Anyone have an idea of what I could do to solve these random underesxtrusion spots? My settings are as follows:
Fillament: Hatchbox Silver PLA
Nozzle Width: 0.4mm
Print Temp: 200C
Extrusion mult: 105%
Print Speed: 70mm/s
Cooling: Enabled
Shell count: 3 (totaling 1.2mm)
I’m thinking my temperature might be a tad too low compared to my multiplier and print speed, or possibly too much drag on the fillament spool (it’s on one of those crappy spool holders that come with the Anet and similar printers, with an M8 rod holding it). Any help would be appreciated.
I’d try dropping your print speed to 60 and bumping your temp 5C. I print my outer shells at 45.
If you want to see exactly where your filament is performing with your current settings print a set of these calibration clips below and see how they fit.
Find a good melt temp by raising your extruder about 35-40 mm above the bed and extruding a steady stream of filament. If it is a good temp it will extrude a straight line and coil like a rope on the bed. Stop extruding and the vertical section will keep standing. This makes little cobra’s if working correctly. If you are too cold you will pig tail below the nozzle and never drop down. Sometimes it will pig tail for a second and then drop down and stay straight. If you are too hot it will stretch and spider web. This will put you +/- 5C of a good print temp.
You print two of them with one rotated 90 degrees. Flip one of them upside down (the bed squish layers should be to the outside top and bottom) and fit them together. Too loose and you are under extruding. Too tight and you are over extruding. A solid easy fit and you are just right. Random gaps is the perimeter shell and you are too cold. Raise the temp 5C to close gaps and lower it 5C to reduce stringing.
Have you calibrated your extruder? Mark off 100mm lengths then force extrude 100mm should be spot on. If that is good next I would check your retraction settings. Almost looks as if you are pulling back to fast and the plastic is breaking off instead of just pulling enough to equalize the pressure. Try dropping your retraction speed and or distance. Mine is perfect at 48mm/s but at 50mm/s it snaps off and I get an under extrusion on the restart.
@Matt_Hallett I thought it was my retraction too, but I’ve found for some reason dropping it below 120mm/s (I know, it’s ridiculously fast) makes it string heavily. I’m going to play with the retraction settings again and see if I can fine tune it a bit better.
I found that with say ESUN PLA+ they recommend 205-225 for print temp but my printer is best at 193, by dropping the temp it got rid on my stringing and I was able to lower my retraction speed. Try bumping up your extrusion after retraction setting. So after it retracts and completes the move it will prime a mm or so before it begins it next print move. I have also found that the more fan I give the more stringing it has so it is about finding a balance. Did you calibrate your extruder steps per mm in the EEPROM? That is the 100mm calibration I was talking about. I also had an extruder that would feed fine at a .1mm height but .2 or .3 it was not delivering enough plastic so I switched to a bondtech qr and never looked back.
@Matt_Hallett yeah, my e-steps are as precise as I can get it. Right now I’m also dealing with a lot of jamming (possibly related to this), where the fillament starts pulling up the ptfe liner in my heatbreak and then expands in that gap and refuses to move. I’m going to be replacing it with an all metal one when it comes in on Tuesday to see if that fixes that issue, then I’ll be working more on the underextrusion issue.
@Matt_Hallett it’s the Alunar M505. It’s basically a knockoff of the Anet A8 that I got on Amazon for cheaper than it would have been after shipping and customs from anywhere else.
I got a Rostock max v3 that I just got up and running and even at 1000.00 kit I still through all the plastic parts out and swapped for carbon fiber and aluminum. Also hated there extruder and hot end so they are now bondtech and e3d. I also have a rise3d and that was just over 3k and still have quality issues. Next up is my own build witch is going to be a solid aluminum tank lol. But I figured if I was going to complain about poor craftsmanship it might as well be my own:
The mechanical precision (e-steps etc) is only the first part. The other side of the equation is the thermal behavior of the material. How much does it shrink or expand as it extrudes out hot under pressure and cools. This is what leads to your final settings with the extrusion multiplier or compensated filament diameter. This is the information the calibration clips give you. Once the thermal behavior is determined you can set your retraction distance and speed. Adjust speed first and then distance.
If you are retracting filament too far and having lots of retractions quickly you can jam from retraction generated heat creep. This can happen in any hot end even all metal ones.
@Matt_Hallett You are right about Printer price not having much to do with print quality. My sub 1K large format aluminum frame printers (Built from kits and then modified) out perform 3K and 9K printers all the time. It comes down to mechanical precision and knowing what they are capable of. Fancy bells and whistles to compensate for poor craftsmanship and design don’t mean better prints. You get the basics right on a home built printer and you will love the results.
