Why 0.32mm layer height in the new profiles? What's wrong with 0.3mm?
Is there any huge advantage to the 0.32mm layer height used by the new 0.6mm nozzle profiles over the MK3's standard 0.30mm?
I usually design objects with the layer height in mind, which makes it easier to fine tune exact placement of things like holes for USB ports, or to tweak the fit of a sliding lid of a box, knowing that what I do in CAD will exactly translate to expected results in the slicer.
The round 0.3mm is much easier to work with than 0.32mm, so why the extra 0.02mm/layer? And when making designs that might be printed (in whole or in part) with 0.2mm or 0.3mm layer heights, you at least know that there will be consistent divisions at 0.6mm. But this doesn't work as well with 0.2mm and 0.32mm layers.
RE: Why 0.32mm layer height in the new profiles? What's wrong with 0.3mm?
I don't know for sure but the rule of thumb is that layer height shouldn't exceed 80% of nozzle diameter, so that makes it 0.32mm layer height. But I totally agree, 0.3 is a lot easier to do math with so I just created my own profile with that layer height plus a few other changes such as avoid crossing perimeters.
RE: Why 0.32mm layer height in the new profiles? What's wrong with 0.3mm?
it is a multiple hight of one motor step.
0.3mm would be between to motor steps. there is a youtube video about this topic. (would have to search for it.)
RE:
Oh, that's interesting. So after a bit of research, it works out like this:
For 1.8º stepper motors, there are 360º/1.8º = 200 full steps per rotation. The Z-axis lead screw has an 8mm pitch, so each full step is 8mm / 200 = 0.04mm. Therefore, layer heights that are divisible by 0.04mm are multiples of full steps.
For 0.3mm layer height, 0.3mm/0.04mm = 7.5 steps. For 0.32mm layer height, 0.32mm/0.04mm = 8 steps. Presumably, 8 steps is better than 7.5 steps.
But then, that just raises additional questions!
- Are micro-steps really that bad, especially for such thick layers with a 0.6mm nozzle?
- Is the z-offset rounded to the nearest 0.04mm in firmware, or will micro-steps be used regardless of layer height?
- If full step layer heights are important, why aren't all the presets adjusted to be divisible by 0.04mm? For 0.6mm nozzles, there are presets for 0.15mm and 0.25mm. For 0.4mm nozzles, there are presets for 0.15mm and 0.30mm.
RE: Why 0.32mm layer height in the new profiles? What's wrong with 0.3mm?
I don't know, I have no practical evidence that this makes any difference. I've been printing 0.3 forever, and it sure looks great for what I'm doing.
RE: Why 0.32mm layer height in the new profiles? What's wrong with 0.3mm?
i can't find the video anymore. but someone tried it out. The Results with 0,32 were better.
the chances for a microstep to fail are much higher.
In the end, the quality is a bit better and the chances for failiures are minimized.
I think it the slicer compensates for it. making the upper most layer a bit higer or lower.
RE: Why 0.32mm layer height in the new profiles? What's wrong with 0.3mm?
How does this play into where the first layer is? That can't be always at a number divisible by 0.04mm. And if all the layers after are at 0.32, then they all be at a mid-step? Or, does first layer calibration come to the nearest 0.04mm? Or do I not understand stepper motors?
RE: Why 0.32mm layer height in the new profiles? What's wrong with 0.3mm?
How does this play into where the first layer is? That can't be always at a number divisible by 0.04mm. And if all the layers after are at 0.32, then they all be at a mid-step? Or, does first layer calibration come to the nearest 0.04mm? Or do I not understand stepper motors?
Exactly. A micro-stepped z-offset would throw off the boundaries and defeat an attempt to maximize holding torque by separating layers at multiples of full steps. It could even be counter productive if you wind up printing everything at a 1/16th step, which from my basic understanding, is much worse than a 1/2 step (less holding torque for smaller micro-steps.)
Further - we know that Z is constantly in motion to account for uneven beds. Is that motion quantized into 0.04mm increments?
RE: Why 0.32mm layer height in the new profiles? What's wrong with 0.3mm?
Doesn't the MK4 use 0.9° steppers? In which case there's 8/400 = 0.02 mm Z-height per full step? This would mean 0.30 and 0.32 mm layer heights are both full steps on the Z-axis. Or are only the X & Y axis steppers 0.9° and the Z-axis are 1.8° still?
How does this play into where the first layer is? That can't be always at a number divisible by 0.04mm. And if all the layers after are at 0.32, then they all be at a mid-step? Or, does first layer calibration come to the nearest 0.04mm? Or do I not understand stepper motors?
Exactly. A micro-stepped z-offset would throw off the boundaries and defeat an attempt to maximize holding torque by separating layers at multiples of full steps. It could even be counter productive if you wind up printing everything at a 1/16th step, which from my basic understanding, is much worse than a 1/2 step (less holding torque for smaller micro-steps.)
Further - we know that Z is constantly in motion to account for uneven beds. Is that motion quantized into 0.04mm increments?
Seems unlikely to me, given that the 0.25 & 0.4 mm nozzle profiles both have 0.05 mm layer height options. If you quantized Z-height unevenness into 0.04 mm increments that's 80% of the layer height!
Still, since microstepping torque is full step torque * sin(90/microsteps), you can half-step with 70% of the full-step torque. 1/16th stepping would be 9.8% of the torque of full steps.
RE: Why 0.32mm layer height in the new profiles? What's wrong with 0.3mm?
Not sure what CAD design tool you're using, but I make extensive use of math functions right in the dimensions with Fusion 360. You could set up layer height as a user defined input parameter, then round to the nearest layer-height-multiple (plus first-layer-height, if that's different). I haven't felt the need to do this for layer height, but I do similar things for other design parameters.
Whatever you find to do with your hands, do with all your might!
RE: Why 0.32mm layer height in the new profiles? What's wrong with 0.3mm?
Whenever I care about the positioning of features, I just use variable layer height.