Problem with extrusion, too few

Hi guys, i write here because i really don't know what to do at this point.
After unstopped the nozzle several times, I finally managed to print something bad
But I noticed that if I push hand, the thread of the PLA with the hands, the material goes out without problems and is also fluid and continuous. But if I start printing then I get that thing there. I left half piece to the printer to print at 200 ° and the result was always the same, the other half I pushed a little 'the thread by hand, giving help to the engine of the extruder and .... like magic has printed very well the other half, without making any noise.
So it's as if I should increase the strength of the extruder. I tried to change the settings of slicing:
95% flow and 200 °
95% flow and 210 °
100% flow and 200 °
100% flow and 210 °

The best result (if this can be defined better) I obtained at 95% and 210 °, but in any case it is not acceptable even visually.

I no longer know what to do:

-I Unstopped several times the nozzle and checked if it worked hand pushing
-I Controlled motor steps extruder
-I Controlled ventilation sink
-I Tried various settings slicing
-I Increased the vref of the extruder motor
-I Increased the maximum acceleration for the extruder

I always this damn problem:
little material is extruded, a quantity not sufficient, resulting in difficulty of adherence to the plate and "tac tac" of the engine (do not know how to describe it).
Only very few times, almost never, the PLA crackles 1 time, it's this whole mega problem? is so rare that I do not think, in any case not being able to bake what can I do?
In the last reply here you can find the images.
I have a reprap prusa i3 with ramps 1.4, marlinkimbra, and E3D hotend bowden extruder.
I swear you can help me, thanks

Edited 1 time(s). Last edit at 01/06/2016 11:13AM by Salvatore94.

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Stampante: RepRap prusa i3 con estrusore bowden
Software: MarlinKimbra

Tak Tak usually means you are loosing steps.
Don't know your extruder but if you can push by hand it should not have any problems at all.
Place the nozzle at first layer height on the plate and extrude 5 or 10mm - it should all ooze out around the nozzle.
If it does not and your extruder starts clicking you have a problem with it.

Did you calibrate your extruder? There can be 10% variation in steps/mm from standard. Also filament can vary by 10% from 1.75mm... you should measure it and adjust the slicer settings correspondingly.

E3D hotends (and especially cheap Chinese "copies") don't like retraction. This can cause the 'tak tak' problem. Make sure that the retraction is set to less than 1mm in your slicer.

If the nozzle is too hot, it can also cause this problem. I print PLA at 190. The cooling fan on your hot end should be on all the time.

Increasing the acceleration of the extruder stepper is likely to make the problem worse, not better. If you try to accelerate a stepper more than it can manage, it will skip (tak, tak).

I don't think this is the problem, but if your nozzle is too close to the bed, it can also cause jams.

Try using the extrude command in your user interface to extrude when the nozzle is up in the air. How well does that work?

I had this issue with two of my printers.
The steps I took to fix it were:
1: Check and adjust the Z- Gap between your nozzle and the print bed-use a piece of paper as a spacer.
2: Check your Hobbed gear on the extruder motor to make sure it isn't packed full of chipped off filament.
3: Watch the gear as you try to print- does it stop? Does is spin too quickly and filament doesn't move? If it does either of those, Its probably an issue with your tension on the filament.

Give those steps a try, and it the problem persists, we can continue troubleshooting.
Good luck!


-Derek

Quote
frankvdh
Did you calibrate your extruder? There can be 10% variation in steps/mm from standard. Also filament can vary by 10% from 1.75mm... you should measure it and adjust the slicer settings correspondingly.

E3D hotends (and especially cheap Chinese "copies") don't like retraction. This can cause the 'tak tak' problem. Make sure that the retraction is set to less than 1mm in your slicer.

If the nozzle is too hot, it can also cause this problem. I print PLA at 190. The cooling fan on your hot end should be on all the time.

Increasing the acceleration of the extruder stepper is likely to make the problem worse, not better. If you try to accelerate a stepper more than it can manage, it will skip (tak, tak).

I don't think this is the problem, but if your nozzle is too close to the bed, it can also cause jams.

Try using the extrude command in your user interface to extrude when the nozzle is up in the air. How well does that work?

