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Inconsistent Sides / Banding Issue

M

mixmasta91

New Member
#1
#1
Hello all,

I'm getting this issue where the side walls of parts are not smooth vertical surfaces, but they have ripples or bands of different widths. I've tried messing with extrusion multiplier, speed, layer height, temperature, lead screw tightness, and fan speed. Any idea how to fix this? The rods seem very straight, and the couplers appear to be doing their job. My next attempt was going to be trying new filament, and then tightening belts some more (but they already are around the tightness of my cr-10 and flashforge belt tightness).

I have the newer type gMax 1.5XT+ with the dual E3D extruder, and the BLTouch sensor. I do not have the heated bed installed. Several models have been tried with various parameters in Cura, and the stock files from the SD card shipped. The image shown is of the g keychain model on the SD card.

Thank you,
--
Andrew
 
gCreate_Joshua

gCreate_Joshua

Administrator
Staff member
#3
#3
Double check that your filament spool is moving freely. This sometimes happens if the spool is getting hung up or if it is hard for it to roll.
 
M

mixmasta91

New Member
#4
#4
Hey guys thanks for the help.

I switched to a different filament and it seems to have helped. Not sure if the old roll was not spinning well, or if the filament was perhaps expired from moisture exposure or what.

Never thought it would have been something so simple.

--
Andrew
 
H

hoovdini

New Member
#5
#5
I’ve noticed that my printer prints certain filaments well, and others like the image you’ve shown...some parts using Polymax PLA ( a personal favorite ) come out with a lot of banding, while other PLA’s do not. PETG prints pretty well with less banding. If I print the same filament on my CR-10 or Hatchbox Alpha, it comes out with super smooth sides. So it’s not just old filaments. I’ve gone through all of the things I can think of - belt tension, bed attachments, x-axis eccentrics tightening, etc...but hasn’t seem to have made a big improvement. I upgraded the steppers on the x-axis and y-axis to 2.1 amp, high torque Nema 17’s, because the bed is large and heavy, and so is the x-axis with dual extruders on it.

The biggest improvement, however, came from changing the extruder multiplier in Simplify3D...mine was too high and caused a lot of over-extruding (even after doing the extruder calibration). I turned it down from the default .97 to .92 and lower, and the layer lines showed less. But still, there seems to just be some sort of very slight layer offsets every few layers that I can’t shake out of my prints.

My CR-10 printer has 2x20 extrusions for the supporting bed rails...and that bed, while the same size, is much, much lighter (and had a larger Nema 17 initially), so it’s easier for that bed to start and stop movements more easily without backlash or overshooting. The gMax only has 1x20 extrusions for a large heavy bed which I find odd, and will be upgrading mine to something stronger soon.

The other weak area is that the dual extruder x-axis is only on (again) a 1x20 extrusion. It therefore has a lot of weight on the axial direction, which may be affecting how squarely the nozzle is to the bed. I’m going to also upgrade this to a 2x20 extrusion carriage to improve that rigidity.

All in all, the printer is very rigid in it’s outer frames, but the x-axis and the bed supports are too weak for dual extruders and the heated glass bed.
 
gCreate_Joshua

gCreate_Joshua

Administrator
Staff member
#6
#6
We have recently started to turn down the x and y jerk settings. They were originally set to around 17 or 18 I believe. We have started to set them at 7. You can find the jerk settings at Menu>Control>Motion, then change both x and y. After that, go up one menu level and store to memory to save it.
 
H

hoovdini

New Member
#7
#7
Mine was already set to 8 on the jerk settings. So that won't help me, but maybe some other folks it will.

The knob is of such low precision, however, that it's impossible to select "7". I can turn it to 6 or 8, but even when it shows 7 and I click the knob in to accept the value, it shows up as 6 or 8. So frustrating.

I would love a knob upgrade, because currently this interaction with the printer is really not user-friendly. Even my CR-10 (which is known to have an inaccurate knob) is easier to select a value.
 
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