Hot-end jams all the time

[gobi]

Hi everyone,

got a problem, started 2 days ago and it makes my life miserable.

each time i started to print i heated up the filament to 195-210 degrees and started printing at 60% speed and everything went fine. all of a sudden, 200 degrees wasnt enough to extrude, it needs 220 now and always jams during prints, between prints and all the time really. i have a 25 minutes print and i cant make it cause it jams. when i push the filament in the hotend it somehow hardens and jams the whole thing.

i tried cleaning it, heated the hotend up to 235-240 degrees but it didnt really solve the problem. i just ordered new heads cause i'm sure i'll have to swap one but anyone had similar problems, maybe you could help me out?

[Hugues]

i never had jamming until now, only the tip was blocked 2 times and i managed to disloged the jam by inserting a tiny wire in the tip.

Have you tried that ? Use a very fine copper wire from an electrical wire, measure it so that it's 0.30mm or less.

Also, do you clean your filament with a little sponge or cloth before it enters the hot end ? This is a must. There is a lost of dust on the filament and some of it won't melt.

[gobi]

i'll try that sure. the thing is that for 3 weeks the machine worked perfectly normal and now this -

thanks for the tip though

update: here are the print results, please take a look at them and tell me what you think. right at the end when the top parts are printed, the head jams, no filament is coming out that's why the objects are so... stringy i guess

[gobi]

what really is interesting that it printed the 10x40 test object perfectly but cant seem to deal with a 11mm object

i tried at 210-220-230-240 degrees and it always fail.

[killejano]

The 10x40 does one loop of continious extruding and when it goes to nex layer it pulls the filament back. So something in your nozle is likely to move back up with avery layer change and that's why it prints the 10x40 ok. Flush your hot end with guitar string or a 0.35mm drill to get the clog out. Guitar string is good if you manage to push the clog through.

I use a dulled out long 2mm drill and the shaft end of a 0.35mm drill to clean my hot end.

[Hugues]

just a thought,
are you using PLA ?
if so, i'm printing at 195 or 200 max,
maybe higher temperatures can cause the problems you have ? at least the stringing i think.

[gobi]

yeah this is pla. i always used 195-205 degrees for printing and worked.
i only heated it up so that any clog could 'wash out' of the hotend but as it seems i have/had some dust in the extruder.

just cleaned it with - well it turns out that the jitter strings are the thinnest strings out there - so with jitter strings, anxious to see the results

[Hugues]

could it be that your temperature reading is wrong ? maybe your extrusion temperature is higher than you think.

have you checked your temperature readings at room temperature ? are they the same ?

[gobi]

no i haven't checked the temperature, i tried to clean the head, but it's still clogged and i can't seem to be able to clean it, maybe i'll drill it out as a last resort until my new heads arrive (though guillaume isn't fast to respond to my order)

but now the thermistor cable came out of the head, the adhesive doesn't stick anymore, i have to glue it back on. any ideas? cause i've never done this kind of thing before in my life -

[Mayhem]

i think heat resistant silicone will do the job, i am planning to use silicone what is ment to but on car engine. casket silicone and it can take 300C