Many of us hobbyist CNC users use very low-powered machines with limited rigidity which causes significant challenges when attempting to machine non-ferrous metals such as brass or aluminium because, with conventional side-milling strategies, we're limited to tiny step downs of a fraction of a millimetre in order to keep radial loads within the our machine's meagre capacity. Plunge Milling is a roughing strategy where the end mill is used much like a drill to create a series of overlapping vertical cuts. This removes all radial loads in favour of axial loads where we generally have a bit more rigidity. So it's a really useful strategy for bulk removal of material on a budget CNC and I'd love to have it available as a strategy within profiling and pocketting.
As and aside, I was wondering about what sort of finish plunge milling will leave on the side wall as there'll be a little fillet of stock left where the successive holes don't quite overlap. So a quick geometric doodle and a calculator showed me that using a ubiquitous 1/8th Inch/3.175mm end mill with a 1mm step over (about 30%) the little fillets stand proud of the side wall by just under 0.1mm, which is within the capabilities of even my machine to clean up with a profile operation.
Plunge Milling
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sliptonic
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Re: Plunge Milling
The idea of plunge milling strategies has come up before. It's one of several strategies that I'd like to implement.
I haven't spent any time on it because I think we need a better abstraction of the existing operations first. We need a structure that lets us implement ideas like this without 1) duplicating tons of code 2) adding icons to the toolbar ad infinitum. 3) complicating the existing operations so much that they become difficult to maintain.
If it's something you need in the short term, it wouldn't be difficult to implement as a macro. If you want to play with that let me know. Perhaps we can eventually work it in as a full-blown strategy.
I haven't spent any time on it because I think we need a better abstraction of the existing operations first. We need a structure that lets us implement ideas like this without 1) duplicating tons of code 2) adding icons to the toolbar ad infinitum. 3) complicating the existing operations so much that they become difficult to maintain.
If it's something you need in the short term, it wouldn't be difficult to implement as a macro. If you want to play with that let me know. Perhaps we can eventually work it in as a full-blown strategy.
Re: Plunge Milling
"Need" might be overstating it somewhat but being able to plunge mill in FreeCAD would definitely extend the range of materials I can use. If I could code it as a macro that would be great. Coding isn't an issue for me as I've got nearly 40 years professional experience as a software developer. I'll have a play and see how far I get before I need to call for help
