Blocked or Clogged

I think we need to make a distinction in what we say or communicate to others when we have issues with the filament not exiting the hot end

There are two conditions that can happen one is not bad at all the other much less common but id more difficult to repair

If the nozzle tip is blocked it means that something that has not melted is at the or near the surface of the nozzle tip and can usually be removed by gently scraping the tip as it extrudes filament.

If you raise the z axis to say 25 and extrude material the stream of filament should drop straight down and begin to coil as it reaches the bed if the tip is blocked it may start to form a loop immediately as the new filament snags on what ever is blocking the tip. Repeated scrapings across the nozzle tip usually removes this. Normally you would not want to start a print if the nozzle is blocked make sure it is a nice clean flow.

Now a clog is totally different it is usually caused by foreign material actually in the material or by a more catastrophic damage done to the hot end parts or by sections of filament that have not been melted properly and now are unable to move to the area of the hotend where it can be melted.

This is usually identified by the fact that during the computer controlled extrusion no filament comes out at AND that filament can not be manually pushed through if the top of the extruder assembly is open as if to change filament.

The process to clean this is usually a long one involving removal of the hot end assembly from the extruder housing and also its disassembly to get access to the internals of the hotend.

A blocked nozzle can temporarily appear as if it is a clog if there is sufficient material stuck to the nozzle tip and it must be cleaned off in order to remove the blockage scraping it each print is a good practice to get into to help keep it clean.


In my setup I have the extruder raise 5mm and extrude 5cm of material just before each print begins.

My process goes like this
I turn on the temp and set it to what I know the print is going to start at
and while it heats up I do other things like finish the slicing and spray the bed with hairspray
then after it heats up and the slicing is finished I run the job my code which has been inserted runs first so the z axis raises and filament begins to extrude I then put my tweezers around the little coil of filament on the bed with one prong on each side of the nozzle tip and wait a few seconds as Repetier determines that the already heated extruder is at the right temp as per its own code. then the nozzle lowers and begins to move to the print area and begin printing, when this happens I simply pinch the tweezers tight and teh nozzle scrapes itself clean on one of the prongs of the tweezer as it moves to start printing. So it starts with a clear nozzle.

In order to get the nozzle to rise I use this code in the custom gcode window
In the slic3r config screen last tab under Gcode you should see two blocks one for before the print and one for after the print

I add this code in the before
G1 Z5 F5000 ; lift nozzle
G92 E0 ;zero the extruded length
G1 F200 E13 ;extrude 13mm of feed stock
G92 E0 ;zero the extruded length again


Others may have different processes that work for them and that is good just try and keep the nozzle clean as you print.

 

Generally if it coils upon exiting the nozzle tip you have a little something right at the edge that the filement catches on as it comes out every print I set mine to extrude while it is at teh home position right before it moves to beging printing and by looking at how it comes out I can tellif something is hanging onit ususally comes out straight and coils on teh bed I place my tweezers around the outside and then just as it moves to start I pinch the tweezers shut and it scrapes the nozzle tip pretty clean and the print usually starts off pretty well right away

 

if that was ABS then it will work but if you have the same happen with PLA it will be much more difficult to remove as PLA does not react with acetone I heard maybe MEK but have not tried it yet

If it was PLA then mostlikely something else happened to cause the filament to loosen up

 

main thing it is cleared Yeahhh

 

It is in the slic3r config screen last tab under Gcode you should see two blocks one for before the print and one for after the print

I add this code in the before
G1 Z5 F5000 ; lift nozzle
G92 E0 ;zero the extruded length
G1 F200 E13 ;extrude 13mm of feed stock
G92 E0 ;zero the extruded length again

 

it pauses because there is a setting in the software that says youhave to be at this temp for x seconds the actual code at that point basically says to set the temp to what every you had in the profile si it just so happens it is already there so it just has to wait fore that one timeout I just mentioned.

As faras clearing it you actaullly leave the little blob in place after when it start to extrude I place the tweezers on both side of that little blob BUT I do not grab it I wait that 10 seconds you salk a bout then right as it begins to move THAT is when I grab the blob and let the tweezers scrape it clean if you wait until the nozzle moves then grab it is only a few seconds until it starts extruding again so no cap can form

Do you understand that now? if not let me know and I can make a vid or something

 

the curling measn that the filament is catching on partof the nozzle repeated scrapings will eventually clean that off


Sometimes after a long period of non printing it starts to extrude but nothing comes out bu tit is simply build up inside and I scrape the tweezers across the tip and it usually starts to come out then

 

the only thing you need to worry about is eith the file is that it could cause more issues because as the file goes over the surface it could inject metal particles into the filament which could get lodge. I have found the tweezers works really well to maintain it but if something is in their now you may need to get some .3 piano wire and clean the nozzle from below and then keep it clean with the use of the tweezers.

not sure about the new settings. My settings are far from what they originally were but I cannot complain about the settings I use or the process I use based on the quality of my prints.

 

I usually give those to the people I have worked with to get the first layers right so that I dont have to start hearing thing like "Jeff's settings don't work my print still keeps popping off" when it has nothing to do with settings. It just start a whole other set of threads I would have to concern myself about if the basic heights are setup using the same process and things I look for when setting mine then I know the settings will be good for you but if you use another method then my settings may not work for you. Don't take this as I amholding them hostage Ijust want tomake sure the foundation is set properly