scholarly journals Laser Micro Polishing of Tool Steel 1.2379 (AISI D2): Influence of Intensity Distribution, Laser Beam Size, and Fluence on Surface Roughness and Area Rate

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1445
Author(s):  
André Temmler ◽  
Magdalena Cortina ◽  
Ingo Ross ◽  
Moritz E. Küpper ◽  
Silja-Katharina Rittinghaus

Within the scope of this study, basic research was carried out on laser micro polishing of the tool steel 1.2379 (AISI D2) using a square, top-hat shaped intensity distribution. The influence of three different quadratic laser beam sizes (100 µm, 200 µm, 400 µm side length) and fluences up to 12 J/cm2 on the resulting surface topography and roughness were investigated. Surface topography was analyzed by microscopy, white light interferometry, spectral roughness analysis, and 1D fast Fourier transformation. Scanning electron microscopy and electrical discharge analyses indicate that chromium carbides are the source of undesired surface features such as craters and dimples, which were generated inherently to the remelting process. Particularly for high laser fluences, a noticeable stripe structure was observed, which is typically a characteristic of a continuous remelting process. Although the micro-roughness was significantly reduced, often, the macro-roughness was increased. The results show that smaller laser polishing fluences are required for larger laser beam dimensions. Additionally, the same or even a lower surface roughness and less undesired surface features were created for larger laser beam dimensions. This shows a potential path for industrial applications of laser micro polishing, where area rates of up to several m2/min might be achievable with commercially available laser beam sources.

2021 ◽  
Author(s):  
Zuofa Liu ◽  
Jie Zhou ◽  
Hang Wang ◽  
Qiuyun Wang ◽  
Qiang Liang ◽  
...  

Abstract In this work, a laser polishing-hardening (LPH) method with integration and high efficiency for the treatment of AISI D2 tool steel was proposed, and the effects of laser hardening (LH), laser polishing (LP) and LPH treatments on the surface topography and microhardness were examined. The results show that LH method had a negligible effect on the surface roughness of the treated sample, while the surface roughness Ra of LP and LPH specimens was reduced by 74.6% and 80.9% respectively, indicating that the milled surface topography had been significantly improved, especially LPH was more effective in reducing the roughness. Besides, the polishing efficiency of LPH was 10 times that of LP approach. In terms of hardness improvement, the near-surface microhardness of LH and LPH samples increased by 1.5 times and 1.3 times respectively, and the effective hardened zone (EHZ) depth was 0.42 mm and 0.24 mm respectively, demonstrating that these two laser processing methods had a beneficial effect on the cross-section microhardness of D2 tool steel, while the increase of LP on the microhardness was insignificant. The comprehensive analysis of the surface morphology and microhardness of LPH specimen indicates that LPH was a feasible laser surface treatment method for D2 tool steel. On the premise of ensuring a high surface finish, the polishing efficiency can be remarkably improved, the subsurface microhardness and EHZ depth of processed specimen can be also significantly enhanced, which provided a feasible idea for the application of laser surface treatment technology in industrial mold production.


2020 ◽  
Vol 977 ◽  
pp. 27-33
Author(s):  
Carmita Camposeco-Negrete ◽  
Juan de Dios Calderón-Nájera

One of the non-conventional machining processes widely used in the industry is the wire electrical discharge machining (WEDM). This process has many advantages, like the great precision and quality that can be achieved. As well as other manufacturing operations, the success of the process relies on a correct selection of the cutting parameters. The present paper outlines an experimental study to optimize the machining time and the surface roughness in WEDM of AISI D2 tool steel during roughing machining. The Taguchi methodology is used to evaluate the effects and contributions of the pulse-on time, pulse-off time, servo voltage, and wire speed, on the response variables. The desirability method is employed to define a set of cutting parameters that allows reducing both machining time and surface roughness at the same time. The pulse-on time is the most significant factor for reducing the machining time, followed by the servo voltage, the pulse-off time and the wire speed. For surface roughness, the pulse-off time is the factor with the greatest influence over the response variable. The results obtained show that the machining time is reduced by 4.65%, and the surface roughness is diminished by 4.60% when compared with the initial values that are commonly used in the machining of AISI D2 tool steel. Therefore, greater production rates can be achieved without compromising the quality of the machined parts.


2014 ◽  
Vol 699 ◽  
pp. 76-80 ◽  
Author(s):  
M.N. Mohammed ◽  
M.Z. Omar ◽  
J. Syarif ◽  
Z. Sajuri ◽  
M.S. Salleh ◽  
...  

Due to the growing demand for cold-work tool steel in various industrial applications, it is crucial to improve the fabrication technique, because complex shapes involve an extensive and costly workshop effort. Hence, a one-step net-shaping process, such as the semi-solid forming, could offer great benefits. With the aim of finding a minimum process chain for the manufacturing of a high-quality production, the microstructural evolution of the ledeburitic AISI D2 tool steel in the semi-solid-state was studied experimentally via the Direct Partial Re-Melting Method (DPRM). Samples were heated in an argon atmosphere up to 1255°C, which corresponded to about 16% of liquid fraction, and held for 0 minute. The microstructural observation after DPRM showed that the equiaxed austenite grains are observable within a small liquid matrix. The microstructure also contains primary, non-dissolved carbides with a new, precipitated eutectic.


