Comparison of transparent objects metrology through diamond cutting edge radii measurements

Abstract

The efficiency of cutting is largely influenced by cutting edge radii. When considering the correct cutting edge radius in the simulations, correct cutting characteristics can be predicted and thus the cutting process optimized. Sharpening the cutting edge of the tool to a specific optimized radius subsequently will improve the service life of the tool, workpiece quality, and performance of cutting. Measuring cutting edge radii of tools already is challenging, especially when measuring cutting edge radii of diamonds cutting tools because of their transparency and their dimension in the micrometer range. Defining a sound framework for selecting the appropriate metrology of transparent objects and clarifying the correct measurement parameters, settings, and proper sample preparation are the main achievement of current work. Tactile profilometer, confocal and focus variation light microscopy, imprinting, scanning electron microscopy (SEM) stereoscopy, and atomic force microscopy (AFM) are used to measure the cutting edge radius of diamonds. The identification of the cutting edge radii are done based on the methodology of the least square circle fit over cutting edge radius, and is determined iteratively. Estimations of uncertainties of the measurements are explained in detail and compared. The same measurement techniques and methodologies can also be applied to measure other transparent or difficult to measure materials. The results of different measurement technologies for the same diamond specimens are compared. In the end, one choice from the utilized measurement methods is suggested based on Analytic Hierarchy Process (AHP), which is one of the methods in Multiple Criteria Decision Analysis (MCDA). The selection process and the proposed set of evaluation criteria can also be applied to other measurements.

0612 Predicting the Springback of Metal Cutting Operations Using Mesh Free Methods

“…Maximum prediction error is 9.5 % for the cutting force and 5.9 % for the normal force. This 9.5 % deviation between simulation and experiment can be explained by considering the uncertainties in experimental results as explained in [17]. Compared with other works [5,6,9], the results are of considerable accuracy.…”

A new value for Johnson Cook damage limit criterion in machining with large negative rake angle as basis for understanding of grinding

“…Given experimental conditions where the tool is in full contact with the workpiece and the cutting forces reach steady state, the three components of the cutting forces were validated with experiment for a damage limit of 0.7. Also as proved by (Akbari et al, 2016), the diamond grains have different cutting edge radii and it is important to understand the role of different cutting edge radii in simulation of machining. It is found that in machining with large negative rake angles, cutting and passive forces were reduced with sharper cutting edges.…”

“…This procedure is necessary to overcome the problems of meshing the diamond. Then based on (Akbari et al, 2016) cutting edge radius of 7 µm is considered for the diamonds.…”

“…Uncertainty of the experimental values stems from several parameters, namely the accuracy of the machine tool, geometric tolerance and parallelization of the two sides of the workpiece, exact orientation of the diamond in the tool holder, measurement errors, influence of the environment and influence of the operator. The procedure of calculating the uncertainty can be found in (Akbari et al, 2016).…”

“…8: (a) IR-thermography of the machining process at a cutting speed of 0.8 m/s and 30 µm depth of cut; the surface of the diamond is defined with lines. (b) 3D simulated temperature; a cutting edge radius of 7 µm is considered based on (Akbari et al, 2016). This image is selected to show that the simulated chip separates from the diamond.…”