- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
A double raster laser scanning strategy for rapid die-less bending of 3D shape
摘要： Double raster scanning approach to 3D laser forming was investigated to obtain a large deformation with one-step laser irradiation, avoiding repetitive scanning. The magnitude of the deformation during raster scanning was found to be strongly dependent on the overlapping between adjacent passes, which can be controlled by changing their spacing and the beam diameter. Therefore, 3D deformation during raster scanning has been analyzed at various overlap ratios, whose effect on the temperature and strain distribution were discussed. As the heat transfer mode significantly influences the uniformity of the bending process, the variations in bending angles with negative and positive overlapping ratios have also been investigated. The ratio of the longitudinal and lateral curvatures decreased with the increasing overlap ratio. Therefore, the effect of the lateral side is more important for specifying the final symmetry of the part, playing a critical role in bending with higher overlap ratios. In a rectangular part, deformation of the lateral side was found to be more difficult, showing strong dependence on the length of the scanning track, compared with the space of the adjacent passes. Through process characterization, the double raster scanning process has been well understood and proved to be a feasible approach to 3D laser forming of rectangular parts.
关键词： Curvature,Overlap,Laser bending,Heat transfer,Laser forming,Raster scanning
更新于2025-09-12 10:27:22
-
Disk Laser Assisted Surface Heat Treatments Of AlSi10Mg Parts Produced By Selective Laser Melting (SLM)
摘要： Metal parts produced with the Selective Laser Melting (SLM) method have a great variety of uses today and because of this the requirements on the surface quality differ between applications. The surface treatments of the printed metal pieces, like other finishing phases, are often still manually worked on and thus are very time-consuming processes. This study focuses on the SLM printed AlSi10Mg aluminium specimen’s surface laser heat treatment with disk laser equipment (wavelength of 1030nm). The goal of this study was to achieve the desired effect on the aluminium’s surface quality with robotized laser heat treatment equipment. This was to show that the used finishing treatment method could be automated or robotized. The study showed that with the correct laser parameters, it is possible to generate desired effects and features on to the AlSi10Mg aluminium piece’s surface with a robotized process.
关键词： Selective Laser Melting (SLM),laser forming,AlSi10Mg,Additive Manufacturing (AM)
更新于2025-09-12 10:27:22
-
Investigation of the Profile of Laser Bends with Variable Scan Distance
摘要： Laser forming is a process capable of bending sheet metal only with the laser beam and without a physical interaction with the part. The part is formed by small and local deformations by the laser beam and it is done in increments with each pass of the laser. This incremental forming makes it difficult to ensure a smooth deformation field, which can result in non-smooth components and difficulties in achieving the required tolerance of the bends. This work presents an experimental investigation of the effect of varying the scan distance, number of passes per scan line and number of scan lines on the profile of a v-bend. The v-bends were measured on both sides by a laser range scanner to determine the surface profile along the bend. To evaluate the quality of the v-bend and define the profile as discrete or continuous, the bend roundness was evaluated manually and automatically by a Least Squares Circles method and by using second order differentiation method. The effect of varying the scan distance was tested experimentally on five samples with 16 mm and five samples with 20 mm bend length. The parts were subsequently evaluated on both the inside and outside of the bend and the bend angle was measured. The results show good correlation between the manual inspection and the automatic examination. The results show that the overlapping of the laser beam paths is required to create a continuous smooth bend.
关键词： Roundness error,Laser forming,Sheet metal bending,Profile scanning
更新于2025-09-12 10:27:22
-
Influence of cooling on edge effects in laser forming
摘要： Edge effects in laser forming influence the possible tolerances that can be achieved with laser forming. Edge effects arise due to uneven temperature profiles along the laser scan line. It has been suggested that an increased cooling rate can minimize the occurrence of edge effects. This work will examine the effect of increased cooling to reduce edge effects. The height profile along the laser scan line is reported and compared for different levels of cooling using experiments and simulations. The results show that increased cooling has no impact on the edge effects.
关键词： Laser forming,Edge effects,Active cooling
更新于2025-09-12 10:27:22
-
Efficiency improvement of thin-sheet-metal bending by femtosecond laser peen forming
摘要： Femtosecond laser peen forming is die-less incremental sheet forming using laser induced shock waves. It was applied to bending of thin sheet micro parts. When severe curvatures are requested, the process needs dense laser pulse irradiation, which reduces sheet thickness remarkably owing to excessive laser ablation. High bending efficiency per pulse is necessary to realize a small radius of curvature without sheet thickness reduction. The authors attempted to improve the bending efficiency by changing scanning velocity and scanning pitch. Optimized scanning achieved 40% smaller radius of curvature than conventional one, in spite of same irradiated pulse density. Obtained knowledge is effective in miniaturization and productivity increase.
