scholarly journals Modeling of hole geometrical features in laser drilling of AISI316L sheet

Author(s):  
Satish Namdev ◽  
◽  
Anand Pandey ◽  
Arun Kumar Pandey ◽  
◽  
...  

Micro-drilling of AISI316L is very challenging task. Unconventional machining process may be used for such type of operation. Laser beam drilling is a best for micro drilling. High thermal energy and converging-diverging property of laser beam affects the quality of laser drilled holes. In present work Nd:YAG laser beam has been used and investigate effects of laser input parameters on responses. To minimize number of experiments, get extreme information for experimental trials. Central composite rotatable design approach has been adopted. Analysis of variance is used to find reliable input parameters, are affecting responses. From this paper, it is found that current and gas pressure are significant for hole circularity at top. Current and pulse frequency are significant for bottom side circularity. Current and cutting speed are significant parameter for hole taper.

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 289 ◽  
Author(s):  
Antonio Rubio-Mateos ◽  
Asuncion Rivero ◽  
Eneko Ukar ◽  
Aitzol Lamikiz

In finishing processes, the quality of aluminum parts is mostly influenced by static and dynamic phenomena. Different solutions have been studied toward a stable milling process attainment. However, the improvements obtained with the tuning of process parameters are limited by the system stiffness and external dampers devices interfere with the machining process. To deal with this challenge, this work analyzes the suitability of elastomer layers as passive damping elements directly located under the part to be machined. Thus, exploiting the sealing properties of nitrile butadiene rubber (NBR), a suitable flexible vacuum fixture is developed, enabling a proper implementation in the manufacturing process. Two different compounds are characterized under axial compression and under finishing operations. The compression tests present the effect of the feed rate and the strain accumulative effect in the fixture compressive behavior. Despite the higher strain variability of the softer rubber, different milling process parameters, such as the tool feed rate, can lead to a similar compressive behavior of the fixture regardless the elastomer hardness. On the other hand, the characterization of these flexible fixtures is completed over AA2024 floor milling of rigid parts and compared with the use of a rigid part clamping. These results show that, as the cutting speed and the feed rate increases, due to the strain evolution of the rubber, the part quality obtained tend to equalize between the flexible and the rigid clamping of the workpiece. Due to the versatility of the NBR for clamping different part geometries without new fixture redesigns, this leads to a competitive advantage of these flexible solutions against the classic rigid vacuum fixtures. Finally, a model to predict the grooving forces with a bull-nose end mill regardless of the stiffness of the part support is proposed and validated for the working range.


Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 590
Author(s):  
Katerina Mouralova ◽  
Libor Benes ◽  
Josef Bednar ◽  
Radim Zahradnicek ◽  
Tomas Prokes ◽  
...  

Wire electrical discharge machining (WEDM) is an unconventional and very efficient technology for precision machining of the Nimonic C 263 super alloy, which is very widespread, especially in the energy, aerospace and automotive industries. Due to electrical discharge, defects in the form of cracks or burned cavities often occur on the machined surfaces, which negatively affect the correct functionality and service life of the manufactured components. To increase the efficiency of the machining of Nimonic C 263 using WEDM, in this study, extensive design of experiments was carried out, monitoring input factors in the form of machine parameters like Pulse off time, Gap voltage, Discharge current, Pulse on time and Wire feed, the output of which was comprehensive information about the behaviour of such machined surfaces, which allowed the optimization of the entire machining process. Thus, the optimization of the Cutting speed was performed in relation to the quality of the machined surface and the machining accuracy, as well as an analysis of the chemical composition of the machined surfaces and a detailed analysis of the lamella using a transmission electron microscope. A detailed study of the occurrence of surface or subsurface defects was also included. It was found that with the help of complex optimization tools, it is possible to significantly increase the efficiency of the machining of the Nimonic C 263 super alloy and achieve both financial savings in the form of shortened machine time and increasing the quality of machined surfaces.


