts 0.3mm oversized.
Kossel Delta Printer
0.4 nozzle
PTEG with 230 degrees
e3d hot-end
Fresh Marlin RC
Cura
Hi printers,
all my parts are a bit oversized. X and Y are 0.3 - 0.4mm too big no mater what size they are.
Calibrated the extruder and fiddled around with the flow rate. Does not solve the problem. The parts have gaps if they have the right size.
Played with the DELTA_DIAGONAL_ROD setting. Does not solve the problem. Because the overall Scale was right with the default settings.
The Problem seems to be somewhere else.
Setting „Line With“ way below the nozzle diameter makes it a bit better but that does not feel like the right way.
Any ideas would be appreciated .
If you have already calibrated extrusion lengths and flow rates it is very likely you are dealing with the thermal expansion properties of the filament. If the error is consistent for all prints in all axis that at least you have determined that you have stable filament. What settings in Cura for the filament diameter are you using? If it is just the measured diameter then you are only half way there.
I use a system for calibrating my filaments for precision assemblies that works really well as it accounts for both the physical and thermal properties of the filament. The only two things you adjust are the temperature you extrude at and the compensated filament diameter. Everything else is mechanical and left at the calculated values.
You determine the right temperature by how the filament flows out of the nozzle. You want a smooth extrusion with no pig tailing (too cold) or spider webbing (too hot). Once you dial in on a good temperature you are generally +/- 5 C of an optimal temperature.
Then, I start with the measured diameter of the filament and use this simple printed clip system found here: http://www.thingiverse.com/thing:1037301
Print two clips with one rotated 90 degrees from the other. Flip one of the clips upside down and snap them together When the clips fit together and are not too loose (Filament size needs to be smaller) or too tight (filament size needs to be larger) then you have that particular filament dialed in and compensated for both it’s dimensional and thermal properties.
Always print the clips with at least two outer shells. If there is a small gap between them yet the clips fit together snugly then bump your temperature by 5C and the gap will generally close.
Then I print an accuracy block with different dimensions on all the axis to verify dimensional stability for mass. http://www.thingiverse.com/thing:1616694
I do this calibration process for each spool of filament (and each nozzle size) and write the results on the spool. When I use that spool for a print I put those settings into Cura and can pretty much guarantee that I get a precision print.
If you decrease the size of the nozzle the temperature will generally need to be raised and the filament diameter will need to be set larger.
For example I have a grey filament that measures 1.76 average but I print at 1.72 and 195 with a 0.4mm nozzle that when used with a 0.3mm nozzle needs to run at 1.82 and 210. Clips printed with each nozzle are interchangeable and fit together easily with no visible gap.
Hmm, that came out longer than I expected so don’t be deterred by the amount of words above as it is really quite easy to do. and generally does not take more than 1 - 1.5 hours to calibrate a roll that will be used for a long time.
Hope this helps.
@Jeff_Parish is right. I have the same problem with PETG, over large prints. When I use the same settings ( aside from temperature ) with ABS, I get perfect parts.
https://www.deltarap.org/printing-undersized-holes/
This gentlemen has also written a view things about it.
@Jeff_Parish Thank you very much for you long answer. I will go trough every point and provide you feedback.
