scholarly journals Effects of Microstructure, Mechanical and Physical Properties on Machinability of Graphite Cast Irons

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 285 ◽  
Author(s):  
Jiangzhuo Ren ◽  
Fengzhang Ren ◽  
Fengjun Li ◽  
Linkai Cui ◽  
Yi Xiong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Surface Roughness ◽  
Standard Deviation ◽  
Cutting Force ◽  
Volume Fraction ◽  
Internal Surface ◽  
Drilling Process ◽  
Turning Process ◽  
Cast Irons ◽  
Mechanical And Physical Properties

Flake (FGI) and spheroidal (SGI) graphite cast irons are often used to produce workpieces, which often need to be machined. Machinability differences under various machining methods are the basis for choosing machining equipment and technology. In this work, FGI and SGI were used to produce tractor front brackets, and the machinability of both materials under turning and drilling processes was compared. The machinability (turning and drilling ability) has been evaluated in terms of machining load, chips shape, surface roughness, and tool temperature. The influence of materials microstructure and thermal conductivity on the machinability was analyzed. In the turning process, the cutting force and its standard deviation of the FGI were larger than the SGI due to the higher volume fraction of pearlite. The surface roughness was similar in both materials. In the drilling process, the even action of the friction and cutting force on the bit turned into similar drilling loads for both materials. Higher friction and lower thermal conductivity caused a higher bit temperature in SGI drilling compared to FGI. The chip breaking was worse in SGI drilling, where the longer chips scratched the internal surface of the holes, resulting in the higher surface roughness.

A Study of Some Mechanical and Physical Properties for Palm Fiber/Polyester Composite

2020 ◽  
Vol 38 (3B) ◽  
pp. 104-114
Author(s):  
Samah M. Hussein
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Date Palm ◽  
Volume Fraction ◽  
Unsaturated Polyester ◽  
Dielectric Strength ◽  
Palm Fiber ◽  
Mechanical And Physical Properties ◽  
Polyester Composite

This research has been done by reinforcing the matrix (unsaturated polyester) resin with natural material (date palm fiber (DPF)). The fibers were exposure to alkali treatment before reinforcement. The samples have been prepared by using hand lay-up technique with fiber volume fraction of (10%, 20% and 30%). After preparation of the mechanical and physical properties have been studied such as, compression, flexural, impact strength, thermal conductivity, Dielectric constant and dielectric strength. The polyester composite reinforced with date palm fiber at volume fraction (10% and 20%) has good mechanical properties rather than pure unsaturated polyester material, while the composite reinforced with 30% Vf present poor mechanical properties. Thermal conductivity results indicated insulator composite behavior. The effect of present fiber polar group induces of decreasing in dielectric strength, and increasing dielectric constant. The reinforcement composite 20% Vf showed the best results in mechanical, thermal and electrical properties.

Advanced Prediction of Surface Roughness by Monitoring of Dynamic Cutting Forces in CNC Turning Process

2012 ◽  
Vol 239-240 ◽  
pp. 661-669 ◽  
Author(s):  
Somkiat Tangjitsitcharoen
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Depth Of Cut ◽  
Turning Process ◽  
Cnc Turning ◽  
Roughness Model ◽  
Developed Surface ◽  
Dynamic Cutting Force ◽  
Force Ratio ◽  
Cnc Turning Process

The aim of this research is to investigate the relation between the surface roughness and the dynamic cutting force ratio during the in-process cutting in CNC turning process. The proposed surface roughness model is developed based on the experimentally obtained results by employing the exponential function with five factors of the cutting speed, the feed rate, the tool nose radius, the depth of cut, and the dynamic cutting force ratio. The dynamic cutting force ratio is proposed to predict the surface roughness during the cutting, which can be calculated and obtained by taking the ratio of the corresponding time records of the area of thedynamic feed force to that of the dynamic main force. The in-process relation between dynamic cutting force ratio and surface roughness can be proved by the frequency of the dynamic cutting force which corresponds to the surface roughnessfrequency. The multiple regression analysis is utilized to calculate the regression coefficients with the use of the least square method at 95% confident level. The proposed model has been verified by the new cutting tests. It is understood that the developed surface roughness model can be used to predict the in-process surface roughness with the high accuracy of 90.3% by utilizing the dynamic cutting force ratio.

