MakerGear Forum

"Inter-layer adhesion issues", maybe?

So I finally cured my stringing issue with a replacement nozzle, but of course a new, completely different, problem has reared its head. Observe this image:



This piece-- the same one I've printed over 100 of-- has three initial solid layers. The first layer goes down smooth (the bottom of the piece is glass-smooth, with the individual extrusion lines almost invisible).

The second solid layer, which you can see in the right half of this image, has an odd, fine wavy appearance.

The third solid layer, at the left side of this image, has a pronounced wavy appearance and is not adhering to the perimeter. I let the print continue for a while past this point and things got progressively worse, with the head dragging un-adhered filament around. Ick.

My first thought was "the layer height is set incorrectly", but it's the same 0.20mm I've always printed with. Ditto for extrusion multiplier (0.90), print speed, et cetera so on and such forth. I also checked a setting hitherto unknown to me, the "Outline overlap" setting in Simplify3D. Nope, that hasn't changed either.

My goal is to someday learn enough to answer other folks' questions here. But for now I'm still in the "WTF?" phase, I'm afraid.

Hate to say this, but different nozzle, different gap. It might not be screwed on as tightly as the other one was, or might have been milled differently or something.

Try adjusting your Z-Offset number to bring the nozzle a little closer to the bed (subtract -0.02 mm from whatever the Z-Offset is now.)

Second thing - increase your temperature a little....(yeah, I know.....I told you to lower it before. But it's a balancing act.....you are trying to hit that golden spot between too much ooze at too high a temp and layers not bonding properly. You will do this every time you change anything, and sometimes just because it's a rainy day.)

(And no, I'm not kidding.....PLA prints differently on a very humid day. )

Oh, might want to slow down the Solid Infill speed too.....it's on the Other tab.

Jules wrote:Hate to say this, but different nozzle, different gap. It might not be screwed on as tightly as the other one was, or might have been milled differently or something.

Try adjusting your Z-Offset number to bring the nozzle a little closer to the bed (subtract -0.02 mm from whatever the Z-Offset is now.)

Oh, I did recalibrate after replacing the nozzle. I may be only an egg, but even I could figure that out! Did the whole "print the calibration cube, measure height, adjust Z offset, reprint cube to verify" thang...

Jules wrote:Second thing - increase your temperature a little....(yeah, I know.....I told you to lower it before. But it's a balancing act.....you are trying to hit that golden spot between too much ooze at too high a temp and layers not bonding properly. You will do this every time you change anything, and sometimes just because it's a rainy day.)

OK, will try raising the temp back to the Makergear-standard 215 and see if that helps.

You are getting the hang of it!

You might just need to print a bit out of the new nozzle too - it takes a few prints to get them dialed in when they're fresh. I've had to run a few every time i changed one out.

Well, it's been fun, but at this point I'm very close to simply bowing out of 3D printing and selling my M2 cheap. It seems that no matter what I do, I'll never be able to achieve the quality of prints I was able to in the first month of owning this machine.

It's insanely frustrating to spend days of effort tweaking settings and seeing the various problems emerge. Jules, I tried your suggestion of increasing the temperature-- I used 215 degrees, the default. This seemed to fix the problem I had with the boundaries of solid infill layers pulling up, but that re-introduced a stringing problem, although not nearly as severe as before.

Switching back to 205 degrees and dropping the Z offset 0.02mm re-introduced the layer adhesion problem. I simply can't understand why a temperature that worked perfectly for weeks with the same spool of filament no longer works AT ALL.

I think I'm going to take a printing break for a few days, then re-Z-stop and re-level the bed, throw away all my Simplify3D settings and start from scratch, just as though the printer had just arrived. And if that doesn't work, it'll be for sale up here for a really great price.

dramsey wrote:Well, it's been fun, but at this point I'm very close to simply bowing out of 3D printing and selling my M2 cheap. It seems that no matter what I do, I'll never be able to achieve the quality of prints I was able to in the first month of owning this machine.

It's insanely frustrating to spend days of effort tweaking settings and seeing the various problems emerge. Jules, I tried your suggestion of increasing the temperature-- I used 215 degrees, the default. This seemed to fix the problem I had with the boundaries of solid infill layers pulling up, but that re-introduced a stringing problem, although not nearly as severe as before.

Switching back to 205 degrees and dropping the Z offset 0.02mm re-introduced the layer adhesion problem. I simply can't understand why a temperature that worked perfectly for weeks with the same spool of filament no longer works AT ALL.

I think I'm going to take a printing break for a few days, then re-Z-stop and re-level the bed, throw away all my Simplify3D settings and start from scratch, just as though the printer had just arrived. And if that doesn't work, it'll be for sale up here for a really great price.

If you're having sticking problems, you might have gone in the wrong direction with the Z-Offset. To reduce the gap and take the bed closer to the bed, you subtract .02 mm from whatever number you currently are using as a Z-Offset number. So if you started with a Global Z-Offset of -0.13 mm, the corrected value to put into the slot would be -0.15 mm.

