Solved Extruder not always extruding on bottom layer.

Hello all!

Right now I am using Hatchbox green PLA 1.75mm
200c ext
35c bed

This is the second major problem that I've had with this printer. Lets hope it doesn't take me two months to fix it like last time.

Anyway, there seems to be spots in the layers that the filament stops moving in the extruder(but the gears are still moving), thereby creating the gaps seen below. I turned the temp up to 250c, which seemed to fix the problem, but I got crazy stringing and parts were not sticking together.

(note on the picture: it's not flat on the bed because I took it with my camera and had SD card issues, so I used my phone but I had already taken it off the bed.)

Thanks!
Eric

 

Did you try seasoning the hot end. Dip the filament into something like canola oil then reinsert it back into the hot end and run a test print. Mine was doing something similar


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Thank you all for responding so quickly!

I will try seasoning a little later in the day(errands to run) and I will get back with you all.

Thanks Again!
-Eric

 

I am using Cura 15.04.6
I don't know what a global parameter is, sorry.

My gcode is as follows:
G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
M107
M565 Z-.2 ;start with the fan off
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops
G29;
G1 Z15.0 F{travel_speed} ;move the platform down 15mm
G92 E0 ;zero the extruded length
G1 F200 E3 ;extrude 3mm of feed stock
G92 E0 ;zero the extruded length again

I know the comments are off, but I'm not sure what goes to what.
G1 F{travel_speed}

I just seasoned the head and I am testing a print now. From what I could gather, I just dipped the first half inch or so in canola oil, then fed it through the extruder. Is that correct?

Anyway, I will post back with pictures when either the print is done, or I deem it a failure.

Thanks so much guys! Couldn't do it without you!

-Eric

 

I use one of these filament oilers:
http://www.thingiverse.com/thing:1460566
He shows a vesion with a bell, I don't use that one.
I use some foam and a few drops of canola oil (higher flash point) for each new spool I load up.
It also filters off any dust that is on the roll so it doesn't get into the nozzle.
Since using it I haven't had a jam so far.
I've never "seasoned" the nozzle or dipped the filament but if it works, great.

 

Yup that's correct


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Here is my latest print(this is just a 50x50x3mm model.

As you can see below I'm still having the same problem. I might have an idea however. When observing this print, I lightly feel the filament as it goes into the extruder. It(the filament) stops moving whenever there are gaps in the print(or there are gaps when it stops moving), but the gears keep moving. Then shortly after the filament starts moving again, and prints fine until it happens again.

What about that gear inside that actually moves the filament? Could there be some sort of deformity? Because looking at this picture, all the parts that aren't printed seem to be pretty evenly spaced.

Also, my printer came with a tube of "Tube Lube" maybe that was supposed to used to season the extruder?
Thanks,
-Eric

(I had to post this picture on a different site then give a link because "it was too big for the server to process")

http://tinypic.com/r/14d0qau/9

 

Loose belts maybe


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How tight are the two srews on the extruder gate? I hand tight mine until they stop.

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Sorry, do you mean the two extruder tensioner screws that are on the top the the extruder assembly?

 

Yup. I once had mine loose enough to squeeze open but mine skipped. I tightened them up finger tight and never looked back.

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I have tightened the screws while printing, (two rotations per layer) and it does help very much. In fact, i do believe that is the solution! I will run a few more prints, but this is definetly the right track.

Thanks!
-Eric

 

@Electonic your startup gcode is missing the M565 Z-#.## command where # are digits defining you z offset. That command should go between the G28 and G29 commands. Start with M565 Z-0.8 and go from there.

 

Thank you all for sticking with me! Turns out it was the combination of the oiler and the extruder tension that fixed the problem.

Thanks again!

-Eric

 

Man I was tired last night. Didn't notice you actually did have M565 called out in your gcode. Sorry about that.