Creality CR-10S initial positioning


#1

When I begin a print on my CR-10S the hot end is initially positioned in the center of the bed and the Z is very close to the bed. It usually deposits a blob of filament there as it heats up. It then goes to the home position, again without any increase in Z height and immediatly returns to begin the print. Between the home movement and the beginning of the print I need to try to remove the blob from the bed and hope none has stuck to the hot end.

What I am used to (via Cura) is the printer positioning home and remaining there at a reasonable Z (I am guessing 20mm.) As the print starts the hot end drops to the first layer height, extrudes a small amount of filament while at the home position before returning to the 20mm and transition to the first print position.

I am not sure how to duplicate this or create something similar.

I am concerned that the center to home transition and back to print may scratch the surface of my bed if my level is slightly off.


Voxelizer Experimental release notes 2018-11-12
#2

Hi Doug, this is something that we have to change from our side, we will look into it.


#3

I really like the save to Octoprint feature. It works very well. However, with the way the printer starts it negates the advantage of Octoprint on the CR-10 since the only way I can guarantee a blob won’t form on the end of the nozzle while it is sitting in the middle of the bed is to be there to physically remove it. I suspect this will be true of all bowden type printers.

I don’t mean to be a pain about this issue but if you are serious about having it work on many printers this is a game changer.

Thanks for all your good work. I am getting to know the features of Voxelizer and it does some amazing things that Cura can’t touch. This one issue is the significant one right now.


#4

Yes I agree, we will address this issue between this and next week.


#5

Thanks for putting weight on this issue, Doug.

It seems that the following things need to be considered at the beginning of the print:

  • the printing head may be at an unknown location -> location needs to be determined by homing
  • the extruder may have any temperature -> it may take time to heat it up
  • the bed may not be completely even -> long movements too close to the table need to be avoided
  • some filament may drip out of the nozzle during heating -> it needs to be dumped in a remote location

The procedure from Cura you described seems to work well for all these conditions. Do you think there’s any other condition that needs to be taken into account?

We’ll probably go for a parameterized version of the print start procedure while making it possible to override with pure gcode.


#6

Hello Kyp,
Yes, I agree with the four things you have cited. I will further describe

Every print I attempt with Voxelization via Octoprint centers on the bed first and waits for the bed and hot end to heat up. That is followed by a quick move to home (I assume X0 Y0 and what I also assume is Z 0.02 which is the first layer height) and then returns to start the print. The Z does not change in that move.

I do a pretty good job of leveling, but it is still a bit scary to see it that close to the bed. Two other things bother me about this situation. First, while it is heating the filament oozes while at the middle of the bed. This, of course, is where the print will be made. One of two things happen if I am not there to remove that blob - 1) the blob stays at the center of the bed ruining the print, 2) the blob attaches to the hot end and is dragged across the bed to home and back. When this happens the print is ruined and the nozzle builds up a very large blob. I am not certain what would happen to the machine if I did not stop it.

The way it works now the bed and the nozzle does not heat until the center position is reached. I have not gone into the g-code to see the exact inputs.

I could use custom g-code using Voxelizer but that does not start until the Voxelized g-code has begun. This means it will still go to the center of the bed and create a blob.

I am not certain that you needed further clarification, but I hope it helps.
Thank you for tackling this issue. I suspect there will be other printers that have the same issue.
Doug


#7

Yes, the new initial start point is a major improvement for my CR-10S. Thank you!