- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Laser-assisted micro-milling of austenitic stainless steel X5CrNi18-10
摘要： This paper presents a novel Laser-Assisted Micro-Milling (LAMM) process of austenitic stainless steel X5CrNi18-10. The LAMM process is compared with the conventional micro-milling process. Ultra-short pulsed laser radiation is utilized for the structuring of the workpiece surface prior to the micro-milling process. Different laser structures are produced on the workpiece surface at a constant laser scanning speed with various laser powers and laser line spans. The high performance of the developed process is shown by experimental investigations. The effect of laser structuring on the micro-milling forces and temperature indicated the superior performance of the new LAMM process. Cutting forces and temperature could be reduced by up to 70% and 50%, respectively. The results of conventional micro-milling showed that increasing the cutting speed, at a constant undeformed chip thickness, reduced the micro-milling forces. Increasing the cutting speed from 50 to 250 m/min halved both the trust and normal forces, while it slightly improved the surface roughness. On the other hand, increasing the feed per tooth degraded the surface roughness and increased the cutting forces. Furthermore, in conventional milling the workpiece was subjected to high plastic deformation during the cutting process, while side flow, smeared material, metal debris, and cavities were observed on the workpiece surface.
关键词： Laser-assisted micro-milling,Austenitic stainless steel,Ultra-short pulsed laser,Laser structuring,Micro-milling
更新于2025-09-12 10:27:22
-
Fabrication of a ball end nose micro milling tool by tangential laser ablation
摘要： The general trend towards miniaturization of components is leading to an increasing demand for micro cutting tools. Such tools are found in a variety of applications like optics manufacturing, mold machining or medical technology. Indeed, micromachining exhibits a high efficiency, accuracy and low cost in comparison to other micro processing technologies. Micro cutting tools are mostly produced by grinding, a mechanical process, which might damage the tool due to induced forces, vibrations and heat. These detrimental effects cause the high scrap rate in the manufacturing of micro cutting tools and limited geometrical flexibility. A new approach for the manufacturing of micro cutting tools is given by the ultrashort-pulsed laser technology: it enables material removal, which is independent of the hardness of the workpiece material and with only a negligible heat-affected zone. In most cases, laser ablation is disadvantaged in contrast to grinding because of its relatively low material-removal rate. When it comes to the manufacturing of micro cutting tools the small amount of material to be removed makes the ultra-short pulsed laser an interesting alternative to grinding. Furthermore, the laser ablation is a force and wear-free process, which ensures high precision. In this paper, a commercially available micro ball end mill geometry is measured by micro X-ray tomography and 3D microscopy. The movement of the mechanical axes and the path of the laser beam for manufacturing the desired tool are determined based on these measurements. The milling tools with a diameter of 100 μm are produced from cemented carbide blanks, on a 8-axis laser machining center. After machining, the tools are analyzed by SEM and using FIB: By creating a cross section perpendicular to the cutting edge the heat-affected zone is examined. Finally, the cutting tool is successfully applied for the manufacturing of micro electrodes in copper for an EDM process while recording the cutting forces.
关键词： ultrashort pulse laser ablation,tangential laser ablation,ball end nose micro milling tool
更新于2025-09-12 10:27:22
-
Helical milling of bore holes in Ti6Al4V parts produced by selective laser melting with simultaneous support structure removal
摘要： Selective Laser Melting (SLM) is a powder bed based Additive Manufacturing (AM) process that is currently being established in the series production of Ti6Al4V components in the aviation industry. One advantage is the significantly lower Buy-to-Fly ratio. However, subsequent machining is necessary in order to remove support structures of the SLM process and to fulfill quality requirements. Experimental results on support structure removal and simultaneous finishing of holes by helical milling are presented. Engagement conditions in helical milling are strongly influenced by the support structure. Material removal rates in both peripheral and axial direction are calculated and agree well with the variation of measured forces in these directions. In addition, the surface roughness of the machined holes is affected by the support structure design and may change along the hole perimeter. The findings indicate how support structures should be designed in order to obtain high quality bore holes in one machining step.
