Analysis of the machining performance and surface integrity in laser milling of polycrystalline diamonds

Abstract

The increasing use of diamond cutting tools necessitates the development of compatible fabrication technologies for the diamond tools, especially for three-dimensional surfaces with micron scale accuracy and good surface quality. In this article, the formation mechanism of surfaces milled using a nanosecond pulsed laser on polycrystalline diamond and the effect of process parameters on the milling performance such as material removal rate and surface integrity are investigated based on a statistically designed experiment. It is shown that laser milling is a viable technology for three-dimensional processing of polycrystalline diamonds with good machining rates and acceptable surface quality. A microscopy analysis indicates that diamond graphitization can occur on the milled surfaces, and laser pulse energy and pulse overlap have a significant effect on the milled surface morphology. Characterization of the machined surface/ subsurface is conducted using Raman spectroscopy, and the relationships between damaged surface layer thickness and process parameters are discussed. It is found that an optimum pulse overlap together with moderate pulse energy may be used, while the scan overlap should be selected in the vicinity of its optimum value at around 50% for a good surface quality while maintaining a high material removal rate.

Microhardness and wear behaviour of polycrystalline diamond after warm laser shock processing with and without coating

“…PCD consists of several randomly arranged single crystals or grains that are separated by regions called grain boundaries, producing a composite structure with isotropic properties [3]. PCD has outstanding mechanical properties which includes excellent hardness and fracture toughness, high chemical inertness (except with ferrous materials), good abrasion resistance, high thermal conductivity, high Young's Modulus and a low coefficient of friction [4]- [6]. These properties decrease the occurrence of bending, catastrophic failures and chip adherence in tooling applications allowing form accuracy, surface quality and low subsurface damage [4].…”

Experimental investigation of surface defects in low‐power CO2 laser engraving of glass fiber‐reinforced polymer composite

“…Laser milling has been previously studied on materials like polymethyl methacrylate (PMMA), [16] copper, [17] poly crystalline diamond, [18] and metal coatings [19] for micromachining related applications. Here, it should be noted that laser engraving and laser milling are the same processes in which a laser been moves in a raster pattern to remove a layer of material.…”

“…At the same time, laser milling or engraving is a potential technique to remove materials layer by layer and can be effectively used for surface structuring as well as small amount of material removal. Laser milling has been previously studied on materials like polymethyl methacrylate (PMMA), copper, poly crystalline diamond, and metal coatings for micromachining related applications. Here, it should be noted that laser engraving and laser milling are the same processes in which a laser been moves in a raster pattern to remove a layer of material.…”

Performance Evaluation and Comparison between Direct and Chemical-Assisted Picosecond Laser Micro-Trepanning of Single Crystalline Silicon

“…Laser technology has been extensively used in material micro-processing fields due to its ability to focus energy into a small irradiation area within a short pulse duration, and hence lead to material removal, regardless of the mechanical properties of the material [6,7]. In terms of micro-drilling application, laser has shown good performance, and several drilling techniques have been proposed according to the relative movement between the laser beam and the workpiece, such as percussion drilling [2], trepanning [8], and laser helical drilling [9].…”