Some layers aren't well printed

[Lmecano]

Hello,


I have a strange problem. The part is well printed except... some layers ! Do you have any ideas where this problem comes from ?
And I'm quite impressed the printer sucessed to finish the part !










Thank you for your time !


Good prints !

[3dkarma]

Looks like filament starvation. Could be a number of things. It would help to know what you're printing with (PLA or ABS), what your print temperature is, what kind of hotend / printer you're using.

For example, if it's PLA, it could be heat creep up the hotend causing filament expansion and temporary blocking, which could be solved with a fan directed at the heat break. It could be gunk in the hot end, which would necessitate cleaning. If you're using a bowden setup, it could be excessive friction in the tube causing skipping or grinding on the filament. It might be solved by increasing the guilder tension. It could be caused by too low a current limit in the extruder stepper.

tl;dr: could be lots of things; please post your setup.

Edit: just occurred to me that it could also be the vref on your extruder motor being too high. It could be overheating and skipping steps until it cools down.

[Lmecano]

Looks like filament starvation. Could be a number of things. It would help to know what you're printing with (PLA or ABS), what your print temperature is, what kind of hotend / printer you're using.

For example, if it's PLA, it could be heat creep up the hotend causing filament expansion and temporary blocking, which could be solved with a fan directed at the heat break. It could be gunk in the hot end, which would necessitate cleaning. If you're using a bowden setup, it could be excessive friction in the tube causing skipping or grinding on the filament. It might be solved by increasing the guilder tension. It could be caused by too low a current limit in the extruder stepper.

tl;dr: could be lots of things; please post your setup.

Edit: just occurred to me that it could also be the vref on your extruder motor being too high. It could be overheating and skipping steps until it cools down.

I'm printing with blue PLA on a K8200 printer with an ebay extruder.
The extruder : http://www.ebay.com/itm/HIGH-Torque-...E:L:OC:FR:3160
I'm using the fan manually at 60%.

I'm agree with you for the filament blocking in the junction between cold and hot end. That happened while I didn't use the fan, I don't have jamming anymore.

The voltage in Extruder stepper motor is quite high for a K8200, I set 0,6V on driver. I don't know what is the current in the stepper motor but there is no noise from it and it's quite cold thanks to the fan.

My slicer set-up. Moreover, I discovered a strange thing... My extruder T° is set to 180°C, but in the GCODE, I have that, wtf ?

M190 S45 ; wait for bed temperature to be reached
M104 S180 ; set temperature
G28 ; home all axes
G90 ; use absolute coordinates
G21 ; set units to millimeters
G92 E0
M82 ; use absolute distances for extrusion
M109 S190 ; wait for temperature to be reached

Besides, I printed an helicoïdal gear and the part is globally well-printed except some teeth !





Dat crazy printer !

EDIT : I measured 61°C for 0,6V. What is the max temperature for a stepper motor driver ? I set the E-driver to 0,48V and I measured 51°C.

[Lmecano]

I'm back with some news !

The extruder was guilty ! He asked to much current from the driver and sometimes, he lost some steps !

I fixed the original Velleman extruder and mount it, the printed part are less accurate (wrong setup, I guess) but there is no lack of plastic !

To help the driver to evacuate the energy, I glue with epoxy a heatsink with a thermic pad.

Besides, I find something strange in setup for Velleman extruder, the extrusion multiplier is to 1.15 and with 600step per mm, I don't extruder the right amount of plastic. I guess the 1.15 factor is here to correct the step per mm and extrude the right amount of wire but... why not enter the right number of step per mm ??


Thank you for your help guys !

[Roxy]

I'm back with some news !

The extruder was guilty ! He asked to much current from the driver and sometimes, he lost some steps !

I had an early problem with my RepRap kit. My extruder motor was kind of whimpy. I put a monster drive gear on the hobbled bolt so the motor had a very low gear ratio. Everything has been fine since I did that.

http://3dprintboard.com/showthread.p...nsive+extruder

This was definitely a 'brute force' solution. But it worked for me.

[3DPBuser]

Note that the problem layers begin where the part has cutouts. This is where the extruder would stop extruding and would jump over the cutout for the first time.

[Lmecano]

I'm back !


Every huges problems are fixed !


The problem was plastic delamination, I followed the triffid hunter guide for nozzle temperature and found 175°C. It was wrong, that PLA needs to be extruded at 185°C and 190°C for the first layer.
Besides, I modified the set-up of wire tension with the screw and so... It changed my E step. I'm now at 703 step/mm for E-motor. I was at 645.5 before.


And, I added an 24V supply for the bed. It's faster to heat up the bed to 60°C for PLA, but I have to wait around 20min to reach 110°C.
For information, I added lots of ferrite cores and increase driver voltage to 0,6V for X-Y axis or theses axis lost steps.
Moreover, I added an voltage regulator to get 12V for the motherboard fan and cool end fan.
And... I observed the Z axis is wobbling so I update the Z axis with flexible coupler.


Sphere in sphere in sphere !



New Z axis



Electronic