MP3DP V2 - Build

Mostly Printed 3D Printer - MP3DP Advice
81

Yes looks better to me, but I do see some bulging in the corners and some ringing on both X and Y axis. You should run Pressure advance to minimize that
Did you measure the cube with a caliper? how off are you from the 20mm?
Did you double check rotation Distance?
I look again on your printer.cfg and you have

[printer]
kinematics: cartesian
max_velocity: 300 
max_accel: 3000
max_z_velocity: 5
max_z_accel: 100

I don’t know that printer but I think those values are a little off. This is what I’m running on my printer.

[printer]
kinematics: cartesian
max_velocity: 200
max_accel: 2000
max_accel_to_decel: 1000
square_corner_velocity: 1.0
max_z_velocity: 50
max_z_accel: 100

I also have Acceleration control (Advance) Disabled on the slicer.

I’m not ruling out the possibility of been a mechanical issue but I would start here.
I was able to print with much higher acceleration 3500, but for a very short time, things start to get loose and I end-up with a bad print. Now that I dropped to 2000 it seams to be holding a good print .

82

The Voron cube I printed has these measurements

Z = 30.03
X = 29.94
Y = 30.02

I tried the pressure advance but I must have done something wrong because after I set it and then went to print something the object was under extruded and the corners were not square.

This is what I had it set too:
#pressure_advance: 0.246
#pressure_advance_smooth_time: 0.040

83

Your printer is a direct drive, your pressure_advance should be on the 0.0something range. When doing the math you probable probable use the FACTOR=.20 instead of FACTOR=0.005

This is mine, and pressure_advance_smooth_time didn’t do anything for me.

pressure_advance = 0.01565

Try it again for Gcode command.

SET_VELOCITY_LIMIT SQUARE_CORNER_VELOCITY=1 ACCEL=500

TUNING_TOWER COMMAND=SET_PRESSURE_ADVANCE PARAMETER=ADVANCE START=0 FACTOR=.005

when doing the math use this.

pressure_advance = 0 + <measured_height> * .005

And we will start again :wink: :grin:

84

I should have added:

I though that cube was a 20mm and not a 30mm
sorry… your measurements are really close and for my standards…Really Good!!

85

Maybe you can tell me what I did wrong with the extruder.

I believe the micro steps set to 16 is correct. However. the rotation distance I don’t think is right. I do think the gear ratio is right. I have the Nema 17 pankcake motor with the gear on it going into the Bontech gear set - I.e. Clockwork 2 Extruder from Voron.

My build I have been using mod parts from “Sebastian” and looking at his cfg file. he has noted these values and he is using a stealthburner.
microsteps: 16
rotation_distance: 22.67895
##gear_ratio: 50:17 # Clockwork
gear_ratio: 50:10 # Sherpa mini

Appears he is using Sherpa mini but his rotation distance is nothing like I have.

I am not sure if I need to change it but given my prints are pretty close to being dimensionally accurate do I just leave it.

[extruder]
step_pin: PB3
dir_pin: !PB4
enable_pin: !PD2
microsteps: 16
rotation_distance: 13
gear_ratio: 50:17
nozzle_diameter: 0.400
filament_diameter: 1.750
heater_pin: PC8
sensor_type: EPCOS 100K B57560G104F
sensor_pin: PA0
#control: pid
#pid_Kp: 21.527
#pid_Ki: 1.063
#pid_Kd: 108.982
min_temp: 0
max_temp: 250
min_extrude_temp: 0
#pressure_advance: 0.246
#pressure_advance_smooth_time: 0.040

86

For the time being I am leaving it is and will do the ringing tower print and will report back. However, I did change the printer details to match yours. Hopefully I print it correct. I print with zero infill and 2 shells.

87

I printed the tower test with pressure advance.

PXL_20220312_175451889
PXL_20220312_1754518891920×2550 184 KB

After the calc I ended up using a pressure_advance = 0.0465

Cube on the left is before and cube on right is with the above setting - I cannot tell the difference.

