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Topic: Strange pattern on first layer

Not sure what's causing this, maybe uneven heating of the print bed? Here are some pictures right after printing the first layer. I just dialed in the z-height. Anything higher than this and the corners don't stick whatsoever. Is it still too high? I feel printing lower causes the filament to bunch up against itself. Or could it be the blue tape? Should I put it on before or after the bed is heated?

https://dl.dropboxusercontent.com/u/8410101/IMG_6871.JPG

https://dl.dropboxusercontent.com/u/8410101/IMG_6872.JPG

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Re: Strange pattern on first layer

It's probably not the tape.

How steady are your extruder temps?  When mine gets too cold the filament isn't smooth (as you said).  Just wondering if your temp dropped too low, though that doesn't look the same as your pic.  Unless perhaps the first layer was too cold, the second covered that up, and the print is on layer 3+?

Do you have a heated bed?  If so, you can print hotter and make your bed hotter.  That should help the PLA stick better.

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Re: Strange pattern on first layer

3d-oodler wrote:

It's probably not the tape.

How steady are your extruder temps?  When mine gets too cold the filament isn't smooth (as you said).  Just wondering if your temp dropped too low, though that doesn't look the same as your pic.  Unless perhaps the first layer was too cold, the second covered that up, and the print is on layer 3+?

Do you have a heated bed?  If so, you can print hotter and make your bed hotter.  That should help the PLA stick better.

What you're seeing is one layer down, and the second one just starting. I'm about an hour into that same print, and it seems like it's sticking pretty well considering a .4 infill. Or is this not supposed to be happening. I didn't want to turn up the heat because the filament tends to change colors and carbonize when it gets much hotter than 195/190 and I definitely don't want to risk another jam.

Adhesion to the bed could be better I suppose, maybe I'll try Kapton again, though I don't remember being all that impressed with it. Got a roll that's maybe 2 years old, it doesn't break down over time does it?

Here are some pics of that same print about an hour in:

https://dl.dropboxusercontent.com/u/8410101/IMG_6880.JPG
https://dl.dropboxusercontent.com/u/8410101/IMG_6881.JPG
https://dl.dropboxusercontent.com/u/8410101/IMG_6880.JPG

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Re: Strange pattern on first layer

Try using a brim...about 5mm.

SD2 - Stock - Enclosure - Heated Bed - Glass Plate - Auto Fire Extinguisher
Ord Bot Hadron - RAMPS 1.4 - Bulldog XL - E3D v6 - 10" x 10" PCB Heated Build w/SSR - Glass Plate
Thanks for All of Your Help!

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Re: Strange pattern on first layer

I have had this same pattern occur when using nylon on garolite.  The garolite was not heated so I doubt its an issue of uneven heating of the bed.  I suspect moisture in the filament could be the cause of this.

SD2 with E3D, SD Press, Form 1+
Filastruder
NYLON (taulman): http://www.soliforum.com/topic/466/nylon/

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Re: Strange pattern on first layer

DePartedPrinter wrote:

I have had this same pattern occur when using nylon on garolite.  The garolite was not heated so I doubt its an issue of uneven heating of the bed.  I suspect moisture in the filament could be the cause of this.

Do you know if moisture in the filament gets there? Is it the storage or the manufacture of the filament, cause this is some pretty cheap filament if I recall correctly.

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Re: Strange pattern on first layer

I had similar issues in the beginning and kind of narrowed it down to moisture in the filament.  Now I keep my filament in a plastic craftsman tool box with a spare Golden rod dehumidifier I had from my gun safe. Seems to working well lately

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Re: Strange pattern on first layer

I would personally advise Kapton with hairspray (aquanet is awesome and cheap).  Spray it on a paper towel and then daub and spread on.  Also, using an extrusion multiplier of 250% for the first layer helps adhesion tremendously without causing a loss of detail for the other layers.  I never get curling anymore with those two tricks.

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Re: Strange pattern on first layer

joshhunsaker wrote:

I would personally advise Kapton with hairspray (aquanet is awesome and cheap).  Spray it on a paper towel and then daub and spread on.  Also, using an extrusion multiplier of 250% for the first layer helps adhesion tremendously without causing a loss of detail for the other layers.  I never get curling anymore with those two tricks.

+1

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Re: Strange pattern on first layer

johnforeman wrote:
joshhunsaker wrote:

I would personally advise Kapton with hairspray (aquanet is awesome and cheap).  Spray it on a paper towel and then daub and spread on.  Also, using an extrusion multiplier of 250% for the first layer helps adhesion tremendously without causing a loss of detail for the other layers.  I never get curling anymore with those two tricks.

+1

What software do you use to print? I don't see specific first layer settings for flow rate in Repetier.

