Settings for Functional Strength  

RE: Settings for Functional Strength

So lets say standard print quality is 2 perimeters and 20% infill. For a stronger part I'll go to 3 perimeters and I'd guess that will be good enough for you. It may not sound like much but think of it making the walls 50% thicker. On very rare occations I've felt the need to use 5 perimeters and go up to 30-50% infill but that was large gears I was making or the walls and plunger of a biomass mold. Larger layer height, bumping up the temp like 10C, and even purposefully over extruding ~5% will also help improve strength but will reduse the surface finish quality.

RE: Settings for Functional Strength

My minimum is 3 perimeters on all my custom profiles, as I mainly do functional parts.  I only really use 1 or 2 when I'm doing very quick draft prints to check scaling and ergonomics, that aren't intended for actual use.  For items that see a lot of physical use like grips etc then 4-5 is also usual for me. I make a lot of lasertag guns that get used for simulated combat outdoors.  You could describe them as high stress parts 🙂

Infill percentage is adjusted based on geometry, not so much for strength, more to make sure there is sufficient to support top layers.  If the part doesn't have many or has small flat areas then 10% cubic infill is usually enough.  For something with larger flat areas though then infill might go up to 40% (using something like support cubic or adaptive cubic).  If you want a large flat area to look good without pillowing then higher infill and 5-7 top layers really does make a difference.

RE: Settings for Functional Strength

Thanks for posting that link, looks useful.  I am going to give that a go although my print settings probably won't be terribly useful to you since I am going to print it out of ABS on my Voron, at the standard settings for Voron parts which is probably overkill, at 4 perimeters and 40% infill.  Mostly with ABS I need to worry about shrinkage since it was probably designed for PLA or PETG

Posted by: @razor

I would like to print this https://www.printables.com/model/385416-hopper-fed-speed-loader-223556300 using Polymaker PLA Pro. I’m using a 4mm nozzle and thinking .2mm height would be fine. I remember that number of perimeters is what you want to increase for functional parts and that infill is a secondary consideration.

How do you know what settings to use? Until now I’ve never really printed anything functional where this would matter.

I’d appreciate any advice. Thanks!

RE: Settings for Functional Strength

Thank you all for the comments and suggestions. I appreciate the help. Having never printed something functional like this I ended up going with 6 walls and 50% infill. I'll tell you what, the pieces felt like something you would buy in a store. I am impressed. Not sure I needed 50%, but wow....

@neophyl if you don't mind me asking, what makes you use support cubic or adaptive cubic infills over gyroid, which is what I used? And are your laser tag parts online anywhere that we can see? I'd be interested in looking at them to have some point of reference. 

I still have to assemble the pieces and and put it to use, but I'll do a follow-up at some point in the future for anyone that happens to come across this post.

RE: Settings for Functional Strength

Basic Cubic support has been my goto support option for a long time.  Its has very similar strength to weight as gyroid.  In my opinion Cubic has several advantages over gyroid too.  The relatively recent additions of support and adaptive cubic just make the pattern in general even more useful.  

Firstly cubic is straight lines, this means the printer doesnt shake around as much as it does with gyroid.  This also has the added benefit of the gcode is smaller.  Every short segment and change of direction is another line of gcode.  
When it comes to printing layers on top of the infill then depending on the direction PS chooses to use you can get unlucky with gyroid.  The cubic pattern rotates more per layer than Gyroid.  In effect you usually end up with shorter line to line gaps at any angle.  

Also from personal experience I've had more trouble with large flat parts (like display bases) warping up with gyroid than I have with Cubic.  Again I suspect that the long curve lines of gyroid act as better springs and can contract more than the cell like structure of cubic.  YMMV though.  It's 3d printing so there are always many different ways and viewpoints 🙂

I don't have anywhere near the full complement of my lasertag designs uploaded anywhere as its a pretty niche hobby.  I do have a couple on my Printables account.  https://www.printables.com/@Neophyl/models  
Even the non lasertag scifi gun models on there have versions that are though.  I just uploaded versions with some of the internal cut-outs and wiring channels omitted.  Only about 2% of designs make it online.

RE: Settings for Functional Strength

Thanks for the explanation on the fill @neophyl! I considered cubic but after reading the notes from Prusa, I chose gyroid. It’s funny because before I started this thread I was thinking about some of the things you mentioned. 

