In this paper, the methodology for design of the system consisting of chromatic confocal displacement sensor integrated with an optical laser head was presented. Furthermore, the results of experimental characterization of optical components of the laser head were also included in the numerical analysis. The designed chromatic confocal displacement sensor was analyzed as an assembly of components widely available on the optical market. Nevertheless, the main goal of the numerical optimization was to determine the influence of individual components of the optical path of the system on its parameters, i.e., measuring range, FWHM of the characteristic spectral peak, and intensity that reaches the detector. The optimized solution was characterized in order to determine the calibration curve, as well as other important application parameters of the system. Moreover, taking into consideration the integration aspect the caustic of the laser beam shaped by the laser head was measured. Finally, the versatility of the system was presented and discussed.
4 February 2019 in Aircraft Engineering and Aerospace Technology
Purpose: The purpose of this paper is to propose cold spraying and laser cladding processes as alternatives to cadmium and chromium electroplating, respectively. There are many substances or chemicals within the coating technology that can be identified as substances of very high concern because of their carcinogenic or mutagenic nature. Cadmium and chromium undoubtedly belong to these items and are the basic constituents of electrolytic coating processes. Finding an alternative and adapting to the existing restrictions of the usage of such hazardous products stands for many to be or not to be in the market. Design/methodology/approach: The research work was focused on down selecting the appropriate materials, producing the coating samples, testing their properties and optimizing process parameters by statistical method. On the one hand, the high-pressure cold spray system and spraying of the titanium coating on the landing gear component, and on the other hand, the high-energy laser cladding facility and the wear resistant cobalt-based coating deposited onto the shock absorber piston. Substrates of these two applications were made of the same material, 4330 – high-strength low-carbon steel. Findings: Meeting the requirements of Registration, Evaluation, Authorization and Restriction of Chemicals implies undertaking research and implementation work to identify alternative processes. The work provides the technical characteristics of new coatings justifying application readiness of the researched processes. Originality/value: Taguchi’s design of experiment method was combined with the measurements and analysis of specified coating properties for the optimization of the cold spray process parameters. There is also laser cladding process development presented as a fast rate technology generating coatings with the unique properties.
In this paper, the results of experimental characterization of an optical system consisting of a chromatic confocal displacement sensor integrated with an optical laser head are presented. As a result of integration, the part of the optical path of the displacement sensor was combined with the optical path of the laser beam. Consequently, a working distance of 250 mm for the optical system was achieved. The main aim of the characterization was to determine the calibration curve, as well as the application parameters of the system. The methodology for spectral data processing with particular emphasis on the effectiveness of various extraction algorithms is presented. The Lorentzian fitting was considered as the optimal algorithm for the optical system. Consequently, a large measuring range of 10 mm was obtained with perfect linear tendency of the calibration curve. The optical system was characterized by high accuracy equal to of the measuring range, as well as 1 µm resolution. Moreover, the functionality of the system was verified on materials commonly used in laser processing and additive manufacturing. Finally, the system was validated through a comparative measurement with a laser profiler.
18 December 2024 in Archives of Civil and Mechanical Engineering
Advanced remanufacturing by additive manufacturing is challenging in aerospace due to the minimization of material costs, preparation times and metal waste. This study analyzed a 40HM low-alloy steel ring as a demo tooling used to produce aircraft engine components. The possibility of using laser cladding with powder process with the additive material NiCrBSi alloy powder was analyzed. Optimal parameters of the process were selected in terms of the assumed structural requirements (geometrical parameters of the clad, its hardness and the size of the heat-affected zone) for the remanufactured surfaces, ultimately obtaining a crack-free multilayer coating with a thickness of 2 mm and a hardness of above 700 HV1. The remanufacturing process was performed on three representative surfaces: flat face, cylindrical external, and internal. This approach allowed an analysis of the possibilities of finishing the laser-deposited layers with the machining methods used in the actual tooling department of the aerospace company: turning, milling, grinding, and center grinding. During chip processing, the defects (holes, cracks) made machining difficult and ineffective, mainly due to accelerated tool wear. Single cracks were observed after the grinding operation, which may reduce the durability of the remanufacturing layer. Both the changes in the microstructure of the demo component and the phases present in the cladding were analyzed. The deposition process was found to form a martensitic structure in the substrate at the cross-section in proximity to the remanufactured surfaces. This was also confirmed by an increase in average hardness from 402 HV1 to 605 HV1 for the analyzed substrate areas.
The recently introduced Coaxial Laser Wire Deposition technology can become a new promising method for remanufacturing high-complexity and expensive cutting tools (e.g., flat broach), which will have a significant impact on their service life. In addition, it is an innovative approach to tool management. An analysis of the feasibility of processing cobalt-added HSS powder steels was carried out for single clads and multilayer structures. The effect of process parameters (laser, beam power, travel speed, wire feed rate) on geometric properties, hardness and microstructure was discussed. In order to avoid cracking during multilayer deposition, an additional preheating to 320 °C was applied. Two sets of process parameters with high and low heat input were obtained. Both sets lead to crack-free structures that fulfill geometric (≥2.5 mm in height) and hardness (≥700 HV) requirements.