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brictone

Calibrating, tuning, with different layer heights.

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So I've been dialing in my settings with SF45 at .2mm layer height and got it down pretty good. So I thought I'd change the layer height to .1mm and see how that goes with the same settings. well I'm finding I have to change width over thickness and increased cooling time for it to work with the lower layer height.

So not only have I been building different profiles for different colors (because the filament diameter is slightly different) I now need different profiles for different layer heights.

It also seems like some objects benefit from longer cooling times and others get worse.

Is something wrong with this? I don't feel like I should have to change those things but... maybe that's just the way it has to go with skeinforge.

I liked the quick settings that came with repg25, although a stand alone SF is far more flexible for my set up.

I feel like it shouldn't be this way...

Anyone else experiencing this?

I don't know...

I'm using Marlin beta 1

and I have this in my start.gcode M92 E926.5

Ideas? suggestions?

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I'm finding I have to change width over thickness and increased cooling time for it to work with the lower layer height.

Not sure why you'd need to change the cooling time but it doesn't surprise me too much..

For the w/t part, it makes perfect sense.. "Thickness" is sf-speak for layer height and "over" is math-speak for divided-by so "width over thickness" is the width of threads divided by the layer height.

If you start with a layer height of 0.20mm with a w/t of, say, 2.0, you have threads that are 0.4mm wide. If you just change the layer height to 0.10mm without changing w/t, SF ends up mapping things out so you have a thread width of 0.2mm wide - that's hard to get right with a 0.4mm nozzle!

There are SF wrappers (like Daid says) that will do this math for you but what I do is just find a profile that I like the quality on and remember the thread width on that - between 0.40mm and 0.50mm will work nicely on an Ultimaker, though the actual usable range is probably around 0.35mm to 0.75mm or so. Once you have that, pick whatever layer height you want then divide the desired thread width by the layer height and plug that into the w/t.

Example: say you like 0.50mm thread widths..

- for layer height = 0.25mm, w/t = 0.50 / 0.25 or 2.0

- for layer height = 0.20mm, w/t = 0.50 / 0.20 or 2.5

- for layer height = 0.10mm, w/t = 0.50 / 0.10 or 5.0

Just remember to change both w/t values.. There's perimeter w/t in Carve and infill w/t in Fill.

Not that I've typed all that in, I wonder if I understand the question.. Does this help?

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First, dump the "W/T ratio", like I did for Skeinforge_PyPy: viewtopic.php?f=8&t=153

That saves you 1 trouble. I took my 0.2mm profile, adjusted the layers to 0.1mm, and printed. Same temperature, same everything. And it came out great.

I've never seen an object get worse from more cooling...

I just took a look at the pypy stuff... I like the sound of not having to change the width/Thickness with layer height changes once you get it right. It should be predictable.

I noticed with cooling that once it starts running really slow... It starts to get blobby. like it's oozing more than it's extruding. could it be from to high of a temp? I'm at 230c. I used to print at 245c but the marlin guys said it was more accurate now and 230 should be good. since then I've stripped the filament a few times.

So with pypy I noticed it's just perimiter width or infill width... do you just set it at say .4 and it's good for all layer heights? <--- that I likey

 

Not sure why you'd need to change the cooling time but it doesn't surprise me too much..

For the w/t part, it makes perfect sense.. "Thickness" is sf-speak for layer height and "over" is math-speak for divided-by so "width over thickness" is the width of threads divided by the layer height.

If you start with a layer height of 0.20mm with a w/t of, say, 2.0, you have threads that are 0.4mm wide. If you just change the layer height to 0.10mm without changing w/t, SF ends up mapping things out so you have a thread width of 0.2mm wide - that's hard to get right with a 0.4mm nozzle!

There are SF wrappers (like Daid says) that will do this math for you but what I do is just find a profile that I like the quality on and remember the thread width on that - between 0.40mm and 0.50mm will work nicely on an Ultimaker, though the actual usable range is probably around 0.35mm to 0.75mm or so. Once you have that, pick whatever layer height you want then divide the desired thread width by the layer height and plug that into the w/t.

