Big Blob Using Cura

[Rikdogski 0]

Hi everyone, I am new around here and appreciate the help!  

 

I have an ender 3s1 and have added a filament change in cura.  WHen I swap the filament and the print resumes it lays down a big blob of the new filament right ontop of the print and then continues with the regular amount of filament.  Can you please guide me in the direction of an answer?  Thank you

[MariMakes 178]

Hey @Rikdogski,

 

Welcome to the Ultimaker Community 🚀

That's an interesting problem! I have a number of questions:

What way did you pause your printer?
Do you perhaps have a picture for us so we can see what's going on? 

Do you have a project file for us? It contains the printer and settings we need for troubleshooting. 
To save a project file go to File -> Save project.

[Rikdogski 0]

Hi thanks for responding.  I pause the printer by selecting "Filament Change" in the cura settings.  The printer automatically pauses as a certain Layer or height of my choice.  I switch filament and hit resume.  I can post a picture tomorrow and also 

CE3PRO_10-232MicCapRoundl.3mf

[Rikdogski 0]

Hi again, 

 

Sorry for the delay.  Here is the picture of the BLOB.  Any ideas on how I can eliminate this problem?  Thank You!

[MariMakes 178]

@GregValiant, you have a little more experience with Creality printers.

Is it more common to use Pause at Height over a Filament Change?
And when a filament change is selected, it it better to use the Firmware Configuration or change the settings yourself? 

[dsp 18]

Perhaps making a dual extrusion tower next to the original model

If I Understand right your swapping fillament on a single nozzle printer right?

If you make sure the first thing it prints is not your actual model but a small print next to it, you should be fine

[GregValiant 1,112]

Hello all,

I prefer to use Pause at Height as the settings are right there and (by comparison) using Filament Change turns it over to the firmware.  Firmware is not a Creality strongpoint.

@dsp is right in that if the first move is to a "support", a "tower" or something else non-critical then that is the best solution,  The blob simply ends up someplace that doesn't matter.  On a small short model you can just print two.  The one with the blob gets discarded.  If it's taller then adding something else that ends just above the color change layer is a good idea.

 

The reason for the problem is that whether you use Pause at Height or Filament Change, when you move the filament the printer loses track of exactly where the end of the filament is in relation to the nozzle.

When I use Pause at Height I do not use the built in retraction settings but do it all by hand.  After the head parks, I pull out the filament and insert the new color and then I advance enough filament by hand to make the color change (going from any color to white requires a lot of purge).  After that is done I do a hand retraction of about my "retraction distance" to relieve the pressure in the nozzle.  The restart is then pretty clean.  It can take a bit of practice but it isn't difficult to figure it out.

 

In my first foray into Python I have made modifications to Pause at Height and when I figure out how to do a proper pull request I'll submit it.  It changes the retraction settings so the "prime after pause" occurs at the park position rather than over the print.  It also allows for multiple lines to be inserted as "Gcode before pause" and "Gcode after pause" and adds an option to have M104 set the resume temperature instead of M109 as M109 can cause a 10 second delay even if the standby temperature and the resume temperature are the same.

 

When Creality made the switch to the 4.2.x mainboards with TFT displays the display and board didn't play well together.  As a consequence, on the early releases of all the Ender 3 models with those boards, the gcode commands that send messages to the display (M0, M1, M117, M600, etc.) didn't work anymore.  M0 is the main command for Pause at Height.

 

My bonafides.  All the color changes in these was with Pause at Height and were printed on my Ender 3 Pro.  (The windows and curtains on the camper sleigh were glued on during assembly.)