The Nature of Chip Formation in Orthogonal Machining

1984 ◽  
Vol 106 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Daeyong Lee

Orthogonal machining experiments were conducted at the cutting speed of 8.5 × 10−2 cm/s with 6061-T6 aluminum, 4340 steel and Ti-6Al-4V titanium to measure strain distributions in the deformed chip using a grid analysis technique. While the aluminum alloy with low strength and the steel with high strain hardening coefficient displayed large uniform strains with a continuous chip morphology, the titanium alloy exhibited highly nonuniform strain distributions within segmented chips. Some of these observations as well as published machining test results could be rationalized on the basis of a shear failure criterion where a specific level of critical shear strain might be estimated on the basis of a thermal-mechanical instability analysis.

2011 ◽  
Vol 188 ◽  
pp. 220-223 ◽  
Author(s):  
H. Guo ◽  
Dong Wang ◽  
Li Zhou

Chip morphology and segmentation play a predominant role in determining the machinability and tool wear during the machining of SiC particulates reinforced Al matrix composites. In this paper, a 2D coupled thermo-mechanical finite element model was used for simulating the segmented chip formation at different cutting conditions. The generation of segmentation is achieved by element erase and the shear failure, as well as the continuous adaptive remeshing technical. The results show that the chip is often discontinuous at lower cutting speeds, and with the increasing of the cutting speed, the chip becomes serrated. Fundamental observations from the simulations are concluded and a guideline for further research is proposed.


1985 ◽  
Vol 107 (1) ◽  
pp. 55-63 ◽  
Author(s):  
D. Lee

Orthogonal machining experiments were conducted at different cutting speeds ranging from 8.5 × 10−2 cm/s (0.17 ft/min) to about 2.5 × 102 cm/s (492.1 ft/min) with 6061-T6 aluminum, 4340 steel, and Ti-6A1-4V titanium to examine the chip formation process. The most pronounced effect of the cutting speed on chip morphology was observed with the titanium alloy; the chips remained segmented at all speeds, but became continuous macroscopically at high cutting speeds. The steel chip also became continuous and oxidized, showing the effect of localized heating. The changing chip morphology that is accompanied with decreasing normal force at the high cutting speed is rationalized on the basis of localized adiabatic heating, which is dependent on the thermal-mechanical properties of each material.


Author(s):  
J. Temple Black

Tool materials used in ultramicrotomy are glass, developed by Latta and Hartmann (1) and diamond, introduced by Fernandez-Moran (2). While diamonds produce more good sections per knife edge than glass, they are expensive; require careful mounting and handling; and are time consuming to clean before and after usage, purchase from vendors (3-6 months waiting time), and regrind. Glass offers an easily accessible, inexpensive material ($0.04 per knife) with very high compressive strength (3) that can be employed in microtomy of metals (4) as well as biological materials. When the orthogonal machining process is being studied, glass offers additional advantages. Sections of metal or plastic can be dried down on the rake face, coated with Au-Pd, and examined directly in the SEM with no additional handling (5). Figure 1 shows aluminum chips microtomed with a 75° glass knife at a cutting speed of 1 mm/sec with a depth of cut of 1000 Å lying on the rake face of the knife.


