Settings for Tool Path Refinement using Infill Modifier

[displaynamenotallowed 2]

Hello I'm posting because I may need a little help if possible. I'm working on a 3D printed R.C. model glider and while I have learned to print parts for it with excellent results using standard infill options I'm now trying to attain a more complex custom infill using Infill Modifier with a honeycomb grid pattern STL.

 

I have a little initial success and have proven the concept is possible but I've had a little struggle getting a "clean" tool path for the infill on subsequent attempts. 

 

I know a number of settings that have made my prints nice but there are many settings that may be able to help that I don't have any or much experience with.

 

If people can help me it would be appreciated and I think this technique I'm working on could be a benefit to many people here not only as a novelty but also as an option for producing very nice aesthetic end use parts.

 

I'll follow up with various screenshots and a more technical description of what I'm doing and the challenges encountered thus far.

Edited October 15, 2023 by displaynamenotallowed

[Slashee_the_Cow 480]

29 minutes ago, displaynamenotallowed said:

I'll follow up with various screenshots and a more technical description of what I'm doing and the challenges encountered thus far.

Traditionally you include those in your first post, don't keep me waiting, I have anxiety issues!

(Technically true but I'll be fine, I just love a challenge so I eagerly await what comes)

[displaynamenotallowed 2]

I thought I'd ask if linking to the blenderartists forum where I'm posting would be cool. 

 

I have more specialized questions for Cura experts here but I've already posted a lot of info and pictures there. I believe an/the answer could be related to the STL model being used as the infill modifier. 

 

I'm going to post a couple screenshots here too. 

 

I'll be asking questions in anticipation for future settings that may help refine the print hopefully if the more prominent issues can be solved too.

[Slashee_the_Cow 480]

4 minutes ago, displaynamenotallowed said:

I thought I'd ask if linking to the blenderartists forum where I'm posting would be cool.

Of course you can. We're here to help, not be jealous about people who are far better at 3D modelling software than I am.

[displaynamenotallowed 2]

In the first picture is the glider models wing tip section and a honeycomb grid STL used as a infill modifier. 

 

The second picture shows the layer view. As can be seen there are parts of the vertical honeycomb cell walls that didn't generate any lines. In the angled parts of the cell walls there are too many lines haphazardly arranged. 

 

In previous tests I scaled the honeycomb grid larger and smaller. The results were when I scaled it smaller the angled sections were more consistently spaced and with Cura 4.8 I was able to get perfectly arranged lines. No double or triple stacked haphazard lines but nearly none of the vertical lines were generated. Conversely when I scaled the honeycomb larger all of the vertical sections had lines generated but the angled sections were haphazard. Broken, inconsistent and or doubled or triple layered.

[Slashee_the_Cow 480]

3 minutes ago, displaynamenotallowed said:

with Cura 4.8 I was able to get perfectly arranged lines

You should probably really use a newer version of Cura. They do improve the slicing engine, among other things.

That, and please put all your information in one post, that way it's a lot easier to follow.

[displaynamenotallowed 2]

https://blenderartists.org/t/new-here-and-to-blender-3d-printing-cura-help-needed/1487840

 

There is a link to my posting on blenderartists.

 

I actually just realized a Cura setting I could try a few minutes ago. 

 

By the way I've been using versions 3.6 and 4.8 on my old laptop (at the moment I'm more comfortable using) but I do have a new laptop with Cura v.5.x

 

A few settings I think (could) benefit what I'm doing is Experimental- Slicing Tolerance- Exclusive and Minimum Polygon Circumference or Maximum Resolution changes.

 

I may want to be looking at Mesh Fixes settings as well but I'm not well versed in using these settings.

Edited October 16, 2023 by displaynamenotallowed

[displaynamenotallowed 2]

You want me to edit my first post and include all the information in my following posts? I don't mind doing that but it would get lengthy and in my experience has the effect of people not wanting to read through it all (makes it harder to follow chronologically speaking)

[Slashee_the_Cow 480]

Just now, displaynamenotallowed said:

You want me to edit my first post and include all the information in my following posts? I don't mind doing that but it would get lengthy and in my experience has the effect of people not wanting to read through it all (makes it harder to follow chronologically speaking)

Nah, we love a challenge here. Much better than the people who give us so little info we can't even figure out what their problem is. I find multiple posts a lot harder to follow, especially when I keep interrupting. Don't worry about it now, just if you're going to add more later please do it in one post instead of doing several posts in a row.

