Hello!
So I decided, as a way to improve my cad skills, that I would take an old laptop of mine and design a case around the motherboard and use it as a micro PC in my work area. I have nearly all of it designed, just shy of the power button.
On account of not having a sautering iron, I would rather avoid sautering a button on and was trying to go a more analogue approach by printing a button into the case that could maybe use a compliant mechanism to press in and come back out, but I am very uncertain how to go about it.
Any help appreciated
Not the exact answer you’re looking for, but if the only thing stopping you from soldering a premade button to your case is a lack of soldering iron (and I’m assuming the knowledge of how to use one), depending on where you live they are incredibly cheap and accessible, and for the kind of soldering you’d be doing here you can learn how to do it very quickly, probably a 15 minute YouTube video and some practice on spare wires.
If you’re into this kind of tinkering, you’re probably gonna need to use one anyways, it’s one of those things where you probably won’t use it all that often but it’s invaluable when you need it. I had to rebuild my printer a few weeks ago which included an upgrade to a stealthburner extruder and I do not trust that simply twisting and taping all of those wires together would’ve been sufficient.
Normally I would just go out and grab one as I have done it a bit before, and I know how useful they are, I am just a bit strapped for cash at the moment. (College student who didn’t manage to grab a job for summer :/)
Maybe I will make a temp solution and then make something more proper later on.
Reasonable. A junk soldering iron will just be a pain point for you for years to come. Ask for a good one for Xmas or something though. Decent soldering iron is a tinkering must have.
The official framework mainboard 3d printed case uses a compliant mechanism to push the power button, you can take at look at the open source STL files to see how they designed it for inspiration/reference.
https://github.com/FrameworkComputer/Framework-Laptop-13/tree/main/Mainboard/Printable Case
Oh wow, this is so cool!
I will take a look at this later and see if I can take inspiration from the project as a whole
Soldering is nothing like welding. Neither task is particularly hard, although welding takes a bit more coordination. Soldering is about as hard as using a hot glue gun or microwaving a meal, or scrubbing a toilet.
When you’ve never done it before, it is easy to build it up in your mind. Here’s the things that matter:
- acid core solder is only for pipes in a home
- flux is important and the mess it makes is not
- for just a small job, any soldering iron is fine, as is any solder
- wet everything you’re joining with flux and the solder will wick into place
- the tip of the iron should be shiny with solder before you start, and this may involve a good bit of solder added to the tip and then removed by a wet sponge or wire ball made for the task
An adjustable iron is nice, and you’ll likely find that eventually you will use it for threaded inserts in prints. There is a lot of marketing about irons and junk, but it is hard to beat the value of one of the Chinese 936 Hakko clone irons. Most of the marketing junk is to try and obfuscate the value and availability of these clones. The Hakko 900 series tips are the defacto standard and there are many extra accessory options available that are only possible with this tip/iron type. Last time I checked a 936 clone is usually under $40. The actual circuit board required to build one is under $5 on AliEx while the iron handle and lead are ~$8. You don’t need this for a basic job, but an adjustable soldering iron is a lifetime useful tool to have on hand.
Good solder makes a big difference on bigger projects when you’re doing this a lot. However, if I was in a zombie apocalypse, I could easily make a single solder connection by heating the tip of a screwdriver in a candle flame, use some resin from a pine tree, and a chip off of the pewter candlestick holder to solder a button to a circuit board.
Buttons can be a bit challenging with 3d printing design. It depends on your goals, but clearances and textures matter a lot more than it may first appear. It is possible to get something that just works, but is loose or crude. Getting a button like the inserts that go into a typical video game controller are quite challenging to clearance and develop a consistent tactile feel. I’ve done this in practice and it took a lot more iterations than I expected.
I’ll suggest Weller irons as a solid alternate as well, pretty much the only irons I’ve used in the last decade or so, mainly because the job I soldered in a lot used Wellers, had some lower end variable ones beat to hell in field bags that still run perfect today (actually my dedicated insert iron). I have a WE1010NA that I use now and it’s a solid tool.
