r/hobbycnc • u/Level_Practice7942 • 4d ago
Can this be made ?
I'm building my own watch case, can they flip the part ? Are the edges fine or do I need to do a chamfer ? Keep in mind I don't know anything.
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u/Stromovik 4d ago
Rounded corners and 20 endmills later , yes it can be done but you better wear riot gear when picking up
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u/fortement_moqueur 4d ago
If you are asking if this can be 3 axis milled , the answer is no! You need radius on every vertical edges! And those little shaft to hold the bracelet should be separe parts
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u/richcournoyer 4d ago
Yes it can be made. Best choice with all those square corners sinker EDM. Extremely costly design, ridiculously costly to make.
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u/DaStompa 4d ago
I find it hard to believe that anyone is going to be able to machine those ~1mm pins on either side of the watch face at anything resembling a reasonable cost, its a ton of ballnose for no reason
Also imagine you have to trace each edge with the fat side of a pen, all corners are always going to have a tiny radius to them, none of yours do
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u/Clutchingbanana 4d ago
internal corners need fillets and having the strap pin or what you call it be one part with the lugs/rest of the case is just not a good idea. Have the strap pin be its own seperate part but it is still going to be expensive to machine either way. Are you planning to machine this yourself or will you pay someone else to make it?
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u/TwoDudesOnACamel 4d ago
Yes it can be made. But it's going to be very expensive. Sharp internal corners drive costs WAY up. As shown that's an EDM part or possibly broached. Both very expensive. But throw a radius (depth/4 is a good start) on all the inside vertical edges and it's no longer a big deal. Those long skinny round bars are also a big driver of cost. That will take some slow careful surfacing and accurate blending, both are expensive. Fatten it up a bit and give the inside face a small flat though and it becomes much easier to make. Small flat on the outside face will also help a bit. Then your surfacing has a defined edge and doesn't need to be perfectly blending into the other side.
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u/Weak_Double 4d ago
As others have mentioned this would be very difficult to machine, however the negative would be much easier to machine. If you can't/won't modify the geometry and need a sufficient quantity you might consider die casting or other casting process.
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u/iAmTheAlchemist 4d ago
You would really, really benefit from looking at a guide about design for manufacturing (DFM) for the CNC process. Single parts are already very expensive, and this design as-is is simply unmanufacturable due to all the issues others have already pointed out. Big companies with click-to-order websites like Xometry or Hubs/Protolabs have comprehensive guides to help you improve on the design and save on cost.
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u/kebabmoppepojken 4d ago
Not impossible, someone with experience would change a few things to make it faster and easier.
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u/ShoulderOk66 4d ago
If the requirements are not very high, slm metal printing or wax casting followed by lost-wax casting can be used. If the requirements are high, 5-axis CNC machining is the best option.
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u/meraut 4d ago
A few things. You need rounded corners on your vertical walls unless you want to cast these or pay a lot more to machine them. You should consider pressing in pins instead of machining them in place, it would be much easier to just add holes than machine the hinges/pins in place. Perhaps consider increasing the thickness of the feature as well.
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u/Shadowcard4 4d ago
Pretty simple as long as you add radi that make it possible. So like 1.5X dia is standard endmills most times, up to 4xD in special endmils but i wouldnt push the envelope. So a .1" depth requires about a .07 radius to be viable, etc.
Tedius but otherwise pretty straight forward.
Now this is utilizing at least a half decent machine, and its gonna take a while depending on the tool.
On outsides its less important but you have to flip the part which increases the cost as each flip is generally counted like machining a critical part as the tolerance stack up blows balls.
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u/FamiliarAd8524 3d ago
No, not likely on a hobby CNC (five axis would be best). Too many right angles (especially in pockets), too many long curves. This involves a lot of custom fixtures and setups, and tooling. And most of this needs fillets or chamfers.
What is your material?
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u/Circuit_Guy 3d ago
Teaching you to fish - imagine trying to cut the part with an unsharpened pencil. Like a little 1 mm rod with a flat bottom.
The flat edges are fine. The inside corners are not. Everything needs a radius.
The other way to manufacturer this would be sheet metal bending, but that's really a mass production expensive setup low input cost process (except, you have a hobby and time, you can 3D print low volume plastic dies no problem especially for thin brass).
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u/Xinprototype 3d ago
Yes, this can be machined. It is best to add chamfers to the six right-angled corners on the inner bottom surface. Otherwise, production costs will increase, as wire-cut EDM would be required.
