Help me understand feedrate for degrees.

[HuFlungDung]

Originally Posted by g-codeguy HFD. 2 things. I couldn't find inverse time mentioned in the manual, and 18 second cycle time is way too long if it were using inverse time feed. So I guess this means the control is using degrees per minute??? Bringing me back to my original question. How do I figure feedrate? Would a call to Daewoo be appropriate? I've always had good luck tapping into the knowledge on forums. BTW, G94 is a canned facing cycle. No G93 mentioned.

By all means, call Daewoo to get the low down if you can't find it in the manual.

By means of a few experimental movements with C axis only, and various feedrates, you should be able to determine if the feedrate is degrees/min. All you need is a stopwatch and program a 360° movement at F360. Should take exactly one minute to execute.

As for calculating the feedrate, it is always going to be a matter of calculating the distance along the circumference, divided by the time taken to do it.
Eg: (1500°/min) / 360 = 4.166 revolutions per minute
Circumference = .426 * Pi =1.338"
Distance = 1.338 * 4.166 = 5.575"/min

The 'feedrate' is only correct at the radius used for the circumference calculation. So if it does turn out to be degrees/min feedrate, then the actual equivalent linear feedrate is proportional to the radius of the part. The control has no idea what radius the tool is cutting at, so that is up to you to calculate and input accordingly.

[jamesweed]

Originally Posted by g-codeguy Bringing me back to my original question. How do I figure feedrate? Would a call to Daewoo be appropriate? I've always had good luck tapping into the knowledge on forums.

I found this on cnczone ;

360*ipm/cir=?

I checked against my conversion program and its close??? This one may not take helix into it but it will get you close.

[HuFlungDung]

Calculation of a ZC vector requires the length of the side opposite and the side adjacent. The Z vector length is plain enough. The C vector is calculated from circumferential distance (not a chord), and to do this you'll need to use a fraction of a circle, which is what you get when you calculate the circumference C, and multiply by C degrees/360 to get the arc segment length C'

Having those two sides, then you can calculate the hypotenuse using A^2 = Z^2 + C'^2

[g-codeguy]

First, James, I can't afford that kind of calculator! Second, I probably couldn't program it if I could.

[g-codeguy]

HFD, 360 degrees at F360. equals one minute. You guys are trying to make me think. You're bad!

I'm swamped right now. No time to sit down, and give it some serious thought. Just wanted to let you know I am keeping track of your postings.

[dcoupar]

g-codeguy,

Don't know where you are on this problem, but I found the attached in a Daewoo/Doosan programming manual.

Hope it helps.

[HuFlungDung]

Good find, Dcoupar.

BTW, that 57.295° figure mentioned in the pdf is not some kind of black magic, it is simply the result of dividing 360/2Pi and is also known as 1 radian.