Z hight / homing wonky?

Sovol SV04 IDEX
1

I cannot maintain a consistent Z height. Please see the video. What am I doing wrong? Also, are these problems glitches or user error? Thanks. (Edit: When I say I move the printer around, what I mean is the Z height up and down, not physically moving the printer.) the video is on Bjorn firmware 1.15.6

@Bjoern

2

@Bjoern

Even though your removed his firmware, he is still the best user to help you.

3

I still use his firmware. I’m on the version released a few months ago. What I was mentioning in the video is a previous version of his, never locked the bed after a tramming, so when you went to adjust the bed height, the bed would move. That’s been fixed, though. (still curriouse about it not homing all axes though. I’m happy wit the firmware and love @Bjoern work. just having issues

4

No real help here but a couple questions.

Are you using “pre compiled” firmware and entering custom offsets for the XY home switches (the SV04 does sensorless homing?) and the nozzle to probe offsets?

—> OR ←
editing the config files and compiling custom firmware?

5

Hi brentfriesen,
I’ve seen your video & identified 3 (4) issues/observations:
#0. Homing has been executed after homing has already been done, but just on Z-axis
#1. Nozzle position differs after adjusting Z-offset & saving
#2. Aux-Leveling position 1 is different from home position, resulting in a nozzle side step
#3. Separate homing is missing before tramming

Before answering the issues one by one I’d like to recall the basic leveling concepts that are under the hood of our SV04 firmware:
Aux leveling and tramming support the process of adjusting the four bed screws iot get hot-bed in a leveled state. Tramming calculates touch sensor probe information into instructions on how to turn the bed screws.
Auto-leveling probes the hot-bed at 64 points and produces a mesh that represents the imperfections across the hot-bed. This mesh is used to compensate nozzle positions when activated (by g-code M420 S1).

Back to your observations:
#0. Homing is done when entering the leveling menu iot get a valid sensor position. Pressing the home-button will call homing again - this time the valid position is already known, resulting solely in homing Z-axis again. That works exactly as intended.
#1: The Z-offset uses babystepping iot to fine-adjust the difference between hot-bed and touch sensor. This Z-offset will have no direct impact on the current nozzle position. It comes into effect during auto-leveling when the bed mesh is being probed. Your paper-test will work after auto-leveling & saving has been done.
#2: The X side-step results from a difference between aux-leveling position 1 [X150,Y150] and home position. The latter is calculated in the center of the printable area, which is 302x302mm.
#3: Homing has already been done after entering the leveling menu. Therefore the sensor position is valid & there is no need to redo homing. Homing can be done again by using the home-button, as you did during #0.

I hope that helps.
/R
Björn

6

Thanks for that info, I will have to read it over a few times.

I guess my question is, when you initially select levelling, why does it not move the bed after probing so the nozzle is at the probe spot? i thought that you needed to set z offset in that position??
I’m still confused why hitting home in the levelling menu would make it so my z height is different from what it was after setting it. sorry for the bother,

7

After initial homing, I always select the House icon which re-homes Z only and that relocates the nozzle when I check my offset.

HTH
Paul

8

thanks @urbnsr , same here. what im confused about is why when i do that.
hit leveling - then hit house button - set my z height - hit save - then go back to leveling - hit the house button - why the z height doesn’t return to the same position? like its always higher than when i set it.
it doesn’t make sense to me. i think @Bjoern tried to explain but im not understanding. thanks

9

I don’t own an SV04, but I will add my thoughts about the House/Home button.

On printers with a screen the House means Home, which you know already.
All this does is Home all the Axis. The nozzle will not be at the correct Z-Offset position because it’s not supposed to be. It will do that when you start your print & the purge line or first layer goes down.

Now the SV04 maybe different, I don’t know
if this helps or not. :grin:

1 Like
10

thanks @Lion,

So my procedure now is to hit the house to home, then set the z offset and save. Now I think you’re saying that once that is done, hitting home again will not bring the nozzle to that same z height. Fair enough, but why? I’m confused about how I would ever double-check my Z offset. Like okay, I got it set. I did a print, and say there was an issue, so I’m like okay, let’s confirm z offset. How would I do that if homing doesn’t bring it to that offset height? Like, how do I ever double-check my Z offset is correct if I can never get to that spot again?

11

In general every printer I’m aware always “parks” the print head a few mm above 0. This is to protect the nozzle and bed on X and Y moves if your Z0 is too small or Negative.

Note the first layer prints at Z0+initil layer height (plus or minus babysteps).

12

Once the Z-Offset is set correctly, you shouldn’t have to set it again until your replace the nozzle or adjust the bed.

Maybe these videos will help.

13

Hi again,
short version:

  1. Homing is sufficient once after power-on (unless you don’t have moved any axis by hand).
  2. Run auto-leveling after changing Z-offset (nozzle to sensor distance) & then save. This will update the bed mesh iot to get a nice first layer.

/R
Björn

14

This may be a stupid advice.
I used to own an SV04 but no longer.
It seems to me that before leveling and homing, you have to set the z-offset using the soup cans supplied by sovol, 2 small pieces of wood. You can also use other cans.
If you don’t have the manual, look for it in the sovol wiki.

15

Does the SV04 have independent Z and Z1 drivers?

Something no one talks about
 Is the bed parallel to the "best X gantry position? While the printer is off it is easy to “tip” the X rail a bit. If you do a manual bed level each time you power up you will be constantly chasing that “sag”

To prevent that find the “best” angle for the X rail, set the bed parallel to that angle and then run “G34 - Z Steppers Auto-Alignment” every time you power up and BEFORE you touch the bed leveling screws

First we find the angle the X rail “wants to be at”:
With the print head(s) 100 (or so) mm above the bed power off the printer. Grasp the motor coupler for either Z motor and slowly turn it clockwise until the OTHER screw turns. Turn counterclockwise until the other screw turns. Turn back and forth and get a “feel” for how much slack there is. Turn the motor so it is at the center of the range. Power on printer.

Next we set the bed parallel to the X rail:
Do a manual bed level using paper at the 4 preprogramed points. Then do a “G34 - Z Steppers Auto-Alignment”. Tram the bed to fine tune the Bed screws then do another “G34”

Mark your bed adjusters and never turn them more than half a turn.

You need to run G34 each time you power up your printer to undo any unintentional “sag” in either Z motor.