machining 12L14 L.L STEEL

[slava69]

i have ongoing problems with surfuse finish (we need N6), while machining parts which are made of 12L14 STEEL (L.L) on swiss type and chucker lathes with oil coolant. I have tried several feed rates and cutting tools.
i need a rcomendation for cutting tools and machining rates for working with 12L14 L.L STEEL , that will help me overcome the surfuce finish problems.
THANKS IN ADVANCE

[timlkallam]

12l14 need about a .01 to.02 inch depth of cut to get a good finish.A light cut seems to tear the materal insted of cutting it.

[slava69]

many thanks for your answer.
we are using the same cut depth as you mentioned , but we still have problem with surface finsh after 30 good parts. we are using iscar cuting tool with IC550 coating or kenametal KC730 coating or sumitomo 530U coating. is there a different cutting tool you recomend order to have N6 surface finish for longer time ?
we work with S=3600rpm and F=0.06 . are there diferent values you think we should use in order to have N6 surface finish.
kind regards
slava

[MailleMas]

I am not familiar with those grades of insert, but I have found that I got better luck going FAST with 12L14, with a moderate feedrate and reasonable depth of cut. in the order of 800sfm, 0.008"/rev (finish pass), with a DOC of around 0.015" (went as high as 0.03"). Another thing to consider is insert geometry, might need to go a little more positive and play with a different tool nose radius. good luck!