I needed to know the Holding-Force capability of Threaded Inserts in PCB for a project.
That compelled me to design a gizmo. Sure, I have hand-held force measuring gizmos but wanted something more repeatable/accurate with ability to Plot the data/curve…
For the Test, I used PCB’s with same size Holes and M2-H2 threaded inserts.
Some Inserts were manually Cold-Pressed in. Some used Heat-Pressing (using a standard tool & Soldering Iron).
I all cases, the Cold-Pressed Insert held far better than the Heat-Pressed Inserts - about 2x stronger. Tests were fairly repeatable.
I tested only One size - the one’s with compatible height of 1.65mm PCB.
The design uses two Arduino Nano’s because: I have a couple dozen of them in a box, wanted independence of “Interrupt’s” for Micro-Stepping (32 steps per pulse) and, more importantly, I use Arduino’s ‘Plotter’ which kills the Stepper motor performance…
(NOTE: There are different styles/brands of Inserts - I tested several and chose these (screenshot))
I can understand this.
Heating those rings will expand and cooling will contract. With respect to the outside surface, the interference fit of a fitted heated ring will not be quite such an interference fit when allowed to cool compared with a cold fitted ring. The opposite for the internal surface.
Thanks for the result table, I’ve sometimes wondered about the strength capabilities of these inserts.
I have not tried those heat-set nuts on a pcb, but a buddy of mine uses them in 3d-printed enclosures. He mounted a soldering iron and the special tip in a gizmo like a dremel drill press (but less cheesy than the toy products dremel sells). They provide a more solid mount point than just using screws like plastite™ with the coarse-pitch/steep-lead threads.
PEM make a variety of broaching/swaging press-in pcb mounts (I have not used these in pcbs either, but I used a lot of pem standoffs in sheet metal products and they were awesome parts:
What I have used on pcbs lately is the solder-in standoff like this one used on M.2 and micromod boards. I wonder how the tensile strength of this compare?
I also use PEM’s and Post’s (with knurling).
I do plan to do Pull tests on the sizes I use (M1 thru M5) - perhaps this week…
I made footprints for a few of them… For my 3D-Printing, I embed them (and Nuts) into pockets and put layers over them to close them up.
How do you embed nuts in a 3d-print? Pausing/restarting? I paused and re-started a print once and my ender-3 lost orientation and the continuation of the print was offset and rotated a little bit. Have not tried it since. Or are you tweaking the g-code? I have looked at cura’s pause-at-height and head-park stuff but never tried it. How is the layer adhesion after restart?
Well, we’ve gone afield from original Kicad related post but, here ya go:
Good question(s)…
Have done many times and works well for my purposes…
• I embed Nuts by making the part (in FreeCAD) with correctly shaped pocket (Hex, for example).
I usually use Simplify3D but have used Repeater too.
I set the custom pause code/script as shown below.
I don’t wait very long so it doesn’t cool too much. Just watch the Display and when near the Z-height before it starts to cover/close the pocket, I grab the Nut and be ready to drop into pocket then, push the Button to Resume (using Prussa MK4).
Of course, I wait until the Nozzle is out of the way.
I do it this way because my machines are old and don’t have ability to store last location (I think I could re-code it, I did hack my Marlin and Repeater codes a few years ago.)
I also have custom Start positioning code and my printers are customized.
Never had problem with layer bonding as I don’t wait long before resuming.
I also changed the ‘Jerk’ to stop machine from shaking to death!
Info below may be of interest… Ignore the Plastic Nut - didn’t want to look for photo with empty pocket… The image has Plastic nut but the parameters shown are to enable Tapping the Threads if not using a real nut… depends on project…
I see – very cool. You always inspire me to try new things. And, well, this is all still kinda kicad-related, as we need to screw the pcb into the case – which leads to exporting the pcb from kicad into FC via StepUp – and the circle is complete
I’m having some mixed feelings about this thread. I appreciate your sharing of your experiments with those inserts, but yesterday I was also tempted to close it for being off topic.
Can someone explain why this would be any different from those generic electronic questions that are getting closed ever faster lately?
I don’t really care for that policy, and instead I decided to just start answering “generic electronic” or other questions myself.
Well, as I mentioned above " we’ve gone afield from original post…" and I thought about closing it. Now’s a good time to do that.
I’ve closed a couple of posts after reasonably answered. And, I have no problem closing my own posts but, unless the post or user is way off base, I don’t want to play self-anointed Policeman…
On the other side - folks I know doing electronics usually need some kind of container/enclosure for their PCB and using KSU/StepUp makes it very convenient. Without good knowledge of Mechanical design, an Electronics-Product based Engineer can easily push out crap (from the physical/mechanical perspective). I have an Apple Laptop with terribly sharp corners/edges that if an Average Mechanical Engineer looked at it, it wouldn’t have gotten out the door.
If a User wants to put Inserts in a PCB done in Kicad, well, may not make sense for him/her to go another site just for that.
