Printrbot Simple Metal - Printing Issue

Troubleshooting talk for software

Printrbot Simple Metal - Printing Issue

Postby xxxMTIxxx » 2015-Mar-Mon-13-Mar

Hey guys. I've had my Printrbot Simplet Metal with heated bed upgrade for about 4 days now, and I seem to have a small issue. I don't think it's a hardware issue, so I'm posting in the software forms for that reason. Originally, I was able to print some decent quality items. See the image attached that looks like a gaming controller. Although it's not finished, the outside of the print and the honeycomb infill are decent. Ever since that print, I'm unable to get anything near that quality. See the other images attached. I've played around with the flow, nozzle and bed temps, etc... As I'm watching the job print, every so often the filament seems to thin out and leave little drops, then it will look normal, then thin out again. When it does this thinning, it messes up the foundation for the rest of the print to lay on. I feel like I've got the Z height set correctly, but I guess I could be wrong. Tonight I plan on resetting back to Cura defaults and opening the Getting Started profile again, and trying out Repetier to see if helps. Any help is greatly appreciated.

Thanks,
Paul
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Printrbot Simple Metal - Printing Issue

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Re: Printrbot Simple Metal - Printing Issue

Postby RetireeJay » 2015-Mar-Mon-15-Mar

I doubt it's a software problem. You could verify that by re-running the exact G-code that you used for the first print.

An occasional thinning out of the extruded trace means exactly what it seems to mean: not enough plastic is getting extruded. The "gear" that pushes incoming plastic down into the throat of the Hot End has to both PULL against the resistance of the viscous molten plastic to force it to come out the nozzle, and it also has to PULL against the resistance of the source of the plastic coming to the extruder. If your "feed" setup has too much resistance, it can cause this. Or, if your nozzle is partly clogged it can cause this.

The colors look different between the successful and unsuccessful tries; is this just due to the lighting and exposure of how you took the picture, or did you actually use different filament? Sometimes different filaments require small adjustments in temperature of the Hot End to extrude properly.

If your nozzle-to-bed clearance is essentially zero for the first layer, then no plastic can come out during the first layer. This can cause the extruder drive gear to either "click" (the motor has too little torque to force the filament through, so it jumps back a full step or two) or else the extruder drive gear to chew against the filament, filling its "teeth" with plastic so that it becomes less effective pushing filament through on later layers. Also, if you are using PLA, having plastic stay "stuck" in the heated area is a bad idea because can "char" and become immovable. There are dozens of threads about extruder jams, so if that's the issue, just search on this forum.
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Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3
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Re: Printrbot Simple Metal - Printing Issue

Postby xxxMTIxxx » 2015-Mar-Mon-15-Mar

Thanks for the quick reply! I don't believe there is that much resistance when the extruder pulls from the source. The printer is sitting next to the wall, and I have a spool wrack mounted directly above it on the wall. That being said, there isn't much tension coming from the source at all. I have check the nozzle, and I don't believe it's clogged. I have cooled it down to about around 100c and another time at around 80c, and both times the filament stretched a bit then popped out. I'm also able to manually extrude the filament and it comes out steady. I did notice however that it doesn't extrude as much sitting idle anymore. It does, but not like it was originally. Should I heat it up a little, pull the filament out, and stick something through the pin hole on the bottom of the hot end? (I can research this myself. Just thinking out loud right now.)

The color was the same. I've only got two colors at the moment, orange and white. Both are PLA. I tried going back to white, thinking the orange may have moisture, but I'm seeing the same functionality as with the orange with it too, now. (Neither color had the issue originally.) As far as the lighting, my wife took the picture that looks like a controller, and I took the others. That's got to be just a lighting issue.

As far as the extruder gear, it doesn't click or have filament in the teeth. It appears to be clean. I've also checked it's grip on the filament itself, and it seems to be pretty firm so I know it's not slipping. The filament doesn't look eaten up either.

I'll research cleaning the hot end and go from there. I'd run the g-code again from the original print, but I admittedly didn't save it. (Unless it's auto saved somewhere. Sorry, I'm still learning.) I've just been loading the STL files in Cura and printing.
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Re: Printrbot Simple Metal - Printing Issue

Postby xxxMTIxxx » 2015-Mar-Mon-20-Mar

RetireeJay wrote:I doubt it's a software problem. You could verify that by re-running the exact G-code that you used for the first print.

An occasional thinning out of the extruded trace means exactly what it seems to mean: not enough plastic is getting extruded. The "gear" that pushes incoming plastic down into the throat of the Hot End has to both PULL against the resistance of the viscous molten plastic to force it to come out the nozzle, and it also has to PULL against the resistance of the source of the plastic coming to the extruder. If your "feed" setup has too much resistance, it can cause this. Or, if your nozzle is partly clogged it can cause this.

The colors look different between the successful and unsuccessful tries; is this just due to the lighting and exposure of how you took the picture, or did you actually use different filament? Sometimes different filaments require small adjustments in temperature of the Hot End to extrude properly.

If your nozzle-to-bed clearance is essentially zero for the first layer, then no plastic can come out during the first layer. This can cause the extruder drive gear to either "click" (the motor has too little torque to force the filament through, so it jumps back a full step or two) or else the extruder drive gear to chew against the filament, filling its "teeth" with plastic so that it becomes less effective pushing filament through on later layers. Also, if you are using PLA, having plastic stay "stuck" in the heated area is a bad idea because can "char" and become immovable. There are dozens of threads about extruder jams, so if that's the issue, just search on this forum.


You were absolutely correct! I was able to unscrew the brass from the hot head and there it was! Thank you so much! Quick question for you. Should I leave the filament in while not using it, or should I try to keep it clean after every use? Thanks again!
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Re: Printrbot Simple Metal - Printing Issue

Postby RetireeJay » 2015-Mar-Mon-21-Mar

I take the nozzle off my extruder only when I have to.
I'm not sure if PLA absorbs moisture, but if it doesn't then I see no reason to take it out. Just don't leave it sitting in the nozzle when it's hot. Keep it moving.
  • 0

Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3
User avatar
RetireeJay
My next printer is...
 
Posts: 4991
Joined: 2013-Jan-Wed-13-Jan
Location: Greenville, SC
Reputation: 498


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