关键词： Femtosecond laser,Bending,Thin-sheet-metal,Laser peen forming,Bending efficiency,Laser induced shock wave,Micro parts
更新于2025-09-12 10:27:22
-
[IEEE 2019 IEEE/MTT-S International Microwave Symposium - IMS 2019 - Boston, MA, USA (2019.6.2-2019.6.7)] 2019 IEEE MTT-S International Microwave Symposium (IMS) - Contra-Directional 3dB 90° Hybrid Coupler in Ridge Waveguides Using Even and Odd TE Modes
摘要： A novel compact wide-band contra-directional single conductor ridge waveguide coupler is presented. It exhibits 50% fractional bandwidth with equal power split between the through and coupled ports while occupying a very compact volume. The design can be exploited in versatile applications, such as beam forming, or high-power combiners. The methodology to design the coupler is presented. It starts with designing the coupling section in a modified double ridge waveguide that supports two independent propagating TE modes. Proper choice of the cross section allows the designer to achieve the required impedance levels for tight coupling values, not common for standard waveguide contra-directional couplers. An S-band proof of concept prototype was synthesized, simulated, fabricated and tested demonstrating excellent measured results without any tuning.
关键词： beam forming,backward coupling,Ridge waveguide,power amplifiers
更新于2025-09-12 10:27:22
-
Path Generation Method for Aero- Engine Free-Form Surface Blade in Laser Solid Forming
摘要： Blade is the critical and extensively used component of aero-engine, which machining quality directly affects engine performance. Due to its ?exibility, laser solid forming (LSF) from powders is widely used to synthesis novel materials, build three-dimensional parts, repair damage part and form surface coating in advanced manufacturing. To repair damaged parts or form surface coating, especially for aero-engine free-form surface blade, process of numerical control or robotic LSF is applied in industry. Nevertheless, on account of the complex geometry of the free-form surface, it’s quite a challenge to generate proper laser beam paths according to the process requirements of LSF. To address this problem, a path generation method based on the differential geometry is presented. The generated paths can ensure the overlap requirements between deposited tracks as well as paths shifts between adjacent layers. The proposed method has been applied to two examples to verify their validity, and there exists a great potential for the applications in aero-engine manufacturing industry, especially in the LSF repair or surface coating of free-form surface blade.
关键词： coating,laser solid forming,Blade repair,free-form surface,path generation
更新于2025-09-11 14:15:04
-
Joining of dissimilar materials by laser induced shock waves
摘要： The demand to implement more functionality on limited amount of space promotes miniaturization. This makes hybrid joints under various conditions and also in the micro range necessary. Existing solutions often have restrictions due to the principle of joining. A plastic forming process based on laser induced shockwaves is used to realize sheet-sheet connections. The knowledge of joining of metallic sheets by laser-induced shock waves should be used to enable the joining of aluminum with dissimilar materials such as glass and plastics. For industrial applications the dimensioning is important in matters of strength and feasibility of a joint. Therefore an upper bond estimation for the joining strength is developed. The design of the joint can be described on the basis of material properties. Moreover, the stiffness of the joining partners can be used as the decisive criterion for the joining possibility in the joining area. The advantages of this process are applied to different material combinations.
关键词： mechanical joining,High speed forming,micro joining,dissimilar materials
更新于2025-09-11 14:15:04
-
In situ tailoring microstructure in laser solid formed titanium alloy for superior fatigue crack growth resistance
摘要： For damage tolerance (DT) titanium alloy, the fatigue crack growth resistance (FCGR) is a critical properties requirement for engineering applications. However, the Ti-6Al-4V-DT parts fabricated by laser solid forming (LSF) suffer from low FCGR, because of predominant basket-wave microstructure. Here, we have explored a novel LSF fabrication design to produce full colony microstructure, via in-situ controlled growth. The creation of such microstructures leads to superior FCGR, which markedly exceed conventional additive manufactured and mill-annealed samples. The present works provide a significant guidance for LSF-fabricated titanium alloy with high DT properties.
关键词： Titanium alloy,Fatigue crack growth resistance,Laser solid forming,Colony microstructure
更新于2025-09-11 14:15:04
-
The δ Phase Precipitation of an Inconel 718 Superalloy Fabricated by Electromagnetic Stirring Assisted Laser Solid Forming
摘要： Fabricating an Inconel 718 superalloy using electromagnetic stirring assisted laser solid forming (EMS-LSF) is a novel method to modify its microstructure and mechanical properties by consuming the Nb element in the γ phase to alleviate interdendritic segregation. The precipitate C after EMS-LSF can help to achieve the uniform di?usion of Nb, and can also improve its mechanical properties. The precipitation behavior of the δ phase in an EMS-LSF Inconel 718 superalloy with di?erent heat treatment processes has been investigated. The results show that the morphology of the δ phase changes from rod-like to a long-needle shape and tends to grow from the inter dendrite to the core dendrite with electromagnetic ?eld intensity increasing, which is accompanied by the “cutting” and “dissolution” of the Laves phase. Through precipitation kinetics analysis, the precipitation rate of the δ phase is seen to increase with the electromagnetic ?eld intensity increasing. Under a combination of electromagnetic stirring and laser solid forming, the microhardness of the Inconel 718 samples increased slightly due to the fact that a higher content of Nb was distributed in the core dendrite resulting from the serious convection of liquid metal, which can strengthen the matrix.
关键词： electromagnetic stirring,laser solid forming,laves phase,δ phase,precipitation behavior
更新于2025-09-11 14:15:04