Manufacturing Processes for Engineering Materials (5th Edition in SI ...
Manufacturing Processes for Engineering Materials (5th Edition in SI ...
Manufacturing Processes for Engineering Materials (5th Edition in SI ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
Cutt<strong>in</strong>g (Mach<strong>in</strong><strong>in</strong>g)<br />
절삭가공<br />
Su-J<strong>in</strong> Kim<br />
School of Mechanical <strong>Eng<strong>in</strong>eer<strong>in</strong>g</strong><br />
Gyeongsang National University
Cutt<strong>in</strong>g<br />
1. Cutt<strong>in</strong>g mechanics<br />
2. Tool wear<br />
3. Tool material<br />
4. Turn<strong>in</strong>g, Turn<strong>in</strong>g center<br />
5. Mill<strong>in</strong>g, Mach<strong>in</strong><strong>in</strong>g center<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Cutt<strong>in</strong>g mechanics (절삭역학)<br />
• Chip <strong>for</strong>mation Shear break off<br />
• Cutt<strong>in</strong>g <strong>for</strong>ce = Specific energy x Area<br />
• Chatter (vibration)<br />
• Cutt<strong>in</strong>g temperature<br />
• Tool wear<br />
• Tool life equation<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Chip Formation (칩생성)<br />
• Chips are produced by the shear<strong>in</strong>g tak<strong>in</strong>g place along a<br />
shear plane.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Cutt<strong>in</strong>g Force (전단이론)<br />
• Accord<strong>in</strong>g to maximum-shear-stress criterion, yield<strong>in</strong>g<br />
occurs when the max shear stress with<strong>in</strong> an element is<br />
equal to or exceeds a critical value (shear yield stress).<br />
Stock<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Tool<br />
σ 1<br />
(Assume no friction)<br />
Fc<br />
σ 1<br />
τ<br />
Mohr’s circle<br />
σ<br />
τ<br />
Ф<br />
Shear angle<br />
Shear plane
Cutt<strong>in</strong>g Force (Shear <strong>for</strong>ce theory)<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
w<br />
t 0<br />
• Shear Area = Width x Depth / s<strong>in</strong> (Shear Angle)<br />
t0<br />
As w<br />
s<strong>in</strong> <br />
Tool<br />
t0 /s<strong>in</strong>(φ)<br />
φ<br />
F s<br />
• Shear Force = Shear Stress * Shear Area<br />
wt0<br />
Fs A<br />
s <br />
s<strong>in</strong>
Cutt<strong>in</strong>g Force (Theory)<br />
• Resultant <strong>for</strong>ce<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
= Shear <strong>for</strong>ce / cos (shear angle + friction angle – rake angle)<br />
R<br />
<br />
cos<br />
F<br />
s<br />
<br />
wt<br />
<br />
s<strong>in</strong> cos<br />
<br />
<br />
0<br />
β<br />
Chip<br />
ф<br />
β-α<br />
Fs<br />
R<br />
α<br />
Tool<br />
Workpiece
Cutt<strong>in</strong>g Force (Theory)<br />
• Cutt<strong>in</strong>g <strong>for</strong>ce<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
= Resultant <strong>for</strong>ce x cos (friction angle – rake angle)<br />
F c<br />
• Shear angle<br />
Rcos<br />
<br />
<br />
= pi/4 + rake angle/2 – friction angle/2<br />
<br />
<br />
4 2 2<br />
Chip<br />
ф<br />
α<br />
R<br />
Tool<br />
Fc<br />
β-α<br />
Workpiece
Cutt<strong>in</strong>g Force<br />
• Rake angle ↑ shear angle ↑, cutt<strong>in</strong>g <strong>for</strong>ce ↓ chip thickness ↓, cooler chip<br />
↓<br />
• Rake angle ↑ tool section ↓ strength at cutt<strong>in</strong>g edge ↓, heat conductivity<br />
↓<br />
• Relief angle ↑ friction ↓ tool life ↑, surface quality ↑<br />
• Relief angle ↑ strength at cutt<strong>in</strong>g edge ↓<br />
• Nose radius ↓ heat ↓, surface quality ↑<br />
Rake angle,α<br />
• Force ↑< yield stress of stock ↑, cut depth ↑, cut width ↑<br />
+<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Shear angle, φ<br />
Nose radius<br />
Relief angle,<br />
r
Cutt<strong>in</strong>g Force Approximation (절삭력)<br />
• Cutt<strong>in</strong>g <strong>for</strong>ce ≈ Specific cutt<strong>in</strong>g energy(비절삭에너지) x<br />
Cutt<strong>in</strong>g area<br />
F c ≈ u t A c<br />
• Cutt<strong>in</strong>g power = <strong>for</strong>ce x velocity<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
P = F c V<br />
Stock A c<br />
Tool<br />
F c<br />
Material Specific cutt<strong>in</strong>g<br />
