scholarly journals Dimensional Accuracy and Surface Quality of AZ91D Magnesium Alloy Components after Precision Milling

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6446
Author(s):  
Jarosław Korpysa ◽  
Józef Kuczmaszewski ◽  
Ireneusz Zagórski

This study investigates a precision milling process conducted with the use of conventional end mills and a standard CNC (Computer Numerical Control) machine tool. Milling tests were performed on samples of AZ91D magnesium alloy using TiB2- and TiAlN-coated three-edge end mills measuring 16 mm in diameter. The following technological parameters were made variable: cutting speed, feed per tooth and axial depth of cut. The effects of precision milling were evaluated by analysing the scatter of dimension values obtained in successive tool passes. In addition to that, deviations from the assumed nominal depth as well as obtained ranges of dimension varation were analysed. The study also examined surface quality obtained in the precision milling process, based on the basic surface roughness parameters: Ra, Rz and RSm. Results have confirmed that the use of conventional cutting tools and a standard CNC machine tool makes it possible to manufacture components characterized by relatively small scatter of dimension values and high accuracy classes. Additionally, the results have shown that the type of tool coating and variations of individual technological parameters exert impact on the dimensional accuracy and surface quality obtained.

Author(s):  
Hongji Zhang ◽  
Yuanyuan Ge ◽  
Hong Tang ◽  
Yaoyao Shi ◽  
Zengsheng Li

Within the scope of high speed milling process parameters, analyzed and discussed the effects of spindle speed, feed rate, milling depth and milling width on milling forces in the process of high speed milling of AM50A magnesium alloy. At the same time, the influence of milling parameters on the surface roughness of AM50A magnesium alloy has been revealed by means of the measurement of surface roughness and surface micro topography. High speed milling experiments of AM50A magnesium alloy were carried out by factorial design. Form the analysis of experimental results, The milling parameters, which have significant influence on milling force in high speed milling of AM50A magnesium alloy, are milling depth, milling width and feed speed, and the nonlinear characteristics of milling force and milling parameters. The milling force decreases with the increase of spindle in the given mill parameters. For the effects of milling parameters on surface quality of the performance, in the milling depth and feeding speed under certain conditions with the spindle speed increases the surface quality of AM50A magnesium alloy becomes better with the feed speed increases the surface quality becomes poor. When the spindle speed is greater than 12000r/min, the milling depth is less than 0.2mm, and the feed speed is less than 400mm/min, the milling surface quality can be obtained easily.


2021 ◽  
Vol 27 (11) ◽  
pp. 1-12
Author(s):  
Giovanni Gómez-Gras ◽  
Marco A. Pérez ◽  
Jorge Fábregas-Moreno ◽  
Guillermo Reyes-Pozo

Purpose This paper aims to investigate the quality of printed surfaces and manufacturing tolerances by comparing the cylindrical cavities machined in parts obtained by fused deposition modeling (FDM) with the holes manufactured during the printing process itself. The comparison focuses on the results of roughness and tolerances, intending to obtain practical references when making assemblies. Design/methodology/approach The experimental approach focuses on the comparison of the results of roughness and tolerances of two manufacturing strategies: geometric volumes with a through-hole and the through-hole machined in volumes that were initially printed without the hole. Throughout the study, both alternates are explained to make appropriate recommendations. Findings The study shows the best combinations of technological parameters, both machining and three-dimensional printing, which have been decisive for obtaining successful results. These conclusive results allow enunciating recommendations for use in the industrial environment. Originality/value This paper fulfills an identified need to study the dimensional accuracy of the geometries obtained by additive manufacturing, as no experimental evidence has been found of studies that directly address the problem of the FDM-printed part with geometric and dimensional tolerances and desirable surface quality for assembly.


2013 ◽  
Vol 315 ◽  
pp. 749-754 ◽  
Author(s):  
M.A. Rahman ◽  
A.B. Baharudin ◽  
S. Adi ◽  
Nur Izan Syahriah Hussein ◽  
H. Isa ◽  
...  

