Discussion Question as to Strength in Orientation Prints

[Ulma Doctor]

is it possible to print objects that end up being more rigid, by re-orienting how they are printed ????

for example,
i have noticed by using the rotation feature in the Cura 4.8.0 slicer, that i can alter print times
i have also learned that the infill percentage will greatly vary the rigidity and the print times too
layer thickness and other nuances aligned with alchemy can be dissected into smaller and more detailed command, all have bearing on the end product.

(without argument of fixed factors, like the same object, same printing material, same infill, same layer thickness , temperatures, blah blah blah.)

Can objects be printed to have superior toughness, by simply re-orienting the object????

please expand if possible, any anecdotes, any thoughts, any engineering or working knowledge would be welcomed!

 

[KevinM]

99% of failures occur between layers. Orienting parts so that the highest stress is perpendicular to the layers greatly increases strength. Higher temps help layers to bond better. Thicker layer heights also bond better due to holding the heat a little longer.

 

[DavidR8]

I'm not sure if this is related but I was having trouble with a print a week or so ago. Sliced it in Cura and it failed twice about an hour into a 3 hr print.
Resliced it in Prusa to see if that would make a difference. Same settings across the board. The Prusa projected print time was about 22-25 mins less than the Cura sliced file. Actual print time was about 2 mins less than the projected Prusa time.
So I wonder if the slicer can make a difference in strength?

 

[7milesup]

Short answer is yes.
If you observe layer placement, there will be greater strength perpendicular to layers versus parallel (shear) to the layer. The strength of course highly depends on material also. Materials present different modulus of elasticity which can greatly affect where and how a print fails.
Higher temps to increase bonding strength may work, but too high of a print temperature may result in the layers "drooping" and poor print quality. It can also cause warping, depending on material.
Infill geometry also affects print strength. I prefer gyroidal formation for my infill. Seems like it is stronger but that is just anecdotal.
As I sit here, my 3D printer is churning away for a drill bit storage solution I am working on. I am using PLA+, from eSun, which is supposed to be up to 10 times the strength of standard PLA. I don't need that strength for what I am doing, but it was the same price so meh, why not. But, that first layer I had to mess with a little bit and upped the bed temp to 70c to get a decent first layer. Mfg suggested the standard 60c temp.

So Mike, it does make a difference on how an object is oriented, not only on strength but print times. I printed some way covers for my mill recently and just by changing orientation decreased print time by 2/3rds.

Also, certain materials benefit from annealing. I don't remember the exact materials and numbers, but Thomas Sanlander developed a YT video regarding annealing and the subsequent results.

 

[7milesup]

Found two videos that I was looking for. Sorry Mike, this doesn't pertain directly to your question but it might be nice to know...

 

[KevinM]

Yes, slicers make a big difference.

Here are my thoughts on some techniques:

When calibrating filament temperatures I do destructive testing to select the best bonding temperature. I print for strength, not appearance.

PLA is great for knick-knacks, gee gaws and trinkets but I only use it for structural components if the objective requires very low flex (therefore brittle).

PETG has some flex but it is very strong and printable on most printers. Stringing can be a problem but with Hatchbox filament and proper retract settings I get almost no stringing at all.

My go-to filament is ABS but it usually requires an enclosure and it does not do well with some chemicals. A lot of people use a cardboard box over the printer successfully. Octoprint is a great help by allowing you to wirelessly monitor the print via a USB or Pi camera when using the box method. I have some printers enclosed with a plexiglass case and active heating for the really difficult prints that want to warp. A large footprint, poor plate adhesion, no enclosure and heavy infill are a great environment for warping. Acetone vapor can be used to make the print glass smooth and shiny.

Nylon is VERY tough. Not just strengt-wise but more difficult to print than ABS. I print it at 260-270C

As far as I know all extruders have "full metal" hotend upgrades available (if needed). Full metal is needed for higher temperatures. All of the printers that I build use full metal hotends. If you have a PTFE liner in the hotend it will melt at higher temps. I think that 240C is the limit.

To reinforce certain areas of a model add a very small hole. The perimeters around the hole will essentially give you a solid area around the hole.

As I mentioned, Octoprint makes 3D printing life much easier, It's free and a Pi4B cost around $35. You will need an appropriate power supply also. You can slice your model as usual and wirelessly upload to the Pi or you can let Octoprint slice it using Cura or Repetier-Host. All functions of the 3d printer except for removing the print when finished can be done using Octoprint. Plug-ins allow a lot of other functions. I can even update my printers firmware wirelessly.

Tom is a great resource

Tom's 3D printing guides and reviews –

toms3d.org