Trying to design a simple photo frame. Please help me understand these print issues.

Submitted ⁨⁨4⁩ ⁨days⁩ ago⁩ by ⁨nieceandtows@programming.dev⁩ to ⁨3dprinting@lemmy.world⁩

https://programming.dev/pictrs/image/e3c55994-aacb-4c4a-bb26-85a21bcfbacf.jpeg

Designing a simple photo frame. I wanted to make it so that it prints without supports. While printing, however, the back support part wobbles/vibrates with movement, and is printing terribly.

Ender 3v3 CoreXZ, PolyTerra matte black filament, using the CR-PLA Matte profile in Creality Print 7. Tried printing at slow speeds, the issue still persists.

I’ve tried making the back support with only 45 degree angles (previously it was an x diagonal), made it thicker (from 0.75mm to 1.5mm). Nothing is working. Please find the stl and 3mf here (www.thingiverse.com/thing:7281179).

Is this a printer issue, a model issue, or a slicer issue? Please advise. Image Image Image Image Image

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Wfh@lemmy.zip ⁨4⁩ ⁨days⁩ ago
There are a few major issues with your design that we could fix to make it work.

your feet connect to the frame at a right angle. You’re concentrating all the forces on a single layer line that would easily fail. Spread the forces by adding a fillet between the feet and the frame

your vertical and free standing parts are waaaaay too thin. From empirical observation, I’d say anything free standing under 5mm thickness is guaranteed to fail. You could easily add bulk by using a triangular or U-shaped cross section. Not only the part will be much more solid, but also more stable while printing.

As others have said, if you absolutely want to keep it thin, print the frame separately from the feet flat on the back so the forces are perpendicular to the layers. A V-shaped groove will print without supports. 45degs will be fine, depending on your printer you might event get away with shallower angles.

if you want to keep it as a single part, you might consider printing it at 45 degrees from vertical. Layers would have much more surface area compared to the current flimsy ones, and you might even not need as much bulk as vertical printing. Most usual forces would be spread at 45 degrees too, which, while not ideal, would be much more solid than parallel from them.
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- nieceandtows@programming.dev ⁨4⁩ ⁨days⁩ ago
  Thanks for the pointers. I tried 45 print, and the vertical part broke off within the first inch or so lol. Should have tried at low speeds, because until it broke, it looked pretty good. May be that filet could have made it not break off that way.
  
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  - Wfh@lemmy.zip ⁨3⁩ ⁨days⁩ ago
    Yeah the most valuable skill when designing parts is to learn how to design for the process. Print orientation should be decided in the earliest stage, reinforcements to compensate for layer lines weakness should be baked in.
    
    If it wasn’t for the groove, my first advice would have been to redesign the part so it could be printed sideways.
    
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- nieceandtows@programming.dev ⁨4⁩ ⁨days⁩ ago
  Could you point me to some images of the u shaped or triangular cross section? I’m having trouble visualizing it.
  
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  - Wfh@lemmy.zip ⁨3⁩ ⁨days⁩ ago
    Yeah sure.
    
    Something like that: Example
    
    The triangular cross section would be much easier on the printer.
    
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  - WildPalmTree@lemmy.world ⁨3⁩ ⁨days⁩ ago
    Image
    
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pro_user@lemmy.world ⁨4⁩ ⁨days⁩ ago
I would say this is a model issue. How about separating the model in 2 parts: the flat bottom part with the legs, and the ‘envelope’ part that stands upright. Both parts can then be printed flat fairly easy. You’ll only need to think of a way to join the two again after printing, perhaps by modeling two holes in the stand part, and adding two pins on the upright part

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- nieceandtows@programming.dev ⁨4⁩ ⁨days⁩ ago
  Printing the upright part flat on the bed is tricky, because it has a 0.75mm channel running through it for the photos. Wouldn’t that cause overhang issues, or is it too small to be a problem?
  
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  - Blue_Morpho@lemmy.world ⁨3⁩ ⁨days⁩ ago
    It would be an overhang problem. You could change the channel to a 45 degree notch. But it wouldn’t hold the photo as secure.
    
    Simplest might be to fill in more of the back so you don’t have that thin rectangle going up high until it meets the other rectangle in the middle. Thickening those parts would also help. The back frame could be changed to a hollow square cross section. That would make it stable without significant material.
    
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roofuskit@lemmy.world ⁨4⁩ ⁨days⁩ ago
Make the back a series of hexagons. They are the bestagons.

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- nieceandtows@programming.dev ⁨4⁩ ⁨days⁩ ago
  I was thinking of that before posting that, but wanted to check if it’s something wrong with my printer before that
  
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  - roofuskit@lemmy.world ⁨4⁩ ⁨days⁩ ago
    Nope, that’s normal behavior for a bed slinger when printing tall thing objects.
    
