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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter 21: Machining of Metals"
]
},
{
"cell_type": "markdown",
"metadata": {
"collapsed": true
},
"source": [
"### Example 21.1, Mechanics of Machining, Page No. 685"
]
},
{
"cell_type": "code",
"execution_count": 12,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"\n",
"Shear Plane Angle for 1040 steel= 22.2946 deg\n",
"\n",
"Shear Plane Angle for Copper = 10.6433 deg\n"
]
}
],
"source": [
"from scipy.optimize import fsolve\n",
"from math import radians, degrees, pi, cos, sin\n",
"\n",
"#variable declaration\n",
"a=6;\n",
"sigma_s=60000.0;\n",
"su_s=91000.0;\n",
"sigma_c=10000.0;\n",
"su_c=30000;\n",
"a=radians(a);\n",
"\n",
"\n",
"#calculation\n",
"def s(fi):\n",
" return cos(fi-a)*sin(fi)-sigma_s/su_s*(cos(pi/4-a/2)*sin(pi/4+a/2))\n",
"def c(fi):\n",
" return cos(fi-a)*sin(fi)-sigma_c/su_c*(cos(pi/4-a/2)*sin(pi/4+a/2))\n",
"fi1=fsolve(s,0);\n",
"fi2=fsolve(c,0);\n",
"fi1=degrees(fi1);\n",
"fi2=degrees(fi2);\n",
"\n",
"#result\n",
"print('\\nShear Plane Angle for 1040 steel= %g deg')%(fi1);\n",
"print('\\nShear Plane Angle for Copper = %g deg')%(fi2);"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Example 21.2, Mechanics of Machining, Page No. 687"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"\n",
"Slip plane angle = 33.1927 deg\n",
"Percentage of total energy that goes into friction = 30.918 percent\n",
"Percentage of total energy that goes into shear = 69.082 percent\n",
"Total energy per unit volume = 0.197285 hp min/in^3\n"
]
}
],
"source": [
"\n",
"\n",
"from math import sin\n",
"from math import cos\n",
"from math import tan\n",
"from math import atan\n",
"from math import radians\n",
"from math import sqrt\n",
"from math import degrees\n",
"\n",
"#variable declaration\n",
"v=500;\n",
"alpha=6;\n",
"b=0.4;\n",
"t=0.008;\n",
"Fv=100;\n",
"Fh=250;\n",
"L=20;\n",
"rho=0.283;\n",
"m=13.36;\n",
"m=m/454; #conversion to lb\n",
"\n",
"#calculation\n",
"tc=m/(rho*b*L);\n",
"r=t/tc;\n",
"alpha=radians(alpha);\n",
"fi=atan(r*cos(alpha)/(1-r*sin(alpha)));\n",
"#fi=degrees(fi);\n",
"mu=(Fv+Fh*tan(alpha))/(Fh-Fv*tan(alpha));\n",
"be=atan(mu);\n",
"Pr=sqrt(Fv**2+Fh**2);\n",
"Ft=Pr*sin(be);\n",
"p_fe=Ft*r/Fh;\n",
"Fs=Fh*cos(fi)-Fv*sin(fi);\n",
"vs=v*cos(alpha)/cos(fi-alpha);\n",
"p_se=Fs*vs/(Fh*v);\n",
"U=Fh*v/(b*t*v);\n",
"U=U/33000; #conversion to hp\n",
"U=U/12; #conversion of ft units to in units\n",
"fi=degrees(fi);\n",
"\n",
"#result\n",
"print('\\nSlip plane angle = %g deg\\nPercentage of total energy that goes into friction = %g percent\\nPercentage of total energy that goes into shear = %g percent\\nTotal energy per unit volume = %g hp min/in^3')%(fi,p_fe*100,p_se*100,U);\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Example 21.3, Tool Materials and Tool Life, Page No. 698"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"\n",
"For High Speed steel tool, increase in tool life is given by: t2 = 322.54 t1\n",
"\n",
"For Cemented carbide tool, increase in tool life is given by: t2 = 10.0794 t1\n"
]
}
],
"source": [
"\n",
"\n",
"#variable declaration\n",
"d=0.5;\n",
"\n",
"#calculation\n",
"t1=(1/d)**(1/0.12);\n",
"t2=(1/d)**(1/0.3);\n",
"\n",
"#result\n",
"print('\\nFor High Speed steel tool, increase in tool life is given by: t2 = %g t1')%(t1);\n",
"print('\\nFor Cemented carbide tool, increase in tool life is given by: t2 = %g t1')%(t2);\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Example 21.4, Grinding Processes, Page No. 703"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Tangential force = 24 N\n"
]
}
],
"source": [
"\n",
"\n",
"#variable declaration\n",
"U=40;\n",
"uw=0.3;\n",
"b=1.2;\n",
"v=30;\n",
"d=0.05;\n",
"\n",
"#calculation\n",
"b=b*10**-3; #conversion to m\n",
"d=d*10**-3; #conversion to m\n",
"U=U*10**9; #conversion to Pa\n",
"M=uw*b*d;\n",
"P=U*M;\n",
"F=P/v;\n",
"\n",
"#result\n",
"print('Tangential force = %g N')%(F);\n"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": []
}
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"language_info": {
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"file_extension": ".py",
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|
