need Ideas as not enough extrude from hotend

Hi all

I was having issues with my wade extruder so thought I'd go Bowden.

so now its all set up and it feeds 50mm when I tell it to however when the hotend is attached and i try to print something the extruded plastic(PLA) runs fine for a while then seems to 'run out'
it keeps coming out in bits that makes the structure like spider web.

I thought maybe not hot enough so i up'd the temp to 210 but still the same.

I thought about slippage in the feeder and yes this does start but the reason seems to be because it has no where to go. if i manually push the pla through it hardly moves and just trickles out the hotend.
I've dismantled the hotend and cleaned it out, that's a hot job lol, and i have also then been able to see the 0.5mm hole on the end with light coming through but it just happens again a layer or so again
in the print.

I've clamped the feeder down tight and no improvement.

Please someone, any ideas??

210 sounds ridiculously hot for PLA, I print at 185/186.

Could this be a slicer problem? Are you using 1.75 or 3mm PLA ? What is it set to in slicer?
Usually I'd say, calibrate your extruder, but if you've done that, I'd measure your filament with a micrometer/caliper and put that in your slicer.

I'd check all your slicing settings are the same as the filament/nozzle and you've not got a high retract value.
(1.5-2.5mm as a start for retract with a bowden)

hope that helps a bit.

Quote
DaveS
210 sounds ridiculously hot for PLA, I print at 185/186.

Could this be a slicer problem? Are you using 1.75 or 3mm PLA ? What is it set to in slicer?
Usually I'd say, calibrate your extruder, but if you've done that, I'd measure your filament with a micrometer/caliper and put that in your slicer.

I'd check all your slicing settings are the same as the filament/nozzle and you've not got a high retract value.
(1.5-2.5mm as a start for retract with a bowden)

hope that helps a bit.

I thouhgt that but it was giving me better results at first. its 3mm pla and .5mm nozzle. and like i say the feeder sends through what i ask as i thought of calibrating that first too.
the filament is set to 2.92mm, extrusion multiplier 1.

Ive tried different feed rates from 15mm to 120mm and it makes no change?? I'll change it back to 186 and see what happens.

Feed rates above 40 mm/sec will be tough to do with any 3mm extruder, let alone a Bowden. I would set a max in your firmware at or below that and move on.

1.75 mm PLA is a bit more common for a Bowden. You sort of feed a bit faster, but have less back pressure.

What are you using for a tube? How smooth is it? How clean is it? How tight is it?

What sort of hot end are you using? How well does it hold temperature?

How dry is your filament?

Quote
uncle_bob
Feed rates above 40 mm/sec will be tough to do with any 3mm extruder, let alone a Bowden. I would set a max in your firmware at or below that and move on.

1.75 mm PLA is a bit more common for a Bowden. You sort of feed a bit faster, but have less back pressure.

What are you using for a tube? How smooth is it? How clean is it? How tight is it?

What sort of hot end are you using? How well does it hold temperature?

How dry is your filament?

Hi

Ive changed the feed rate to 30mm/sec along with halfing the print speeds.

I'm using ptfe tube with 3.2mm inner diameter. initially i had the PLA reel in a plastic box at the back of the printer, the feeder attached to this box and then the tube going
to the hotend which ment the tube was a good 600-700mm. I think the fit is to tight for this length so i have moved the feeder to above the x axis, making the tube length
about 400mm. Ive then got the other bits of tube from the PLA box to the feeder. Trying to keep the PLA as dry as i can.

The hotend is from this. [reprapworld.com]

If i can believe the temp I get through repetier then setting the temp to 186, and it bounces between 185 and 187. averaging 186. which sounds good to me.

How do i know how dry my filament is?? its only recently started to be kept in the plastic feed box and has a pack of silica in it.

cheers for any help

Do you have a fan on the top of your hot end?
From your description it sounds like the PLA is swelling in the hot end creating too much back pressure.

Also, it sounds like you calibrated without the hot end in place. I have always calculated with the
hot end on so that any minor slippage/back pressure is accounted for. But if you can't get it to
extrude consistently then it will be hard to calibrate.

Quote
bytemedwb
Do you have a fan on the top of your hot end?
From your description it sounds like the PLA is swelling in the hot end creating too much back pressure.

Also, it sounds like you calibrated without the hot end in place. I have always calculated with the
hot end on so that any minor slippage/back pressure is accounted for. But if you can't get it to
extrude consistently then it will be hard to calibrate.

Hi no I don't. I have a fan down on the print but not the PTFE. I have pulled it out of there before and its been swollen so maybe I'll try that. thank you all