 

6 minutes ago, displaynamenotallowed said:

By the way I've been using versions 3.6 and 4.8 on my old laptop (at the moment I'm more comfortable using) but I do have a new laptop with Cura v.5.x

You should definitely be testing it in newer versions of Cura primarily, since they do improve the slicing engine as well as updating other things.

 

First and foremost, you made this honeycomb in Blender? Not a great idea. This is the sort of thing that is exactly what parametric CSG (constructive solid geometry) software is designed for. FreeCAD will let you make a honeycomb incredibly easily (just create a sketch, add a hexagon, pad it out then make an array). OpenSCAD is a little more complex (especially if you don't know anything about programming) but it also makes it incredibly easy to create an array of hexagons (just make a six-sided circle). Blender isn't really designed for this sort of thing, even with what seems like simple shapes, it treats them like meshes, just as it would treat a garden gnome or a wizard's hat. It makes for a cluttered and not always dimensionally accurate (not to mention often not valid) STL files. A CAD program will just add the simple, parametrically defined shapes to the STL file. It's clean and accurate.

 

24 minutes ago, displaynamenotallowed said:

A few settings I think (could) benefit what I'm doing is Experimental- Slicing Tolerance- Exclusive, Minimum Polygon Circumference or Maximum Resolution.

Given the problem seems to be some pieces are missing you're likely to have better luck setting the Slicing Tolerance to Inclusive. That ensures everything which is in the model file will appear in Cura, but it also means that it might have to add little bits to the model. Exclusive will cut parts away if they don't exactly fit.

Minimum polygon circumference (as long as it's not set insanely high, the default is fine) shouldn't affect lines like that because those are going to be larger than the setting. Maximum resolution is also unlikely to make a difference, since it affects how short lines can be before it'll consider joining them with other lines, and you're deliberately drawing longer lines.

 

44 minutes ago, displaynamenotallowed said:

In previous tests I scaled the honeycomb grid larger and smaller. The results were when I scaled it smaller the angled sections were more consistently spaced and with Cura 4.8 I was able to get perfectly arranged lines. No double or triple stacked haphazard lines but nearly none of the vertical lines were generated. Conversely when I scaled the honeycomb larger all of the vertical sections had lines generated but the angled sections were haphazard. Broken, inconsistent and or doubled or triple layered.

I think what this really comes down to is the model size (and tolerance) having to match up with the layer height and line width you're using precisely (and as I said earlier, the precision from a Blender file isn't great).

 

If you scaled it smaller and none of the vertical lines were generated, that could be because they were narrower than the minimum line width - try turning on Walls > Print Thin Walls. If you scaled it bigger and your angled sections weren't great, that's probably a combination of layer height and line width - if your angled section hasn't quite gone one line width over then it might compensate by doing two layers on the next line to get back as close to the model as possible.

 

For best results, you're going to want to be using the thinnest layers and lines you possibly can - on a 0.4mm nozzle (pretty standard) that's about 0.12mm layers and 0.26mm line width - some people can and do go lower, but those are about the lowest reliable sizes. That will most accurately follow the model. There is one potential downside with line width though - the narrower the line, the less overhang you can do on the next line, which can make it hard to follow shallow slopes.

[displaynamenotallowed 2]

I'm trying to print at .15 layer height. I've played with layer height and line width and yes those both contribute to the results. For the angled sections I wanted to keep line width as wide as possible at .34-.38 for the reason of better overhang. The angles aren't particularly shallow and I was able to get them to print pretty good when I used a single cell hexagon as a test that was modelled with primatives in Matter Control. That was my best result so far. I could try applying an array to that single hexagon but the rendering in Matter Control is hit and miss when the models are more complex. As far as Blender the model I made looked very accurate but perhaps there were little parts that weren't accurate enough. I'm not experienced enough to know for sure but I think Blender is gaining the functionality of other CAD design  programs and not just graphic design. For example there are now what are called Geometry Node tools. Those add a parametric nature to the design flow from what I understand. 

 

I do have FreeCAD as well and will look into modelling a honeycomb grid with it. 

 

I have also used print thin lines setting and while it dose help in certain instances there are a lot of variables going on that contribute to the overall result. 

 

It's easier for me to wrap my head around a particular geometry of the modifier STL than considering every Cura setting that may or may not have a desired effect but would like to better understand those and I have at least a little better understanding in that regard from what you told me I think. 

 

I'll keep at it. Trying different modelling software and techniques for producing the honeycomb and try newer Cura versions as well. I may also try ideaMaker to see how it handles the same task (a software I had become pretty familiar with but haven't used in a while)

 

Another thing I worked on was increasing infill flow rate % to compensate for the angled sections. Doing that caused the vertical sections to print a line width a little wider than I'd like though. 