PXL_20220312_175337426
PXL_20220312_1753374261920×2550 265 KB

PXL_20220312_175348604
PXL_20220312_1753486041920×2550 259 KB

PXL_20220312_175357029
PXL_20220312_1753570291920×2550 256 KB

PXL_20220312_175410110
PXL_20220312_1754101101920×2550 249 KB

88

I tried a couple more prints… for the life of me cannot figure out what is causing this rough print surface.
Is it z wobble or an extrusion issue ??

I printed the part in the X orientation and Y orientation and get the same results.

PXL_20220312_213219826
PXL_20220312_2132198261920×2550 207 KB

PXL_20220312_213211743
PXL_20220312_2132117431920×2550 241 KB

89

I’ve seen that when the heated bed springs are too loose, and allow the bed to wobble a little. It’s not an uncommon problem on a bed-flinger style printer.

90

Your tower test print looks pretty good. Was that with the same slicer?

91

The last prints were done in super slicer per suggestion from gpagnozzi.

I had this posted to a Facebook group page and someone said that the Z is loosing steps and that is causing this issue.

From what I can tell the Mini SKR E3 V2.0 shares the Z driver between motors.
In Klipper the run_current is set to 0.580

92

What slicer made the test tower, that looks considerably better. What infill percentage are you using?

93

The square tower was done in super slicer but then prior to printing you set these command since its a pressure advance test print.

SET_VELOCITY_LIMIT SQUARE_CORNER_VELOCITY=1 ACCEL=500

TUNING_TOWER COMMAND=SET_PRESSURE_ADVANCE PARAMETER=ADVANCE START=0 FACTOR=.005

94

If that were true, the total height would be smaller. Is it?

95

Its still dimensionally accurate.

I changed the current to .800 —

Print to the left is with the increased current the two the right are the previous versions printed.

PXL_20220313_001706094
PXL_20220313_0017060941920×1446 211 KB

PXL_20220313_001742888
PXL_20220313_0017428881920×1446 194 KB

The bed springs are stiff - not super stiff not sure if this is the cause or maybe the lead screws.
The belts are super tight, the grub screws are tight on the steppers. I have a different lead screw coupler I am using -
Image 2

Oh and I am not printing fast maybe 40mm/s

96

All I can see is three faces. :open_mouth: :open_mouth: :open_mouth:

It kind of looks like the later right above the eyes is thicker on both sides. If that’s true, then that layer is being squished. Not anything to do with X or Y, it has to be Z, right?

Something on the head is lifting or lowering, or something on the bed is lifting or lowering. I think you need to start poking at stuff and see if you can figure out what is moving.

Check the grub screws on those couplers.

97

Yeah - I will keep looking… like you say something has to be shifting.

98

What do you have as steps/mm for your Z. It looks fairly consistent, which leads me to think that it’s something systemic. What size nozzle is it, and what is your layer height? Try re-slicing the model for a different layer height?

If you are using 400 steps/mm for Z (Pretty typical) what Z speeds and acceleration do you have set? Z doesn’t need to be fast, but with good motor control it can still go reasonably quickly. For a 4 start (8mm lead) screw, layer heights in multiples of 0.4mm (0.16, 0.2, 0.24, 0.28) are all very good, as they are multiples of a full step on the motor, which makes them (usually) the most consistent. (But then, I use a 0.333mm layer most often, so take that with a grain of salt…)

99

120v bed? If so did you set the pid?

The bed does need freedom to expand a bit or it will buckle when heated worse that it already does. It seem like it is very close.

Are you sure your extruder is not moving? it looks like it is getting knocked a bit back and forth. Almost like a layer shift but less. If those are like 15% infill I have no idea how it is happening.

The tower looks okay or I would say you are over extruding. Maybe double check the 100mm test just to be sure you are not.

-I have never seen anything like this -

100

Running Klipper-
Z is:
microsteps: 16
rotation_distance: 8
full_steps_per_rotation: 200

Nozzle is .4 and my layer height on these prints is .20

The tower print which was for a pressure advance test was printed at .30 as that is a requirement for said test.
I don’t recall the Z speed but its nothing fast - same for acceleration.