Author(s):  
P Zhang ◽  
B Wang ◽  
Y Liang ◽  
M J Jackson

Elgiloy™ is a cobalt-based alloy with excellent physical and chemical performance, and is used widely in medical and industrial applications. The machining accuracy, surface topography, and surface damaged layer play an important role in the use of the alloy for specific applications. In this paper, an experimental study on the surface roughness of precision micromilling of Elgiloy is accomplished by using a super-fine-grained tungsten carbide milling cutter. The surface topography of the surface of the slots milled is achieved with different values of feed speed and axial depth of cut. Three-dimensional (3D) measurement results are considered to reflect the surface topography based on a comparison of the difference between two-dimensional (2D) and 3D surface roughness measurements. The arithmetic mean deviation of the slots’ 3D surface is achieved by using a white light interferometric profilometer. By using analysis of variance (ANOVA), the factors of feed speed, axial depth of cut, and their interaction are proven to be the most important factors relating to the magnitude of surface roughness.


Author(s):  
M.A. LAJIS ◽  
A.N. Mustafizul KARIM ◽  
A.K.M. Nurul AMIN ◽  
A.M.K. HAFIZ

2021 ◽  
Author(s):  
Roberta Pirazzini ◽  
Henna-Reetta Hannula ◽  
David Brus ◽  
Ruzica Dadic ◽  
Martin Scnheebeli

<p>Aerial albedo measurements and detailed surface topography of sea ice are needed to characterize the distribution of the various surface types (melt ponds of different depth and size, ice of different thicknesses, leads, ridges) and to determine how they contribute to the areal-averaged albedo on different horizontal scales. These measurements represent the bridge between the albedo measured from surface-based platforms, which typically have metre-to-tens-of-meters footprint, and satellite observations or large-grid model outputs.</p><p>Two drones were operated in synergy to measure the albedo and map the surface topography of the sea ice during the leg 5 of the MOSAiC expedition (August-September 2020), when concurrent albedo and surface roughness measurements were collected using surface-based instruments. The drone SPECTRA was equipped with paired Kipp and Zonen CM4 pyranometers measuring broadband albedo and paired Ocean Optics STS VIS (350 – 800 nm) and NIR (650-1100 nm) micro-radiometers measuring visible and near-infrared spectral albedo, and the drone Mavic 2 Pro was equipped with camera to perform photography mapping of the area measured by the SPECTRA drone.</p><p>Here we illustrate the collected data, which show a drastic change in sea ice albedo during the observing period, from the initial melting state to the freezing and snow accumulation state, and demonstrate how this change is related to the evolution of the different surface features, melt ponds and leads above all. From the data analysis we can conclude that the 30m albedo is not significantly affected by the individual surface features and, therefore, it is potentially representative of the sea ice albedo in satellite footprint and model grid areas.</p><p>The Digital Elevation Models (DEMs) of the sea ice surface obtained from UAV photogrammetry are combined with the DEMs based on Structure From Motion technique that apply photos manually taken close to the surface. This will enable us to derive the surface roughness from sub-millimeter to meter scales, which is critical to interpret the observed albedo and to develop correction methods to eliminate the artefacts caused by shadows.</p><p>The UAV-based albedo and surface roughness are highly complementary also to analogous helicopter-based observations, and will be relevant for the interpretation of all the physical and biochemical processes observed at and near the sea ice surface during the transition from melting to freezing and growing.</p>


Author(s):  
Pijush Samui ◽  
H. Yildirim Dalkilic

This chapter examines the capability of Gaussian Process Regression (GPR) and Relevance Vector Machine (RVM) for prediction of surface and hole quality in drilling of AISI D2 cold work tool steel. This chapter uses GPR and RVM as regression techniques. The database contains information about cutting tool, feed rate, cutting speed, surface roughness, and roundness error. Cutting tool, feed rate, and cutting speed are considered inputs of GPR and RVM. The outputs of GPR and RVM are surface roughness and roundness error. In RVM, radial basis function is adopted as kernel function. GPR uses radial basis function as covariance function. The obtained variance can be used to determine uncertainty. A sensitivity analysis is also carried out. This chapter gives robust models based on RVM and GPR for prediction of surface and hole quality in drilling of AISI D2 cold work tool steel.


2016 ◽  
Vol 686 ◽  
pp. 57-62 ◽  
Author(s):  
Branislav Sredanovic ◽  
Gordana Globocki Lakic ◽  
Davorin Kramar ◽  
Janez Kopac

The development of industry in the last ten years has caused the production of parts with relatively small dimensions. This has led to intensive development of efficient micro-technologies through research of processes, machines and tools. This paper presents the research of machinability, channels micro-milling in AISI D2 tool steel (X155CrVMo-5), hardened to 62 HRc. As the tool is used micro-milling cutter with diameter of 0.6 mm and relatively large working length of 5 mm. Analysis of surface roughness, burr on workpiece edges and reduction of cutter diameter due tool wear was performed.


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