First layer issues?

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JRAlvarez
Posts: 22
Joined: Fri Sep 08, 2017 8:14 pm

First layer issues?

Post by JRAlvarez » Fri Sep 08, 2017 8:35 pm

At least I think that's the problem. I've had my Taz 6 and have been printing happily for months now, but recently I've been having my first print failures, I had narrowed it down to some prints not sticking to the bed and it was when I started printing these calibration cubes that I saw this issue.
0908171841a.jpg
So I started watching the first layer like a hawk and noticed some strangeness and stopped the print several times with this result
0824172212a.jpg
Now, i'm still new at this, learning as I go, but I thought this was maybe overextrusion? So I performed the extruder calibration instructions here: https://ohai.lulzbot.com/project/extrud ... libration/

It was only off by a few millimeters, so I edited it as instructed. Still no joy. So I thought to myself, Maybe i've changed something, let me go back and factory reset it, and print my first rocktupus again using the included file and the Ngen they provided. After all, my first print was pretty nice, especially it's first layer as you can see here:
0824172212b.jpg
Except for the fact that I broke a leg getting it off the plate :) (It was my first time!)

But, printing another Rocktupus ended up like this:
0824172213.jpg
Yes, I broke two arms off of this one....I was frustrated...Anyway.

Thoughts? I've attempted to change the Z Axis with little success. Starting at 1.500 I've decreased it little by little and am now down to 1.437 and it doesn't seem to be working.

I'm still new at this so any advice you can give is appreciated, thanks.

nuroo
Posts: 151
Joined: Mon Apr 10, 2017 2:08 pm

Re: First layer issues?

Post by nuroo » Wed Sep 13, 2017 11:24 am

At least I think that's the problem. I've had my Taz 6 and have been printing happily for months now, but recently I've been having my first print failures, I had narrowed it down to some prints not sticking to the bed and it was when I started printing these calibration cubes that I saw this issue.
If you haven't changed your zoffset but prints are starting to not stick, I'd try a couple of things below.

Clean bed thoroughly, with alcohol and lint free cloth. Try a reprint.

But I suspect your pei sheet may be fading a little. So try a pva glue stick in area your printing. Try a reprint

Use a brim. Try a reprint

You could continue to lower your zoffset. Be prepared to adjust:
initial layer thickness
initial layer line width
1st layer speed
Try a reprint.

Lightly sand your pei sheet (look on youtube and find good video) <<< probably not necessary yet

Replace your pei sheet <<< probably not necessary yet
Last edited by nuroo on Wed Sep 13, 2017 1:07 pm, edited 3 times in total.

nuroo
Posts: 151
Joined: Mon Apr 10, 2017 2:08 pm

Re: First layer issues?

Post by nuroo » Wed Sep 13, 2017 11:26 am

Your first layer lines are a little to close, in the photo showing 3 squares.
If your esteps are calibrated
Could be your zoffsets too close to hotbed
Or extruding too much 1st layer

U want this
XiPmH3Z.jpg
With good adhesion

nuroo
Posts: 151
Joined: Mon Apr 10, 2017 2:08 pm

Re: First layer issues?

Post by nuroo » Thu Sep 14, 2017 7:16 am

If you want to change zheight lower it in .5 increments.

My factory z height was -1.361
If needed it lower for better adhesion or different type filament I'd try the following
-1.411
-1.461
-1.511
-1.561
-1.611
-1.661
And so on
I've gone as low as -1.761. to try and print a 1st layer that adhered without extra line width or layer height.
With a layer height of -1.361 you need extra initial line width and height. But with a much lower z height you can keep the same line width and height as the rest of the print. Helped fighting elephants feet.
My nozzle never hit the build plate, but I was scared to go so low, so I kept my finger on power button just in case.

JRAlvarez
Posts: 22
Joined: Fri Sep 08, 2017 8:14 pm

Re: First layer issues?

Post by JRAlvarez » Thu Sep 14, 2017 8:43 am

Everyone seems to be pointing me to z offsets, which I thought I had been attempting, but nuroo points out I might have to adjust it far more then I had been attempting. Will give this a try!

nuroo
Posts: 151
Joined: Mon Apr 10, 2017 2:08 pm

Re: First layer issues?

Post by nuroo » Sat Sep 16, 2017 2:48 am

For your future reference if you ever need to rehab your pei sheet

Thomas Sanladerer the man himself
https://youtu.be/DzaPFlEKP10

JRAlvarez
Posts: 22
Joined: Fri Sep 08, 2017 8:14 pm

Re: First layer issues?

Post by JRAlvarez » Sat Sep 16, 2017 9:24 pm

I did see that video! Gotta love Thomas. Thanks.

By the way, I seem to have solved my problem, I didn't realize that somehow my inital layer height got set to .425. I lowered it to .2 and lo and behold, much better quality prints!

Thanks everyone for the suggestions, I still learned a few interesting things I need to do/learn more about. Much appreciated.

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