Speed

[kjm30]

I may have started a thread like this in Fanuc thread but I would like to start over with a clean mind in this thread and print everything out then take it to work.
By far I was told by you that I got my formulas right but would like to understand it better.

I have some question about speed and feedrate for Fadal 4020 Fanuc OiM VMC.

For Kennametal Indexable Drill 1 1/4 with inserts in them. I found the correct information from Kennametal Catalog. Here are some facts.

750 SFM for Grey Cast Iron Pecking Drill
0.004 IPR (not sure but average)

Then with the formula to find the RPM.
750 x 12 / 3.14 x 1.25

For feedrate its
750 x 0.004.

Then when programming in Macro Cycles you put 2292 for Spindle Speed. and 0.004 or 3.0??? for Feedrate which is IPM. Then on the Manual Guide i screen the actual RPm which is 2292 and 3.0 for Feedrate will be shown? To me this looks like too fast but I assume thats CNC way.

Our CNC Lathe isnt Fadal but wouldnt hurt to ask. Lathe is exactly the same way except RPM isnt used only SFM which is used for CSS Mode (G96S) correct? Then to find the feedrate its SFM x IPR and then the G50S (maximum Spindle Speed is the highest SFM that can be used with the certain insert converted to RPM? Confusing because the highest RPM I can go is 1,500 so a work piece being one inch with CNMG insert would be well over 1,700????

Asked some professionals through email but they were too short with the answers.

[Neal]

The RPM and the feed rates are independant from each other. Coordinateing the two will directly effect the chip load per tooth of the operation. I think that this is where you need to consentrate.

Neal