Experimental and Numerical Studies on Defect Characteristics During Milling of Aluminum Honeycomb Core

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Qinglong An ◽  
Jiaqiang Dang ◽  
Weiwei Ming ◽  
Kunxian Qiu ◽  
Ming Chen
Keyword(s):  
Cell Walls ◽  
Surface Defects ◽  
Tensile Deformation ◽  
Optimization Method ◽  
Cutting Process ◽  
Machining Process ◽  
Honeycomb Core ◽  
Machined Surface ◽  
Entrance Angle ◽  
Aluminum Honeycomb

The honeycomb sandwich structure has been widely used in the aerospace industry due to its high specific strength and stiffness. However, the machining defects of the aluminum honeycomb core (AHC) have become the key factor that restricts its application. In this paper, the defects' characteristics including the formation mechanism, distribution characteristic, and cutting process of honeycomb cell walls during AHC milling process were experimentally investigated. Furthermore, using normalized Cockcroft and Latham ductile fracture criterion and Johnson–Cook (JC) constitutive model, the numerical simulation of the AHC machining process was conducted concerning the entrance angle. It is indicated that six categories of milling defects are obtained and the quantity as well as distribution regularity of AHC milling defects are determined by the double effects of both the entrance angle and cutting force. Most of the surface defects of honeycomb materials were found concentrated in three regions, named by zones I–III, in which extruding, shear, and tensile deformation was mainly generated, respectively. Besides, the finite element simulation results also agree well with the experimental findings. Finally, a novel optimization method to avoid defects in the aforementioned regions by controlling the entrance angle of all the honeycomb walls during the cutting process was proposed in this paper. Meanwhile, the optimal control equations of the entrance angle for all cell walls were derived. This method was verified by milling experiments at last and the results showed that the optimization effect was obvious since the quality of the machined surface was greatly improved.

scholarly journals Three-Dimensional Synthesis of Manufacturing Tolerances Based on Analysis Using the Ascending Approach

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 203
Author(s):  
Badreddine Ayadi ◽  
Lotfi Ben Said ◽  
Mohamed Boujelbene ◽  
Sid Ali Betrouni
Keyword(s):  
Surface Defects ◽  
Three Dimensional ◽  
Tolerance Analysis ◽  
Machining Process ◽  
Dimensional Synthesis ◽  
Machining Processes ◽  
Machined Surface ◽  
Manufacturing Tolerances ◽  
Machining Fixtures ◽  
Set Up

The present paper develops a new approach for manufacturing tolerances synthesis to allow the distribution of these tolerances over the different phases concerned in machining processes using relationships written in the tolerance analysis phase that have been well developed in our previous works. The novelty of the proposed approach is that the treatment of non-conventional surfaces does not pose a particular problem, since the toleranced surface is discretized. Thus, it is possible to study the feasibility of a single critical requirement as an example. During the present approach, we only look for variables that influence the requirements and the others are noted F (Free). These variables can be perfectly identified on the machine, which can be applied for known and unknown machining fixtures; this can be the base for proposing a normalized ISO specification used in the different machining phases of a mechanical part. The synthesis of machining tolerances takes place in three steps: (1) Analysis of the relationship’s terms, which include the influence of three main defects; the deviation on the machined surface, defects in the machining set-up, and the influence of positioning dispersions; then (2) optimization of machining tolerance through a precise evaluation of these effects; and finally (3) the optimization of the precision of the workpiece fixture, which will give the dimensioning of the machining assembly for the tooling and will allow the machining assembly to be qualified. The approach used proved its efficiency in the end by presenting the optimal machining process drawing that explains the ordered phases needed to process the workpiece object of the case study.

scholarly journals FEASIBILITY STUDY OF ULTRASONIC FREQUENCY APPLICATION ON FDM TO IMPROVE PARTS SURFACE FINISH

2015 ◽  
Vol 77 (32) ◽  
Author(s):  
Maidin, S. ◽  
Muhamad, M.K. ◽  
Pei, E.
Keyword(s):  
Surface Roughness ◽  
Surface Finish ◽  
Surface Defects ◽  
Complex Geometry ◽  
Acrylonitrile Butadiene Styrene ◽  
Optical Microscope ◽  
Machining Process ◽  
Ultrasonic Frequency ◽  
Machined Surface ◽  
Machining Parameter