I haven't change the extruder but only the hotend, anyway i've calibrated it and nothing change. If i extrude when the nozzle is, up the PLA goes without any problems , leaves a straight and continuous filament (at 200°).

Quote
Downunder35m
Tak Tak usually means you are loosing steps.
Don't know your extruder but if you can push by hand it should not have any problems at all.
Place the nozzle at first layer height on the plate and extrude 5 or 10mm - it should all ooze out around the nozzle.
If it does not and your extruder starts clicking you have a problem with it.

Yes it does without problems

Quote
Kered124
1: Check and adjust the Z- Gap between your nozzle and the print bed-use a piece of paper as a spacer.
2: Check your Hobbed gear on the extruder motor to make sure it isn't packed full of chipped off filament.
3: Watch the gear as you try to print- does it stop? Does is spin too quickly and filament doesn't move? If it does either of those, Its probably an issue with your tension on the filament.

Yes i did each of 3 steps but no problems and no results:
1: the paper is free to move but i can feel the nozzle
2: Hobbled gear is clean
3: What i see sometimes is that the filament goes back with the hobbled bolt and the motor does "tak tak"

I saw that even when motor doesn't have problems, the extrusion is too few and the print is not good.

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Stampante: RepRap prusa i3 con estrusore bowden
Software: MarlinKimbra

It is either the currents supplied from the step stick is insufficient or the tension is too strong on the extruder

Quote
sarf2k4
It is either the currents supplied from the step stick is insufficient or the tension is too strong on the extruder

What do you mean with tension on the extruder? The motor's voltage?

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Stampante: RepRap prusa i3 con estrusore bowden
Software: MarlinKimbra

Quote
Salvatore94

Quote
sarf2k4
It is either the currents supplied from the step stick is insufficient or the tension is too strong on the extruder

What do you mean with tension on the extruder? The motor's voltage?

I think he means the tension on the extruder spring. But I don't think it's possible to have too much tension.

Try this:
1. Heat to 200
2. Extrude 5mm a couple of times via user interface
3. Retract 5mm
4. Extrude 5mm

I suspect that you'll find that this will cause a jam.

What slicer are you using? What settings do you have there, especially retraction?

Depending on your hotend design it is quite possible that your melting chamber is much wider in diameter than the cold end / teflon tube.
Especially when printing with the correct emperature (that means not too hot) those systems tend to fail as the plastic forms a blob in the lower bit of the telfon tube, or the cold end itself on an all metal design.
In such cases it is often easier to buy a cheap knock off hotend to have a direct flow to the nozzle.
This means the inside diameter of the the system does not change until reaching the nozzle itself.

Adding to what the previous guy said... it's important to properly assemble the hot end. Otherwise you also get a large diameter chamber.

I've posted thee process several times here, but if you can't find it, let me know and I'll post it again.

Quote
Downunder35m
Depending on your hotend design it is quite possible that your melting chamber is much wider in diameter than the cold end / teflon tube.
Especially when printing with the correct emperature (that means not too hot) those systems tend to fail as the plastic forms a blob in the lower bit of the telfon tube, or the cold end itself on an all metal design.
In such cases it is often easier to buy a cheap knock off hotend to have a direct flow to the nozzle.
This means the inside diameter of the the system does not change until reaching the nozzle itself.

How can i verify it?

Quote
frankvdh
Adding to what the previous guy said... it's important to properly assemble the hot end. Otherwise you also get a large diameter chamber.

I've posted thee process several times here, but if you can't find it, let me know and I'll post it again.

I've tried and the motor does "tak tak" when i extrude 5mm before retracting, but only sometimes, after retracting it doesn't make noise

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Stampante: RepRap prusa i3 con estrusore bowden
Software: MarlinKimbra

It almost works
I had to set 220° and lowered the printing speed, now i have a good print but i have a problem with the first layer.
It always has less material and too much space between the fill.
What can i do? aren't 220° too much for PLA?

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Stampante: RepRap prusa i3 con estrusore bowden
Software: MarlinKimbra

Sounding like a partial clog. Higher temps will let plastic get through easier.

"I don't think it's possible to have too much tension" -- With softer filaments (like PETG that I use), I've had the high tension flatten the filament so that it had trouble getting through the pathway; especially on multiple retractions. I even took one of the springs out so it would only have half the tension.