关键词： titanium,helical milling,support structure removal,modeling,force,surface roughness,SLM
更新于2025-09-12 10:27:22
-
Study on Charge Transfer Mechanism in Mechanically Milled Co3O4 by UV-Vis Spectral Analysis
摘要： The consequences of mechanical milling instigated strain and particle size reduction on optical properties of cobalt oxide (Co3O4) have been deliberated by virtue of X-ray powder diffractometry, transmission electron microscopy and UV-Vis spectroscopy at 300 K. Based on this study it is deduced that: (i) the lattice constant and thus X-ray density values are not affected by mechanical milling induced particle size reduction but the strain is generated on 7 hrs. of milling in Co3O4 spinel composition (ii) the UV-Vis spectra for un-milled and 7 hrs milled samples show two absorption bands corresponding to Co2+-O2-and Co3+-O2-charge transfer mechanisms. The observed redshift in energy band gap is mainly due to the milling induced vacancies but vacancy formation is not identical at the tetrahedral and octahedral environments. The red-shifted electronic band for the milled sample is also due to the highly stressed particles. The mean refractive index, molar electronic polarizability, and optical energy band gap have been determined from X-ray density value.
关键词： Optical properties,Mechanical milling,Spinel,Charge transfer mechanism
更新于2025-09-12 10:27:22
-
Highly-efficient laser ablation of copper by bursts of ultrashort tuneable (fs-ps) pulses
摘要： Ultrashort pulse laser, capable of varying pulse duration between 210 fs and 10 ps and producing a burst of pulses with an intra-burst pulse repetition rate of 64.5 MHz (time distance between pulses 15.5 ns), was used to investigate the ablation efficiency of the copper. The study on ablation efficiency was done for various numbers of pulses per burst between 1 and 40. The increase in the ablation efficiency by 20% for 3 pulses per burst compared to a non-burst regime was observed. The comparison was made between the beam-size optimised regimes. Therefore, the real advantage of the burst regime was demonstrated. To the best of our knowledge, we report the highest laser milling ablation efficiency of copper of 4.84 μm3/μJ by ultrashort pulses at ~1 μm optical wavelength.
关键词： ultrashort pulse laser,laser milling,ablation efficiency,copper ablation,burst mode
更新于2025-09-11 14:15:04
-
Optical and photoelectrochemical properties of Cu2SrSnS4 thin film fabricated by a facial ball-milling method
摘要： Earth-abundant and non-toxicity quaternary chalcogenide Cu2SrSnS4 is prepared by a facial ball-milling method. Its formation is revealed to be from the reaction between Cu2SnS3 and SrS at 600 oC. The bandgap of the prepared Cu2SrSnS4 film is speculated around 1.78 eV according to absorption test. The carrier lifetime of the prepared Cu2SrSnS4 film is about 2.06 ns. The photocurrent density of the Cu2SrSnS4 film is about 150 at -670 mV bias vs Ag/AgCl electrode and it repeats after 10 cycles of 1000 s. Its notable generation of photocurrent and photoelectrochemical stability indicates its potential for photoelectric conversion application.
关键词： Ball-milling,Thin films,Solar cell,Cu2SrSnS4,Optical,Solar energy materials
更新于2025-09-10 09:29:36
-
Structural Differences of BaTiO3 Ceramics Modified by Ultrasonic and Mechanochemical Methods
摘要： Barium titanate powders were synthesized by the modified solid-state method with ultrasonic (5 min) and mechanochemical (12 h) deagglomeration methods. The structure of the samples was verified using Fourier transform infrared spectroscopy (FT-IR) and X-ray diffractometer (XRD). Scanning electron microscopy (SEM) analysis of the powders showed that using ultrasonic deagglomeration significantly decreased the particle size with perfect homogeneity in the shortest time. The particle size of the powders was calculated as 44.7 nm and 80.4 nm for ultrasonic and mechanochemical deagglomeration, respectively. The sintered pellet by ultrasonic method had no abnormal grain growth, and the grain sizes were between 10 and 30 μm. The pellet by mechanochemical method had an abnormal grain growth, and the grain sizes were between 10 and 100 μm. The results showed that ultrasonication remarkably improved the structure of the samples in the shortest time.