energy (GPa)<br />
Alum<strong>in</strong>um alloys 0.4-1.1 480<br />
Copper alloys 1.4-3.3 500<br />
Cast irons 1.6-5.5 200<br />
Steels 2.7-9.3 840<br />
Tensile<br />
strength (MPa)
Ex ) Cutt<strong>in</strong>g Force<br />
Turn<strong>in</strong>g steel, depth of cut d = 0.1 mm, feedrate f = 0.01<br />
mm/rev, Specific cutt<strong>in</strong>g energy of steel u = 2.7~9.3 GPa.<br />
Cutt<strong>in</strong>g <strong>for</strong>ce? Cutt<strong>in</strong>g speed v = 10 m/s. Cutt<strong>in</strong>g power?<br />
F = u A = u d f<br />
= 2.7~9.3 (10^9 N/m^2) x 0.001 x 10^-6 m^2 = 2.7~9.3 N<br />
P = F v = 2.7 ~ 9.3 N x 10 m/s = 27 ~ 93 W<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Chip morphology (칩생성)<br />
• Type of chips produced<br />
<strong>in</strong>fluences surface f<strong>in</strong>ish<br />
and mach<strong>in</strong><strong>in</strong>g operation.<br />
1. Cont<strong>in</strong>uous chips<br />
2. Built-up-edge chips<br />
3. Serrated chips<br />
4. Discont<strong>in</strong>uous chips<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Steel: http://www.youtube.com/watch?v=4bOzJiYAZD4<br />
Sta<strong>in</strong>less: http://www.youtube.com/watch?v=DzAjpHFy4fw<br />
Cast Iron: http://www.youtube.com/watch?v=RoooeTEEMxY&feature=related
Chip breaker<br />
• Chip breaker shorter chip<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Groove Chip breaker
Chatter (Self-excited vibration)<br />
• Chatter vibrat<strong>in</strong>g with high frequency noise is caused by<br />
<strong>in</strong>teraction of chip-removal process with flexibility of the<br />
tool.<br />
• It could be avoided by <strong>in</strong>creas<strong>in</strong>g dynamic stiffness and<br />
damp<strong>in</strong>g, by decreas<strong>in</strong>g depth of cut and proper<br />
selection of sp<strong>in</strong>dle speed .<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Depth of cut (mm)<br />
Chatter<br />
Safe<br />
Sp<strong>in</strong>dle (rmp)<br />
http://www.youtube.com/watch?v=uv3yUCl27wM
Temperature (절삭열)<br />
• Cutt<strong>in</strong>g power P=FV Heat Increase the<br />
temperature of chip, work piece, and tool<br />
- Temperature <strong>in</strong>crease = specific heat x mass : dT = c m<br />
- Specific heat (kJ/kgK): iron 0.45, alum<strong>in</strong>ium 0.91, copper<br />
0.39<br />
• As temperature <strong>in</strong>creases, it will affect the properties of<br />
the cutt<strong>in</strong>g tool, dimensional accuracy.<br />
- Thermal extension: dL = a dT L<br />
- Thermal extension coefficient of iron 10 x 10^-6<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Ex) Temperature of chip<br />
Material removal rate? m/t = ρ A v = (kg/s)<br />
If we assume 100% of cutt<strong>in</strong>g power used to heat chip,<br />
Temperature of chip? P = Q/t = c dT m/t<br />
If workpiece temperature <strong>in</strong>creased 10 ℃, thermal<br />
expansion of workpiece?<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Tool wear (공구마모)<br />
• Mechanical wear<br />
1. Abrasive wear - hardness<br />
2. Adhesive wear - junction<br />
3. Fatigue wear - crack (toughness)<br />
• Thermo Chemical wear<br />
1. Diffusion wear (확산)<br />
2. Solution wear (용해)<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Tool wear<br />
• The wear behaviour of cutt<strong>in</strong>g tools are flank<br />
wear(measure width of wear land), crater wear(at high<br />
speed, diffusion wear is the major reason, measure<br />
depth), nose wear, and chipp<strong>in</strong>g of the cutt<strong>in</strong>g edge.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
crater wear<br />
broken edge<br />
flank wear nose wear
Tool life (F.W. Taylor, 공구수명)<br />
• Tool-wear relationship <strong>for</strong> cutt<strong>in</strong>g various steels is<br />
• Tool-life is also effected by depth and feed rate.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
VT C<br />
n <br />
VT<br />
n<br />
d<br />
x<br />
f<br />
Cutt<strong>in</strong>g speed V<br />
C<br />
y<br />
Log<br />
C<br />
V : cutt<strong>in</strong>g speed / T : time (m<strong>in</strong>) / C : constant.<br />
n : exponent depends on cutt<strong>in</strong>g conditions<br />
HSS 0.14-0.16, Carbides 0.21-0.25, TiC <strong>in</strong>sert 0.30,<br />
