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filament wont go through hotend

Posted by hapo1313 
filament wont go through hotend
July 30, 2017 12:40PM
Hi gize, i am building my first 3d printer. Most of the parts are done and working, but i can figure it the last error i am encountering.

So i have my filament extruder working and got the white teflon tube and 1.75mm ABS filament. The extruder works and it does pull the filament throught the tube until 3/4 of the hotend. The problem is, it does not go throught the last part of the hotend where it heats. When i go pushing by hand it does come out the melted filament ( so i know it is not getting stuck or jammed), but i cant make it with the extruder and i really dont know what else to do. Any ideias?


Another question, my heatbed takes a lot of time to heat (40min) what can i do to make it faster? It can reach 100 degrees in about 20min, but man the last 10 C degrees takes another 20-30min. I use good wire, under the heatbe there is foil tape and on top there is a 3mm fosted glass. (to the last 10 C degrees i normally have to use a black plastic bag to even make it work).

Thanks for the help!

Edited 2 time(s). Last edit at 07/30/2017 12:43PM by hapo1313.
Re: filament wont go through hotend
July 30, 2017 08:11PM
Please answer these question for us to assist you.

Power Supply voltage and Current, show wiring for heat bed, do you know what size wire you are using to power the Controller and Heat bed.
Have you taken any voltage measurements during the heating process. voltage on power supply, voltage on controller and voltage on heat bed.
This information will make it easier to assist you.
Re: filament wont go through hotend
July 30, 2017 10:31PM
Heya, thanks for the support.

Im using a 12v 10 A power supply.

I am using a 2mm diametrer flexible parallel wire for the heatbed to the controller and i use a 4mm diameter parallel cable on the power supply (non flexible).

The voltage are
Power supply: 12.38 v
Controller: 12.38 V from power supply and 11.04 V from controller to heatbed
Heatbed: 10.8 V

Edited 1 time(s). Last edit at 07/30/2017 10:33PM by hapo1313.
Re: filament wont go through hotend
July 31, 2017 01:49AM
Most heated beds use 11amps on their own at 12v...

add in another 5amps for hotend and steppers etc...

so your short at least 6 amp.

And if the power supply comes from china make sure it reads twice what you need so it has some hope of having enough current. (most use 30a 12v from china)

Edited 2 time(s). Last edit at 07/31/2017 01:50AM by Dust.
Re: filament wont go through hotend
July 31, 2017 10:11AM
Agreed you need a larger power supply.
Re: filament wont go through hotend
July 31, 2017 07:28PM
Oh damn, power supplies are so expensive in my country, but i guess thats what i have to do then. Thanks!

Do you gize have any ideia on how to solve my other problem?
Re: filament wont go through hotend
July 31, 2017 11:31PM
Can you explain a bit, what the extruder does or does not, when trying to push the filament?
The shaft doesn't turn? Raise driver-Vref to increase stepper current.
Is the shaft turning, but the gear doesn't? Tighten the grub screw or grind a dent in the shaft, where the grub screw fits into.
Is the gear turning, but the idler gear is not pressing enough? Tighten the idler pressure screw. ( If there is any )

Edited 1 time(s). Last edit at 07/31/2017 11:37PM by o_lampe.
Re: filament wont go through hotend
August 01, 2017 01:14AM
So, the extruder works on turning and it does push the filament throught the teflon tube until it reaches the hot end. In the hot end there are 2 parts, the entrance and the exit. The extruder can manage to make the filament enter the hotend entrance and it pushes until it gets to the last part of the hot end (Nozzle part), where it heats and then leave. The last part is where i am getting error. It just not pushing the filament in the end (it does come out if i use my hand to push it, but i cant manage to make the extruder do that).

OBS: i know there is a space in the hotend where filament usually get stuck, but thats not the problem since i usually put the filament inside the hole already.
Re: filament wont go through hotend
August 01, 2017 09:42AM
What temp is the hot end at when you try to extrude ?

What type of fillament are you using ?
Re: filament wont go through hotend
August 01, 2017 01:53PM
1.75mm ABS filament.

Temperature is around 230 C - 250 C

It does melt the filament but it only goes through the nozzle with my hand pushing
Re: filament wont go through hotend
August 01, 2017 10:32PM
Quote

The last part is where i am getting error. It just not pushing the filament in the end (it does come out if i use my hand to push it, but i cant manage to make the extruder do that).

Ok, now observe the extruder stepper while it tries to push and choose which of the errors it is and what countermeasures could help:
A mark on the shaft with a felt pen might help seeing whats going on.

Quote

The shaft doesn't turn? Raise driver-Vref to increase stepper current.
Is the shaft turning, but the gear doesn't? Tighten the grub screw or grind a dent in the shaft, where the grub screw fits into.
Is the gear turning, but the idler gear is not pressing enough? Tighten the idler pressure screw. ( If there is any )
Re: filament wont go through hotend
August 05, 2017 08:45PM
The shaft and the gear turns (when it reachs the nozzle it just stop pushing, but they still rotate). I did a test with no nozzle and it works but it wont work with the nozzle only. I am thinking of a little probable jam? Like, so little that with my strenght it would go, but not with the extruder perhaps?I will try to acquire a new nozzle and/or clean the one i have to see if it works and i will let you gize know if it works!
Re: filament wont go through hotend
August 05, 2017 11:05PM
So, it's getting clearer now. Your drive gear strips filament.
The nozzle could be clogged as you mentioned, but that would lead to a noticeable higher pressure for manual pushing too.
I put my money on idler gear tension too low .
Don't you have a tensioner screw on your extruder? Some cheapo extruder manufacturers believe they can get along without one. But then users have to find workarounds, like raising filament temp and slow down print speed.
Re: filament wont go through hotend
August 06, 2017 09:39PM
Inthe stepper motor itself i dont. It does have a tension screw in the driver gear (which is attached to the extruder motor). I wont be at home until saturday. I will try by then to get the tension better to see if it works.

Ps: changed nozzle and did not work, so not a clogging problem.
Re: filament wont go through hotend
August 06, 2017 10:56PM
I think you are confusing the tension screw with the grub screw of the drive gear. The image posted should help you even if your extruder looks different
Attachments:
open | download - extruder.jpg (111 KB)
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