Author(s):  
A. Pandey ◽  
R. Kumar ◽  
A. K. Sahoo ◽  
A. Paul ◽  
A. Panda

The current research presents an overall performance-based analysis of Trihexyltetradecylphosphonium Chloride [[CH3(CH2)5]P(Cl)(CH2)13CH3] ionic fluid mixed with organic coconut oil (OCO) during turning of hardened D2 steel. The application of cutting fluid on the cutting interface was performed through Minimum Quantity Lubrication (MQL) approach keeping an eye on the detrimental consequences of conventional flood cooling. PVD coated (TiN/TiCN/TiN) cermet tool was employed in the current experimental work. Taguchi’s L9 orthogonal array and TOPSIS are executed to analysis the influences, significance and optimum parameter settings for predefined process parameters. The prime objective of the current work is to analyze the influence of OCO based Trihexyltetradecylphosphonium Chloride ionic fluid on flank wear, surface roughness, material removal rate, and chip morphology. Better quality of finish (Ra = 0.2 to 1.82 µm) was found with 1% weight fraction but it is not sufficient to control the wear growth. Abrasion, chipping, groove wear, and catastrophic tool tip breakage are recognized as foremost tool failure mechanisms. The significance of responses have been studied with the help of probability plots, main effect plots, contour plots, and surface plots and the correlation between the input and output parameters have been analyzed using regression model. Feed rate and depth of cut are equally influenced (48.98%) the surface finish while cutting speed attributed the strongest influence (90.1%). The material removal rate is strongly prejudiced by cutting speed (69.39 %) followed by feed rate (28.94%) whereas chip reduction coefficient is strongly influenced through the depth of cut (63.4%) succeeded by feed (28.8%). TOPSIS significantly optimized the responses with 67.1 % gain in closeness coefficient.


2020 ◽  
Vol 2 (1) ◽  
pp. 5-8
Author(s):  
Arnas A.M Patonangi ◽  
Cahyono Cahyono ◽  
Muhlis Ruslan

Penelitian ini bertujuan untuk mengetahui apakah motivasi, kedisiplinan berpengaruh terhadap perilaku kerja, apakah motivasi dan kedisiplinan berpengaruh terhadap prestasi kerja, apakah perilaku kerja berpengaruh terhadap prestasi kerja, apakah motivasi berpengaruh terhadap prestasi kerja pegawai melalui perilaku kerja, serta apakah kedisiplinan berpengaruh terhadap prestasi kerja pegawai melalui perilaku kerja pada DKIPS Provinsi Sulawesi Barat. Teknik pengumpulan data melalui observasi, interview dan dokumentasi serta kuesioner. Sedangkan teknik analisis data yang digunakan adalah analisis statistic deskriptif, statistik infe-rensial, PLS (Partial Least Square), pengujian hipotesis. Hasil penelitian menemukan bahwa motivasi kerja berpengaruh positif dan signifikan terhadap perilaku kerja, Kedisiplinan berpengaruh positif dan signifikan terhadap perilaku kerja, Motivasi kerja berpengaruh positif dan signifikan terhadap prestasi kerja, Kedisiplinan berpengaruh positif dan signifikan terhadap prestasi kerja pegawai, Perilaku kerja berpengaruh positif dan signifikan terhadap prestasi kerja pegawai, hasil uji mediasi menunjukkan bahwa perilaku kerja dapat memediasi motivasi kerja terhadap prestasi kerja pegawai pada DKIPS Provinsi Sulawesi Barat, serta hasil uji mediasi menunjukkan bahwa perilaku kerja dapat memediasi disiplin kerja terhadap prestasi kerja pegawai pada DKIPS Provinsi Sulawesi Barat. This study aims to determine whether motivation, discipline affect work behavior, do motivation and discipline affect work performance, does work behavior affect work performance, does motivation affect employee performance through work behavior, and does discipline affect work performance through work behavior in West Sulawesi Province DKIPS. Data collection techniques through observation, interviews and documentation and questionnaires. While the data analysis technique used is descriptive statistical analysis, inferential statistics, PLS (Partial Least Square), hypothesis testing. The results found that work motivation has a positive and significant effect on work behavior, the discipline has a positive and significant effect on work behavior, work motivation has a positive and significant effect on work performance, the discipline has a positive and significant effect on employee work performance, work behavior has a positive and significant effect on employee work performance, mediation test results indicate that work behavior can mediate work motivation on employee work performance in DKIPS Province of West Sulawesi, and mediation test results indicate that work behavior can mediate work discipline towards employee work performance at DKIPS Province of West Sulawesi.


