scholarly journals Analysis of machining-induced residual stresses of milled aluminum workpieces, their repeatability, and their resulting distortion

2021 ◽  
Author(s):  
Daniel Weber ◽  
Benjamin Kirsch ◽  
Christopher R. Chighizola ◽  
Christopher R. D’Elia ◽  
Barbara S. Linke ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Cutting Speed ◽  
Past Research ◽  
Hole Drilling ◽  
Statistical Confidence ◽  
Measured Stress ◽  
Main Driver ◽  
Milled Surface ◽  
Force Signal ◽  
Repeatability Standard Deviation

AbstractMachining-induced residual stresses (MIRS) are a main driver for distortion of thin-walled monolithic aluminum workpieces. Before one can develop compensation techniques to minimize distortion, the effect of machining on the MIRS has to be fully understood. This means that not only an investigation of the effect of different process parameters on the MIRS is important. In addition, the repeatability of the MIRS resulting from the same machining condition has to be considered. In past research, statistical confidence of MIRS of machined samples was not focused on. In this paper, the repeatability of the MIRS for different machining modes, consisting of a variation in feed per tooth and cutting speed, is investigated. Multiple hole-drilling measurements within one sample and on different samples, machined with the same parameter set, were part of the investigations. Besides, the effect of two different clamping strategies on the MIRS was investigated. The results show that an overall repeatability for MIRS is given for stable machining (between 16 and 34% repeatability standard deviation of maximum normal MIRS), whereas instable machining, detected by vibrations in the force signal, has worse repeatability (54%) independent of the used clamping strategy. Further experiments, where a 1-mm-thick wafer was removed at the milled surface, show the connection between MIRS and their distortion. A numerical stress analysis reveals that the measured stress data is consistent with machining-induced distortion across and within different machining modes. It was found that more and/or deeper MIRS cause more distortion.

Analysis of Surface Integrity for DIN 100Cr6 Steel Conical Bearing Rings after Hard Turning

2011 ◽  
Vol 223 ◽  
pp. 473-482 ◽  
Author(s):  
Sergio Delijaicov ◽  
Carlos Eddy Valdez Salazar ◽  
Éd Claudio Bordinassi ◽  
Linilsson Rodrigues Padovese
Keyword(s):  
Tool Wear ◽  
Residual Stresses ◽  
Hard Turning ◽  
White Layer ◽  
Cutting Speed ◽  
Hole Drilling ◽  
Machining Parameters ◽  
Hole Drilling Method ◽  
Conical Bearing ◽  
Bearing Rings

This work studies the influence of machining parameters, such as cutting speed and forces, feed rate, cutting depth, and tool flank wear, on the generation of surface residual stresses in DIN 100Cr6 steel conical bearing rings submitted to a hard turning process. A complete factorial planning was used to perform the tests and projected measurement. Cutting forces were measured by a piezoelectric dynamometer and residual stresses were determined by the hole-drilling method using strain gage. Results showed that after 2000 m of tool machining, phase transformations had been observed on sample surfaces, with white layer formation, and deeper, a dark layer whose thickness varied depending on the severity level of turning and the tool wear (in machined distance). Increase in tool wear generated minor values of compressive residual stresses and the surface roughness presented almost the same values in all experiments, except when the bigger parameters were used.

scholarly journals Intermethod Comparison and Evaluation of Measured Near Surface Residual Stress in Milled Aluminum

2021 ◽  
Author(s):  
C. R. Chighizola ◽  
C. R. D’Elia ◽  
D. Weber ◽  
B. Kirsch ◽  
J. C. Aurich ◽  
...  
Keyword(s):  
Residual Stress ◽  
Material Removal ◽  
Flat Surface ◽  
Cutting Speed ◽  
Hole Drilling ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
Near Surface ◽  
X Ray ◽  
Milled Surface

Abstract Background While near surface residual stress (NSRS) from milling is a driver for distortion in aluminum parts there are few studies that directly compare available techniques for NSRS measurement. Objective We report application and assessment of four different techniques for evaluating residual stress versus depth in milled aluminum parts. Methods The four techniques are: hole-drilling, slotting, cos(α) x-ray diffraction (XRD), and sin2(ψ) XRD, all including incremental material removal to produce a stress versus depth profile. The milled aluminum parts are cut from stress-relieved plate, AA7050-T7451, with a range of table and tool speeds used to mill a large flat surface in several samples. NSRS measurements are made at specified locations on each sample. Results Resulting data show that NSRS from three techniques are in general agreement: hole-drilling, slotting, and sin2(ψ) XRD. At shallow depths (< 0.03 mm), sin2(ψ) XRD data have the best repeatability (< 15 MPa), but at larger depths (> 0.04 mm) hole-drilling and slotting have the best repeatability (< 10 MPa). NSRS data from cos(α) XRD differ from data provided by other techniques and the data are less repeatable. NSRS data for different milling parameters show that the depth of NSRS increases with feed per tooth and is unaffected by cutting speed. Conclusion Hole-drilling, slotting, and sin2(ψ) XRD provided comparable results when assessing milling-induced near surface residual stress in aluminum. Combining a simple distortion test, comprising removal of a 1 mm thick wafer at the milled surface, with a companion stress analysis showed that NSRS data from hole-drilling are most consistent with milling-induced distortion.

