When do you use Constant Surface Speed on a lathe?

[McLaren]

Greetings everyone. I'm wondering at what point do you start using CSS when turning on a lathe? Is there a start to finish diameter ratio you use, or do you just always use it? Thanks in advance for any and all replies!

[Tony35]

i always use it when turning

[jeff]

We always G96, except when drilling,threading/tapping then we program for constant RPM.

Unless there is a rare occasion to where you need constant RPM's.

[jeff]

Just don't forget that G50!!

[Goldorak]

We always G96, except when drilling,threading/tapping then we program for constant RPM.

Unless there is a rare occasion to where you need constant RPM's.

 

 

+1

 

and I use fixed RPM on small parts that I can run the program entirely at nearly full machine RPM

 

 

and +1 gor the G50, bad things can happen

[kh012]

+1 on gold

+2 on the g50

 

i do a quick cal. on smallest dia to largist dia. if the dif. is only a couple hundred rpm clamp it.

if not use g96 , or if the finish req. needs it use g96

[McLaren]

Thanks everyone. I thought that more people would have issue with the spindle ramping up and down causing an increase in cycle time. Looks like I'll change my ways.

[Scott Lundin Shopware Inc.]

If I am working on .375 diameter stock or less I often go to direct RPM to avoid the spindle speed ramping up and down during tool changes. Specifically during large quantity production runs.

[jeff]

Thanks everyone. I thought that more people would have issue with the spindle ramping up and down causing an increase in cycle time. Looks like I'll change my ways.

 

This is situational, if you're always doing small work to where the G96 is hurting you with cycle time, then yes use G97.

[chris m]

I thought that more people would have issue with the spindle ramping up and down causing an increase in cycle time

 

This can definitely be an issue, but insert changing is also time consuming and G97 can be tough on your cutting tools as they are running outside of their sweet spot a lot unless you are finish turning a shaft or something that has a more-or-less constant diameter.

 

C

[Tony35]

If I am working on .375 diameter stock or less I often go to direct RPM to avoid the spindle speed ramping up and down during tool changes. Specifically during large quantity production runs.

 

+1