Model-based analysis of the surface generation in microendmilling - Part II: Experimental validation and analysis

The surface-generation models for the microendmilling process developed in Part ! (Liu, DeVor, and Kapoor, 2007, J. Manuf. Sci. Eng., 129(3), pp. 453-160) are experimentally calibrated and validated. Partial immersion peripheral downmilling and full-immersion slotting tests are performed over a wide range of feed rates (0.25-12 mu m/flute) using two tools with different edge radii (3 mu m and 2 mu m) and runout levels (2 mu m and 3 mu m) for the investigation of sidewall and floor surface generation, respectively. The deterministic models are validated using large feed-rate tests with errors within 18% for both sidewall and floor surfaces. For low feed-rate tests, the stochastic portion of the surface roughness data are determined from the observed roughness data and the validated deterministic model. The stochastic models are then calibrated and validated using independent data sets. The combination of the deterministic and stochastic models predicts the total surface roughness within 15% for both the sidewall and floor surface over a range of feed rates. The models are then used to simulate micromachined surfaces under a variety of conditions to gain a deeper understanding of the effects of tool geometry (edge radius and edge. serration), process conditions, tool tip runout, process kinematics and dynamics on the machined surface roughness.