I have made this bracket for mounting a small network switch that I need to print a few of. I have tried PLA and PETG so far but the clips that hold it secure are just too brittle and after pulling it in/out once or twice they break off. I have not really used anything other that PLA/PETG/TPU so I am looking for a recommendation for a filament that would be strong like PETG but a little more flexible so the clips can handle a little more flex. The bracket itself works great and holds strong once the switch is installed.
There are probably many potential solutions for this issue but I’ve had really good luck with firmer TPU such as TPU for AMS. It’s quite strong and just has a tiny bit of flex - it can work well for parts like this one (where my guess is that the clips are failing along the layer lines). It’s also quite easy to print.
If you print it with that orientation, spreading the tabs will stress the inter-layer bond and the print will separate along layer lines. 3D printed parts will not perform the same as an injection molded part, they’re not isotropic. You need to beef up areas that are going to see significant stress in the Z axis.
100% exactly this. The orientation is unsuitable for maximum durability for this use case.
The problem lies in the orientation, not the filament itself. It must be positioned at an angle, even if this unfortunately means that support or brim is required. For this part, I would recommend 90 degrees, i.e. standing upright. The layer lines must be aligned so that they run along the force and do not create a predetermined breaking point.
The right question should not (only) be which filament, but which orientation.
The video explains perfectly when you need which orientation and how extremely this affects durability.
I love TPU for AMS, but its layer adhesion is the worst in the entire lineup.
@RetroSharky found the first mitigation step. @MaKim, your material choice might work with the help of the printing orientation, but poor adhesion is a scary prospect for this type of print.
@wb3 Honestly, I would try to thin out the amount of flex needed. That looks like it would engage around 2-3 mm’s of flex and could probably be fine at less than 1mm. Print some tests and see how low you can go. Then use @RetroSharky’s tip. Also in the model modification, I would make the neck of each clasp consistently thin by moving the gussets down or doing away with them. They currently brace the clasp too high and will make any flex way more difficult than it needs to be.
As an alternative, you can make them separate parts and use a screw to secure the top of the clasp and maybe add a detent nub for positive position finding, so you can articulate them away with a rotation.
That’s interesting - I haven’t had issues with that but I also haven’t used it on a wide range of models - it may just have been well suited to the ones I used it on.
Yeah, I was surprised to find that in Bambu’s TDS because it has never been a problem for me, but I’m probably stacking the deck the way I use the material because I design stuff in a way that has the least chance of failure (at least that I can foresee).
I would suggest a redesign. As is, the tabs won’t last. Can the network switch be inserted from the top (the bottom side in your image) and therefore eliminate the need to bend the tabs? If not, try to reduce the length of the holding bars so that the tabs don’t have to be bent as much. Or make the tabs as separate parts so that they can be printed lengthwise. Or just use those hook-and-loop fasteners instead of 3D printing
Thanks for all the info… I need this to stay similar to the way it is designed but perhaps I can make it snap or screw in from the top.. First I think I am going to try some hard TPU. I reprinted out of some softer TPU I had and that seems to solve much of my problem but does not hold the switch as secure. I ordered some 74d and will give that a shot.
@RetroSharky that’s a great video and I will keep that in mind.
Just to close this out, I printed it with CC3D 72D TPU Filament and it worked great. I was also able to use the AMS with this TPU so I could make the support interface out of PLA. Worked fantastic.