2021 ◽  
Vol 5 (2) ◽  
pp. 51
Author(s):  
Zongze Li ◽  
Hiroki Ogata ◽  
Ryuta Sato ◽  
Keiichi Shirase ◽  
Shigehiko Sakamoto

A cubic-machining test has been proposed to evaluate the geometric errors of rotary axes in five-axis machine tools using a 3 × 3 zone area in the same plane with different tool postures. However, as only the height deviation among the machining zones is detected by evaluating the test results, the machining test results are expected to be affected by some error parameters of tool sides, such as tool length and profile errors, and there is no research investigation on how the tool side error influences the cubic-machining test accuracy. In this study, machining inaccuracies caused by tool length and tool profile errors were investigated. The machining error caused by tool length error was formulated, and an intentional tool length error was introduced in the simulations and actual machining tests. As a result, the formulated and simulated influence of tool length error agreed with the actual machining results. Moreover, it was confirmed that the difference between the simulation result and the actual machining result can be explained by the influence of the tool profile error. This indicates that the accuracy of the cubic-machining test is directly affected by tool side errors.


Buana Bastra ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 26-31
Author(s):  
Prily Yulia Utomo Putri ◽  
Tri Indrayanti

This research is a research follow class by using the secound cycle that there is the first cycle and cycle II. On the cycle I and cycle II each cycle there four stage of the (1) planning, (2) implementation of action, (3) observations, and (4) reflection. Each cycle has two meetings in one week, namely the first meeting and the second meeting with the allocation 2 x 40 minutes of each meeting. Subject in research is learners class VIII G SMPN 24 Surabaya totaling 37 learners contained 16 learners men and 21 learners woman. This school is located in Jl. Kebraon Indah Permai Blok K/23 A Surabaya. Data collection techniques to use the observation and test, data analysis technique using the percentage of. Based on the results of data analysis, it can be concluded that using pictorial writing media on the meme on Instagram can improve the writing skills of class students VIII G SMPN 24 Surabaya. This can be seen from (1) population activity in the cycle I 84,61% on the cycle II 100%, (2) activity learners in cycle I 83,44% on the cycle II 90,20%, (3) the test results writing skills poerty in cycle I 56,73% one the cycle of II increased 83,70%.


Author(s):  
Nejah Tounsi ◽  
Tahany El-Wardany

Abstract Part I of these two-part papers will investigate the effect of three FEM representations of the milling process on the prediction of chip morphology and residual stresses (RS), when down-milling small uncut chips with thickness in the micrometer range and finite cutting edge radius. They are: i) orthogonal cutting with the mean uncut chip thickness t, obtained by averaging the uncut chip thickness over the cutting length, ii) orthogonal cutting with variable t, which characterizes the down-milling process and which is imposed on a flat surface of the final workpiece, and iii) modelling the true kinematics of the down milling process. The appropriate constitutive model is identified through 2D FEM investigation of the effects of selected constitutive equations and failure models on the prediction of RS and chip morphology in the dry orthogonal machining of Ti6Al4V and comparison to experimental measurements. The chip morphology and RS prediction capability of these representations is assessed using the available set of experimental data. Models featuring variable chip thickness have revealed the transition from continuous chip formation to the rubbing mode and have improved the predictions of residual stresses. The use of sequential cuts is necessary to converge toward experimental data.


2017 ◽  
Vol 902 ◽  
pp. 33-40
Author(s):  
Cong Thuat Dang ◽  
Ngoc Hieu Dinh

Old reinforced concrete buildings constructed around 1980’s in many developing countries have been designed against mainly gravity load. Beam-column joints in these buildings contain slightly or no shear reinforcement inside the panel zones due to the construction convenience, and are vulnerable to shear failure in beam-column joints under the action of earthquake loads, especially for the exterior beam-column joints. This experimental study aimed to investigate the seismic performance of five half-scale exterior beam-column joints simulating the joints in existing reinforced-concrete buildings with non-shear hoop details. The test results showed that the structural performances of the beam-column joints under earthquake including failure mode, load-drift ratio relationship, shear strain of the joints and energy dissipation are strongly affected by the amount of longitudinal reinforcing bars of beams.


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