Experimental and Numerical Investigation into Residual Stress During Turning Operation for Stainless Steel AISI 316

2020 ◽  
Vol 38 (12A) ◽  
pp. 1862-1870
Author(s):  
Safa M. Lafta ◽  
Maan A. Tawfiq
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Orthogonal Cutting ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Percentage Error ◽  
Depth Of Cut ◽  
Main Role ◽  
Turning Operation ◽  
Aisi 316

RS (residual stresses) represent the main role in the performance of structures and machined parts. The main objective of this paper is to investigate the effect of feed rate with constant cutting speed and depth of cut on residual stresses in orthogonal cutting, using Tungsten carbide cutting tools when machining AISI 316 in turning operation. AISI 316 stainless steel was selected in experiments since it is used in many important industries such as chemical, petrochemical industries, power generation, electrical engineering, food and beverage industry. Four feed rates were selected (0.228, 0.16, 0.08 and 0.065) mm/rev when cutting speed is constant 71 mm/min and depth of cutting 2 mm. The experimental results of residual stresses were (-15.75, 12.84, 64.9, 37.74) MPa and the numerical results of residual stresses were (-15, 12, 59, and 37) MPa. The best value of residual stresses is (-15.75 and -15) MPa when it is in a compressive way. The results showed that the percentage error between numerical by using (ABAQUS/ CAE ver. 2017) and experimental work measured by X-ray diffraction is range (2-15) %.

scholarly journals Analyzing the Effects of the Kinematic System on the Quality of Holes Drilled in 42CrMo4 + QT Steel

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4046
Author(s):  
Mateusz Bronis ◽  
Edward Miko ◽  
Lukasz Nowakowski
Keyword(s):  
Cutting Speed ◽  
Hole Drilling ◽  
Internal Cooling ◽  
Hole Quality ◽  
The Third ◽  
Kinematic System ◽  
Turning Center ◽  
Dimensional Errors ◽  
The Relationship

This article discusses the relationship between the kinematic system used in drilling and the quality of through-holes. The drilling was done on a CTX Alpha 500 universal turning center using a TiAlN-coated 6.0 mm drill bit with internal cooling, mounted in a driven tool holder. The holes were cut in cylindrical 42CrMo4 + QT steel samples measuring 30 mm in diameter and 30 mm in length. Three types of hole-drilling kinematic systems were considered. The first consisted of a fixed workpiece and a tool performing rotary (primary) and linear motions. In the second system, the workpiece rotated (primary motion) while the tool moved linearly. In the third system, the workpiece and the tool rotated in opposite directions; the tool also moved linearly. The analysis was carried out for four output parameters characterizing the hole quality (i.e., cylindricity, straightness, roundness, and diameter errors). The experiment was designed using the Taguchi approach (orthogonal array). ANOVA multi-factor statistical analysis was used to determine the influence of the input parameters (cutting speed, feed per revolution and type of kinematic system) on the geometrical and dimensional errors of the hole. From the analysis, it is evident that the kinematic system had a significant effect on the hole roundness error.

Effects of Cutting Parameters on Residual Stresses in High-Speed Milling of Ti-17

2013 ◽  
Vol 834-836 ◽  
pp. 861-865 ◽  
Author(s):  
Yong Shou Liang ◽  
Jun Xue Ren ◽  
Yuan Feng Luo ◽  
Ding Hua Zhang
Keyword(s):  
Experimental Study ◽  
Residual Stresses ◽  
High Speed ◽  
Experimental Parameter ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Single Factor ◽  
Cutting Depth ◽  
High Speed Milling ◽  
Parameter Ranges

An experimental study was conducted to determine cutting parameters of high-speed milling of Ti-17 according to their effects on residual stresses. First, three groups of single factor experiments were carried out to reveal the effects of cutting parameters on residual stresses. Then sensitivity models were established to evaluate the influence degrees of cutting parameters on residual stresses. After that, three criteria were proposed to determine cutting parameters from experimental parameter ranges. In the experiments, the cutting parameter ranges are recommended as [371.8, 406.8] m/min, [0.363, 0.412] mm and [0, 0.018] mm/z for cutting speed, cutting depth and feed per tooth, respectively.

Influence of Milling Parameters on Surface Residual Stresses of 7050-T7451 Aluminum Alloy

2012 ◽  
Vol 723 ◽  
pp. 208-213 ◽  
Author(s):  
Yi Wan ◽  
Chen Li ◽  
Zhan Qiang Liu ◽  
Shu Feng Sun
Keyword(s):  
Aluminum Alloy ◽  
Residual Stresses ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Orthogonal Direction ◽  
Mechanical Coupling ◽  
Surface Residual Stresses ◽  
Compressive Residual Stresses

Residual stresses generated in milling process affect the performance of machined components. Milling residual stresses correlate closely with the cutting parameters. In this paper, the generation and distribution of surface residual stresses in milling of aluminum alloy 7050-T7451 was investigated. The cutting speed changes from 300m/min to 3000m/min. In the experiments, the residual stresses on the surface of specimen are detected by X-ray diffraction technique. The result shows that compressive residual stresses are generated when cutting speed is under 500 m/min. In feed and its orthogonal direction, the effect of cutting speed and feed rate on residual stresses is similar. The formation of the residual stresses can be explained by thermo-mechanical coupling effects.

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