2006 ◽  
Vol 505-507 ◽  
pp. 847-852 ◽  
Author(s):  
Xu Yue Wang ◽  
Wen Ji Xu ◽  
Ren Ke Kang ◽  
Yi De Liang

An experimental analysis is presented which investigates the relationship between cutting parameters and the volume of material removal as well as its cutting quality on a Nd:YAG laser cutting system. The parameters that varied on two testing thickness during cutting include cutting speed, incident laser power and focal position in a continuous through cut. Various trends of the kerf geometrical features in terms of the varying process parameters are analyzed and shown to be reasonable. Discussions are also given on kerf geometry control in situations with cutting parameters. It shows that the effects of varying parameters such as cutting speed, laser power and focal position on cutting kerf width, surface roughness, and striation that have provided a deeper understanding of the laser machining.


2013 ◽  
Vol 10 (1) ◽  
pp. 12-17
Author(s):  
Karol Vasilko

Abstract Tendencies towards increasing cutting speeds during machining can be observed recently. The first wave of increasing cutting speeds occured in the 60s of the previous century. However, suitable tool material was not available at that time. Increasing cutting speed is possible only following the development of cutting material, resistant against high temperatures, abrasive, adhesive and diffusive wear. It is obvious that the process of chip creation, quality of machined surface, dynamics of machining process and temperature of cutting change considerably with cutting speed. To be able to apply higher cutting speeds in production machining, it is necessary to know the dependence of those characteristics on cutting speed. Some of those phenomena, which are linked with cutting speed, will be explained in the paper. Key words: machining, cutting speed, tool durability, surface quality


2017 ◽  
Vol 756 ◽  
pp. 71-79
Author(s):  
Martin Lachman ◽  
Jiří Šafka

Laser technologies are considered to be unconventional technologies. Laser cutting is one of the most popular industrial operations that use a laser beam. Fibre lasers are most commonly used for cutting metallic materials. The aim of this paper is to experimentally demonstrate a procedure for determining the focal length of a laser beam from the output of the cutting head of a JK400FL fibre laser. Along with other factors, the correct position of the focal point of a laser beam cutting materials, plays a vital role in the quality of the cut and also in determining the cutting speed. It is possible to use a higher cutting speed of the laser machine, without compromising the quality of the cut.


2019 ◽  
Vol 44 (1) ◽  
pp. 21-27
Author(s):  
Dobre Runchev ◽  
Filip Zdraveski ◽  
Irena Ivanova

The main objective of the research covered in this paper is to present results for the quality of surfaces thermally cut with a laser beam. The variety of steel materials used as samples on which laser cutting is performed are the following Č.0146 (1.0330), Č.0147 (1.0333), Č.2131 (1.5024), SS Ferbec CR, HARDOX 450 and HARDOX 550. Thermal cutting is carried out with a CNC controlled Fiber laser BAYKAL type BLS–F–1530. The quality of the cut surface is analyzed based on varying the power of the laser beam, changing cutting speed and the type of additional gas (oxygen, air and nitrogen). By visual inspection, measuring the roughness of the cut surface and measuring the width of the intersection, it is determined the influence of the factors like type of the base material, type of gases, the power of thelaser beam and the cutting speed, in accordance with the standards DIN EN ISO 9013-2002 and the JUS C.T3.022.


2011 ◽  
Vol 692 ◽  
pp. 83-92
Author(s):  
Pedro Jose Arrazola ◽  
A. Villar ◽  
R. Fernández ◽  
J. Aperribay

This article describes a practical machining training aiming that the students acquire the theoretical-practical knowledge of chip formation process. The training takes place after theoretical lessons of machining processes. Thus, this practice allows strengthening the knowledge gained during the lessons. The practical training lasts for five hours, and the student assisted by the teacher analyses the influence of some machining entry parameters (cutting speed, feed rate...) on exit parameters like: (I) cutting forces and power consumption, (II) surface roughness, and (III) chip typology. The practical session is carried out on an experimental set-up (Lathe CNC Danobar 65) equipped with sensors and devices to measure forces (sensor Kistler 9121) and power consumption. In addition, a portable rugosimeter (Hommelwerke) is employed to perform surface roughness measurements. No especial devices are needed for the chip typology analysis. In the case of cutting forces and power consumption, the following input parameters influences are analysed: feed rate, depth of cut and cutting speed. In the case of surface roughness analysis, the following input parameters influences are analysed: feed rate and nose radius of the cutting insert. Finally, regarding chip typology feed rate and depth of cut are examined. The experimental results are compared with model predictions (theoretical calculations) for the three issues studied. The students have to compare both results: theoretical an empirical and they need to explain the reasons when discrepancies appear. Results obtained during the last years demonstrate the student acquires better knowledge of the machining process, and at the same time realises of the process complexity.