But if your current Global Z-Offset value is +0.13 mm, your new corrected value would be +0.11 mm. Moving in a negative direction takes the bed closer to the nozzle. Moving in a positive direction takes the bed farther away.

If you're close, you do not have to keep re-doing the whole Z-Stop routine - just make a small adjustment to the offset in the Global Z-Offset slot of the S3D software.

Take a break for a bit, but before you throw in the towel, you might want to consider hanging on to the printer until the Rev. E upgrade is available for existing users. (You do not have to do this kind of adjustment any more with the Rev. E. It sets a fixed (un-varying) gap for you. No more calibration squares, no more Z-Offsets, etc.) Then all you have to concern yourself with is the properties of the plastic itself.

3D printing is a challenge...it's why there aren't more folks out there doing it. And you haven't even owned yours long enough to be out of the learning stage yet....give it some time. (Heck, i've probably printed thousands of calibration squares.....After a while, making a tiny tweak becomes automatic, and prints become very uniform.)

Go have a great Easter - sometimes it helps to step away for a while.

Jules wrote: If you're having sticking problems, you might have gone in the wrong direction with the Z-Offset. To reduce the gap and take the bed closer to the bed, you subtract .02 mm from whatever number you currently are using as a Z-Offset number. So if you started with a Global Z-Offset of -0.13 mm, the corrected value to put into the slot would be -0.15 mm.

Oh, I know: reducing Z moves the bed closer to the head, increasing Z moves it away. I figured that out real early.

Here's a question: previously, I used a 0.15mm feeler to set the "head gap" the "V4 way": bring everything up to temp, home Z, center the bed, put the feeler under the head, and loosen the screw to drop the head on top of the feeler.

Then I'd print a 2mm calibration square and it would always be 2.15-2.20mm high. Having to put in that large an offset (-0.15 or larger) offended me somehow, so this time, after installing the new nozzle, I used a 0.10mm feeler.

Didn't seem to make much if any difference: I think I wound up with a 2.18mm high square this time. But I wonder: is it possible I'm putting the head too close? The bottoms of even the messed-up prints are glass-smooth, with almost invisible extrusion lines. I always thought that as long as the first layer stuck, the effects of head gap would be minimized in succeeding layers. The print might not be as precise as it should be in Z, but I wouldn't expect stringing or layer adhesion problems after 10 layers had been printed.

What would the symptoms be for a head that's too close? The extruder isn't clicking or anything (as it was with the clogged nozzle). Should I print the "bed level test" pattern and try to measure the width of the extrusion lines?

Jules wrote:...you might want to consider hanging on to the printer until the Rev. E upgrade is available for existing users. (You do not have to do this kind of adjustment any more with the Rev. E. It sets a fixed (un-varying) gap for you. No more calibration squares, no more Z-Offsets, etc.) Then all you have to concern yourself with is the properties of the plastic itself.

Tell me more about the "Rev. E upgrade". I know there are a couple of printers out there, like the Lulzbot Mini, that do software-based Z stop and bed leveling before each print...

In the meantime I shall go work on getting this 1978 BMW R80/7 running better. It's a simple machine compared to the M2.

What would the symptoms be for a head that's too close?

The dead giveaway for the bed being too close is a sharp little lip on the first layer. (It's getting squashed too flat, and it has no where to go but out.)

The extruder isn't clicking or anything (as it was with the clogged nozzle).

That's caused by a different problem - the Filament Drive Screw tension was off and stripped or jammed the filament. (Or the partial clog caused the jam.)

Tell me more about the "Rev. E upgrade". I know there are a couple of printers out there, like the Lulzbot Mini, that do software-based Z stop and bed leveling before each print...

Well, just my opinion, but I think what MakerGear has done with the latest and greatest is better than auto-leveling. With auto-level, you have to wait while the grid gets established, and if that has to happen before every print, you're going to waste a hell of a lot of time sitting around waiting for prints to start.

The Rev.E basically takes a certain amount of control away from you. It sets a fixed size gap, once, and then that never varies. An experienced user will be able to make modifications to that through a separate process that's under development, (or through G-Code), but for a beginner it's gonna be a Godsend.

Beginners have more trouble with setting that gap, through either the Z-Stop or the Z-Offset, than any other issue. And neither of those has to be done with a bottom set Z-stop, and the new firmware.

Jules wrote:The Rev.E basically takes a certain amount of control away from you. It sets a fixed size gap, once, and then that never varies. An experienced user will be able to make modifications to that through a separate process that's under development, (or through G-Code), but for a beginner it's gonna be a Godsend.

Beginners have more trouble with setting that gap, through either the Z-Stop or the Z-Offset, than any other issue. And neither of those has to be done with a bottom set Z-stop, and the new firmware.

Has this been announced somewhere?