Finding process parameters for laser-drilled blind holes often relies on an engineer’s experience and the trial-and-error method. However, determining such parameters should be possible using methodical calculations. Studies have already begun to examine the use of neural networks to improve the efficiency of this situation. This study extends the field of research by applying artificial neural networks (ANNs) to predict the required parameters for drilling stainless steel with a certain depth and diameter of blind holes, and it also pre-simulates the drilling result of these predicted parameters before actual laser processing. The pre-simulated drilling results were also compared with real-world observations after drilling the stainless steel. These experimental findings confirmed that the proposed method can be used to accurately select laser drilling parameters and predict results in advance. Being able to make these predictions successfully reduces time spent, manpower, and the number of trial-and-error shots required in the pre-processing phase. In addition to providing specific data for engineers to use, this method could also be used to develop a set of reference parameters, greatly simplifying the laser drilling process.

Micro-scale hole drilling on metallic sheets has been employed in a wide range of personal computing devices, such as smart phones and tablet computers. Laser machining, micro-electro-discharge machining, and chemical etching are the methods used for fabricating micro-scale holes. In this paper, we propose a hybrid sequential stamping and laser machining process. The alignment in the hybrid process is critical, and a patented device called the ball-cone-hole magnet was used in the experiments to achieve an alignment error of less than 1 µm. The fabrication results obtained by laser-only, stamping-only, and the proposed hybrid process were compared. The diameters of inlets and outlets, as well as the cross-section of holes, were compared herein. The surface roughness of the sidewalls’ inside holes was measured. The proposed hybrid stamping and laser machining process provides an alternative fabrication method for the micro-scale hole drilling process with better hole quality than a laser-only machining process.

The forming of a micro tapered hole is based on nanosecond pulsed laser processing, which conforms to fast processing time and high throughput; however, the microhole quality should be improved. Micro stamping is a technology providing high precise size and speed. The greatest difficulty in forming a microhole by micro stamping is the precision alignment of the punch head to the lower die. In order to overcome the difficulty, we proposed a concept of stamping without die (SWD). Without a lower die, the tapered punch head was directly applied to the workpiece for micro stamping, and a thicker workpiece surrounding the punching area provides a better support to the stamping process. Thus, a successful forming of micro tapered holes is completed. The micro tapered hole depth is 300 μm, and the maximum ratio of inlet to outlet diameter is 18:1. In order to reduce the number of experiments, the finite element analysis software DEFORM-3D was used for forming analysis. The simulation forecast result was compared with the experimental processing, which was well validated. Under different experimental parameters of laser energy and defocusing distance, drilling results by two methods show that the microhole quality by stamping process is better than by laser processing.

In this paper, a technique that combines digital image correlation and wire electrical discharge machining for the measurement of the residual strain is presented. The significant potential benefits of this work include noncontact, high-speed, and online measurement. A ring-core-based groove in the surface of the specimen is cut to release the residual stresses present inside the core. The deformation due to these stresses can be measured by digital image correlation to measure the relieved strains. Moreover, the sizes of the reference areas on the specimens and the tracks of these areas after wire electrical discharge machining are investigated. The proposed method is applied to six different specimens to characterize their relieved strains.

With an aging population, the number of joint replacement surgeries is on the rise. One of the most common implant materials is cobalt–chromium–molybdenum (CoCrMo) alloy. Hence, the surface properties of this alloy have attracted increasing attention. In this study, nanosecond and femtosecond laser processing, followed by annealing, was employed to modify the CoCrMo surface. The effects of the treatment conditions on the surface morphology, structure, composition, hardness, roughness, contact angle, wear properties, and corrosion current were studied. Femtosecond laser processing with an energy density of 1273 mJ/cm², followed by heat treatment at 160 °C for 2 h, produced laser-induced periodic surface structures (LIPSS) without altering the chemical composition of the alloy and rendered the surface superhydrophobic. In contrast, nanosecond laser treatment at higher laser energy densities promoted the formation of an oxide layer, which improved the hardness and corrosion resistance of the substrate. Overall, the CoCrMo samples processed using the femtosecond laser system exhibited superior corrosion and wear resistance, with a protection efficiency of approximately 92%.