 

Is there a way I can apply a higher flow %, line width etc specifically to the angled sections of the honeycomb (maybe through bridging settings) and leaving the vertical sections unaffected by the higher flow rate/line width? Being that all the infill lines those at an angle and vertical are all "bridging" the part at 90° maybe that wouldn't work. Is there any other way I could achieve that?

[displaynamenotallowed 2]

I played around with a few settings and modelled a new honeycomb in Matter Control with primatives which worked well.

 

Not perfect yet but definitely progress using print thin lines and Slicing Tolerance Inclusive. Lost the vertical sections which is weird considering the settings but I'm going to keep working on it and think I'll get to a good result. I think I may need to adjust resolution as the lines are broken in places and it seems like that is what that setting is used for as you had described it Slashee. Here is a screenshot of most recent results.

[Slashee_the_Cow 480]

2 hours ago, displaynamenotallowed said:

I played around with a few settings and modelled a new honeycomb in Matter Control with primatives which worked well.

 

Not perfect yet but definitely progress using print thin lines and Slicing Tolerance Inclusive. Lost the vertical sections which is weird considering the settings but I'm going to keep working on it and think I'll get to a good result. I think I may need to adjust resolution as the lines are broken in places and it seems like that is what that setting is used for as you had described it Slashee. Here is a screenshot of most recent results.

I think one really important thing you need to keep in mind is - do the dimensions in your model match the dimensions you're trying to print? If your vertical lines are thinner than the infill line width (it's in the quality section, if it's not visible I know in recent version you use the hamburger menu - three lines - to change settings visibility), I don't think Cura will ever print infill much thinner than the infill line width. Another great reason to use CAD software - you can change the line width in about five seconds flat (okay, I'll admit I don't actually know how hard that is in Blender because it's not something I've ever tried in Blender - precisely because CAD software is much better fit for the purpose).

 

For something like this, you're probably going to want your models' line widths and heights to match your infill line width and layer height.

[displaynamenotallowed 2]

Yes I agree absolutely. This is the primary consideration I've had. I realized that the honeycomb file (STL) needs to have cell walls vertically that don't constrain the slicer algorithm too much but need the angular walls to constrain the algorithm enough that it won't stack multiple lines in the same place or haphazardly. 

 

I've tried to model the honeycomb in that way with primatives but the precision isn't available with that type of modelling. I've decided that dedicated CAD is the only way I'll be able to do it. Now it's just a matter of learning how to use Blender or FreeCAD well enough to do that. 

 

I've recently posted to the FreeCAD forum asking for assistance with learning how to model such a grid and am as you know on blenderartists forum doing the same.

 

So far I've only gotten responses from people that doubt it can be done or have suggested things that are irrelevant. Just have to wait and hope more experienced users will jump onboard and help me with doing it right. I know there are at least a couple ways to model a honeycomb grid in Blender and FreeCAD one is direct modelling and the other is scripting based. 

 

I have modelled the honeycomb directly in Blender but have no experience with scripting in either of those programs but I can and will learn.

 

The challenge and results from my proof of concept testing showing what's possible are too good not to pursue.

Edited October 17, 2023 by displaynamenotallowed

[displaynamenotallowed 2]

There are slicer settings that I still would like to know more about or what settings could achieve better print quality once I have an adequate honeycomb STL to work with and appreciate help with those and thank the Ultimaker/Cura community in advance.

[Slashee_the_Cow 480]

3 hours ago, displaynamenotallowed said:

So far I've only gotten responses from people that doubt it can be done or have suggested things that are irrelevant. Just have to wait and hope more experienced users will jump onboard and help me with doing it right. I know there are at least a couple ways to model a honeycomb grid in Blender and FreeCAD one is direct modelling and the other is scripting based. 

"Can't be done"... you can do almost anything in FreeCAD, usually three or four different ways. I've had better results asking for help when I do a shoddy job and ask for help and people tell me off and say how to do it properly. Anyway, in FreeCAD, go to Tools > Addon Manager and search for honeycomb.

 

There's two macros I've found in there that work - FCHoneycombMaker seems to be the easier one to work with. Install the macro, tell it yes to adding the toolbar button (just so it's easier to find), open a new document, and click the button for it. It generates a honeycomb grid and a spreadsheet you can use to change the specifications for the honeycomb, including how big it will be, the radius of each hexagon, and more importantly, the separation - which is how thick the line between the hexagons are.

 

I fully intend to steal its maths to create my own in OpenSCAD 😄

[displaynamenotallowed 2]

It was actually from someone on blenderartists that wrote they didn't think the way I wanted to print honeycomb infill would be possible. I think the comment was less from a (could the grid I wanted to model be done) and more a (not possible to slice/print) one. 

