Prusa i3v --- Filament Jamming and Slipping --- Replacement/Upgrade Extruder ?

[jtice]

Been a while since I really read up on all this, so I might be mistaken...

But, I though that if the upper end of the hotend, where its fins are, got too hot, that it would cause the filament to melt a bit in it and start to stick, causing jams.
That is the main reason I have been afraid to go over 190
That is why I went ahead and installed that upgraded cooling system shortly after building it.

The other day was my worst jam ever, after if was printing for about an hour. I left it overnight.
Next morning, I heated up the nozzle, and when I went to pull the filament out, and it snapped off, down in the metal part a bit,
So I had to poke a guitar string up through the bottom to force the filament out.

[tonybuckley]

Don't rule out borderline low temperature as part of what is going on.

I print PLA at 225 on my E3d. My infrared temp sense says it is 180! But of course that is an exterior temp.

As with all this stuff. EXPERIMENT and do not believe the readings. As I said watch and listen. A simple long exttrusion from Z height is very revealing. See how it flows straight, or if it coils.

[jtice]

I print PLA at 225 on my E3d. My infrared temp sense says it is 180! But of course that is an exterior temp.

As with all this stuff. EXPERIMENT and do not believe the readings. As I said watch and listen. A simple long exttrusion from Z height is very revealing. See how it flows straight, or if it coils.

What is the coiling a sign of?
Mine will coil, like mad. Pretty much always has.
If I have recently cleaned out the tip with the guitar string, its a bit better, but generally, will never fall straight out of the extruder, it will coil and kinda ball up.

[tonybuckley]

What is the coiling a sign of?

So what I was suggesting was raise the z axis a fair bit and then extrude via a tool such as pronterface. That's my procedure for loading new filament and running it through to change colours for example.

In my opinion, you should see a nice line of filament coming through and stringing down to the base under gravity, very quickly cooling and setting from the hot end.

If it madly coils under those conditions, I would suspect it is far too hot so as it comes out, it is shocked and coils and clumps.

I'd be very interested to see what the thermos report as your temp to achieve a nice clean line of filament?

I will say again. I am a noob on this so take everything I say with a pinch of salt and my only experience is the e3d hotend which I chose after looking at the designs and been very pleased with. I don't mind being shot down in flames (nicely) but this is the behaviour I would expect.

[kd7eir]

I've had much better luck since increasing my PLA temp to 225°. I have the same setup except that I am using 3mm filament.

The coiling is most definitely a sign of either a clog in the nozzle or something at the very tip of it. I once found a small piece of lint just touching my nozzle and causing the filament to coil. You can easily clean the tip of the nozzle of such stuff by CAREFULLY placing a small lid with some isopropyl alcohol in it right against the nozzle tip while it's heated to extrusion temperature.

I always raise my Z axis and extrude several millimeters of filament through the nozzle anytime that I change filaments.

[tonybuckley]

Don't know then.

But you could use it to your advantage :-) http://www.bbc.co.uk/news/science-environment-35171408