PCD 0.33, TiN <strong>in</strong>sert 0.35, Ceramic coated <strong>in</strong>sert 0.40<br />
d : depth of cut, f : feed rate<br />
-n<br />
Tool life T<br />
Log
Ex<br />
Increas<strong>in</strong>g tool life by reduc<strong>in</strong>g the cutt<strong>in</strong>g speed<br />
Given that n=0.5 and VT n =C, if the V reduced 50%, calculate the<br />
<strong>in</strong>crease of tool life.<br />
Solution<br />
VT 0.5 =C (1)<br />
0.5VT 2 0.5 =C (2)<br />
(2)/(1)<br />
0.5(T 2/ T) 0.5 =1<br />
T 2 =4T<br />
Increase tool life 4 times.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Surface F<strong>in</strong>ish (표면조도)<br />
Feed marks<br />
• In turn<strong>in</strong>g, peak-to-valley roughness is<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Stock<br />
r<br />
t<br />
<br />
2<br />
fr<br />
8r<br />
r<br />
Tool<br />
f r : feed rate (mm/rev)<br />
r : tool nose radius (mm)<br />
f r<br />
r t
Cutt<strong>in</strong>g Tool <strong>Materials</strong> (공구 재질)<br />
• HSS<br />
• Carbide<br />
• Ceramic<br />
• Diamond<br />
• CBN<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Cutt<strong>in</strong>g-Tool <strong>Materials</strong><br />
• A cutt<strong>in</strong>g tool has the follow<strong>in</strong>g characteristics:<br />
1. Hardness<br />
2. Toughness<br />
3. Wear resistance<br />
4. Chemical stability<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
HSS (하이스)<br />
HSS (High-speed steels)<br />
• HSS cuts faster than carbon tool steel, hence the name<br />
high speed steel, but slower than carbide tools.<br />
• It is often used <strong>in</strong> power saw blades and drill bits.<br />
TiN-Coated HSS<br />
• PVD (physical vapor deposition), TiN coat<strong>in</strong>g reduces<br />
tool wear.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
HSS Drill: http://www.youtube.com/watch?v=98DvSQNHLMU
Carbides (초경)<br />
Carbides<br />
• Better wear resistance, stiffness, hot hardness<br />
• Tungsten carbide: WC + Co(<strong>for</strong> toughness) powder<br />
metallurgy (s<strong>in</strong>tered), suitable <strong>for</strong> non-ferrous, grey cast<br />
iron<br />
• Titanium carbide: TiC + Co : TiC is suitable <strong>for</strong> steel and<br />
cast iron<br />
Coated Carbide<br />
• Carbide + TiC, TiN, Al 2O 3 coated<br />
by CVD (chemical vapor deposition)<br />
• Chemically stable greatly reduce crater wear<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Cermets<br />
Ceramics<br />
Alum<strong>in</strong>um oxide(Al 2O 3), Silicon-nitride(SiN), cold pressed and<br />
hot s<strong>in</strong>tered<br />
Hot hardness ↑, toughness ↓ (chipp<strong>in</strong>g), thermal shock<br />
Cermets<br />
Ceramic(Al 2O 3) + metal b<strong>in</strong>der(TiC)<br />
Hot hardness ↑, toughness ↓, thermal expansion ↑<br />
http://www.youtube.com/watch?v=Om9gzgNPf80<br />
Insert: less thermal stress, elim<strong>in</strong>ate gr<strong>in</strong>d<strong>in</strong>g by user, less<br />
sett<strong>in</strong>g time<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Diamond, CBN<br />
Diamond (Poly crystal diamond)<br />
• Hardest material, Not good <strong>for</strong> steel<br />
http://www.youtube.com/watch?v=vAvfrrlMZg4<br />
CBN (polycrystall<strong>in</strong>e cubic boron nitride)<br />
• 2nd hardest material, brittle, expensive<br />
http://www.youtube.com/watch?v=mKxX50OMBd4&p=9B6D9EAE75875D9D<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Tool materials<br />
Tool materials, feeds, and cutt<strong>in</strong>g speeds<br />
• Characteristics of cutt<strong>in</strong>g-tool materials gives a range of<br />
cutt<strong>in</strong>g speeds and feeds <strong>for</strong> different applications.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Speed (Hardness)<br />
PCD<br />
CBN<br />
Cera<br />
mic<br />
Cermet<br />
Coated carbide<br />
Carbide<br />
Coated HSS / HSS<br />
Feed (Toughness)
Workpiece materials (소재 재질)<br />
• Workpiece materials and cutt<strong>in</strong>g speeds when Carbide<br />
tool or coated carbide tools is used <strong>for</strong> turn<strong>in</strong>g<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Material Cutt<strong>in</strong>g speed (m/m<strong>in</strong>)<br />