关键词： deagglomeration,grain size,milling,ultrasonication,BaTiO3
更新于2025-09-10 09:29:36
-
Effect of Milling on the Densification of SiC-BasedComposites from Polysilazane
摘要： High density SiC-based composites from polysilazane were fabricated by high energy milling and hot pressing. After cross-linking at 200 °C, the polysilazane was pyrolysed at 1000 °C in N2 for 2 h to form amorphous Si-C-N-O followed by high energy milling for 1 h. Milled amorphous Si-C-N-O was sintered in hot pressing at 1600 and 1700 °C for 1 h in vacuum under the applied pressure of 50 MPa. Although no sintering additives were used, dense SiC-based composites were obtained with this method. Sintered density was 3.04 g/cm3, while only 2.57 g/cm3 for amorphous Si-C-N-O without milling. It is suggested that the liquid phase generated during the formation of Si2N2O facilitated the densification of the composite.
关键词： polysilazane,Si2N2O,high energy milling,SiC-based composites
更新于2025-09-10 09:29:36
-
Research on the Relationship between Cutting Force and Machined Surface Quality in Micro Ball End-Milling of Potassium Dihydrogen Phosphate Crystal
摘要： Potassium dihydrogen phosphate (KDP or KH2PO4) crystal is widely used as terminal frequency converters in inertial confinement fusion (ICF). However, KDP crystal is a typical difficult-to-cut optical crystal with the characteristic of soft-brittle. In this work, the relationship between cutting force and processed surface quality in micro ball end-milling of KDP crystal with various depth of cut and spindle speed is studied by carried out the micro-milling experiments. Fast Fourier Transform (FFT) algorithm is used to diagnose the recorded cutting force. The periodic change of cutting force and the cutting force after filtering noises can be got through FFT analysis. Through calculating the correlation coefficients between the static component of thrust force and roughness value Ra of machined grooves, as well as the peak-valley (P-V) value of thrust force and dimensional error of machined grooves, the roughness value Ra and dimensional error of machined grooves would be predicted by monitoring the static component and P-V value of the thrust force, respectively. The relatively large spindle speed helps to reduce the roughness value Ra. The spindle speed with moderate value is recommended to reduce the dimensional error of machined groove because the dimensional error of machined groove will increase when the spindle speed is small enough (causing brittle cutting) or large enough (reducing cutting stability).
关键词： micro ball end-milling,KDP crystal,cutting force,FFT analysis,machined surface quality
更新于2025-09-10 09:29:36
-
Direct and Efficient Conversion from Low-Quality Graphite to High-Quality Graphene Nanoplatelets
摘要： Low-quality graphite (L-graphite), containing various impurities (e.g., metals and inorganics), can be directly and efficiently converted into high-quality iodine-doped graphene nanoplatelets (HIGnPs) via mechanochemical ball-milling in the presence of iodine (I2) with subsequent work-up procedures. Despite using L-graphite, the resultant HIGnPs show high-quality characteristics, including large specific surface area (969 m2 g?1), lower metallic residues, and well-maintained graphitic structure. In addition, HIGnPs display remarkable electrocatalytic performance for oxygen reduction reaction (ORR), involving benefits such as higher selectivity, longer-term stability, and better tolerance to methanol crossover/CO poisoning effects. Therefore, simple mechanochemical ball-milling in solid state can produce high-quality graphene nanoplatelets in large quantity at low-cost for commercialization, regardless of the initial quality of the graphite.
关键词： Oxygen reduction reaction,Mechanochemical reaction,High-quality graphene,ball-milling,Low-quality graphite
更新于2025-09-10 09:29:36