I’d like to talk about roughing endmills. Do people use them? Do they not? Why or why not?
From what I read about them, they are prone to much less chatter than standard endmills due to a lack of a harmonic frequency that they vibrate at and that it is spread over a wider range instead. From reading on Practical machinist and other sources, they require less power and remove more material than standard endmills. This seems like a good combination for use chatter-prone, low power hobbyist folk. Yet I can’t find anything (other than brief conversations with @Vince.Fab) that indicates people in the Shapeoko community ever think about or consider these.
I don’t bother. For me it’s not worth having another tool. I use a regular (older) tool to rough, and the “bad finished” from roughing doesn’t matter - I’ll take it off with a finishing pass anyway.
When you have a 10lb block and need to machine 90% away they can have a significant advantage. It really depends on type of rougher and depth of cut. Imo if you aren’t taking deep enough docs to get into the chipbreakers then they’re really isn’t a point compared to a normal variable flute. Lets say you are dropping down 0.500 doing adaptive, thats where they really shine because you won’t have 1/2 long chip shards everywhere, they tend to break into squarish chips.
They also use less force to cut but most of us aren’t power limited anyway. So that’s a yes if you cut more aggressive than normal and want better chip management. Also most roughers will have a radius or chamfered corner which makes them very chip resistant.
You can have a variable flute endmill that isn’t a rougher. Lakeshorecarbide has all the options and they are very good at helping when emailed questions.
I use Carbide Create but have a startup license for Fusion 360. How do you implement the roughing pass. I think the Aspire software has the option for roughing and finishing but does Carbide Create. So my projects have not required Fusion 360 and my learning curve for it is stuck at a -1 out 10. I have watched the “Absolute Beginner” videos over and over and still cannot get Fusion 360 to work for me. I thought I would get proficient at Carbide Create and then have another go at Fusion 360.
But how do you implement roughing and finishing passes. Is this strictly a software feature in particular applications.
@gdon_2003, there are ways to do roughing+finishing passes in CC, but it’s not built-in, you have to manually create additional geometry, there are a few threads on the forum, most by @WillAdams, here’s one:
Basically, you manually create a slightly scaled up version of the geometry you want to cut, and cut that using aggressive settings, that’s the roughing pass, and then use the original geometry and cut it at a more conservative setting, that’s the finishing pass. The idea is that since 95% of the material will have been removed in the roughing pass, the finishing pass only has to cut a thin onion skin of material, which puts very little load on the tool, which helps the finish quality.
Other more advanced CAM tools have this as a built-in option, where you don’t need to duplicate any geometry: you just tell it it’s a roughing pass and how much “stock to leave” you want, and then you can create a second toolpath on the same geometry, with stock to leave at zero (or even a small negative value, but let’s not get into that now), and that’s your finishing pass.
If you can’t wrap your head around Fusion360 just now, I’d recommend VCarve, it’s the perfect in-between solution (albeit at a price). It’s as easy to use as CC (arguably, easier) and it has support for roughing/finishing, for example for pockets they call it the “Do A Separate Lass Pass” option, and it’s even simpler, it does it all in a single toolpath (i.e. it does 95% of the cut as roughing, and then at the very last step-down it removes the stock that was left in a single light pass at full depth)
Now, back to the original thread, sorry for the sidetrack.
@mikep, right but I’d probably use one of these more often than my 1/16" ball endmill and I have one of those. More and more I’m working with aluminum on projects so I want to understand all the tools available to me. Their benefits and downsides.
@Vince.Fab, good to know. I’m not taking 0.5" DOC at this point, I’m sure I have rigidity issues to solve before I’ll get to that point. The chip breakers look like they start pretty quickly so even if I am taking 0.2" DOC, I should see benefits of using it.
Right, and variable flute will help reduce chatter as well.