BUG: Printing starts at incorrect height when using Layer Modifications

[Großschmackhaft]

When I set "Start printing at height" to 1.70mm and have a layer height of .2 mm , the toolhead will be at a height of 1.8mm instead of 1.9 (1.7 + .2) for the first layer. That means effectively I only have .1mm first layer height at 200% extrusion.

I am trying to print text and images onto objects in a different color by using different files for the coins and changing the filament between files (Sidewinder X1 does not support the Pause/Change Filament command) but it looks terrible because of this bug.

The attached factory file contains the process "logo" where this bug occurs.

[parallyze]

Hmm....

Looking at the preview using your factory file, this is what S3D does:

bottom: 1st layer at 0.2560 -> 127% = 0,32512mm (really?*) rounded to -> 0.325mm layer height
middle: layer 2 - 6 (0.565mm, 0.805mm, 1.045mm, 1.285mm, 1.525mm), 0.24 layer height each
top: layer 7 - 8 (1.605mm, 1.685mm), 0.08mm layer height ("magic" numbers?) each
logo: layer 9 - 11 (1.885mm, 2.085mm, 2.285mm), 0.20 layer height each

bottom is set to use 0.32
middle is set to use 0.32 - 1.54 @ 0.24 layer height -> 0.56 -> 0.8 -> 1.04 -> 1.28 -> 1.52 (note the 0.02 difference)
top is set to use 1.54 -1.70 @ 0.08 layer height -> last layer was printed at 1.52, so this will use 1.52 + 0.08 -> 1.6 -> 1.68 (again, 0.02 difference)
logo is set to use 1.70 - 2.3 @ 0.2 layer height -> last layer printed at 1.68, 1.68 + 0.2 -> 1.88 -> 2.08 -> 2.28

So S3D does keep the set layer heights. They just don't add up to the numbers you entered, that would leave minor gaps/wrong z heights for certain layers...

When setting process "logo" to use 0.1mm layer height it starts correctly at 1.785mm instead of 1.885mm.

* when using one process for the first layer only, why not simply use 0.32mm @100%? And when using 0.6mm extrusion width on a 0.4mm nozzle the first layer width of 130% (0.78) get's you beyond what's usually recommended (depending on nozzle shape/geometry up to 175% of nozzle diameter).

Edit:
When selecting process "logo" only the preview will start at 1.8mm.
Guess: Layer height is set to 0.2mm, so it's probably some kind of "sanity check" saying 1.7 isn't a "valid value", adding the difference to the next multiple (1.8).

[parallyze]

Guess: Layer height is set to 0.2mm, so it's probably some kind of "sanity check" saying 1.7 isn't a "valid value", adding the difference to the next multiple (1.8).

Wrong

Even when selecting lower layer heights that process will start at 1.8...

I am trying to print text and images onto objects in a different color by using different files for the coins and changing the filament between files (Sidewinder X1 does not support the Pause/Change Filament command) but it looks terrible because of this bug.

One workaround might be using the G-Code Offsets on the G-Code tab to align each process to the certain height you need them at.

There's a TFT-firmware supposedly adding M600 support on the X1, don't know if that's maybe of interest to you:
https://github.com/wgcv/RAWR-TFT-Firmware-Artillery3D

(and numerous other firmware-mods... do you happen to know if there's some kind of official fw update out there for that printer?)

[Großschmackhaft]

using the G-Code Offsets on the G-Code tab to align each process

Yesss! that's just what I needed! I never look at the G-Code tab and now it holds the solution to my problem

Yes I know it works fine if I slice all the processes at once. I'ts definitely a bug and I can't find any rhyme or reason to it.

Anyway, that's great about the firmware too, I definitely need to install a custom FW for PID tuning and mesh bed leveling anyway but it's a bit of hassle. I'm not keen on using Linux

Until now I worked with an unsatisfactory workaround: Reducing the height of the coin base itself. But those are meant as trolley tokens and should fit as exact as possible. Or you could create various single layer processes and adjust the extrusion ratio, or adjust the bed everytime.

