E-steps and Z Offset Differences Between Different Filaments and Nozzles

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njgsx96
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Joined: Fri Aug 05, 2016 12:56 pm

E-steps and Z Offset Differences Between Different Filaments and Nozzles

Post by njgsx96 » Fri Jan 25, 2019 8:03 am

Greetings everyone! Looking for some info. I finally got around to building my spare extruder for my TAZ 6, swapping out my printed parts with the strengthened models and swapped over to a micro swiss .3mm nozzle as well. Next up is refreshing my original extruder, same treatment but a .5mm micro swiss nozzle.

Prior to any changing of parts, I was able to run some test prints and both extruders worked from the same settings and printed just about identical. With the new .3mm nozzle, I noticed I had to adjust my z-offset, quite a bit. the first layer was not sticking well and the micrometer measures .37mm first layer, even though I had it set in Cura to .2mm. The z-offset was at -1.435 prior and is now at -1.5, and I can probably set it to have the nozzle a little closer still. I measured both extruder configurations and there is no difference. Did the Z-offset have to be adjusted due to the filament coming out being thinner? Any other reasons for the big difference?

Part 2 deals with filament changes. I print mostly in PLA and my prints are great. The printer could use some maintenance, but overall, quality is excellent. When I switched to ABS to do the extruder parts, my first layer was squiched way too much, almost looking solid and not having lines showing the path of the filament. It seems to have halved the distance of the nozzle to the bed, just by printing in ABS. How can changing filament change the Z-offset?

Thanks, Rich

Galadriel
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Re: E-steps and Z Offset Differences Between Different Filaments and Nozzles

Post by Galadriel » Fri Jan 25, 2019 9:13 am

When you switch to a smaller nozzle diameter it will almost always necessitate adjusting your Z-Offset to be a bit closer to the build platform. Just as you posited this is because the thinner strand of filament will require the nozzle be a bit closer to the build platform to achieve the same amount of squish.

In regards to the ABS causing your first layer to get closer to the build platform, this isn't something I have heard of before. One thing that we do see cause your first layer to suddenly become closer to the build platform is if there was an issue during the autoleveling procedure. Our printers automatic bed leveling procedure is done by electrical contact. The most common way this will fail is due to a dirty nozzle that prevents this contact until the filament is "pushed" to the sides and electrical contact is made. This will cause your printer to think the bed is lower than it actually is, and can create a lower than intended initial layer. If you ever notice that your toolhead is pushing down the corner of the build platform during autoleveling stop that print clean the nozzle and restart the print to ensure that autoleveling is completed successfully.

njgsx96
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Joined: Fri Aug 05, 2016 12:56 pm

Re: E-steps and Z Offset Differences Between Different Filaments and Nozzles

Post by njgsx96 » Fri Jan 25, 2019 10:16 am

Been there, done that! I had a nice mishap from having a dirty nozzle where it pushed on those washers during levelling enough where it gouged the bed. Thank goodness it was not too deep as I was able to sand it away but now I make sure every print starts properly and the nozzle is clean as a whistle.

Very strange though that the ABS prints had the nozzle seem closer than when in PLA. Maybe someone can help explain or maybe my printer is just weird. lol

thanks!

Brent.I
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Re: E-steps and Z Offset Differences Between Different Filaments and Nozzles

Post by Brent.I » Fri Jan 25, 2019 10:44 am

njgsx96 wrote:
Fri Jan 25, 2019 10:16 am
Very strange though that the ABS prints had the nozzle seem closer than when in PLA. Maybe someone can help explain
A lot of it has to do with the different material properties of the filament. Chances are what you are running into is the different Die Swell. Essentially when molten plastic is forced through a small opening, it expands once it gets out. Depending on the specific blend of material, this expansion rate will differ.

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