I seem to have a size issue, filament expansion or something, 4mm hole in CAD is coming out around 3.5mm. Externally the round part is 16mm diameter in cad and printing at 15.7mm. Suggestions? Anyone got a good link to a guide for tuning for this type of thing? printer was working well, was getting .1-.05 variations before now it seems to have gotten very bad.
Check filament diameter and extrusion steps per mm first. If that’s all good you’ll have to check each motor axis. It may be possible that your power supply is failing and not giving enough power to your motors, although usually you’d have skipped steps and shifted layers. I guess unless its a delta.
- find the correct temperature for bed and extruder (print the temperature tower and see at which point it actually layer adhesion is the best).
- print the calibration cube without top or bottom layers, 0 infill, 3-4 external perimeters and change the extrusion multiplier to the point that the actual width of the wall matches 3 or 4 times the extrusion width you have set - this is assuming you are using simplify3d.
Usually holes will always come undersize in FDM printers. In Slic3r, in Print settings, Advanced, XY size compensation is there. Here you can give minus value to get the holes bigger.
Same in Simplyfy3d, under ‘Other’ Horizontal size compensation option is there.
@Adam_Steinmark It’s a Delta. Before this happened cooling on the steppers failed, I switched out a fan and lowered the 3 axis steppers from 1600mA to 1400mA just before this issue, could that have messed up print size? what is the effect of adjusting Milliamps on steppers?
@AlohaMilton current (amps) can be imagined as the amount of water going through a pipe. reducing the mA means less water will flow through the motor and as such the motor power will be slightly reduced. however, unless your printer has some sort of very heavy gantry i doubt a 1600 to 1400 mA change can make any difference you can measure.
@Selvakumaran_Ganesan size compensation seems to be the issue for the through hole, 20x20 test cube is at 20.02 x 20.04 measuring cross grain to the layers with calipers to get the average for the faces. looks clean and smooth. not sure what is up with the round objects exterior diameter though. also occasional chunky globby areas. It may be the old PETG filament (its 6+ months out of the bag, left on a shelf through a wet winter in northern California).
Any links to theory and practice for tuning fitting parts, especially a Delta based guide, are greatly appreciated.
Here’s some info on why holes do what they do http://hydraraptor.blogspot.com.au/2011/02/polyholes.html
As for why it’s only recently started, maybe you have a little bit more slack in the belts? Parts worn in? Nozzle orifice worn out to a larger size?
You might also want to try drying your filament out (don’t ask me how, I’ve not had to, maybe try a dry box with some silica gel and a warm lamp?)
found the issue, steam at the nozzle every so often from the 6-8 month old left out in the open PETG. My Nylon doing it as well. Ordered new filament.
the little puffs of steam are hard to see without looking at the nozzle tip area, 60c-70c heated bed and they disappear before getting out from under an E3Dv6 heater block. A tiny cloud that almost instantly evaporates between the 240c hotend heater block and the 60c heatbed. they do make little popping sounds, which I thought were extruder skipping at first.
interestingly some areas of the spool roll are apparently drier than others. a few prints are fine then one just pops and steams repeatedly for a section of filament, then it calms down again. I suppose I imagined filament would absorb about the same, I am now guessing that the filament creates small channels through gaps in the wrappings, and air and moisture flow more through specificly larger channels which makes the filament very unevenly saturated.