Bad adhesion between first and second layer

[pmazz850]

Hi everyone,
Got my rostock max built and printing. I'm rather new to 3d printing and need help understanding something. I seem to be getting bad adhesion between first and second layers. Almost like a gap. I don't really know what to change to correct this. It's printed in pla, 60 bed temp, 190 nozzle. I'm printing on pei sheet adhered to build plate. no issues with sticking. I tried increasing first layer height but outcome is the same. I'll try to attatch a pic here.
Any suggestions for a newbie??

[gestalt73]

It's a bit hard to make out in the pic, but it looks like your build height may be off. It looks like your first layer is printing kinda above the plate, then your second layer kinda sits on top of that, then layers 3 on are more or less ok.

the brim looks kinda ok, but I think I'd expect it to be a bit more squished.

As it lays out the brim (that outside outline that it lays out first), get up close and personal and watch it. does the line get squished into the build plate as it's laying out? or is it kinda dropping out of the nozzle and onto the build plate

heat up your hot end a bit then do a G0 Z0 and check the clearance with a single sheet of paper. if the paper kinda grabs the hot end, you're close. if it slides freely you're too high.

[pmazz850]

I don't think its getting squished like it should. I will double check this and let you know. Might not be till tomorrow.
Thanks

[Mac The Knife]

It looks high to me also,,, resetting your z height should cure that.

[pmazz850]

When I first calibrated my machine I didn't have the pei sheet on there yet. After I added the sheet I had to reset my Z. Is there anything else that should have been redone also?

[pmazz850]

Update,

So i checked my Z and it was off. Now first layer prints better. Now that i have my Z corrected i can see that my build platform is a little uneven. One side of first layer is thicker then the other. I've been trying to find the right info on fine tuning this max, and haven't been able to find a solid how to. Just bits and pieces of info. Can someone point me to a solid guide to fine tune this machine??

Thanks.

[gestalt73]

Yep, not sure which Max you have, but Geneb has outlined the calibration procedure in the build guides, available here:

http://seemecnc.com/pages/downloads

iirc, (sorry, I'm not using a RAMBO anymore, so I don't remember the exact steps) it more or less goes like this:

1. following the guide, use the setscrews to get the axis height in the right ballpark, using the a piece of paper between the print head and build plate as a guide
2. use x y z offsets in the EEPROM to really dial them in
3. check center, and adjust build radius if the center is too high or too low compared to your x y z calibrations
4. repeat until you're "close enough"
5. print out one of those calibration circles to see where you're at and make further adjustments to really dial it in.

I usually resort to these if I'm levelling the bed and and want to check it. It's really easy to see the high and low spots in the resulting print:
http://www.thingiverse.com/thing:50505/#files