Understanding variable layer height (adaptive setting)  

RE: Understanding variable layer height (adaptive setting)

That line is the z-seam. Unfortunately, it's a limitation of current consumer-grade FFF printing. You can move the seam. You can try to hide it in corners. You can tweak extrusion settings to reduce it. On cylinders it can be frustrating.

Is it possible you're using different print settings between your 2 results? Look particularly at the seam placement option under Print Settings.

It would be helpful if you could post closeup pics of your good and bad results. I've used variable layer heights as you've described and they should be independent settings. 

RE: Understanding variable layer height (adaptive setting)

Posted by: @bobstro

That line is the z-seam. Unfortunately, it's a limitation of current consumer-grade FFF printing. You can move the seam. You can try to hide it in corners. You can tweak extrusion settings to reduce it. On cylinders it can be frustrating.

Is it possible you're using different print settings between your 2 results? Look particularly at the seam placement option under Print Settings.

It would be helpful if you could post closeup pics of your good and bad results. I've used variable layer heights as you've described and they should be independent settings. 

The print settings should be identical.  The only difference is that for one I slice it after loading the .stl file, for the other I simply load the .stl, push the variable layer height button, and push the adaptive button then slice it.  The variable layer height version gives me good threads but gives the z-seam as a vertical line.  Without using the adaptive setting the z-seam disappears but the threads don't come out very well.

I took a look at the seam settings and it is set to "Nearest".  Should I try "Random" instead?

RE: Understanding variable layer height (adaptive setting)

Posted by: @buckeyestargazer 

Itook a look at the seam settings and it is set to "Nearest".  Should I try "Random" instead?

RE: Understanding variable layer height (adaptive setting)

@bobstro

Here's the .3mf project file.  

Differences between 3MF files?

Posted by: @buckeyestargazer

@bobstro

Here's the .3mf project file.  

Attachment removed

Thanks. I'll take a look at it. What is the difference between the two files? I assume the one with the "2" at the end of the name is the latest, correct? Does this correspond to your "good" or "poor" result?

RE: Understanding variable layer height (adaptive setting)

@bobstro

How about this. 

Attached is a .3mf file "BAD_THREADS_NO_Z-SEAM" - this one I just loaded the .stl file and sliced it.  This one does not show the Z-seam, but the threads come out irregular and the parts don't mate as well.

And another .3mf file "GOOD_THREADS_Z-SEAM" - this one I loaded the .stl and used the Adaptive setting before slicing.  This one clearly results in a Z-seam running vertically, but the threads come out much better and the parts screw together easily.

Also the original .stl file.

THANKS!

RE: Understanding variable layer height (adaptive setting)

Perfect, thanks. I'm going to do a print of your canister (cut down for speed) with my settings as a baseline. Then as that prints I'll take a look at these 3MF files. Here's how I've sliced the parts:

• 0.4mm nozzle.
• Inland PLA filament (what I have mounted ATM).
• 0.32mm layer heights (for speed).
• Manually adjusted layer heights at threads (trying for close to 0.15mm).
• Z-seam set to "rear" (to narrow down where it appears).

This is what I've got now:

I'll try to update later in the day.

RE: Understanding variable layer height (adaptive setting)

@bobstro

Thanks for your efforts!  One thing I don't know how to do is "manually adjust layer heights at threads".  

RE: Understanding variable layer height (adaptive setting)

Posted by: @buckeyestargazer

[...] Thanks for your efforts!  One thing I don't know how to do is "manually adjust layer heights at threads".  

It's not exactly obvious. Prusa is starting to put together some documentation pages, but in the meantime, we have to help each other out. Here's a screengrab that might help. Click on the image to see it full size.

The process is:

1. Click on the part in editor mode (the box at bottom-left below the parts).

2. Click on the Variable layer height button (the varying size striped button, 3rd from right at the top - highlighted in orange box).

3. Use the mouse to manipulate the layer heights in the vertical bar at the right (highlighted in orange boxes). Left click moves the bar to the left, decreasing layer height. Right click does the opposite. The mouse wheel will increase or decrease the affected layers. Shift-right click will smooth. It's not overly precise. You have to hover for a second to see the layer heights.

Hopefully Prusa will work on this to allow more precise setting of layer heights, but it works for now when doing threads.

Edit: I split the parts apart by right-clicking and selecting Split->To objects.

RE: Understanding variable layer height (adaptive setting)

Posted by: @bobstro

Posted by: @buckeyestargazer

[...] Thanks for your efforts!  One thing I don't know how to do is "manually adjust layer heights at threads".  

Left click moves the bar to the left, decreasing layer height. Right click does the opposite. The mouse wheel will increase or decrease the affected layers. Shift-right click will smooth. It's not overly precise. You have to hover for a second to see the layer heights.

This finally clicked for me.  I knew I could manipulate the graph/bars, but I didn't know what the effect was.  Now I know how to decrease or increase the layer height which is really helpful.  

RE: Understanding variable layer height (adaptive setting)

I just want to point out that thinning the overhangs of the threads may not be a good idea, as the overhangs will have difficulty to solidify if the hot nozzle returns to them over and over extruding a thin layer.