Fuse Deposition Modeling (FDM) offer several advantages such as less expensive material, lack of expensive lasers and allows complex geometry to be built. However, FDM have limitations such as seam lines appear between layers and excess material residue, leading to surface roughness and poor finish. Ultrasound has been applied in various conventional machining process and shows good machined surface finish. However, from the literature review, it was found there is no investigation made on the application of ultrasound for Additive Manufacturing (AM) especially for FDM. This paper presents an adaptive approach to improve surface finish of FDM sample by applying ultrasonic vibration. The papers discuss the result of the surface finish of test piece printed via a desktop FDM system whereby an ultrasound device that was securely mounted onto the platform during printing process. Frequency that was used in the experiment is 11, 16 and 21 kHz with acrylonitrile butadiene styrene (ABS) material. Optical microscope with the aid of pro VIS software version 2.90 was used to measure the surface roughness of the four samples printed with a vibration in the above specified frequency. It was found that a 21 kHz frequency applied to the FDM process achieved the best surface finish due to less surface defects found and thickness had finer layers being produced. The results from this study could potentially be applied to other AM system such as the selective laser sintering, electron beam machining and stereolithography. The new data on effects of ultrasonic FDM technique and machining parameter for achieving improved surface finish has potential benefit to be used in various industries such as automotive, consumer, medical, sports, etc to produce prototypes or customized end used product or part. The data will benefit in term of product design and development elimination of manual post processing. Further study that could be done is to use different types of material such as polyactic acid (PLA) or composite material.

Cutting stability and optimization of process parameters for the large-pitch screw high-feed turning

2019 ◽  
Vol 233 (19-20) ◽  
pp. 6851-6865
Author(s):  
Xiangfu Fu ◽  
Zhe Li ◽  
Minli Zheng ◽  
Xiurui Wang ◽  
Junwei Li
Keyword(s):  
Process Parameters ◽  
Optimization Method ◽  
Stability Domain ◽  
Spindle Speed ◽  
Machining Process ◽  
Turning Process ◽  
Machined Surface ◽  
Shape Accuracy ◽  
Optimization Of Process Parameters ◽  
High Feed

In this study, the machining characteristics of the large-pitch screw in high-feed turning are initially analyzed, and a dynamic model for the screw subjected to moving forces is proposed to study the chatter, which has been taken into consideration “quasi-regeneration effect” of the machined surface and the actual machining path. Then, a stability model of the lobes between the amount of feed and spindle speed in the turning screw finishing stage is achieved, taking into consideration deformation of the workpiece and the tool, on the basis of the vibration equation of the workpiece and the dynamic equation of the tool, and is experimentally verified as well. The dynamics model, and stability domain provide a basis upon which multiobjective process parameter optimization method including the amount of feed and spindle speed can be put forward during high-feed turning process. Experiments are likewise performed and the results show that no chatter occurs, verifying the optimization of machining process parameters for large-pitch turning. Meanwhile, it should be noted that the surface quality and shape accuracy of the machined surface are equivalent to the high-feed turning process.

The Forming Mechanism of Surface Defects on Machined Surface in High-Speed Cutting of SiCp/Al Composites

2013 ◽  
Vol 579-580 ◽  
pp. 171-176
Author(s):  
Yang Jun Wang ◽  
Ming Qiang Pan ◽  
Tao Chen ◽  
Li Guo Chen
Keyword(s):  
High Speed ◽  
Surface Defects ◽  
Fem Simulation ◽  
Cutting Parameters ◽  
Cutting Process ◽  
Machined Surface ◽  
High Speed Cutting ◽  
Forming Mechanism ◽  
Simulation And Experiment ◽  
Method Model

For investigating the machined surface defects in high-speed cutting of SiCp/Al composites. The simulation and experiment of high-speed cutting process is done. The simulation of high-speed cutting process using the Cowper-Symonds model is established to explore the forming mechanism of the machined surface defects. The results show that the machined surface defects include small pit, big pit, groove and the raised particle. The experiment which uses the same cutting parameters with the simulation of FEM (Finite Element Method) model is carried out to verify the results of FEM simulation. The results indicate that the forming mechanism of machined surface defects prove to be true.

Simulation Studies of the Cutting Process on SiCp/Al Composites with Different Volume Fraction of Reinforced SiC Particles

2014 ◽  
Vol 800-801 ◽  
pp. 321-326 ◽  
Author(s):  
Bei Bei Wang ◽  
Li Jing Xie ◽  
Xi Bin Wang ◽  
Xiao Lei Chen
Keyword(s):  
Surface Defects ◽  
Volume Fraction ◽  
Orthogonal Cutting ◽  
Cutting Tools ◽  
Failure Surface ◽  
Cutting Process ◽  
Machined Surface ◽  
Alloy Matrix ◽  
Sic Particles ◽  
Sic Reinforcement

SiCp/Al composites (aluminum alloys reinforced with SiC particles) are classified as the typical difficult-to-machine materials by serious tool wear, premature tool failure, surface defects, etc. In order to understand the formation mechanism of chip and machined surface, the two-dimensional finite element modeling technology of the cutting process for SiCp/Al composites are investigated by using ABAQUS explicit. The actual microstructure is modeled by a multi-phase modeling approach with a circular SiC reinforcement phase randomly distributed in a 6061aluminum alloy matrix phase. The effect of volume fraction of SiC particles is studied by simulating the orthogonal cutting process of aluminum alloy and three SiCp/Al composites with multiplied increasing volume fraction of SiC reinforcement particles. The cutting forces vs. time due to the interaction between cutting tools and SiC particles in the cutting process and the stress distribution in three deformation zones are analyzed. Finally, surface defects including particles debonding, small pits, raised particles and traces of ploughing are predicted and verified by the experimental surface topography.

