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aerotitan

Terrible First Layer

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I've got my Ultimaker set up, but I'm really struggling with the first layer. Here is a picture of the first layer (0), followed by the second.

https://plus.google.com/photos/111070485779128774679/albums/5872013331658329297?authkey=CM2isKbzzMap0AE

From what I have found, it sounds like an adhesion problem. The first thing I tried was applying isopropyl alcohol to the acrylic before taping, then applying a very small amount of the alcohol to the top of the tape. Putting the alcohol on the tape proved to be a total cluster, so I repeated the steps again wearing gloves so the oil from my hands didn't interfere. I still got the first layer. Every layer after that has been more than adequate.

Any ideas of what to do to improve the first layer? Thanks.

 

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I think your platform may not be real level.

Zero your platform and then using a piece of paper under the nozzle at all four corners adjust the screw so it takes a bit of pull to pull the paper out from under the nozzle. Do it for all 4 corners and go around again.

 

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Definitely check that the bed is level and at the right height. Before you start printing, and after the homing move is completed, the nozzle should be just touching the surface of the tape - although in general it looks like adhesion is pretty good - I'm just really not sure what is causing the wavy lines across your print; is the surface of the bed smooth and flat - or are there gouges under the tape or something?

You don't need to worry particularly about grease from your fingers, it's not that sensitive. Just put the blue tape down onto the bed (no need to wipe the bed down with alcohol, unless it's just really dirty). Then wipe the tape over quickly with a piece of tissue or a makeup removal cotton pad, soaked in a little isopropyl alcohol. If you do that, then the plastic should still really well.

I presume you are printing with PLA? What temperature are you using?

 

I've got my Ultimaker set up, but I'm really struggling with the first layer. Here is a picture of the first layer (0), followed by the second.

https://plus.google.com/photos/111070485779128774679/albums/5872013331658329297?authkey=CM2isKbzzMap0AE

From what I have found, it sounds like an adhesion problem. The first thing I tried was applying isopropyl alcohol to the acrylic before taping, then applying a very small amount of the alcohol to the top of the tape. Putting the alcohol on the tape proved to be a total cluster, so I repeated the steps again wearing gloves so the oil from my hands didn't interfere. I still got the first layer. Every layer after that has been more than adequate.

Any ideas of what to do to improve the first layer? Thanks.

 

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The pictures are blurry so it's hard to see but it looks like the table isn't close enough to the nozzle on the first layer. At least that's what the skirt looks like to me but like I said, it's blurry. The first layer should be flattened a bit by the nozzle. It should be wider than it is high. This is more obvious on the skirt. Also it looks like you might be over extruding, but again, it's blurry. So to fix this you need to level better with a piece of paper. Make sure the nozzle is clean and not hot when you level.

For example this looks good to me:

gallery_67_16_3920946.jpg

 

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I had exactly the same thing as you. Some parts that seem to be 'higher' then others (when printing a big square). And also the strang lines in it. I think that if you have a deformation in one line, all the adjacent lines get the same deformation on that spot because it sticks to the deformation.. if you know what I mean.. the printed line folows the form of the previous line.

I did not worry about this issue much because the second or third layer fixed it most of the time.

 

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Thanks for all the advise. When it comes to the paper and the level of friction, should I be able to slip the piece of paper back in between the nozzle and the print bed or not? I've leveled with the paper already in place and sometimes when I pull the paper out there is a very faint "thunk" as the bed pushes back up. I would take that to mean the friction was too high (as was the bed).

So should I be able to slip the paper back in with a little wiggling?

 

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After spending a few hours leveling it seemed to problems came down to adhesion and proximity to print bed. For leveling, I used the paper between the nozzle and the bed. I used the bed wizard in Cura - Marlin. When I go to print around the edges, the front and left side of the bed is right on top of each other, yet the back and the right have a print-width gap in between, yet I can't find a picture anywhere of what that should look like. I'm interpreting it to mean the lines should be side-by-side.

I printed a calibration triangle from Thingiverse. This is how it came out. *I am posting links as the image tool says I'm not allowed to use it on this community (?)

Mid-Print:

https://plus.google.com/photos/111070485779128774679/albums/5872013331658329297/5873528457458433122?banner=pwa&authkey=CM2isKbzzMap0AE

Finished:

https://plus.google.com/photos/111070485779128774679/albums/5872013331658329297/5873531231686799410?banner=pwa&authkey=CM2isKbzzMap0AE

This was printed at 220 degrees and speed of 80. I missed getting a shot of the first level, which sucked until I moved the bed down one click, lowered the temp and speed. I had previously read a suggestion that said running the first layer one click closer, at 230 degrees and 100 mm/s.

The other problems I am having are spaces in between adjacent lines (leveling still) and if you look at the pic, in the front left corner, the nozzle is stopping momentarily on each level and wherever it stop is creates this round bulge of course. Any ideas on the nozzle pausing? I was having a retraction problem, but I increased the retraction speed in Cura to 45.0 mm/s and between that and temp and speed, stringing really seemed to go away.

 

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1) 45mm/sec is way too fast so you probably have an older version of cura and marlin that has a bug where it actually retracts slower than you request. Otherwise you would have serious trouble at 45mm/sec for retraction. When you upgrade your Marlin some day, lower that to maybe 20mm/sec.

2) You still seem to be printing too high off the bed on the first layer. I'm not 100% sure but look at the picture I posted and look at your picture and the skirt doesn't look squished enough to me. I think I can see where you clicked the z and it looks kind of bad on that level.

When you slide the paper in it should be easy to slide under but not so easy that you can't feel anything. You should be able to do it with one hand *pushing* the paper under (as opposed to two hands holding the paper very tight and sliding it under that way).

Another way to think of it - slide the paper back and forth with one hand, lower the bed until there is no resistance, then raise the bed until you just barely feel resistance. Be careful not to push too hard on the screwdriver while sliding the paper as that moves the bed also and changes things.

So you want the minimum resistance where you are sure there is a difference.

Your pyramid doesn't look too bad.

I'm not sure what the pausing is - but it might be the "z seam" which is where the head is sitting when the z axis moves. Hold one hand on the z axis while watching the print job and when you feel the z axis move pay attention to where the print head is.

You can sometimes move the z seam by rotating the part but your part is symmetrical. But for example if you were printing yoda you could rotate the z seam to the back of yoda's head.

You can sometimes improve the z seam by speeding up the z axis acceleration and velocity a bit (about double is safe). Or you can use other slicers which let you put the z seam in a random spot, or you can change the order of loops, infill, perimeter to try to get the z seam in an interior location. If you have double thick walls (.8mm), the inner wall is part of "loops" so you can do loops last. Otherwise if you have no loops you can do fill last.

 

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Looking again at your pyramid - maybe the first layer is fine (bed levelling fine).

By the way, after you practice it shouldn't take an hour - just about 1 or 2 minutes at the most.

I'm thinking the pyramid in my picture is .1mm layers including the bottom and skirt layers whereas the pyramid in your photo is .2mm or .3mm for the first layer. So maybe it's fine as is. Maybe your leveling is just fine.

 

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I just wanted to thank everyone once again. I found that bed leveling wasn't the issue, but instead it was a thick first layer. The default first layer in Cura was 0.3, so I changed that to 0.0 (it said this would print each level the same) and slowed the speed down to 50 mm/s. The print came out perfectly I was so damned happy.

 

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I'm glad. Just be warned, the thinner your first layer, the more accurately you need to level/home. So when you decide to slice at .1mm layers, you will need to re-level every hour instead of once per day and you will need to be very good at it.

Anyway, I'm glad your print came out well.

 

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