Example: say you like 0.50mm thread widths..

- for layer height = 0.25mm, w/t = 0.50 / 0.25 or 2.0

- for layer height = 0.20mm, w/t = 0.50 / 0.20 or 2.5

- for layer height = 0.10mm, w/t = 0.50 / 0.10 or 5.0

Just remember to change both w/t values.. There's perimeter w/t in Carve and infill w/t in Fill.

Not that I've typed all that in, I wonder if I understand the question.. Does this help?

Thanks Dave! This helps. To me it made sense to change them for different layer heights, it just re-assures it hearing from someone else.

I have my perimeter and infill w/t slightly different... to me it makes sense to have them the same... should it be?

What I'm trying to accomplish in the long run is build a set of Gcodes for different objects. That are for different colors or quality. So I can take the .2mm object in black or white and print it, without calculating the gcode on the spot. or grab a new object and pick the color and quality I want hit calculate and send to printer. eventually automating these things with check boxes or something...

So that's why I'm asking do I need to build different profiles for color and layer height? then if I wanted to change or tweak one thing (like cooling)I have to update them all. Doesn't sound like fun :(

It sounds like I need to build my own wrapper which I can change layer height, color or filament diameter, speed... oh wait... it's in repg25 called quick overrides, must... reverse engineer...

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So with pypy I noticed it's just perimiter width or infill width... do you just set it at say .4 and it's good for all layer heights? <--- that I likey

Indeed. The whole W/T ratio comes from the old "I have no control over the extrusion speed" extruders. If your extrusion speed is fixed, then a W/T setting makes more sense, because if you change your layer thickness then the line width will change at the same speed.

But with step extruders like the ultimaker, a line width setting makes much more sense. And it's a very simple change in the code. Because the code already did: "lineWidth = widthOverThicknessRatio * layerThickness" so I just had to remove the multiply by layer thickness. It also explains the calculations shown by ddurant.

The way RepG implemented the overrides won't work very well with the PyPy version. But I understand the need for it.

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What I'm trying to accomplish in the long run is build a set of Gcodes for different objects. That are for different colors or quality. So I can take the .2mm object in black or white and print it, without calculating the gcode on the spot. or grab a new object and pick the color and quality I want hit calculate and send to printer. eventually automating these things with check boxes or something...

We're getting closer but still aren't quite to the point of really automating that sorta thing.. What (IMO) is really needed is a new M gcode to tell the firmware the filament size then replace the current G1 E component, which specifies the length of filament to take in, to be a G1 V component that specifies the volume to extrude for that particular thread.. Maybe a gcode to specify what Dimension\Filament Packing Density does today, too.

If we had that you could, for example, take gcode generated for 1.75mm ABS filament that needs 220C and with just a couple extra lines of gcode at the top, print it with 2.85mm PLA filament that extrudes at 190C. Or on a screw-drive-extruder that takes plastic pellets. Or whatever..

We're not quite there yet, though. Just like this time last year was VERY different than now, this time next year should have some big steps forward..

 

So that's why I'm asking do I need to build different profiles for color and layer height? then if I wanted to change or tweak one thing (like cooling)I have to update them all. Doesn't sound like fun :(

Yes. This is what I used to do and it quickly got unmanagable.. No, not fun.

 

It sounds like I need to build my own wrapper which I can change layer height, color or filament diameter, speed... oh wait... it's in repg25 called quick overrides, must... reverse engineer...

That's one option but I think it does other things under the covers that may or may not do what you want.. That's one of the issues with all the SF wrappers: by doing things for you, they take the control from you. This isn't necessarily bad, it's just something to be aware of. My preference is to use SF by itself - there are only a handful of settings to change and you get all the control to try other stuff, if you want. 13 months ago, I had probably 20-30 different SF profiles. For the last year (once the volumetric stuff got going this time last year) I've had just one - I have a base profile that's 99% correct for everything I do and just change the other 1% as needed..

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