Smudging In Same Spot

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Smudging In Same Spot

Postby Awhedbee22 » 2017-Jan-Sun-15-Jan

I am very new with my printer and have had very minimal success. I have a older printrbot simple metal. It seems no mater what model I print it smudges in the same area. Even if I move the model to print in different part of the board. I have already calibrated z. If I let it go it then clogs and then turns to a giant blob. Any thoughts?

IMG_1974.JPG


IMG_1973.JPG
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Smudging In Same Spot

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Re: Smudging In Same Spot

Postby RetireeJay » 2017-Jan-Sun-15-Jan

Mostly this looks like a problem with bed adhesion. The first layer has to stick well to the bed, otherwise you just end up with a blob. There are hundreds and hundreds of posts about getting good bed adhesion. Happy searching!
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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
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Re: Smudging In Same Spot

Postby Awhedbee22 » 2017-Jan-Sun-16-Jan

RetireeJay wrote:Mostly this looks like a problem with bed adhesion. The first layer has to stick well to the bed, otherwise you just end up with a blob. There are hundreds and hundreds of posts about getting good bed adhesion. Happy searching!


I get great adhesion. There isn't warping bring it up or anything. In those areas it seems to push extra filament or go on top of the previous line. If I let it continue running I get a giant ball of filament.
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Re: Smudging In Same Spot

Postby RetireeJay » 2017-Jan-Sun-20-Jan

Awhedbee22 wrote:I get great adhesion. There isn't warping bring it up or anything.

I guess I don't understand. In your first and second pictures, there is a portion of the model, close to the camera, that is clearly warped upwards. Have you already peeled this up from the bed and the picture was taken after un-sticking it from the bed?

On the other hand, sometimes, if you are extruding significantly too much material for the layer thickness, you can get "bulldozing" where the nozzle plows through plastic leaving a "bulldozed" path with ridges on either side of the nozzle. This is generally only a problem on the first layer, caused by having the Z clearance set a little too low. But if it's serious, the model never recovers; you just keep on building up and pushing around excess plastic until finally the nozzle snags the model and lifts it off the bed. After that, you only get bird's nests and blobs.
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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
User avatar
RetireeJay
My next printer is...
 
Posts: 4666
Joined: 2013-Jan-Wed-13-Jan
Location: Greenville, SC
Reputation: 477

Re: Smudging In Same Spot

Postby Awhedbee22 » 2017-Jan-Sun-21-Jan

RetireeJay wrote:
Awhedbee22 wrote:I get great adhesion. There isn't warping bring it up or anything.

I guess I don't understand. In your first and second pictures, there is a portion of the model, close to the camera, that is clearly warped upwards. Have you already peeled this up from the bed and the picture was taken after un-sticking it from the bed?

On the other hand, sometimes, if you are extruding significantly too much material for the layer thickness, you can get "bulldozing" where the nozzle plows through plastic leaving a "bulldozed" path with ridges on either side of the nozzle. This is generally only a problem on the first layer, caused by having the Z clearance set a little too low. But if it's serious, the model never recovers; you just keep on building up and pushing around excess plastic until finally the nozzle snags the model and lifts it off the bed. After that, you only get bird's nests and blobs.


Sorry, I guess I should of been clear on that image. So what is going on is its sticking very well, but as it comes around to the start the next row it floods with more it seems causing blobbing. Then when it stacks up a bit more and then it catches and pulls it up and floods out. Exactly what u stated above. So maybe I'm not calibrated properly...
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Awhedbee22
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Re: Smudging In Same Spot

Postby RetireeJay » 2017-Jan-Mon-08-Jan

1) When it comes to the quantity of filament to extrude, the slicer (in your computer) calculates it based on the Volume of plastic needed to fill in the trace correctly (layer height X layer width X trace distance until the next turn or stop). The slicer uses the filament diameter that you gave it and calculates the Extruded Length of filament needed to create the Volume. The Extruded Length is what it embeds in the G-code sent to the printer.

tl;dr: You need to make sure that the filament diameter you specify in the slicer is equal to the ACTUAL filament diameter you are using. It's best to measure with digital calipers (knowing that the filament may be a bit oval, so you measure the largest and smallest "diameter" you can discover at a point on the filament and take the average). If you don't have digital calipers, you'll have to use the default - probably 1.75.

2) When it comes to extruding the desired quantity, Marlin (in the printer itself) relies on the Extruder calibration in steps per millimeter. In other words, the slicer sends a demand for X millimeters, and Marlin translates that into X * E to find out how many steps to send to the stepper motor. While X, Y, and Z calibrations are determined quite exactly by the mechanical parts used, the E calibration is a bit less pre-determined. So you should verify your E calibration (there have been many posts about how to do that).

3) Once you have the right numbers for both filament diameter and Extruder steps per mm, then your slicer's "Extrusion Multiplier" should be 1.0 or very close to it. The E.M. is available to you for fine tuning to get the very best result; change it in increments of 0.05 to get the extruded quantity perfect.
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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
User avatar
RetireeJay
My next printer is...
 
Posts: 4666
Joined: 2013-Jan-Wed-13-Jan
Location: Greenville, SC
Reputation: 477


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