Printer stops extruding PLA after about one minute, running out of options.

I have build my own delta printer (delta-pi) and everything works great, except for one issue. The PLA stops coming out of the hotend after about one minute. I have tried lots of things, but no success. I desperately need some inspiration where to look next. Any thoughts are welcome!

What I have tried so far:
- I exchanged the budaschnozzle for a J-head and mounted a fan on that.
- I exchanged the MK7 tootht wheel on the air tripper extruder for a MK8.
- I used a different Bowden tube from another supplier.
- I used another PLA filament from another supplier.
- I went from a .3 to a .5 nozzle.
- I took everything apart and put it back together very carefully.

Things I noticed that might be related:
- the extruder has to work very hard. I can hardy move the filament by hand.
- the filament has very little friction in the Bowden tube.
- I need to set the temperature very high, to about 230 Celsius.

Once again: all ideas are appreciated since I am completely stuck!

"- I need to set the temperature very high, to about 230 Celsius."

Why?

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Waitaki 3D Printer

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waitaki
"- I need to set the temperature very high, to about 230 Celsius."

Why?

If I don't, it stops even sooner. If I push the filament by hand (with a lot of force), it extrudes as low as 190 Celsius.

I've got pro filament and standard China filament, both from MatterHackers. The China filament is very easy to extrude, I can do that from 220-230C [I've got an E3D, and thermal paste to help heat contact on both the cartridge and thermistor, measures are instant and accurate, so I'm in actual temp, where most are lower shown temp than actual]. But with my pro filament, I have to go to 250C, and even then it will jam. I've noticed the filament seems to spread heat within itself well, and holds it well. Small parts are a no go with this filament, it will heat, expand, and become a mess. I can't walk away from a pro filament print, it has a tendancy to jam if there is a lot of retraction in a print.
Basically, it may not be your printer, could be your filament. And I'm sure it's more than one supplier's filament that has this.

Edited 1 time(s). Last edit at 06/01/2014 03:22PM by MrDoctorDIV.

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

Check the filament where it is pinched between the gear on the motor and the bearing. Is there a round divot cut into the filament? If so it indicates that the hot-end is jamming. Play with the temperature setting of the hot-end- don't trust the electronics to read the correct temperature unless you can verify it for yourself with a reliable thermometer- either a thermocouple or RTD. If you can adjust the spring tension on the pinch wheel, crank it up. Check the extruder motor current- make sure it has enough- check the temperature of the motor and the motor drive chip- if the chip is getting too hot it may reduce current to the motor to protect itself. If the motor is getting too hot because you're running the current too high the motor will misbehave. It is possible for the motor to get too hot without the driver chip getting too hot, so you must check both of them.

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the_digital_dentist
Check the filament where it is pinched between the gear on the motor and the bearing. Is there a round divot cut into the filament? If so it indicates that the hot-end is jamming. Play with the temperature setting of the hot-end- don't trust the electronics to read the correct temperature unless you can verify it for yourself with a reliable thermometer- either a thermocouple or RTD. If you can adjust the spring tension on the pinch wheel, crank it up. Check the extruder motor current- make sure it has enough- check the temperature of the motor and the motor drive chip- if the chip is getting too hot it may reduce current to the motor to protect itself. If the motor is getting too hot because you're running the current too high the motor will misbehave. It is possible for the motor to get too hot without the driver chip getting too hot, so you must check both of them.

Thanks for the advice! I will be checking that tomorrow.

Where did you get the J-head from? If it is a china clone I would go back to the Buda.

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Sublime
Where did you get the J-head from? If it is a china clone I would go back to the Buda.

I got it from rewrap.me, which is a european (Danish) manufacturer / store that is regarded quite good. The buda actually is an asian clone (from Gadgets3D).

For future reference: it turned out the J-head was not assembled properly. There was a gap between the end of the PTFE-tube and the nozzle. Filament was collecting there, clogging the hotend.

Thanks everybody for your help!

Good!