BLTouch probe and filament

When running, my BLTouch probe stays lit red. Is that normal. It seems to work fine, but it strikes me as strange that when printing, it stays lit red.

When the auto-level process is taking place, filament keeps dropping out of the head. Not a lot, but a few cm here and there. The bad thing is, once printing started, this messy gob decided to fall off into the fresh, hot skirt material.

What is the secret to having no filament extruded while the printer is levelling, so that when printing starts, the head is clean?

I used some “Flexible-Adhesive-Manual-Print-in-Place-TPU-Like-Ribbon-Filament”, FAMPPTLRF, for short (some call it electrical tape) to cover most of it, I have my nozzle at 120C for leveling, and I do a purge of 30mm on my purge slide before every print.

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An interesting way to counter the red-light. I can only assume this means that if it stays lit for you, and for me, then anecdotally anyway, this is normal operations?

mine does stay lit. I start every print with a purge line that gets rid of any ooze

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Yeah, I think so.
Like Facebook, always wants everyone to look at it.

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Yes it is normal to be lit. The ooze is also typical I have found cheaper hot ends seem more prone than better ones with finer tolerences. My E3d (not cloned) drools slightly a 8 mm ooze thats it. The cloned E3d has a drool of many CM I am careful to grab it as it starts to print. One of the reasons why I replaced the whole hot end from a clone volcano to a real volcano and the BMG wind. It just works better. I was not using an ender so it might not be appropriate to use that model, but the cloned hot ends are poor copies of the orginal IMO.

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Hi. What is a purge command? I can easily insert one into my gcode file, and I am guessing it would come before my M420 S1 or G29 if I re-level the bed. If I am not mistaken I read that one can keep the hot end temperature LOWER than full melt during these commands, and only raise it to operating temperature once leveling is done? I am not sure of that recipe, but that also makes some sense.

I level at 120/50, then up to print temp, and purge right before printing.
Before I had a bucket, I used a couple rounds of skirt to purge.

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My printhead dragged a chunk of plastic around, during the laying out of the skirt, and it finally fell off, in the still hot skirt material, making it a great candidate for ruining the start of a print. So for me, it is important I learn how to ensure my hot end begins it’s long journey clean, and not dragging around the dregs of whatever was squeezed out during warm-up and bed levelling etc. So I guess I need to learn how to control timing and hot end temperatures better in my gcode.

mmm, I certainly don’t regret setting up a purge bucket/GCode

The red light on the BLtouch is normal, being on is a good thing. Technically the blue light is also on but the red floods it out .

as for your oozing here is a very quick start Gcode that will help. I pulled it out of one of my ender startup scripts

G90 ; use absolute coordinates
M83 ; extruder relative mode
M104 S120 ; set temporary nozzle temp to prevent oozing during homing and auto bed leveling
M140 S[first_layer_bed_temperature] ; set final bed temp
G4 S10 ; allow partial nozzle warmup
G28 ; home all axis
G29 ; auto bed levelling
G1 Z50 F240
G1 X2 Y10 F3000
M104 S[first_layer_temperature] ; set final nozzle temp
M190 S[first_layer_bed_temperature] ; wait for bed temp to stabilize
M109 S[first_layer_temperature] ; wait for nozzle temp to stabilize
G1 Z0.28 F240
G92 E0
G1 Y140 E10 F1500 ; prime the nozzle
G1 X2.3 F5000
G92 E0
G1 Y10 E10 F1200 ; prime the nozzle
G92 E0

hope this helps