1. The Evaluation of Cutting-Force Coefficients Using Surface
Error Measurements
Journal of Materials Processing Technology 196 (2008) 42-51
Mariana Dotcheva, Huw Millward, Alan Lewis
Presenter: Andrew Gerla
07 October 2009 1

2. To provide a new approach for the determination of cutting forces.
Purpose
To provide a new approach for the determination of cutting forces. 2

3. References

4. Cutting Force Affects... Required machine power rating Tool wear
Tolerances
Surface finish
Required lubrication and cooling
Economy of prototyping and small batches 4

5. Old Methods Use mechanistic models with empirical coefficients
Require expensive instrumentation to gather empirical data
Require skilled technicians to record and process data
Applicable only to the conditions under which test was performed
Not easily implemented for prototyping or small batch work 5

6. The Proposed Method Cutting force is proportional to tool deflection
Tool deflection is related to surface finish
Empirical relationship may apply to operations with different cutting conditions
Find equations like these:
Tangential force KT(tc) = Ct1(tc)−kt1
Radial force KR(tc) = Ct2(tc)−kt2 6

7. Method

8. Method Discretize cutting tool by: Flute Angle of rotation
Discs normal to axis of rotation

9. Analytical Models Cutting Forces: FX(θ(i, k, j)) = KT(EX1 + KREX2)
FZ(θ(i, k, j)) = KT(EZ1 + KREZ2)
FY(θ(i, k, j)) = KT(EY1 + KREY2)

10. Analytical Models
Tool Deflection:
δ(h) = δs + θs(h) + δt(h)

11. Experimental Procedure

12. Experimental Procedure Cutting Test
Cut two strips with the same cutting conditions
Vary axial depth by ∆a
Calculate difference in surface finish
Difference in surface finish mainly due to additional forces from elemental disc ∆a
12 different feed rates

13. Experimental Procedure Cutting Test
End milling operation
HSS 3-flute 16mm cutter
Aluminum alloy 6082
Down-milling (climb-milling)
Radial depth 3 mm, axial depths 8 and 9mm
∆a = 1mm

14. Experimental Procedure Data Acquisition
CNC operated profilometer
Maximum error 3.2%
Straight measuring tool paths, 0.1mm increment

15. Analysis

16. Results
MATLAB curve fit:

17. Conclusions
Analytical model accurately predicts experimental data in similar cutting conditions
Uncut chip thickness can be calculated
Study needs more verification of accuracy for different cutting conditions
Different materials require different coefficients