I’m trying to print this custom design, but having some issues. What would be the best way to investigate the problem I am having?
https://www.dropbox.com/scl/fi/r55guo1linxap4yy3fm8a/20230925_075218.jpg?rlkey=ruefuccqm6kddyh15wead957j&dl=0 https://www.dropbox.com/scl/fi/3st6yvi2ce6ojpyjsojax/20230925_075306.jpg?rlkey=5dmmmp5hukynfamh2ryhjqw1v&dl=0
To display images inline you need to add an exclamation point before the square brackets, like this:
But also you want to use the direct link to the image itself, not the Dropbox page for the image, so this:
The problem here is that the vertical bars are too tall and thin. You have to think of each one as a lever while the top is unfinished and not connected. The bottom part where it’s connected is the fulcrum, and the nozzle is the load. When the nozzle is printing at the top of the bar, it is pulling on the bar in the direction of movement, causing it to bend. If there’s a weak point it will snap.
You could fix this by making the bars thicker, or by increasing the number of horizontal connections so that the unsupported vertical pieces aren’t as tall, or possibly by slowing down your print speed - but it’s really a design issue.
You could fix this by making the bars thicker, or by increasing the number of horizontal connections so that the unsupported vertical pieces aren’t as tall, or possibly by slowing down your print speed - but it’s really a design issue.
another solution might be to angle the bars so they criss cross in a skinny-X pattern, but I agree it’s a design issue. especially if it’s always breaking at the same spot.
Second this. If it’s PLA, improving layer cooling might help stiffen the last layer before the next is applied. If it’s not PLA, slowing the print down can reduce the horizontal forces for slower-cooling filaments like PETG/ABS. If there’s any warping or over extrusion leaving little blobs on the surface, your nozzle can bump into them, breaking cantilevered features like this one, or breaking the part off the build plate. Getting retraction to blob less or making sure no over-extrusion exists could help. If it’s PETG or Nylon, printing slightly wet (where the surface doesn’t look bad) can cause blobs on the top layer that the nozzle hits and causes those horizonal forces.
Drooping like this means something is too soft (speed up cooling on PLA, reduce print speed to give more cooling time and better layer adhesion for any material)
Prints like this aren’t impossible. I’ve printed a PETG storm drain that had vertical slots like this when I couldn’t buy one I needed. It turned out great but I had to print really slow.
Thank you for the help with the photos. I’m still struggling with it for some reason…
I appreciate the feedback on the vertical bars being too thin, that makes sense. I’ll do some adjustments to the design, do some calibration prints, and give it another shot.
For the images, try right-clicking on one and clicking “Open image in new tab” so you can see just the image without anything else. Use that link.
For designing, keep in mind that at the tip of the nozzle where the soft plastic is hardening on the model, the nozzle movement is pulling on the hardening plastic and actually putting a lot of force on that part of the model… there’s nothing you can really do to change that, it’s just how printing works. You kind of have to design around it.
From what I can see in the images, your calibration looks fine. The layers are actually aligned really well, I wouldn’t change anything there.
We’re gonna need way more than that if we’re going to help you.
- printer info
- materials- both what your printing in, and in fdm, what you’re printing on, etc
- the actual problem you’re having
- your offering to the goddess of spaghetti prints.
Edit: did naiboofTabr drop photos of the problem? on that assumption… how’s you’re layer adhesion generally? I would recommend testing that with a spiral-mode tower- take any solid shape- I use calibration cubes changed in the slicer to be 10x10x50mm and print it in spiral mode, testing layer adhesion by seeing how well the single perimeter is stuck- and also, filling it with water and checking for seeping. this also lets you check for flow settings and such.
if that test print comes out good, then, it’s possibly being created by stress risers in the part itself. Specifically near where the bridges come down. As you drop each layer, it cools off, shrinking a bit, changes in cross section between layers, that force can cause it to be weak in that specific spot no matter how good your layer adhesion normally is.
The other thing I’m seeing is a nice long tall lever being printed on. While normally negligible, there is some pull as the nozzle moves over the part. Being tall and skinny like that turns it into a bit of a spring.
Assuming your layer adhesion is okay, I would suggest tackling the other two problems with a change in the part itself. increase the number of bridges connecting things, while also staggering their connections across the vertical axis. Also, consider changing the bridge’s geometry. Another option here is, to instead angle the pillars so they criss-cross, becoming both the pillar and the bridge.
also, I would suggest checking your flow and estep calibration as well as running a temp tower if you’ve not done it. I like the teaching tech guides, and their troubleshooting section is also generally helpful.
Ender 2 pro, using PETG (offering to the goddess of spaghetti prints) https://previews.dropbox.com/p/thumb/ACCu0iDFgAuIf12PdScFyfgBu5f92ltGXkf1W5QuB2fjbNtB8FhegjBAwwp-GJOca2XoL1Sn1-iZr3xBdM53PAomijdgWT5Pq7PKfNAhlncv3fDX09iAugiLd21fyRRH4kLtYz0a8AP-mnf3KxyWpxQSDwPO84CBfgMF06nSeJk94lY3cXEm-ta6jOCNVKAEh89gbonYC0Hi5P6Pfj152R8cw_hkqJHFYFB0H8rN_MKM5dymh-BHanC_zCVMXgsvX41ocaOESlcHumvo0MVoyE19pcrEB7QYQhVvIAqdMO-PawYbS7t8AITZOpKqsR-SeX_LfRfYQ3NoylC1u8JFBAoU/p.jpeg
He did. The layer adhesion seems ok, generally? I’m still pretty new to all this. I’ll give your spiral mode tower a test soon, thanks. I’m currently printing a temperature tower, so I’ll see how that turns out too.
I could definitely add more bridges and stagger them like you said. The design was made by using slot cutouts in Fusion360. I’d have to play around with it to figure out how to alter the design for cutouts to form an x pillar/bridge combo like you mentioned.
Thanks for the help.
so, in f360, the way I’d do it is to create a is create a pair of pillars- one in each direction- then create patterns. use the combine tool to join them into a single body. Then I’d create the top and bottom of the box. When using the combine tool, I would advise not selecting ‘keep tools’. this will help keep you from bogging down the computer and you can always go back in your history. (its a problem in f360 whenever you start going crazy with patterns. or patterns of patterns…)
but it should be okay if you stagger the braces, I’ve had some idiotic design choices myself. (including a spirally-fin-shaped lamp shade that would have looked sWeEt. like a long sort of jet turbine. except it was 200mm tall and the fins were bobbing and weaving. ooops. sometimes it’s only obvious in retrospect.)
