Effects of Cutting Parameters and Tool Wear in Hard

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					Effects of Cutting Parameters
and Tool Wear in Hard Turning
           Ty G. Dawson
        Dr. Thomas Kurfess
   Georgia Institute of Technology
           July 17th, 1999
Progression of Crater Wear
Progression of Crater Wear
Changes in Cutting Edge Geometry


New Tool




Pass 20
                                    Rate of Flank Wear

                                         Condition #1 Flank Wear Progression
                      200


                      180


                      160
                                                                                   y = 72.517x0.41
                                                                                    R2 = 0.9875
                      140
Flank wear (micron)




                      120


                      100


                      80


                      60


                      40


                      20


                        0
                            0   1    2      3       4        5         6       7   8         9       10
                                                   Material Removed (cm^3)
                                    Rate of Flank Wear

                                          Condition #3 Flank Wear Progression
                      160


                      140
                                                                                        y = 34.911x0.41
                                                                                         R2 = 0.9982
                      120
Flank wear (micron)




                      100


                       80


                       60


                       40


                       20


                        0
                            0   5    10        15        20        25         30   35            40       45
                                                    Material Removed (cm^3)
               Surface Finish



Condition #1




Condition #3
       Surface Finish Comparison

                     Zygo (micron)            Profilometer (micron)
             Ra           Rq         Rt     Ra         Rq          Rt
Condition1
   10        1.03        1.19        5.06   1.03      1.16       6.14
   30        0.90        1.02        3.97   0.94      1.06       4.70
   50        0.94        1.09        4.47   0.87      0.97       4.39
   70        0.61        0.72        3.44   0.61      0.70       3.20


Condition4
   20        0.37        0.46        2.32   0.27       0.34       3.30
   40        0.38        0.47        2.38   0.28       0.35       2.67



                    Theoretical roughness values
                    Ra1 = 0.914 µm, Ra3 = 0.229 µm
                    Rt1 = 3.656 µm, Rt3 = 0.914 µm
       White Layer Comparison



Turned Surface               EDM Surface




        No apparent damage     Significant white layer