Performance of machining processes is assessed by dimensional and geometrical accuracy which is mentioned in this paper as dimensional deviation. A part quality does not depend solely on the depth of cut, feed rate and cutting speed. Other variable such as excessive machine tool vibration due to insufficient dynamic rigidity can be deleterious to the desired results. The focus of the present study is to find a correlation between dimensional deviation against cutting parameters and machine tool vibration in dry turning. Hence cutting parameters and vibration-based regression model can be established for predicting the part dimensional deviation. Experiments are conducted using a Computerized Numerical Control (CNC) lathe with carbide insert cutting tool. Vibration data are collected through a data acquisition system, then tested and analyzed through statistical analysis. The analysis revealed that machine tool vibration has significant effect on dimensional deviation where statistical analysis of individual regression coefficients showed p<0.05. The developed regression model has been validated through experimental tests and found to be reliable to predict dimensional deviation.


Author(s):  
Eyyup Aras ◽  
Derek Yip-Hoi

Helical milling is a 3-axis machining operation where a cutting tool is feed along a helix. This operation is used in ramp-in and ramp-out moves when the cutting tool first engages the workpiece, for contouring and for hole machining. It is increasingly finding application as a means for roughing large amounts of material during high speed machining. Modeling the helical milling process requires cutter/workpiece engagements (CWEs) geometry in order to predict cutting forces. The calculation of these engagements is challenging due to the complicated and changing intersection geometry that occurs between the cutter and the in-process workpiece. In this paper we present a geometric modeling methodology for finding engagements during helical milling with flat end mills. A mapping technique has been developed that transforms a polyhedral model of the removal volume from Euclidean space to a parametric space defined by location along the tool path, engagement angle and the depth-of-cut. As a result, intersection operations are reduced to first order plane-plane intersections. This approach reduces the complexity of the cutter/workpiece intersections and also eliminates robustness problems found in standard polyhedral modeling and improves accuracy over the Z-buffer technique. The reported method has been implemented and tested using a combination of commercial applications. This paper highlights ongoing collaborative research into developing a Virtual Machining System.


2005 ◽  
Vol 488-489 ◽  
pp. 519-522
Author(s):  
Qiang Wang ◽  
Bao Cheng Li ◽  
Zai-xin Feng

Aimed at characteristics of the profile such as complex shape, high dimensional accuracy and mechanical properties, the reduction zone length and devided flow taper of female die were designed by FEM and extrusion experiments were carried out for as-cast AZ31 magnesium alloy. Technological parameters were determined and microstructure and properties of the extruded profile were examined. The results show that magnesium alloy profile can be extruded if technological parameters such as deformation temperature, tool temperature and ratio of extrusion are controlled strictly. Each of the above mentioned technological parameters has its different influence on microstructure and properties of extruded profile. In comparison with as-cast alloys, microstructure is refined from 120~140μm to about 10μm and tensile strength is enhanced from 171~200MPa to above 260Mpa. This suggests that fine grain and high strength are attained for AZ31 magnesium alloy by extrusion deformation. The extruded profile can meet high properties demands for carrying parts. It provides a possibility for broader usage of magnesium alloy profiles.


Author(s):  
P. Franco ◽  
M. Estrems ◽  
F. Faura

Milling is a widely used manufacturing process with the main purpose of generating high precision mechanical components of shapes and sizes given by the numerical control programmed cutting tool trajectory. These mechanical components frequently needs the application of milling operations in order to satisfy the technical specifications that corresponds to their dimensional, geometrical and surface quality requirements. For that reason, the effects of different factors such as cutting tool dynamics, fixturing system design, workpiece material behaviour and applied cutting forces on the desired dimensional precision must be studied, as well as cutting tool and machine tool performance. In this work, the relation between machine tool inaccuracies and geometrical tolerances is analyzed, and a methodology is proposed for improving flatness in planing operations by the correction of imperfections detected in cutting tool displacement according to machine tool axis. These machine tool error correction methodology could be implemented in the current CAD/CAM/CAPP techniques as a means of increasing the milling process performance by identification and correction of CNC milling machine imperfections. The deviations in machine tool displacement during cutting process are identified by metrological analysis, and a modified trajectory for cutting tool is defined by direct numerical control (DNC) from systematic error compensation in machine tool.


