5-axis vs 3-axis machining rigidity

[Gabe Newell]

I'm curious about the trade-off in rigidity between 5-axis vs 3-axis machining.

With 5-axis, I can see tool lengths being shorter. With 3-axis, you have an inherently more rigid machine.

Most of my time I'm cutting tool steel, and optimizing for surface finish on curved surfaces.

I've assumed that moving to a 5-axis setup (e.g. adding a tilt+trunnion table) would impact how long it takes to get to a given surface finish.

Alternately, you'd have to pay a lot more $$$ to get a machine that can achieve the same surface finish going from 3- to 5- axis.

Of course this could be totally the wrong thing to be optimizing. It might turn out that in the real world, simply using the more optimal part of your ball mill is way more important than inherent 3- versus 5- axis rigidity in achieving a given surface finish in a given amount of time.

Maybe it's the part rigidity that is critically important, and that adding 20% thickness to a thin part is a vastly more effective than worrying about machine rigidity.

Anyone doing 5-axis thin wall work care to enlighten me?

The one paper I could find (2001) only looked at tool path length comparisons between 3-axis and 5-axis, and the 3-axis paths were 2.5X to 4X as long as the 5-axis paths. Most of this was due to using tool shapes that more closely matched the part geometry (a 3-axis ball got beaten by a corner radius end mill being driven by a 5-axis machine). 3+2 wouldn't get this specific benefit.

[underthetire]

Can't help with specifics, but there has been a lot of advancements in 5 axis machine build. One comes to mind is the new mori 5 axis that you can even use for turning applications. I know okuma has a new one, I think mazak does to. Most are getting away fromnthe trunion set up and building a machine designed for 5 axis from the drawing board.

[5axisguy]

We have a Fidia, which is a head-head machine, and a FPT Stinger, which is a head-table machine. The 5axis machines are most certainly not as rigid as our larger 3x machines, but they are quite robust, we do most of our roughing mold work on the bigger machines and boring bars, save the finishing for the 5x machine.. We use the 5x mainly to avoid the edm machine, we can tip the head and reach way way down in mold cavities, I have a 24k spindle and can run a .3mm dia ball to dig out corners. We do use the simulatnious programming on occasion, but to be honest that is mostly for showing off to customers as they walk by. In the real world where I earn my paycheck it's much much more efficient to cut using "3 plus 2" method, which is just orientating the tool to avoid collision and cut from there. It faster cutting, faster programming and better surface finish. I always chuckel when I look at u tube videos of 5x cutting, the table is spinning all over the place and the tool is hardly even taking a chip, ya it looks cool but it does not make you any money. The ONLY 5x video worth watching it the guy that does a motorcycle helmet on a DMG with openmind software,, very impressive.

[greatcncwebsite]

Try www.fiveaxismachining.com It's a great new educational resource specifically for 5-Axis machining.

Best Regards.