I just got the printer in yesterday. First one, and really excited about it.
Went through the initial rocktopus print and a few other resolution test prints.
So far I have noticed the initial layer is very thin, nearly translucent with the included nGen filament. I switched over to PLA and it looks slightly better, but the brim is measuring out about 0.3mm. I have also noticed some issues, generally in the first few layers, where the nozzle seems to be digging into the layers below it and pushing the previous layer around. But once you go up a layer or two, it seems ok.
The picture attached is from a 6.35x6.35 cylinder.
The bottom layers are coming out extremely smooth, but it may have been too smooth, where some of the initial prints may have damaged the PEI surface a bit.
I have checked the frame for square and everything is spot on.
I have seen a few places recommend just adjusting the z height up ~0.1 or so. Is this needed for every print, or is there a way to change the system settings for this? Also are there any risks to making these changes?
Thank you for the help.
The print shaped residue on the PEI surface is normal and you can ignore it. Basically the prints chemically and mechanically bond with the PEI surface, and removing the part will leave a mark, but it would take you about 4 million years to wear through the PEI with regular printing. Your PEI is not damaged.
Adjusting the Z height up has no risk of damage. worst case scenario, the part doesn’t stick and falls off. The Taz configuration also out of the box specifies overextrusion on the first level to promote better bed adhesion. That causes the small bulge at the base of the parts, but it’s a better configuration for new users since having the part fall off the bed mid print is more frustrating than having to trim a small amount of plastic. Adjusting the Z height down too far risks a nozzle impact with the bed which can cause damage, so make sure you take the adjustments slow and in small increments. The setting applies to all prints made with that slicer profile. You can make a test profile to play with settings and keep the stock one as is for comparison, etc. Typically someone will have several profiles, a “slow, high quality one” a “fast, lower quality”, and maybe a test profile or two.
Thanks, that explains a good bit, and also makes me feel better about the print surface.
Searching around earlier I did find this pagehttps://www.lulzbot.com/content/taz-bed-leveling. The images shown of the first layer, the one on the far left is about what I have (may have even been thinner than that).
Would that be more of an adjustment to z axis or the 125% initial layer line width?
Also, I see in CURA where I can adjust the z axis incrementally in the control panel, or am I missing somewhere else in the settings that I can adjust z height?
I think Cura lists it as “Z offset” if I remember right. I don’t use Cura though. Ideally you would want to adjust the extrusion rate to less than 125% . Either way will basically accomplish the same thing, but by lowering the extrusion percentage you are doing it the correct way. By squishing the layer closer to the bed, you theoretically lose 0.010mm accuracy, etc. because your part will be that much shorter.
You can adjust the z offset from the printer’s display. Go into the configuration menu and adjust it there. Once adjusted, save the setting and it will stay that way for all subsequent prints. I designed a simple cylinder, 30 mm diameter and 1 mm height, and did a lot of testing with z offset to get it just right. It’s a print job that takes less than 10 minutes, and you can watch all the layers forming up. Afterwards, you get a nice little poker chip that can be measured, twisted and bent to verify print dimensions, layer adhesion and material strength.
