Actual layer height vs. programmed?

Bambu Lab Software Bambu Studio
1

We have an H2D Pro here at work and I have been using Studio 2.7.n. This morning the IT department installed 2.8.2.60.

I have a job on the machine, single-filament, slim tree supports, no separate interface material. I sliced it with the 2.7.x from a saved job file.

From the machine readout the print is 679 layers high. The part is 137.7mm and I sliced it with .20mm initial layer and .20mm constant layers (no variable layer height). 137.7 / 689 = .203 layer height, which agrees. I am used to tracking the print with the Preview pane and coordinating with the readout from the Machine pane in Studio. But I cannot do that with my sliced file because the Preview disappeared with the re-installation of Studio and the job doesn’t save the slicing.

I loaded the same job file in 2.8.2.60, changing no settings, and get a sliced file that is 1099 layers high. Geometry is still 137.7mm tall, but I get layer positions like 56.60, 56.78, 56.80, 57.00, 57.06, 57.20, 57.34 etc. In other words many “fractional” layer heights. It does not coordinate in any way with the job in the machine’s memory.

Has something changed in Studio (i.e. some hidden/obscure switch that I need to set), or has the slicing engine been changed to “optimize” layer heights somehow?

Thanks for any insights! :slight_smile:

2

there is a setting for “variable layer height”, look for it in search

edit i cannot read please ignore this post

3

Your supports are generating their own layers and at their own height. Every now and then you’ll run into a “least common denominator” and both the print and the support are on the same exact layer plane. This can happen also with multiple objects on the plate each with overridden layer heights. Without sharing the project or screenshots etc not much to go off of.

Independent support layer height is the setting toggle IIRC, but I don’t know if bambustudio has it.

4

Thank you, @Eponymous . I did check for that and it is not enabled. I have used it on smaller parts but this is big and chunky (a 1/9 pie slice of a disk 20" across)

5

I misread where you said you already checked that. sorry.

6

Thank you, @Bullocks . I will not worry about it then. I’m just wondering why it changed between 2.7.n (I don’t know the exact version) and 2.8.n from the same exact saved project. Sorry, I can’t share a screenshot because the part is a mockup of a proprietary component of one of our customers.

So I’m taking it that the .20mm constant layer height is actually a “cap” height since there can be fractional layers. That’s cool. 2.8.n must just have a little more sophisticated slicer than 2.7.n…

7

NP, I appreciate your reply.

8

A project slicing result shouldn’t change with a new slicer version. Unfortunately BL doesn’t always seem to understand that. I would absolutely assume it’s a bug unless proven otherwise (in programming terms that’s called a “regression”). And find the difference if forced to use a new version. The 2.8 versions are rather buggy in general, I’m not using them yet.

-Max

9

I will keep a lookout for any other wonkiness… :slight_smile: Thank you for the heads-up.

10

Your part still has constant 0,2mm layers. Only the supports have their layers at different heights. So at the first layer (0,2mm), you might have both supports and part. maybe support only has 0,15mm layer height due to “independent support layer height”.
So layer 2 will be at 0,35mm but it’s only support is printed there. then layer 3 at 0,4mm, only a part layer is printed.
Already at that point, the printer has printed 3 layers, but only 2 for the part.

At the end, the part has been printed with exactly the number of layers you would expect from part height and 0,2mm layer height. There are just some additional intermediate layers for the support.

That capability has been available for quite some time. Maybe in your project, the setting was deactivated, but the Studio update contained new process profiles, that have overwritten the project profiles?

11

Thank you for the additional details, @Alex_vG . At this point I’m not worrying about it, was just wondering. Maybe the Studio update explains it. But mainly, this is a 30" diameter, 5.5" thick part that I have broken into 9 “pie slices” to fit the H2D build plate, and am printing them in consistent orientation so they will be consistently printed. I added dowel pin holes so I can keep them aligned while I glue them. :slight_smile: If it wasn’t a propietary customer part I’m mocking up (actual part is machined from aircraft aluminum) I’d attach a screenshot.