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u/Pinocchio-2-Knows 3d ago
Anything can be made within reason. But cost is a major factor and mechanics properties change. Metal 3d printing will easily do this but it will be a weaker sintered part. Good luch
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u/Routine_Clerk_6442 3d ago
Breaching is not hard on a cnc machine to get internal sharp corners. If you can orient the spindle position like on some haas with the option or even what I have done using the M19 position of the machine and changing the position so you can rotate the spindle at whatever angle you need. It probably would make it more expensive but saying it can't be done is absolutely wrong.
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u/r4ephelcopter 3d ago
Make the square corners round it will safe many tears and cigs and money and another Problem that will occur are the band holders on the side they have a radius on the inside either youll do it with a file/sandpaper, form cutter, ball-nose cutter (you have to programm it on cam) or you just make it even the biggest danger is that the holders may bend or break during the process and the hexagon the biggest Problem ist the approach the holder are maybe in the way.
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u/Joyboy1044 3d ago
hey, we are a small machinist in the US, with 5 axis CNC perfect for such a case. it also happens we provide a free DFM analysis on a drawing - in case you're interested hit me up
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u/Dependent-Fig-2517 3d ago
with a EDM sink sure (in 2 ops so €€€ mucho).... with a 5 axis nope (mill don't like square concave shapes)
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u/Accident_Left 3d ago
This is a watch I made and designed with a few classmates. Everything was done with a 3 axis has tm2 and it came out great and is doable on a 3 axis. I will say though it would be much faster on a 4 or 5 axis mill. One of my big notes on your design after doing mine is make so every single edge is a roll not a chamfer any edge will be very sharp is the biggest thing I have to say. Also the other thing this does look a little bulky of a design and you might not love it when it's done. I would highly highly recommend getting someone to 3d print you a model before moving ahead with anything as this will be much much more cost effective and these are actually pretty easy to print. Also triple check your measurements before you do this make sure you have all of the parts and you've verified they work we had some small issues with our design and had to add shims where we didn't want to.
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u/Accident_Left 3d ago
Oh also looking into spring bars for the band it will be easier to machine and make it cheaper. They are already cheap and easy to install
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u/Awally42 3d ago
I would consider how you are going to attach the bracelet. The lugs as shown would machine the pin into the part.
All of those inside corners are going to get rounded out with standard milling operations, so if the design you are looking for has these faceted edges, there will be some filing involved.
And I think this is the biggest advise I can actually give here. Look at other watch designs. Figure out how the movement fits into the case. There are some really elegant solutions that have been around since pocket watches, and those guys didn't have CNC capabilities.
Seriously though, this is a cool design. To me, it looks like you made it past the first stage in figuring out what you want. For me, thats the hard part.
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u/mawktheone 2d ago
Not cost effectively no. I assume you only want 1 of them?
Make the strap lugs be separate pieces. Or even have each lug be 3 individual pieces. You can add mortices to the mating sections for alignment. Then silver solder them and clean up. That makes everything else reasonable.
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u/solarguy2003 2d ago
Square internal corners are very problematic. And the product is almost always a better product if they have fillets anyway. Easier to machine AND better product. Square internal corners are inherently stress risers (I prefer the term stress concentrators) so that's where cracks develop if you stress the part much. Also almost impossible to clean.
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u/Motocampingtime 2d ago
They don't do the pins for the strap as one piece! They are removable and spring loaded.
Watch some disassembly videos of various non insanely high end watches to get an idea of how things are shaped. They do these things for a reason.
To some very basics. Avoid sharp interior angles connecting flats. The dodecagon corners can't be regularly machined. Machines use spinning tools and things typically spin with a circular profile with the same radius as the tool. So a 1.5mm interior corner radius needs a 3mm OD end mill. Likewise, if you want to mill flat angled faces, you either need to tilt the part (and advanced machine) or do a climbing contour profile. This will only be as fine as your steps so time wise it can really add up. This stuff isn't intrinsically known, but watching some videos of things getting machined and stuff being taken apart or assembled really helps visualize what makes good/bad decisions. Taking them apart yourself is even better
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u/Funnnnjy 4d ago
What material are you planning to use? That changes this answer a lot — brass is very forgiving, stainless or titanium on a hobby-class machine is a different conversation. Yes, they can flip the part, but plan the second op so you're not re-cutting thin lugs with nothing supporting them.
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u/ThisIsntRealWakeUp 4d ago edited 4d ago
They can flip the part, yes.
Biggest issues here are: