I have been looking in kicad and online for footprints and 3D models for these microswitches thingies. I found really nice footprints and 3D models for those miniature toggle switches. I figured that I could not possibly be the only one who would have a need for these microswitches.
I can make my own footprints ofcourse. But creating my own wheel if somebody else already made a nicer wheel would be illogical (though this propably will take me 5 minutes). + I am not yet making 3D models and I am secretely hoping to find one
So does anybody perhaps know about somebody who already made footprints for these microswitches by any chance?
There are probably about 10 or more websites who specialize in this stuff. They have a big database with a million or more footprints, and they generate footprints for a number of different PCB programs on demand.
Snapeda is one of such sites, and I also see them on this forum now and then if there is a chance to improve their export to KiCad.
PCBlibraries is another one, and is also a sponsor of KiCad, so I assume they also generate KiCad compatible Footprints.
I am living on the other end of the spectrum myself and prefer to make my own footprints. One of the reasons I choose for KiCad long ago was because of the quality and similar feel of the symbol and footprint editors.
Because the holes are slots, they are cut using a sideways cutting router bit. To avoid breaking these bits, they need to be robust enough to withstand significant lateral forces. Board houses usually have a minimum slot width and some charge extra for slots. Slots look fine to me.
True that Mill bits do what is called ‘Facing’ but, that is Not how Slots are cut in PCB’s.
Slots in PCB’s are cut with an ‘End’ mill bit (which can also be the same as the Bit used for Facing). But, for Slots, the Bit is Stepped-Down incrementally and basically ‘Pockets’ the cutout.
I do this a dozen times per week on my CNC Milling of PCB’s for the Power Jack and a few others such as Switches…
ADDED: I use a 0.7mm to 1.0mm Diam EndMill bit, depending upon the terminal’s width.
Yep, milled my own boards and CNCd other materials too.
Sure, you can think of cutting a slot a bit like cutting a pocket. There are a couple of significant forces to consider. At the leading edge of a pocket the mill will be cutting laterally where it engages the workpiece - this will be related to feed rate and whatever your step down is. There is thus a lateral force acting between the collet and the workpiece through the mill. There is also a torsional force between the collet and the flute depending on the angle of engagement, depth of cut and feed as well as rpm. If the mill is cutting both sides of a pocket ie when the mill is the same width as the slot, the torsional forces are doubled as the mill is engaging in both the conventional and climb milling directions.
You can cut fine slots if you are careful with your choice of mill i.e you need to consider geometry, flute numbers, helix type, coating, shank vs flute length etc. The smaller the diameter the mill is, the more prone it is to break - especially if you are not careful with extracting dust and ensuring the spindle has a very low runout. Generally for a given material, the finer you make a cut, the lower the maximum material removal rate. This means that you need a low feed rate (and high spindle speed) for a fine deep cut. The high speed isn’t so much a problem in a commercial set up but the low feed rate certainly is. End mills will break easily if you push the feed rate is too high.
Slow cutting speeds and needing to stop to replace broken mills do not make a happy commercial setup. To avoid this, manufacturers usually specify a minimum slot width which I expect is slightly bigger than the mill they use.
I never break Bits. Never! Why? Because I know what I’m doing from 60 yrs of Milling (so, the cautions you indicate are built-into my Logic/machine parameters. I can do these cutouts all day. 0.6mm do break without my resetting Feed/Speed. So, I stick with 0.7mm as smallest diameter.
I use CopperCam and the setting’s panels take care of the work (with your knowledge) you can Glean much from screenshots below.
Also, out of Laziness, I sometimes use CopperCam for 2D milling of, for example, Pickguard for Guitars - it’s like cutting the PCB’s shape and uses the same setup. Yes, I can set a greater Depth of Cut… But, why? I alread get what I want/need…
Ignore the Rotation Speed - it’s just a paceholder for my work as I manually set it on the Mill (usually at 6500rpm).
For an 0.8mm bit they also specify a “Max stack” of 3.2mm. and they probably route two boards in a single pass with such a mill. They really don’t have time for doing multiple passes just to get through a single 1.6mm thin PCB.
But you would need higher quality machines for such machining parameters. But for us end users it’s simple. You just select a PCB manufacturer and then stick to their recommendations. Finer milling is often possible, but it has to be done slower, and time costs money, and you have to pay extra for finer features.
I mill both FR4 and Poly boards at the same Contour-Cutting Feed Rate of 150mm/min. So, making boards of say, 100mm x 100mm with Depth of Cut = 0.5mm, from larger stock of 1.6mm thickness, takes from ≈8 to ≈10 minutes, depending upon if I set Depth/pass to a hair more (to 0.6mm). Yes, a Fab-house would want to do it faster. But, I’m not a Fab-house and I have lot’s of Coffee…
I wish you lots of coffee during your hobby, but it seems unlikely that bask185 is interested in this. I assume he just wants his PCB’s manufactured, and therefore what those guys do is more relevant.
Also, I don’t believe what you wrote earlier:
Those pro’s route the whole PCB thickness in one pass. No time for peeling off in thin layers, which also causes excessive tip wear. The video below gives some idea about production speed.
You assume too much in thinking most folks want PCB’s from fab-houses. Even so, if using JLCPCB, they cut them from Sheets, not stacked.
I just asked them - below is Chat response…
ADDED: I may as well clarify: ‘If’ I’m not too lazy plus, needing to route NPTH holes larger than 1/8 inch, I change the bit to 1/8" and do the full depth of cut so, I can do it faster than if stepping down.
I wish you lots of coffee during your hobby, but it seems unlikely that bask185 is interested in this
I almost thought that my thread was somehow joined with an other one… Anyways I just finished my 2nd cup of joe
Why the Heck would anybody want to ‘mill’ PCB by choise. We had such a machine on high school and I made some things with it. We also had an oven for smd assembly but I saw nobody ever touch it. We never knew nor were bothered how to make a stencil and how to apply paste. Btw the thing did not work for the first 3 months or so. It turned out the TL tube was interferring with the camera system… it took them so long do discover that
Most people were still doing Thru-hole stuff. So for thru hole it is okay I guess. But soldering thru hole… I mean the labour… My group did do some SMD pcb, but I really really hated soldering vias…
So milling?, Thanks, but no thanks. I will just throw a little money at it and order pcb with smt assembly from jlc… with exception of certain microswitches ofcourse… and be cool with it. For me it is worth the save an labour. I still have enough screw terminals and other thru hole connectors to solder by hand.
Milling PCB’s is a very niche application, but it does have it’s place. Some companies use it for quick prototyping. Take for example the design of a PCB antenna. You can modify a design and mill a new one within half an hour or less, which allows for multiple design iterations in a single day.
I also once heard about a company which was into very high frequency radar equipment (10 to 20GHz, maybe beyond) and they had to mill their PCB’s because the etched sides of PCB tracks caused irregular reflections.
Milling PCB’s can’t compete on price with having PCB’s manufactured. And with both though hole and via metalization, solder mask and silk screen on PCB’s is most often well worth waiting a few days or weeks for delivery. I guess it’s mostly the quick turn around that also makes it attractive to hobbyists. But there is also the idea of satisfaction from watching a CNC machine mill a self designed PCB.