But your suggestion with the offset is a much better solution, I was not aware of that and will try it asap. I never look at the Gcode tab

I noticed S3D isn't really being developed anymore, so I'm not holding my breath for a bugfix, but at least S3D allows me to split models into different files at all.

Look at my coins, aren't they pretty? Altough the new coins with the circular infill from that factory file I posted look even better.

[parallyze]

using the G-Code Offsets on the G-Code tab to align each process

Yesss! that's just what I needed! I never look at the G-Code tab and now it holds the solution to my problem

Glad it's working for you.

Yes I know it works fine if I slice all the processes at once. I'ts definitely a bug and I can't find any rhyme or reason to it.

It's quite hard to understand why a single process doesn't start at the exact height defined, yes. But honestly, I'm still trying to find
a situation where one would need this (except broken pause/change commands), so I don't think it's "critical"

Anyway, that's great about the firmware too, I definitely need to install a custom FW for PID tuning and mesh bed leveling anyway but it's a bit of hassle. I'm not keen on using Linux

As far as I can tell the TFT-Firmware update is done by using a prepared SD card. And the FW from the printer itself seems to be based on Marlin, so actually I don't see a need for Linux here. But I'm not using a Sidewinder, so maybe I'm missing something here...

I noticed S3D isn't really being developed anymore, so I'm not holding my breath for a bugfix, but at least S3D allows me to split models into different files at all.

There's been quite some discussion about this, so I don't want to go into this any further. But I'm not that pessimistic, yet...

Look at my coins, aren't they pretty? Altough the new coins with the circular infill from that factory file I posted look even better.

I noticed you had the bottom with circular infill printed while the top layers had been printed using 32 outlines. Any specific reason for this? ^^

Schmackhafte Grüße ;D

[Großschmackhaft]

I noticed you had the bottom with circular infill printed while the top layers had been printed using 32 outlines. Any specific reason for this? ^^

Yes, if I print circular infill on top, there will be a blob in the middle. I guess it's because of the hot nozzle staying in the same small area for too long. I need that slow printing speed for a nice surface, but slowly printing very small circles in the same small area just ruins it due to excess heat and then the blob will at best shine through the logo, at worst distort it.

So I want the center rectilinear to avoid that problem. I also noticed I can cover the entire layer with perimters printed inside-out. This will not create a blob in the middle, but that pushes the outer perimeter further out than it's supposed to be, so the top diameter is too big. I guess this is due to overextrusion, but if I lower the extrusion multiplier enough, there will be unseemly gaps between the perimeters.

So I print the perimters outside-in and have a patch of rectilinear in the midle that will be covered by the logo.

But honestly, I'm still trying to find a situation where one would need this

You need it if you want to print some base models first and then decide later what to print on top of them. You could set up a stand at a fair and print people's names on pre-printed objects.

As for Linux: I thought the FW would be flashed over USB using a Linux shell because that's what I saw in a YT tutorial. But if I just have to copy some files to a MicroSD, I don't have any excuse for not flashing a custom FW anymore.

[parallyze]

But honestly, I'm still trying to find a situation where one would need this

You need it if you want to print some base models first and then decide later what to print on top of them. You could set up a stand at a fair and print people's names on pre-printed objects.

If you plan to turn off the printer in between you might be in for some surprises. And if using mesh bed levelling/abl you'll need to take care of that, too (ABL -> printing the base. New process without ABL - because you can't do ABL when there's stuff on the bed - will require some offset. The one ABL has been using for the first print, if it's not Z=0...)

As for Linux: I thought the FW would be flashed over USB using a Linux shell because that's what I saw in a YT tutorial. But if I just have to copy some files to a MicroSD, I don't have any excuse for not flashing a custom FW anymore.

When talking about "the FW" you should take note there's two firmwares running on that printer. The one inside the control panel/screen and the "printer firmware" (based on Marlin, it seems) itself. The one I linked to is supposed to add M600 by replacing the TFT FW. Adding/changing things inside the printers FW will be a bit more complicated and require some prerequisites...