I have a decent amount of experience with cnc milling, but now I'm about to go down the path of cnc lathe. After doing some reading, it seems that there are just SO many variables and opinions when it comes to choosing the proper tool. I work with mostly 7075 aluminum and for milling it was pretty simple. Most agree that 3 flute endmills are a good balance of chip evac, rigidity, and resists resonance, Zrn coating for aluminum. Thats what i use and it works excellent. Turning on the other hand seems like quite the mess with far more variables and inconsistent opinions. I want to do light to medium work on aluminum with a great surface finish and would prefer to use carbide inserted tooling. Many would say anyone learning lathe work should start by grinding hss blanks and learn about geometries, but I would really prefer to use tooling that's ready to go without having to hone my skills at grinding, even though it's obviously a good skill to have when you need a special tool fast. The other side of that, some say hss tooling is capable of taking a sharper edge and can actually give better surface finish with the downside of not lasting as long. Are there really not carbide inserts capable of giving just as good of finish in aluminum? Is it true that you need to go faster to get carbide to cut nice?
My spindle has a max rpm of 3000 and I'll be turning mostly around 1 inch diameter aluminum parts. Will carbide inserts do well in this scenario? Or do I really need to consider hss for best finish? I will also be running kool mist coolant.
So assuming I can stick to inserts and not bother with grinding hss, where do i start? Like i mentioned, ill be doing light to medium work in aluminum. I understand that the base shape of the insert is gonna depend on geometry of the part. C and d type seem most common, c type being preferred if geometry of part allows it. D or E if I need clearance in tapered areas with drawback of less strength in the insert. What about rake and relief? This is one of those things that everyone seems to have their own opinion on. Some say positive, some say negative. I understand it depends on the application, but in my case, what do i want for getting a great finish on aluminum with coolant, considering a max rpm of 3000, most turning at 1 around inch diameter, and no need for crazy removal rates? One thing people seem to agree on is polished uncoated inserts for aluminum. As for size of the tool, I don't see a reason to go small. Ill be machining my own tool post setup so I can design for larger tools to get best rigidity. I can also make adapters to hold round boring tools in the tool post, or separate holding all together. This is a mill turn spindle on a mill, so I can make use of both x and y for gang setups with multiple tools in different places.
So where do i start? I imagine I need a few different tools for different shape inserts and different orientations. Just want to make sure I pick tools that are compatible with readily available inserts that are proper for my application.
I know this is a really loaded question with many variables, just looking for a general idea of what to start with for what I want to do. I'm sure I will need to expand my collection of tools as I run into features that maybe don't have clearance with the common inserts.