Milling round parts vs turning them (2024)

I have been recently milling round parts that look like they should be done on a lathe machining inconel 718.
Are Lathes more efficient in removing material then a mill.
On a mill the cutter in rotating constantly hitting the part to cut chips off as well as interrupted cuts.
On a lathe it seems more smooth more of constant cutting.
I have been machining 10 year now and i kinda thought this but when you cut inconel718 it makes you think.

This all depends on your rigidity of the machine and width of cut you are taking on a mill.
In most cases its faster to use a lathe if you can hold it good. If I have the choice of a mill or a lathe for turning, I'm using a lathe. Rare circ*mstances I would put it in a mill. Mostly cause I can't hold it good enough on lathe

Ya if were talking about a ridge set up on both mill and lathe and and all circ*mstances at their best.
a 50 dollarfor 1/2 in carbide endmill vs 50 dollars for 5 carbide inserts whats able to take off more material faster and out last the other
i was dealing with inconel 718 it suxs

i think a lathe is more efficient in removing material

Some time ago a boss once told me. "Never mill what you can turn. Never turn what you can saw"

Turning is almost always faster than milling.
The exception would be internal milling like the AGFM machines or other internal milling cutters.
Turn-broaching or skiving methods may also outrun plain turning ops.
A normal milling tool spends a lot of time cutting air on a round part.
Bob

95% of the time you are better off turning what you can....finishes are easier to attain, tooling is less expensive....if it is production, fixturing (usually a chuck and 3 or 4 jaws) is readily available and re-usable. I( have however ran in to a few occasions when we will mill something that otherwise might be turned in some small production jobs that we regularly do just for simplicity and to eliminate an operation..........sometimes the best results are to be able to load 1 machine and pull out a finished part....one advantage that milling a turnable surface has is accuracy.....its pretty easy (usually) to hit your dims. when everything is done in one op.

A lot of times I'll mill a bunch of round parts out of a block in the vise. Like a row of 10 plastic parts that don't need to be perfectly round. Buzz them out, slice off on bandsaw (or slitting saw on mill) and 2nd op the back in manual lathe. It's a really fast way to get a bunch of dumb parts.

Turning will remove more material faster than milling, but with tough, ductile materials (like 718) milling might have the advantage of chip control. Generating a bird's nest of Inconel razor wire can get exciting...

I don't have a cnc lathe, so the cnc mill has done a fair bit of short run production on ti castings that should have been lathe parts, Was more consistant and faster then manual turning. Thread milling large diameter threads is a dream vs manual. A lot easier to contain the chips as well.

On a flip side to this topic, I've seen some jobs run on a screw machine that the only turning done was the parting-off into the subspindle. Everything else about the part were milled features, even the subspindle ops. Even though a mill may have had a faster per part cycle time, the screw machine had the advantage of minimal fixturing (EDM'd collet for the subspindle) the elimination of loading and unloading, and substantial unattended running. Bar feed milling on six sides of the part.

In most cases turning on a lathe there are no fixturing issues to effect how aggressive you can remove material. Most of the time in roughing the only limit you face is horsepower. You don't have to worry about snapping a cutter, vibration or pulling a part out of a vise if you try to do too much.