2012 ◽  
Vol 217-219 ◽  
pp. 1880-1884 ◽  
Author(s):  
Chun Jiang Zhou ◽  
Jian Cheng Liu ◽  
Adrian Avila

This paper is to experimentally investigate the mechanical micro machining properties of AL6061-T6 using tungsten-carbide micro end mills. The cutting simulation based on Finite Element Analysis (FEA) method is also conducted to estimate cutting forces, cutting temperature, and minimum chip thicknesses. The simulation results are used for the determination of experimental machining conditions such as depth of cut, feed rates and cutting speeds. A number of slot micro-milling experiments were performed using 400um diameter micro end mills on a 3 Axis CNC machining center attached with a high precision and high speed spindle unit. The machined surface quality, geometric feature shape, cutting burr generation as well as build-up edges are observed in the cutting experiments. Optimum cutting parameters for a better surface quality and smaller burr sizes are suggested.


2008 ◽  
Vol 141-143 ◽  
pp. 623-628 ◽  
Author(s):  
Ju Fu Jiang ◽  
Ying Wang ◽  
Zhi Ming Du ◽  
Shou Jing Luo

In this paper, thixoforging of a magazine plate made of AZ91D magnesium alloy were investigated by means of numerical simulation and experiments. Numerical simulation results show that with increasing punch displacement, local bending, formation of a concave shell part and bulk plastic deformation occurs in billet continuously. Equivalent strain and stress increase and the temperature of the semi-solid billet decreases. When the temperature of the semi-solid billet or the die temperature is elevated, equivalent stain and stress decrease. Optimal technological parameters such as a billet temperature of 545°C, die temperature of 450°C and punch velocity of 15 mm/s were obtained by numerical simulation. Experimental results demonstrate that magazine plates with high mechanical properties such as tensile strength of 316.8 MPa, yield strength of 228.3 MPa and elongation of 12.6 % can be manufactured successfully when the optimal technological parameters selected according to the results of numerical simulation are applied.


2014 ◽  
Vol 1019 ◽  
pp. 318-324
Author(s):  
Jean Claude Fwamba ◽  
Lerato Crescelda Tshabalala ◽  
Cebo Philani Ntuli ◽  
Isaac Tlhabadira

<span><p align="LEFT"><span><span style="font-family: Times New Roman;" face="Times New Roman">Titanium and its alloys have been experiencing extensive development over the past few decades. They have found wide applications in the aerospace, biomedical and automotive industries owing to their good strength-to-weight ratio and high corrosion resistance. Machining performance is often limited by chatter vibrations at the tool-workpiece interface. Chatter is an abnormal tool behaviour which is one of the most critical problems in the machining process and must be avoided to improve the dimensional accuracy and surface quality of the finished product. This research aims at investigating chatter trends in the end milling process and to identify machine parameters that have effects on chatter during machining. The machine parameters investigated include axial feed rate, spindle revolute speed and depth of cut. In this research, experimental data was collected using sensors to analyze the existence of chatter vibrations on each processing condition. This research showed that the combination of the machine parameters, feed rate and spindle speed within certain proportions has an influence on machine vibrations during end milling and if not managed properly, may lead to chatter. </span></span></p> <p align="LEFT"></p>


2005 ◽  
Vol 291-292 ◽  
pp. 513-518 ◽  
Author(s):  
Ming Jun Chen ◽  
Ying Chun Liang ◽  
Ya Zhou Sun ◽  
W.X. Guo ◽  
Wen Jun Zong

In order to machine complex free surface parts, a micro NC (numerical control) three-dimensional machine tool is developed, integrated the PMAC control. Based on this NC machine tool, the influencing of the technological and tool’s parameters on machining accuracy of micro complex surface parts are analyzed, and the cause to lead to the machining errors is explained. Therefore, the cutting parameters and tool geometry parameters to machine micro complex surface, such as the human’s face, can be selected optimally. Finally, the micro complex human’s face is machined on this developed micro machine tool under optimal parameters. The experimental results show that the machined surface is smooth and continuous. The machined quality is satisfied.


Sign in / Sign up

Export Citation Format

Share Document