[bspear]

Had to put this on my mill 'cause too big for my lathe, I reckon took a good 4 times longer, the roughing wasn't too bad but the finishing takes for ever relative to a lathe, in detail, why? intermittent cut/chip load? Tool stability? For cylindrical components why are lathes quicker then mills?

[deadlykitten]

hi i thought you were going to discuss that an ( Y ) lathe with live tooling & proper fixtures & custom jaws & custom chuck & quick change setups is quicker than a vmc mill, especialy for small parts

the hydraulic chuck is a very tough rotary axis:
... rotated synced with the M spindle : hobbing, flat-cuts, skiving
... rotated it free and the M spindle too, without syncronization : grinding
... rotated it free, M stop: rotary broaching
... keep it steady, rotate the M axis : excentric shapes, broaching
... rotate it intermitently, rotate the M axis ( add Y ) : 3 & 4 axis mill
... etc



a mill can't deliver turning operations as fast as a lathe, but sometimes is better to interpolate those operations, so to avoid the auxiliary time that comes with moving the parts to a lathe



if you wish to avoid interpolation on a mill, goth 4 & 5th axis + google d'andrea tools and pls check post #9 & #10 in here :

https://www.cnczone.com/forums/okuma...f-big-www.html

more $$, more customization / kindly

[deadlykitten]

the hydraulic chuck is a very tough rotary axis:
... rotated synced with the M spindle : hobbing, flat-cuts, skiving
... rotated it free and the M spindle too, without syncronization : grinding
... rotated it free, M stop: rotary broaching
... keep it steady, rotate the M axis : excentric shapes, broaching
... rotate it intermitently, rotate the M axis ( add Y ) : 3 & 4 axis mill
... etc

list continues with this :

... rotate it intermitently, M stop : organic shapes ( only this one is slower than a vmc, but you may deliver 3d complex shapes, that a vmc can not deliver without a 4th-5th axis; also surface rugosity is not ok, because speed is too low )

there are okuma lathes capable of high speeds for such complex operations ( cam function ); 3d shape complexity may be limited because of tool interference with the part; to remove also this interference limitation, than a multitasking machine is required; however, such a machine does not has the cam function, so it will deliver the part by pure milling operation ( cycle time is slower than using the cam function, but surface rugozity is at it's best )

[skrubol]

Same basic reason a 2.5D op takes less time than a 3D op on a mill. Only a tiny part of the cutter is actually being used for the cut.
On a lathe all basic ops are 2D, so never need to worry about 3D interpolation.

[deadlykitten]

hi skrubol i don't know exactly how to say it, but lathes are cutting pretty fast; a mill has more positioning comands, and it cuts a bit slower

actually this is the reason why i don't like millling : because i feel like my life is wasting when i wait for the cycle time to complete; a lathe enviroment, especially with live tooling, is more dinamycal, and it suits me

go inside a classical sector : lathe guys are always standing near the lathe, while mill guys are sitting, waiting for the tool to get out of the part cncs only scale this ratio ...

the longer the cycle time, the more patience is required / kindly