scholarly journals Effect of Cutting Parameters and Tool Geometry on the Performance Analysis of One-Shot Drilling Process of AA2024-T3

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 854
Author(s):  
Muhammad Aamir ◽  
Khaled Giasin ◽  
Majid Tolouei-Rad ◽  
Israr Ud Din ◽  
Muhammad Imran Hanif ◽  
...  
Keyword(s):  
Feed Rate ◽  
Surface Defects ◽  
Thrust Force ◽  
Cutting Tools ◽  
Chip Thickness ◽  
Cutting Parameters ◽  
Spindle Speed ◽  
Machining Process ◽  
Tool Geometry ◽  
Drilling Process

Drilling is an important machining process in various manufacturing industries. High-quality holes are possible with the proper selection of tools and cutting parameters. This study investigates the effect of spindle speed, feed rate, and drill diameter on the generated thrust force, the formation of chips, post-machining tool condition, and hole quality. The hole surface defects and the top and bottom edge conditions were also investigated using scan electron microscopy. The drilling tests were carried out on AA2024-T3 alloy under a dry drilling environment using 6 and 10 mm uncoated carbide tools. Analysis of Variance was employed to further evaluate the influence of the input parameters on the analysed outputs. The results show that the thrust force was highly influenced by feed rate and drill size. The high spindle speed resulted in higher surface roughness, while the increase in the feed rate produced more burrs around the edges of the holes. Additionally, the burrs formed at the exit side of holes were larger than those formed at the entry side. The high drill size resulted in greater chip thickness and an increased built-up edge on the cutting tools.

Surface Roughness and Cutting Force Components Evaluation in Hard Turning by Differently Shaped Cutting Tools

2016 ◽  
Vol 862 ◽  
pp. 26-32 ◽  
Author(s):  
Michaela Samardžiová
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Hard Turning ◽  
Cutting Tool ◽  
Single Point ◽  
Machining Process ◽  
Tool Geometry ◽  
Machined Surface ◽  
Cutting Force Components ◽  
Force Components

There is a difference in machining by the cutting tool with defined geometry and undefined geometry. That is one of the reasons of implementation of hard turning into the machining process. In current manufacturing processes is hard turning many times used as a fine finish operation. It has many advantages – machining by single point cutting tool, high productivity, flexibility, ability to produce parts with complex shapes at one clamping. Very important is to solve machined surface quality. There is a possibility to use wiper geometry in hard turning process to achieve 3 – 4 times lower surface roughness values. Cutting parameters influence cutting process as well as cutting tool geometry. It is necessary to take into consideration cutting force components as well. Issue of the use of wiper geometry has been still insufficiently researched.

scholarly journals The Comparative Study on Cutting Performance of Different-Structure Milling Cutters in Machining CFRP

2018 ◽  
Vol 8 (8) ◽  
pp. 1353
Author(s):  
Tao Chen ◽  
Fei Gao ◽  
Suyan Li ◽  
Xianli Liu
Keyword(s):  
Carbon Fiber ◽  
Cutting Force ◽  
Surface Quality ◽  
Cutting Edge ◽  
Cutting Performance ◽  
Machining Process ◽  
Carbon Fiber Composites ◽  
Machined Surface ◽  
Milling Cutter ◽  
Machined Surface Quality

Carbon fiber reinforced plastic (CFRP) is typically hard to process, because it is easy for it to generate processing damage such as burrs, tears, delamination, and so on in the machining process. Consequently, this restricts its wide spread application. This paper conducted a comparative experiment on the cutting performance of the two different-structure milling cutters, with a helical staggered edge and a rhombic edge, in milling carbon fiber composites; analyzed the wear morphologies of the two cutting tools; and thus acquired the effect of the tool structure on the machined surface quality and cutting force. The results indicated that in the whole cutting, the rhombic milling cutter with a segmented cutting edge showed better wear resistance and a more stable machined surface quality. It was not until a large area of coating shedding occurred, along with chip clogging, that the surface quality decreased significantly. At the stage of coating wear, the helical staggered milling cutter with an alternately arranged continuous cutting edge showed better machined surface quality, but when the coating fell off, its machined surface quality began to reveal damage such as groove, tear, and fiber pullout. Meanwhile, burrs occurred at the edge and the cutting force obviously increased. By contrast, for the rhombic milling cutter, both the surface roughness and cutting force increased relatively slowly.

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