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j4k3@piefed.world ⁨4⁩ ⁨days⁩ ago
Honestly, it is a bit of a noob design, and I do not mean that in any kind of negative or insulting way whatsoever. The main issue here is how you are thinking in terms of other materials and processes. Every product is primarily constrained by the manufacturing process. The design aesthetics are constrained by this process. The trick is to understand these constraints well enough to make something aesthetically pleasing within the process. To be fair, ~95% of designs shared and printed have this type of issue. Your design here looks like something I would make out of brass sheet and brazing. There is nothing fundamentally wrong with the approach. I see what you were trying to do.

The floating thin sections on layers, lack the flow consistency to maintain temperature regulation of the heat block. The heater cartridge in the print head is managed by a PID control loop. This will always have some overshoot and undershoot of temperature when the flow changes substantially. There are a number of contributing factors to this issue in the printer hardware design. I could go into a lot of depth here but that is an aside.

I would not use thin floating sections. Let’s say the whole backing was solid in a FreeCAD design body. I would then do something like an egg shaped ellipse pocket out of the middle. Another option might be a % like shape with the thinnest section offset so that the layer lines are still substantial.

My most advance approach would be to print the face of the frame on the bed, and the rear face of the backing plate also on the bed as a second part. If designed well from the start, and if the bed is large enough, you design the print to finish the backing plate before the face is completed. Then you add a print pause, remove the backing plate, insert it into the front plate, and continue the print to encapsulate it as a single part. This makes any 2D pattern for the backplate possible, and you do not need to deal with fasteners or whatnot. You end up with a perfect picture frame slot using this method.

A total aside, but this idea can also be used to make your own printed supports manually for perfect overhangs. You print the support to size, add a pause, and remove the printed support shape. Ideally, you add a ~0.1mm-0.2mm clearance gap, paying very close attention to how your slicer layers height and first layer correspond to the support dimensions, or rotate the support to utilize better x/y dimensional accuracy if possible in some designs. You can even create a printed alignment jig on the build plate just to hold this manually created print support. The trick is to then apply gluestick to the interface between the manually printed support and your overhang. This can produce nearly first layer like print quality on an overhang with dimensional accuracy too.

Another super advanced trick: let’s think if the picture frame standing vertically upright in Cartesian planes. It is facing forward on the X-Z plane (X = -><- = >< = left to right). Let’s assume the origin 0,0,0 is properly centered in the frame. Now if we look at a X/Y Top, section view, we are looking at the picture frame as if someone had used a hacksaw in the middle of the sides of the frame. In other words, we are looking at the frame’s profile view. Now typically, people approach this like a [. Now this takes a lot of practice, but it is possible to design a profile something like ɭ̅̅̅ ̅ ̅˻ ̅ ̷̅ – the print bed is ↓. If you design this just right, the left side is the frame and the right is designed with a small connection to the bed and an angle where this connection is close to the rest of the frame. The thin bridge overhang is going to contract and shrink towards the larger heat mass of the frame, especially because of the printed layers above the bridge. This contracting force will be set into the part like a spring, but will remain compressed due to bed adhesion. You may want to add a small first layer connection or inner skirt to hold this section in place firmly throughout the print. When the part is removed from the bed, the bridge spring will pull the right section back. This will create the slot for your picture and potentially a way of holding other types of backing, while not worrying about conforming to other types of manufacturing process constraints like a wood router or sheet metal profile.

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- nieceandtows@programming.dev ⁨4⁩ ⁨days⁩ ago
  I definitely want to get better, which is why I’m asking for feedback on the model as well. Please give me some tips and tricks to think and plan for efficient models that are best suited for 3d printing. How would you recommend I modify this model?
  
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  - j4k3@piefed.world ⁨3⁩ ⁨days⁩ ago
    Did you see I wrote that comment into a spoiler to shorten it in the post replies so it is not a wall of text? Sorry if my thoughts are hard to follow at times. I write in an abstract rough draft like format. I wrote several tips and how I approach a problem like this.
    
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Attack0fthenerd@lemmy.dbzer0.com ⁨4⁩ ⁨days⁩ ago
If you cut the model into 2 pieces. The triangles could have a little peg and the base a slot, glue them with a little super glue (CA glue). Print them both flat and you won’t have that particular issue

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stealth_cookies@lemmy.ca ⁨4⁩ ⁨days⁩ ago
Yeah, that isn’t going to work. The nozzle has drag force due to the molten plastic so any tall and thin beams are going to flex as the layers are deposited.

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stephen@lemmy.today ⁨4⁩ ⁨days⁩ ago
Looks like that’s on the back hidden behind the photo?

No issue!

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- nieceandtows@programming.dev ⁨4⁩ ⁨days⁩ ago
  Yeah the front looks great, but I feel like it’s not good enough with an ugly back
  
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Lasherz12@lemmy.world ⁨4⁩ ⁨days⁩ ago
Since your printer moves the platform you’ll need to provide supports to avoid this. You can slightly mitigate by reducing speed. The supports don’t need to necessarily originate from the bottom, it could just provide a thin beam to resist wobbling in that particular direction.

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- nieceandtows@programming.dev ⁨4⁩ ⁨days⁩ ago
  I tried with 50% speed, and even silent option which is even slower. Still happened. May be a hexagonal pattern might work better. I just want to build a simple photo frame that one can print without supports, and one that uses minimal filament.
  
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