 

I posted a picture of an actual print I did that does confirm it (is) definitely possible.

 

Thanks for the instruction. I haven't tried it yet but I do wonder about the separation though through that method. If the algorithm spaces the cells equally in relation to each other (all cell walls equal thickness) that's not what I'm trying to do. 

 

I can already achieve that. The resulting model would perhaps be more accurate with FC than what I got from Blender which could make enough difference to work but the way I envisioned the optimal grid for this would almost be a guarantee to work. 

 

I watched a FC tutorial where I think the user was utilizing scripting for modelling a honeycomb and it looks like I could achieve exactly the spacing I'm trying to get that way. 

 

Scripting is a little intimidating for me to use though. I don't understand how that works at all. 

 

I've spent a number of years learning about 3D printing though, what's a few days or weeks to learn this part of the process.

Edited October 18, 2023 by displaynamenotallowed

[Slashee_the_Cow 480]

2 hours ago, displaynamenotallowed said:

I watched a FC tutorial where I think the user was utilizing scripting for modelling a honeycomb and it looks like I could achieve exactly the spacing I'm trying to get that way. 

 

Scripting is a little intimidating for me to use though. I don't understand how that works at all. 

FreeCAD uses Python for scripts doesn't it? If what you want isn't too different to that tutorial I'm happy to have a crack at it, just point me towards the tutorial and tell me what you need different.

[displaynamenotallowed 2]

 

 

I uploaded a picture from my posting in the blenderartists forum where I annotated with red lines to show the cell walls that need to be narrower than those not marked with red lines. 

 

The honeycomb is to be used in the orientation in the picture with 2 sides of the cells that are predominantly parallel vertical. Those vertical cell walls need to be approximately .5mm at the narrowest .6mm perhaps is better. The cell walls that are noted with red (those at angles) should be .4mm or less. The angled sections are I think most critical and may need to be fine tuned from .4-.3 or maybe even slightly less. I'd say anywhere between .4 and .35 should be the best starting point. 

 

I thank You Slashee for being willing to help. If nothing else I could learn from studying the file afterwards and perhaps get me to a place where I could simply fine tune the dimensions. 

 

If you have any further questions or concerns along the way let me know and I'll try to get back to you a.s.a.p.

[displaynamenotallowed 2]

Oh and the grid dosen't necessarily need to have square edges but would be best if can encompass a model at least 40mm in thickness x 160mm tall x 160mm wide. 

Edited October 18, 2023 by displaynamenotallowed

[Slashee_the_Cow 480]

Kind of important detail: what's the radius of each hexagon?

[displaynamenotallowed 2]

Right I had thought of that after I posted yesterday. 12mm radius I think would be good.

Edited October 18, 2023 by displaynamenotallowed

[displaynamenotallowed 2]

It was a wonder I was able to figure out how to navigate FreeCAD and use the file you made. I did though and then proceeded to spend most of a night and until the next afternoon slicing adjusting settings, scaling, back into FreeCAD using the spreadsheet then slicer settings scaling in the slicer, screenshots, etc etc. 

 

I printed a part that shows it works again but it's not correct yet. I can post more later but I'm really struggling with issues of anxiety from essentially poverty/injustice and can't necessarily be working on this consistently. 

 

As much as I thank you and would enjoy seeing this work I also question if this is important for me to be doing and if this particular way of going about it is a good use of my time for such.

[displaynamenotallowed 2]

On the other hand 3D printing and models are one of the only things I have that I can enjoy to a degree.

[Slashee_the_Cow 480]

As someone dealing with anxiety issues myself: if it's something you enjoy doing, go for it! As it is I'm already a bit on edge that my printer is out of commission until at least tomorrow and there's stuff I'd really like to be printing so I can work on iterating the designs right now.

[displaynamenotallowed 2]

I think it's important to have a thing or two to do that's at least a little enjoyable. I downloaded the Cura v.13.x.x. as well as 5.x.x. to see if I can get better/easier results with those and will try them soon.

 

I also was helped by a guy that wrote a geometry nodes process for Blender to generate honeycomb grids that are parametric for me to use. He said the results he got looked good. 

 

I'm going to try Blender and with the FreeCAD route you prepared both and see what I can get.

 

I hope you can get you're 3D printer working again soon because I think you deserve it to be. I'm not great with software/firmware but understand hardware aspects of 3D printers pretty well. I'm happy to help you out with anything hardware trouble shooting related if you would like Slashee.