Numerical Analysis of the Effects of Pulsed Laser Spot Heating Parameters on Brazing of Diamond Tools

Abstract

A 3D finite element (FE) model is built to numerically analyze heating parameters on temperature during brazing diamond grains by the pulsed laser spot heating. A pulsed Nd:YAG laser is used for experimental validation. The results show that during laser heating, the temperature varies periodically because of the pulsed heat flux. Four key thermal indices, the maximum temperature Tmax, the minimum temperature Tmin, the average temperature Tav and the temperature fluctuation amplitude ΔT are addressed. The primary factor affecting Tmax, ΔT and Tav is the pulse power and on Tmin is the pulse frequency. The secondary effect factor on Tmax, Tav and ΔT is the pulse width and on Tmin is the pulse power. For engineering practice, the order of designing heating parameters is recommended as: pulse power, second frequency and last width.

Bionic Repair of Thermal Fatigue Cracks in Ductile Iron by Laser Melting with Different Laser Parameters

“…Oil stains were cleaned with an ultrasonic cleaner containing an acetone solution to form smooth and clean surfaces. All test samples imitating the anti-crack structure of leaves were fabricated using a solid-state Nd-YAG pulsed laser (XL-500WF, Rofin, Munich, Germany) with a wavelength of 1064 nm and a maximum rated output power of 500 W ( Figure 5) [22]. Then, long cracks were segmented into several smaller cracks.…”

Manufacture and mechanical-tribological assessment of diamond-reinforced Cu-based coatings for cutting/grinding tools

“…Furthermore, the thermal expansion mismatch between diamond and the self-sharpening metal matrix must be minimized, since the high residual compressive stresses accumulated at the interface, which are responsible for the mechanical retention capacity, might lead to the early dislodging of the embedded diamond particles [14]. There are many different alternative techniques capable of achieving a better level of metal-to-diamond bonding to overcome these problems nowadays, such as: the molten salt method [15], chemical vapor deposition [16], plasma spray [17], spark plasma sintering [18], hot isostatic pressing [19], and laser brazing methods [20], which have been employed in the manufacture of different metal-bonded diamond abrasive tools with different results. Among them, brazing technologies have evolved much more than the others because of the use of filler alloys with active carbide elements such as molybdenum [21], tungsten [22], chromium [20], and titanium [23], which make it possible to establish chemical and metallurgical bonds between the brazed diamond particles and the self-sharpening metal matrix, much more resistant than those developed by purely mechanical, adhesive, and diffusion means [24,25].…”

“…There are many different alternative techniques capable of achieving a better level of metal-to-diamond bonding to overcome these problems nowadays, such as: the molten salt method [15], chemical vapor deposition [16], plasma spray [17], spark plasma sintering [18], hot isostatic pressing [19], and laser brazing methods [20], which have been employed in the manufacture of different metal-bonded diamond abrasive tools with different results. Among them, brazing technologies have evolved much more than the others because of the use of filler alloys with active carbide elements such as molybdenum [21], tungsten [22], chromium [20], and titanium [23], which make it possible to establish chemical and metallurgical bonds between the brazed diamond particles and the self-sharpening metal matrix, much more resistant than those developed by purely mechanical, adhesive, and diffusion means [24,25]. Moreover, the nucleation of these carbides at the surface of the diamond particles prevents their graphitization and/or oxidation [26] during the compaction and sintering process of the powders [27].…”

Numerical Simulation of Temperature Characteristics and Graphitization Mechanism of Diamond in Laser Powder Bed Fusion

“…However, it is challenging to measure the temperature of diamonds directly during the processing, often requiring simulation methods to obtain the diamond temperature. Y. Wang et al established a three-dimensional Finite Element (FE) model to numerically analyze the temperature parameters of diamond grain during pulse laser spot heating for brazing [ 10 ]. J. Gan et al established a temperature field model for single-track scanning with different laser powers, resulting in appropriate SLM process parameters [ 11 ].…”