2014 ◽  
Vol 808 ◽  
pp. 19-33 ◽  
Author(s):  
Sanjeev Kumar ◽  
Rupinder Singh ◽  
Ajay Batish ◽  
T.P. Singh

The present experimental study has been focused to evaluate surface characteristics of cryogenically-treated (shallow/deep) tool-electrodes using powder mixed electric discharge machining. Due to the continuously growing demand of complex and precise parts, tool-electrodes have its own importance, because quality of the machined parts depends upon the surface quality of electrode. On the analogy, eighteen experiments were performed based on L18orthogonal array of Taguchi’s methodology, which consist eight input parameters. Analysis of variance (ANOVA) was employed to designate the level of significance of input parameters. Electrode material has maximum influence followed by the current and pulse on-time on electrode finish. The combination of optimum factor’s level of identified parameters was determined using Taguchi’s technique for single response. Confirmation experiments were conducted using suggested optimal parameters with its respective level to minimize the tool-electrode surface roughness. Surface characteristics of tool-electrodes were analyzed using Scanning Electron Microscope (SEM) and Energy Dispersive Spectrograph (EDS) followed by X-ray diffraction (XRD) on selected samples. The results exposed that significant material transfer from workpiece and powder mixed dielectric fluid in compound form on the tool surface.


2015 ◽  
Vol 6 (1) ◽  
pp. 47-60 ◽  
Author(s):  
Mohammad Zadshakoyan ◽  
Vahid Pourmostaghimi

Tool wear prediction plays an important role in industry automation for higher productivity and acceptable product quality. Therefore, in order to increase the productivity of turning process, various researches have been made recently for tool wear estimation and classification in turning process. Chip form is one of the most important factors commonly considered in evaluating the performance of machining process. On account of the effect of the progressive tool wear on the shape and geometrical features of produced chip, it is possible to predict some measurable machining outputs such as crater wear. According to experimentally performed researches, cutting speed and cutting time are two extremely effective parameters which contribute to the development of the crater wear on the tool rake face. As a result, these parameters will change the chip radius and geometry. This paper presents the development of the genetic equation for the tool wear using occurred changes in chip radius in turning process. The development of the equation combines different methods and technologies like evolutionary methods, manufacturing technology, measuring and control technology with the adequate hardware and software support. The results obtained from genetic equation and experiments showed that obtained genetic equations are correlated well with the experimental data. Furthermore, it can be used for tool wear estimation during cutting process and because of its parametric form, genetic equation enables us to analyze the effect of input parameters on the crater wear parameters.


Optimization is required everywhere particularly in the industrial sector. As a part of that machining emphasized in this paper to optimize the parameters involved in the turning and drilling operation on CNC machines using the Aluminum and Stainless steel alloys. The task is initiated with design of experiments and hence the cost of operation is also reduced. During the experimental process the input parameters involved for turning were considered as cutting speed, feed and depth of cut. And for the drilling operation the input process parameters considered were speed of drill, feed. The output parameters emphasized were surface roughness and dimensional accuracy. By the investigation using the experiments, it in turn leads to an optimized environment for the operation that was carried out. Taguchi technique is a widely used and efficient technique for correlating the process parameters for an efficient and effective operation. Then the process L9 and L16 orthogonal arrays were chosen and signal to noise ratios were computed. At the end the input parameters speed, feed, depth of cut, depth of drill and outcome parameters surface roughness, material removal rate and time of operation were optimized.


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