You can’t do a lot of things with other irons like you can with a 900 tip, especially with 3d printing. There are hundreds of specialties. Like I have tips for ribbon cables, a Xacto blade holder, common heatset inserts installation tools, but also the specialty threaded removal tools from McMaster. That is in addition to all of my specialty soldering tips.
I’ve been tempted in the past to go to a faster heating setup for my rework station, probably a T12, but instead I made my own circuit boards for mine. I have the old digital soldering station from RadioShack. It is a 900 series clone from Atten that uses a 2 wire element with the thermocouple in series with the element. I mase circuit boards that offset the element to contact one side of the tip and adjusted it to extend closer to the end of the tip bore. I also modified my station to have dual irons so that I do not need to change tips often, I just swap irons with a switch.
I think a case for a different setup can be made for soldering, but for 3d printing, there is no replacement for the number of options available for crafting extras and heatset inserts options. Like I wouldn’t do iterative designs with heatset inserts in many cases if I had no ability to remove them.
Totally fair, on the tip side I’ll totally admit I’ve modified some to fit in my older Weller station I use as a dedicated heatset iron, it has heater cartridge that’s semicircular so the tips run the length of the iron. That said, I mainly do through hole and connector soldering, I’m not doing a lot of precision work, pretty much grabbed it because I was familiar with the iron and knew that it’d be comfortable for me. Think I use my heatset iron the most out of anything tbf, got me thinking about tools to recover inserts, that’d be super nice to have.
I just got lucky with the RadioShack unit having been the most convenient option and a 900 series iron. I got into electronics long before 3d printing. The hot knife attachment mixed with Xacto blades has some uses and the attachment is nice for a way to add a longer threaded stud for other custom stuff.
In a pinch, it might be possible to add a single threaded turn to a sharp conical tip, especially if you can find the cheapest copper ones without the hard plating. Before I learned about the 900 series tips from McMaster, I had a couple of conicals that I used a die to cut a single thread into. That thread is enough to save the insert, but the ones from McMaster make the task more precise in a press jig that can pull too. There is a decent chance of getting an insert out methodically and saving a larger print with the threaded removal tips, you’ll just need a larger diameter insert if you can get the old one out cleanly.
The issue with Weller is their price in a competitive market.
Considering no alternative the entry level Weller is fine. Ersa has their awesome itool with this really short distance between soldering iron tipp and finger grip: https://ts.kurtzersa.com/electronics-production-equipment/soldering-tools-accessories/soldering-desoldering-stations/produkt-details/i-con-pico-1.html
Performance: Weller and Ersa are more or less equal. For generic solder joints both are great. If there are high thermal mass and it isn’t possible to use a large tipp than the Hakko T12 is the superior technology. Changing tips on the Ersa (while not recommended by the manufacturer) can be done with the iron heated up and tool free within 5 seconds.
Ergonomics: 100% Ersa. The only reason it has been my daily driver for half a decade and is here to stay. Before this station I actually had a Weller.
JBC has a similar tool handle to the Ersa but those are very expensive with little benefit.
The price to performance king are genuine Hakko T12 tipps with a China station.
Oh for sure, totally appreciate that Weller is pricey, and I’d totally expect good tips on a knockoff to perform well. For me it’s going to come down to preference, wish I could try a bunch of different irons before buying, I at least had experience with wellers so I knew that I found them comfortable to work with and I’m not doing a ton of surface mount or fine stuff so meets my needs.
Compliant mechanisms are cool, I used it ones before and it works quite well. If you can get everything lined up properly that is.
All you really have to do is give the button a cutout, which is supported on only one side. Make the supporting area not too thick so it’s easy to press (1 or 2 mm should be good I think) and give the button some shape that makes it easy to feel by hand.
It’s a bit difficult to give any real tips without any pictures, but that’s the gist of what you need to do
I’d just search YT or the regular interwebs for tutorials on designing compliant mechanisms in CAD (pick upur favorite software). I know Teaching Tech has done a couple videos on this
Something like the reset button on the Prusa MK4 screen maybe?