Also I didn’t know laser tag was still a thing. I tried paintball last fall and had welts for 2 months. 😂

RE: Settings for Functional Strength

Just a quick follow up. I had a little time to mess around today and re-sliced the parts with adaptive cubic. It cut 3 hours of printing on one of the parts! While it’s too late for this go around, I will be using adaptive cubic more in the future. Thanks again for the advice.

@neophyl is right, different infills for different effects.

I use three different basic fill patterns, well, just two mostly:

Cubic is the fallback and preferred when stiffness matters; I may be wrong but I feel it also warps less during printing.  Adaptive and support cubic are also useful on occasion for good top surfaces.

Gyroid for resilence, it's a relatively good shock absorber and dampener, use it for parts that will be subject to vibration or shocks - especially with PETG to take advantage of the slightly springy toughness.

And the third?  3D honeycomb can give useful stiffness to parts where the slight directional bias of cubic matters, I may only need it once or twice a year but it's worth considering when resonance issues occur.  Not to be a regular feature 'though, it shakes the printer even worse than gyroid.

And for strength?  The fill makes little difference, the number of perimeters and the orientation of the part on the print-sheet are far more important...

... NEVER use 100% infill for strength, reserve high densities for parts where the weight is important, if a part is stressed close to breaking 100% makes it more likely to shatter, 80% is about the most to use as the small voids act as crack-stoppers and the mode of failure is less catastrophic.

In practice, if you find  yourself adjusting infill above 30% for *strength* then you are best advised to revisit your design - eliminate stress concentrators, realign to accommodate strain vectors and the like.

Cheerio,

RE: Settings for Functional Strength

As I print prosthetics I've put some research and testing to use in our prints. One surprising thing is print speed and extruder temp. From a materials testing lab we got the numbers on print temp and print speed effects on tensile strength. It boiled down to print at the max temp the manufacturer calls for and print at 45 mm/sec. That was for both PLA and PETG. Other materials weren't tested and not a big concern to us anyways. Yes, it can take some tweaking to deal with stringing and quite frankly a heat gun works wonders. Also drying filament, especially in our humid climate, right out of the bag though most PETG is already wet! PLA has been hit and miss so we dry as standard practice. We've settled on adaptive cubic at 20 to 30 percent for infill and use three walls minimum but occasionally more. Just my experience from my world.

RE: Settings for Functional Strength

@sailoreric I purchased a PrintDry Pro last year and agree, it makes a big difference with PETG, even new material fresh out of the box. Haven’t used it much with PLA except for the PolyLite Wood that I use from time to time.

Never thought about the crack stopping features of infill. Thanks @diem for mentioning that.

RE: Settings for Functional Strength

Also from personal experience I've had more trouble with large flat parts (like display bases) warping up with gyroid than I have with Cubic.

Now that's an interesting thought… One model I'm selling is basically a large brick filling the diagonal of an Mk3S. I need to use brims—and paper clips to hold the steel sheet to the print bed!—to avoid warping, and even then there's a bit of it. For my next print I'll be switching from gyroid to cubic to see if it makes a difference. Interestingly, with my XL I'm now able to print 3 at once, and I see no warping at all, so I'm also wondering if a less than ideal heat distribution on the Mk3S print bed may be a contributing factor. 

Like others have said, I use 3 perimeters and mostly gyroid and adaptive cubic as my go-to infill patterns, as the baseline config for functional models. In most cases, gyroid gives me the shortest print time—and it looks cool. At least in my hands, I never saw much difference between adaptive and support cubic. My defaults are set for 15% infill, sometimes I go lower, and for large horizontal top surfaces I go up to 40%. For non-functional models, I find myself using Lightning more and more. Works surprisingly well.

RE: Settings for Functional Strength

I have a couple of comments...  First, to the moderator who moved this thread from General Discussion to this subheading of the Mk3 subforum.  That made no sense at all.  If the OP said anywhere that he was printing it using a Mk3 then I missed it, and he has multiple printer types listed in his signature.  I wanted to see if he said what filament he was using, and I had to hunt for the thread since it was no longer where I remembered it, and for no discernible reason.

