Hotend melting problem

Hello 3D printers

I purchesed me an chinese version of the prusa i3 and generally I can print but I have some probleMs with my hotend. If I want to print pla I have to set the hotend to 250 degrees otherwise the extruder isnt strong enough to press the filament outof the hotend.

My first intention was that the extruder is bullshit but then I found out that its realy very hard to press it trough the hotend by 230 degrees. So the pla smells very strong at 250 degrees while I am printing.
And also at 250 degrees is just barely working the steppermotor for the filament is still at its limit.

Have anyone an idear what I can do ?

and have a nice day

Hi,

I think your hot-end could be blocked in some way.

Would you be able to take some pictures of your extruder and hot-end?

Regards

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NFireLabs - The World First Modular 3D Printer - At An Affordable Price!

When the nozzle is hot and you push filament from the outside against the nozzle, does it melt easy?
If yes, you probably have a blocked nozzle.
If not, you have a wrong temperature setting.

First of all, I wouldn´t trust your temperature reading.
What thermistor version did you choose in firmware?
-Olaf

Thanks for your fast answers

@ayouden I added some pictures to this post from my hotend and extruder.. I know the hotend is dirty but thats not the problem I clean it always befor I start to print.

@o_lampe I can't check this at the moment but I didnt know that there is a setting to choose the thermistor version ? Do you know where this setting is in repetire host ?

Ehhh.... I want to say the selection process for thermal regulation is like line 33 in the firmware, but I use Marlin paired with Pronterface, so don't quote me on that. There's something like 50 different thermal regulators which have a predefined performance curve built into the software. Repetier probably also has such a thing.
It's the first bit of code after you declare your hardware configuration for the firmware.

As far as that goes though, you might need to simply attach the thermistor with better insulated material.
Even if the thermistor is nested into a hollow space on the heating block of the hot end, it can give readings which aren't correct; though that usually gives false lows, not false highs.
An airdry clay, a high temperature epoxy, water glass, or, maybe, high temperature silicone would all work for this.

Hi,

By looking at the images you have a knock-off e3D hot-end.

I have used these in the past and they are quite frankly awful! (I have about 5 or 6 in my bits-box as I didn't learn the first few times!)

The main reason is that the inside of the heating chamber isn't always smooth. It is rough and plastic LOVES to stick to these imperfections and makes it near impossible to force it through.

It may also be that there is some PTFE tubing which is in there, so it is not truly an all-metal hot-end.

This can burn and melt if you take the temp too high! Again, this makes the hot-end useless.

My recommendation would to buy an e3D hot-end or a legitimate J-Head.

I have 4 e3D's now and they last AGES! I have had my V5 for 2 years now and it hasn't faulted me yet.

For me, a 3D printers quality is in the hot-end. Poor hot-end = Poor 3D prints!

If you are just printing with PLA, I strongly recommend a V6 Lite.

Hope this helps.

Regards

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NFireLabs - The World First Modular 3D Printer - At An Affordable Price!

@ayouden So now I looked a bit better on the hotend and saw that at first the filament came out of the hotend top and I also noticed on my print from yesterday that when my printer goes from one higher place to another, there is still coming out some filament.
But the extruder isn't shifting, so the filament sticks on the hotend and there are always black burned plastik parts in my printed object Do you think all this problems would be solved by buying an V6 ?

Have a nice day

Hi,

I think it would solve many problems! If it doesn't solve all, then we can discount it from out investigations thats for sure.

You may also need to turn the current up on the extruder motor if it makes a guttering sound.

Regards

Quote
o_lampe
When the nozzle is hot and you push filament from the outside against the nozzle, does it melt easy?
If yes, you probably have a blocked nozzle.
If not, you have a wrong temperature setting.

First of all, I wouldn´t trust your temperature reading.

What thermistor version did you choose in firmware?
-Olaf

If you can´t answer these questions, the best hot-end in the world wouldn´t help you.

@o_lampe

Yes the Filament melts easy if I push the Filament from the outside to the nozzle.

But I can't answer the second question because I didnt found a option to chose the thermistor version :/

I also noticed that the filament came out of the top from the hot part and it all sticks in the whole part of the hot part from the hotend.

My hotend have a PTFE Tube inside.

Have a nice day.

@ayouden

Is there an Option to set the current of the Motor higher ?

Have a nice day.