In-Process Monitoring and Prediction of Surface Roughness in CNC Turning Process

2011 ◽  
Vol 199-200 ◽  
pp. 1958-1966 ◽  
Author(s):  
Somkiat Tangjitsitcharoen
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Prediction Accuracy ◽  
Cutting Speed ◽  
Least Square ◽  
Depth Of Cut ◽  
Turning Process ◽  
Roughness Model ◽  
Force Ratio ◽  
Cnc Turning Process

The objective of this research is to propose a practical model to predict the in-process surface roughness during the turning process by using the cutting force ratio. The proposed in-process surface roughness model is developed based on the experimentally obtain result by employing the exponential function with six factors of the cutting speed, the feed rate, the rank angle the tool nose radius, the depth of cut, and the cutting force ratio. The multiple regression analysis is utilized to calculate the regression coefficients with the use of the least square method. The prediction accuracy of the in-process surface roughness model has been verified to monitor the in-process predicted surface roughness at 95% confident level. All those parameters have their own characteristics to the arithmetic surface roughness and the surface roughness. It has been proved by the cutting tests that the proposed and developed in-process surface roughness model can be used to predict the in-process surface roughness by utilizing the cutting force ratio with the highly acceptable prediction accuracy.

Effect of Silicon Content of Aluminum Alloy 6351 in Turning Process

2012 ◽  
Author(s):  
Daniel Fernandes da Cunha ◽  
Marcio Bacci da Silva
Keyword(s):  
Surface Roughness ◽  
Aluminum Alloy ◽  
Cutting Force ◽  
Feed Rate ◽  
Silicon Content ◽  
The Other ◽  
Depth Of Cut ◽  
Edge Region ◽  
Turning Process ◽  
Free Region

The machinability of three commercial samples of the 6351 aluminum alloy with different silicon content was investigated in this work. Several parameters were used to evaluate the machinability in turning process, including the quality of the machined surface and cutting force. A design of experiments with three levels was used focusing on low values of feed rate (0.10, 0.15 and 0.2 mm/rev). The other parameters involved were: depth of cut (1.0, 1.5 and 2.0 mm), the silicon content (1.1, 1.2 and 1.3%) and two sets of cutting speed, one in the build up edge region (80, 100 and 120 m/min) and the other in a built up edge free region (200, 600 and 1000 m/min). The surface roughness parameter evaluated was Rq. A second design of experiment with three levels using higher values of feed rate (0.2, 0.35 and 0.5 mm/rev) and depth of cut of 2.0 mm was used to evaluate the influence of the silicon content in the cutting force. The effect of cutting fluid (dry machining, minimum quantity of fluid and over head cooling) was also analyzed. The results show that the silicon content has influence on the surface roughness. The statistical model in the build up edge region explains 79.95% of the total variation of roughness and 99% for cutting forces, for the other region this value is 81.99% for surface roughness and 98.96% for cutting force. The diameter of the workpiece has an influence on the results because the variation of hardness.

scholarly journals Development of Surface Roughness Generation Model for CFRTP Manufactured by LFT-D

2020 ◽  
Vol 14 (2) ◽  
pp. 208-216
Author(s):  
Motoyuki Murashima ◽  
Takaharu Murooka ◽  
Noritsugu Umehara ◽  
Takayuki Tokoroyama ◽  
◽  
...  
Keyword(s):  
Surface Roughness ◽  
Standard Deviation ◽  
Carbon Fiber ◽  
Volume Fraction ◽  
Regression Line ◽  
Surface Generation ◽  
Thermal Shrinkage ◽  
Generation Model ◽  
Cross Sectional ◽  
Estimation Formula