Second, this model didn't work well for me.  Maybe because I used ABS, or maybe some other factor.  The parts fit together well, and it kind of sort of works some of the time, but when it's easier to do a task by hand that a tool is designed to make faster and easier, then the tool isn't all that useful.  I see that the OP rated it 5 stars on Printables, so I was hoping to hear if you are still happy with it (granted it's only been a week and a half since you posted your make), or if you have encountered any issues with it.

RE:

Posted by: @netpackrat

I have a couple of comments...  First, to the moderator who moved this thread from General Discussion to this subheading of the Mk3 subforum.  That made no sense at all.  If the OP said anywhere that he was printing it using a Mk3 then I missed it, and he has multiple printer types listed in his signature.  I wanted to see if he said what filament he was using, and I had to hunt for the thread since it was no longer where I remembered it, and for no discernible reason.

Second, this model didn't work well for me.  Maybe because I used ABS, or maybe some other factor.  The parts fit together well, and it kind of sort of works some of the time, but when it's easier to do a task by hand that a tool is designed to make faster and easier, then the tool isn't all that useful.  I see that the OP rated it 5 stars on Printables, so I was hoping to hear if you are still happy with it (granted it's only been a week and a half since you posted your make), or if you have encountered any issues with it.

Thanks for the heads-up, I did not notice this was moved. How would one even know to move it to this forum? I do have multiple printers and for all anyone knows, my signature could be outdated and I could be printing this on my current XL.

Moderators please return this to the general discussion. Functional strength and number of perimeters is something relative to all printers. If I were looking for guidance on this topic General Discussion would be the one place to look. Thank you in advance!

RE: Settings for Functional Strength

One think I notice is the image in the OP link shows the hopper standing upright. I’m not sure how it is supposed to be printed but I am assuming it is supposed to be placed on its back which would give max strength  

RE: Settings for Functional Strength

Absolutely you have to take that in to consideration on any print. Without looking at my various G-CODE files, and from what I remember, I positioned the pieces so that a minimal number of supports would be needed. Six walls and 50% were more than enough. Knowing what I know now, there are parts I would have reduced those values. For example, the top loading bin has no stress on it. Four walls, 35% infill would be my next go at this. All in all, this was a great GENERAL lesson (hint hint moderators) in printing parts which require strength.

I was a little gun shy (no pun intended 😄) from the time I spent working with my old Adventure 3.  I couldn’t get good adhesion/dimensional accuracy/quality to save my life.

Posted by: @john-6

One think I notice is the image in the OP link shows the hopper standing upright. I’m not sure how it is supposed to be printed but I am assuming it is supposed to be placed on its back which would give max strength  

 

 

 

RE: Settings for Functional Strength

Hi,

To achieve functional strength for the 3D print of the Hopper-Fed Speed Loader using Polymaker PLA Pro and a 4mm nozzle, follow these settings:

Layer Height: Use a layer height of 0.2mm. This will balance print speed and quality, providing a good compromise for functional parts.

Number of Perimeters (Walls): Increase the number of perimeters (wall lines) to enhance the strength of the printed part. For functional parts, setting 3 or more perimeters (walls) should be sufficient. More perimeters increase the overall strength, but also increase print time and material usage.

Infill Percentage: While infill is a secondary consideration, you can set the infill to a medium percentage (around 20-30%) to provide some internal support and ensure the part is not hollow. A higher infill percentage will increase strength but also consume more material and printing time.

Top and Bottom Layers: Add a few top and bottom layers (usually 3-5 layers) to provide a more robust and smooth surface for the functional part.

Print Speed: Lower the print speed slightly for better adhesion and to maintain print quality. A speed of 50-60 mm/s is usually a good starting point.

Print Temperature: Follow the manufacturer's recommended print temperature for Polymaker PLA Pro. Printing within the recommended temperature range ensures proper layer adhesion and minimizes issues like stringing and warping.

Cooling: Enable part cooling to prevent overheating and improve the print quality, especially for small features and overhangs.

Before printing the functional part, consider doing a small test print with the chosen settings to verify the quality and strength. Adjust the settings as needed based on the test results. As with any 3D print, it's essential to calibrate your printer and ensure proper bed adhesion for successful functional prints.

I hope this will help.

Thanks