Just wondering, is there a parameter in a fanuc 6MB controller to tell it what diameter part your running in the 4th axis, so it will compensate linear and rotational feedrates to be the same? And if you know what parameter it would be, that would help out greatly ;)
OK, so not being able to do this, and finding out that it runs the 4th axis in degrees per min, not inches per min.. any idea how I can come up with a formula to do a tangital arc segment movement, and find the correct feedrate?
I came across This text, not sure what machine it is for, but looks like it might work.. But I run into a problem..
Feed Rate Calculation for Linear Interpolation with Rotary Axis Caution concerning the feed rate must be applied when linear interpolation between the rotary axis and the Z-axis is done. The tangential feed rate along the tool path becomes high when the arc length of the rotary axis move is relatively short in comparison to the travel distance along the Z-axis. The feed rate must be reduced, accordingly. It can be calculated as shown in the example, below. Example: Machining is done on the OD of a 1.5? diameter part, rotating the Caxis Angle = 30° while moving the Z-axis minus 1?, at the same time. The desired feed rate along the tool path F = 5?/minute. Calculate the feed rate to be used for the interpolation command: G1G98 H60. W-1.0 F___? Steps for calculation of the tangential feed rate:
Calculate the length of the 30° arc segment on the periphery of a 1.5? diameter circle: Arc length=2Rx /360x60=2x0.75x3.14/360x30=0.392?
Calculate the length of the tool path: L= Square root of (0.392²+1²)=1.07? F ° per minute =F (IPM) x 57.296 / R F ° per revolution =F (IPR) x 57.296 / R
Calculate the time it should take for the 1.07? long cut, applying the feed rate of 5? per minute. Time = 60/5x1.07=12.84 seconds.
Calculate the feed rate in degrees per minute that is required for a rotation of
30 degrees in12.8 seconds: F=30/12.8*60=141 degrees per minute. Or apply the following formula, where: F = feed rate in inches per minute, A= C-axis rotation angle L = Length of the tool path
F ° per minute =F (IPM) x A / L
Feed rate in degrees per minute =5 x 30 / 1.07=141 degrees per minute
So with the below snippet of code, and if I'm doing my math right, the F?????? would be F1468.31.. and that just doesn't seem right.. Sounds like a busted endmill to me..
Sorry my mistake no g93 is available on the fanuc 6
I have the operator manual publication # B54044E /02 here wherin rotary / linear feed rate ( additional axis simultanious option enabled allowing three axis combined ) ( as well as simultanious 4th axis control option enabled where 4 combined axis moves can be combined ) is explained on pages
55 / 56
On pages 204 /205 the rapid only type index table is covered wherein rotary moves will always be in rapid--attempting to combine a linear will result in an alarm.
Anyways I may be able to scan these pages so if you don't have an operators manual let me know....