In this study, we propose a new surface generation model for carbon fiber reinforced thermoplastics (CFRTP) manufactured by the long fiber thermoplastic-direct (LFT-D) method. CFRTP are considered to be a next-generation structural material because of their high productivity as well as high mechanical strength and lightness. Conversely, CFRTP have a rough surface, which does not meet the automotive outer panel standard of a “class A surface.” In the present study, we establish a surface roughness generation model based on a thermal shrinkage mismatch of thermoplastic resin to carbon fiber and non-uniform carbon fiber distribution. Furthermore, we construct a surface roughness estimation formula based on the model. In the calculation, a cross-sectional image of CFRTP is divided into many vertical segments. Subsequently, the thermal shrinkage of each segment is calculated with a standard deviation, an average, and a probability density of the amount of carbon fiber in each segment. The surface roughness of the manufactured CFRTP was measured using a surface profilometer. The result showed that the arithmetic surface roughness increased with the volume fraction of carbon fiber. We applied the surface roughness calculation to cross-sectional images of the specimens. Consequently, the estimated surface roughness showed the same tendency, in which the surface roughness increased with the volume fraction of carbon fiber. The slope of a regression line of the estimated surface roughness with respect to the volume fraction was 0.010, which was almost the same (0.011) as the slope of a regression line of the measured surface roughness. Furthermore, the estimation formula using a thermal shrinkage effective depth of 395 μm was able to estimate the surface roughness within a 3% average error. Using the estimation formula, it was predicted that the surface roughness increased with the standard deviation of the amount of carbon fiber in a segment. To confirm the reliability of the model and the formula, we measured the standard deviation of the amount of carbon fiber in CFRTP specimens, showing that the trend for CFRTP specimens matched the estimated values.

Effects of Tool Wear on Surface Roughness and Cutting Force in Thermoplastics Turning

2018 ◽  
Vol 5 (1) ◽  
pp. 1-11 ◽  
Author(s):  
János Farkas ◽  
Etele Csanády ◽  
Levente Csóka
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Cutting Force ◽  
Cutting Process ◽  
Turning Process ◽  
Monitoring Tool ◽  
Tool Breakage

This paper presents a study of the effects of tool wear on cutting force and surface roughness. The cutting force was measured using a piezoelectric force meter which was attached to the cutting machine's revolving head. The surface roughness was measured after the cutting process was complete using a mechanical touch method. A range of thermoplastic materials and cutting layouts were used to give a broader understanding of the topic. After the measurements were taken, the data were evaluated statistically and the effects of tool wear are illustrated graphically. Furthermore, to understand all of the types of wear which can occur during thermoplastics turning, worn turning inserts taken from industrial machines were examined under a microscope. The aim of the study was to define a method for monitoring tool wear during the turning process to avoid tool breakage and/or reduce the number of scrapped parts.

Experiment Research on Cutting Performance of High Volume Fraction SiCp/Al Composites in Rotary Ultrasonic Machining

2012 ◽  
Vol 184-185 ◽  
pp. 971-976 ◽  
Author(s):  
Gui Qiang Liang ◽  
Jian Fu Zhang ◽  
Ping Fa Feng ◽  
Ding Wen Yu ◽  
Zhi Jun Wu
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Volume Fraction ◽  
High Volume ◽  
High Volume Fraction ◽  
Test Scheme ◽  
Machining Parameters ◽  
Ultrasonic Machining ◽  
Rotary Ultrasonic Milling ◽  
Silicon Carbide Particulate

High volume fraction silicon carbide particulate reinforced aluminum matrix (SiCp/Al) composite are new class of difficult-to-machine materials due to their high strength. This paper presents an experimental investigation on the machinability of 60 vol% SiCp/Al composites by comparing the rotary ultrasonic milling method with the conventional machining method. The test scheme is designed, and the measurement method of the cutting force, surface roughness and morphology are illustrated. Based on the constructed experimental platform, the influences of machining parameters, such as cutting speed, feed rate and cut depth, on the cutting force and surface roughness are discussed. The experimental results show that ultrasonic machining is an effective method for machining high volume fraction SiCp/Al.

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