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Re: Strange pattern on first layer

gettingbored wrote:
johnforeman wrote:
joshhunsaker wrote:

I would personally advise Kapton with hairspray (aquanet is awesome and cheap).  Spray it on a paper towel and then daub and spread on.  Also, using an extrusion multiplier of 250% for the first layer helps adhesion tremendously without causing a loss of detail for the other layers.  I never get curling anymore with those two tricks.

+1

What software do you use to print? I don't see specific first layer settings for flow rate in Repetier.


In RH/slicer config/print settings/advanced I think there is a first layer with setting in percent or mm.

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Re: Strange pattern on first layer

Hum I see settings for extrusion width, is that what you're refering to? Also, there is a "Flow" section but the only variable mine contains is "Bridge flow ratio"

Does your software have more options? haha

13 (edited by joshhunsaker 2013-09-27 17:47:00)

Re: Strange pattern on first layer

gettingbored wrote:

Hum I see settings for extrusion width, is that what you're refering to? Also, there is a "Flow" section but the only variable mine contains is "Bridge flow ratio"

Does your software have more options? haha

Right under "default extrusion width" there should be a "first layer" setting.  You can punch in a percentage amount.  This is in Slic3r 0.9.7.

That's funny, I can see you're building the same carriage upgrades I am wink

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Re: Strange pattern on first layer

joshhunsaker wrote:
gettingbored wrote:

Hum I see settings for extrusion width, is that what you're refering to? Also, there is a "Flow" section but the only variable mine contains is "Bridge flow ratio"

Does your software have more options? haha

Right under "default extrusion width" there should be a "first layer" setting.  You can punch in a percentage amount.  This is in Slic3r 0.9.7.

That's funny, I can see you're building the same carriage upgrades I am wink

Heh, I already printed them and installed them. Still, the rods that came with the Solidoodle are pretty rough, and the bearings tend to make a bit more noise than I'd like. If there was a local place to get smooth metric rods that are plated or polished I'd upgrade them in a second. I highly recommend getting new rods with the upgrade for maximum smoothness and quietness.

My Slic3r version is 0.9.10b sooooo I don't even know. Seems like you have a higher version, but are you on a Mac or a PC? I'm on a Mac, but I didn't think the software was any different at all.

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Re: Strange pattern on first layer

I am having the same problem with a large flat plate. I can confirm it is -not- a problem with the filament picking up moisture. I went from the solidoole blue that sat on the spool for a few months, to a brand new roll of octave white, which had little time to pick up moisture (Maybe 5 min, tops).  The problem still occurs.

I'm still trying to figure it out.

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Re: Strange pattern on first layer

gettingbored wrote:

My Slic3r version is 0.9.10b sooooo I don't even know. Seems like you have a higher version, but are you on a Mac or a PC? I'm on a Mac, but I didn't think the software was any different at all.

I'm on PC (Windows 8).

I also found out that the actual metal print bed on my unit isn't actually flat!  The stupid thing bows to be closer to the nozzle in the middle.  Ugh.  Eventually I'm going to just use this to help me build a completely different 3d printer...

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Re: Strange pattern on first layer

I had that problem as well. Somewhere around here there are posts from someone who used lapping compound to get a mirror finish flat plate. I figured it couldn't hurt, and following instructions for lapping heatsinks, managed to get mine flat to .14mm over the entire bed on both axes. I would have given it one more shot, but I have almost ground away the area near the heater screws (I have light marks from the sandpaper on top of those screws now.)

I don't believe thats the root cause of the problem, however. Even with the 'fixed' plate, I still get those bumps on large flat areas sad I'm beginning to wonder if maybe my glass has microscopic bumps....

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Re: Strange pattern on first layer

Damn my next thought was to get a piece of glass to use as the bed. Thought that might help with any of the unevenness of the metal surface.

Wonder what the most reliably flat glass that you can generally find locally is...

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Re: Strange pattern on first layer

Glass + Hairspray = definite win. Very little corner lifting on a 5.9" x 5.9" print smile
I bought cheap window glass from Home Depot. 10"x12" was < $10. Others around here are using borosilicate glass, which may be better.

Keep in mind, I'm not sure it really is the glass, either smile

When you go the glass route, look for clips that hold the sides, and don't clip on the top of the glass. I'm using binder clips atm, and I can see the glass flex when I put the last clip on, so that may be -my- problem. When I get a chance, I'm going to find something better.

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Re: Strange pattern on first layer

Okay, I had a chance to play with this today, and.....

1) I lapped the bed another round. Hey, I had it off already.
2) I added angle clips that hold the side of the glass, but don't press down on it
3) I re-leveled (and re-leveled, and re-leveled) the bed. Accurate to about 0.07 mm now.

....and the pattern is -almost- gone.

My conclusion ? Yeah, its due to the bed being warped. But it is fixable. You can probably get good flat glass and not have to monkey with lapping the bed, but you will need to make sure everything is super-level when it's time to print. Use a dial gauge to make sure.