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Colorfabb xt-cf20 problem.  

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Angel'sVenom
(@angelsvenom)
Eminent Member
Colorfabb xt-cf20 problem.

Filament sticks around the nose and at a certain height, for some reason, that blob sticks on the print, freezes and when the nose passes again from that point it kicks the part off the bed. How do i solve this?

Should i reduce the extrusion multiplier? Now it is on default(1.05).Btw this is happening(blob around the nose) on 150% speed but the failure occurs at 100% speed(I change it back to finish the print). 

The speed settings are on default. I just add the "M220 S150" and "M220 R" commands at specific layer heights. 

Posted : 16/10/2021 11:29 pm
bobstro
(@bobstro)
Illustrious Member
Had to slow it WAY down

I only had success with Colorfab XT-CF20 when I reduced Maximum volumetric speed to 1. Had to print at a crawl. 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 17/10/2021 12:52 am
Angel'sVenom
(@angelsvenom)
Eminent Member
Topic starter answered:
Too much filament

I haven't mess with MVS yet. The thing is that the part is printing fine at 100% speed(the whole thing). If i have a blob, doesn't that mean that i extrude too much filament?

Posted : 17/10/2021 9:50 am
Angel'sVenom
(@angelsvenom)
Eminent Member
Topic starter answered:
Extrusion multiplier

The extrusion multiplier is at 1.05 but in the normal "XT"(white) it is at 1. Could that little difference has to do anything with my problem?
Could it be the retraction? I mean, when it retracts the filament, because it has the fibers in it, it could be harder to retract it, so it stucks around the nose.

Posted : 18/10/2021 2:53 pm
bobstro
(@bobstro)
Illustrious Member
Calibrate your extrusion multiplier for best results
Posted by: @angelsvenom

The extrusion multiplier is at 1.05 but in the normal "XT"(white) it is at 1. Could that little difference has to do anything with my problem?

Absolutely. If you're getting a bit of over extrusion, it can show up as excess filament in a number of ways, including build up on the nozzle if lower layers are printed a bit high. Definitely calibrate your extrusion multiplier for each filament. 

Could it be the retraction? I mean, when it retracts the filament, because it has the fibers in it, it could be harder to retract it, so it stucks around the nose.

Probably not. As your extrusion multiplier gets more accurate, the need for retraction is reduced. I rarely use more than 0.2-0.4mm retraction and 0.4mm z-lift. I've got more notes on related topics here that you might find interesting.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 18/10/2021 3:13 pm
Angel'sVenom
(@angelsvenom)
Eminent Member
Topic starter answered:
Default presets

Both the retraction(0.8 length, 0.4 lift z) and extrusion multiplier is at default. You are talking about calibration but shouldn't prusa have already done this? I mean the profiles exist for that reason, so you don't have to set up anything by yourself. 
In either case, i'll try to reduce extrusion multiplier and see if it changes anything. Now i am printing it but with default cooling. I forgot to say that i had changed the cooling for bridges from 50% to 80% and i am very certain that the blob was sticking at the print when it was printing a bridge. And i cleaned the powder coated steel plate with dishwasher and hot water and now i have better adhesion.

Posted : 18/10/2021 3:24 pm
bobstro
(@bobstro)
Illustrious Member
More accurate slicer settings produce more accurate gcode
Posted by: @angelsvenom

Both the retraction(0.8 length, 0.4 lift z) and extrusion multiplier is at default. You are talking about calibration but shouldn't prusa have already done this? I mean the profiles exist for that reason, so you don't have to set up anything by yourself. 

The factory presets will work well enough for most people in most situations. That includes people that don't know anything about moisture absorption and environmental variables. Many of the Prusa-supplied presets start out as community contributions. For people trying to get their first Benchy to print well, close is good enough, but as you progress, you'll find that minor adjustments can help fine-tune away issues such as stringing and blobbing (see my notes pages). 3D printing is a physical process, and physics matter. We're not at toaster level simplicity yet, at least not for optimal results.

For the most accuracy, you want to make sure your slicer settings most closely match your combination of printer, filament, hotend, and nozzle. Even tiny deviations can make a difference, with slight under or over extrusion being the typical result.  I've had the same spool of filament print radically differently on different days depending on local weather conditions (resolved by drying).

A LOT of features in slicers are workarounds intended to help hide the results of under or over extrusion and filament inconsistency. Retraction, z-lift, coasting (Cura), elephant's foot compensation, and others all try to deal with a slicer producing gcode that isn't quite matched to the printer hardware. By setting your filament diameter and calibrating your extrusion multiplier, you're matching your slicer settings to your specific hardware and will have less need for many of those features. I find I can minimize retraction and z-lift, and don't have to bother with coasting, elephant's foot compensation, and other workarounds.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 18/10/2021 4:02 pm
Angel'sVenom
(@angelsvenom)
Eminent Member
Topic starter answered:
.

I see. Thank you very much Bob, for the information.

Posted : 18/10/2021 4:05 pm
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