Alum<strong>in</strong>um alloys 200-1000<br />
Copper alloys 50-700<br />
Cast iron, gray 60-900<br />
Steels 50-500<br />
Titanium alloys 10-100
Cutt<strong>in</strong>g Tool Makers (공구 제작사)<br />
• www.taegutec.co.kr<br />
• www.yg1.co.kr<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Cutt<strong>in</strong>g Fluids (절삭유)<br />
• Also called lubricants and coolants, cutt<strong>in</strong>g fluids.<br />
• Used extensively <strong>in</strong> mach<strong>in</strong><strong>in</strong>g operations to:<br />
1. Cool the cutt<strong>in</strong>g zone<br />
2. Reduce friction and wear<br />
3. Reduce <strong>for</strong>ces and energy consumption<br />
4. Wash away chips<br />
5. Protect surfaces from any environmental attack<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Saw<strong>in</strong>g and saws (톱)<br />
• A cutt<strong>in</strong>g operation where the tool consists of a series<br />
of small teeth that removes material.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Disk saw<br />
Belt saw
Turn<strong>in</strong>g (선삭)<br />
• A piece of material is rotated and a s<strong>in</strong>gle po<strong>in</strong>t cutt<strong>in</strong>g<br />
tool is traversed along 2 axes of motion to produce the<br />
cyl<strong>in</strong>der, tubular components and various rotational<br />
geometries.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Lathe (선반)<br />
• Turn<strong>in</strong>g can be done manually, <strong>in</strong> a traditional <strong>for</strong>m of<br />
lathe, which frequently requires cont<strong>in</strong>uous supervision<br />
by the operator.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
1 st Korean Lathe<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
CNC Lathe, Turn<strong>in</strong>g center<br />
• Turn<strong>in</strong>g can be done by us<strong>in</strong>g a computer numerical<br />
control, known as CNC.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Turn<strong>in</strong>g center<br />
• Turn<strong>in</strong>g center has additional<br />
mill<strong>in</strong>g axis is called TurmMill<br />
(복합기)<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
http://ma.gnu.ac.kr/vod/mach<strong>in</strong><strong>in</strong>g/TurnMill.AVI
Turn<strong>in</strong>g process (선삭공정)<br />
• Straight turn<strong>in</strong>g<br />
• Taper turn<strong>in</strong>g<br />
• Profil<strong>in</strong>g (Couture turn<strong>in</strong>g)<br />
• External groov<strong>in</strong>g<br />
http://www.youtube.com/watch?v=tDc0l9Gm8D4<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
http://www.youtube.com/watch?v=5AB_etoHesI&p=9B6D9EAE75875D9D<br />
© 2012 Su-J<strong>in</strong> Kim GNU
Math <strong>for</strong> Turn<strong>in</strong>g<br />
• Cutt<strong>in</strong>g speed(mm/m<strong>in</strong>) = 3.14 x Diameter x Sp<strong>in</strong>dle<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
V = π D S<br />
• MRR (Material Removal Rate) = Volume / Time = 3.14 x<br />
Diameter x Depth x Feed per revolution x Sp<strong>in</strong>dle<br />
D<br />
df S<br />
MMR avg r<br />
• Cutt<strong>in</strong>g time = Distance / (Feed per revolution x Sp<strong>in</strong>dle)<br />
V<br />
S<br />
t<br />
<br />
l<br />
f S<br />
r<br />
S
Ex) Turn<strong>in</strong>g<br />
A 15.24-cm-long, 1.27-cm-diameter 304 sta<strong>in</strong>less-steel rod is be<strong>in</strong>g reduced <strong>in</strong><br />
diameter to 1.2192 cm by turn<strong>in</strong>g on a lathe. The sp<strong>in</strong>dle rotates at N=4000 rpm<br />
and the tool is travell<strong>in</strong>g at an axial speed of 20.32 cm/m<strong>in</strong>. Calculate the cutt<strong>in</strong>g<br />
speed, material-removal rate, cutt<strong>in</strong>g time, power dissipated, and cutt<strong>in</strong>g <strong>for</strong>ce.<br />
Solution<br />
Maximum cutt<strong>in</strong>g speed is<br />
Cutt<strong>in</strong>g speed at mach<strong>in</strong>ed diameter is<br />
Depth of cut and feed is<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
V D N <br />
0<br />
1. 27400<br />
15.<br />
959 m/m<strong>in</strong><br />
V<br />
1. 2192400<br />
15.<br />
321m/m<strong>in</strong><br />
<br />
1.<br />
27 1.<br />
219<br />
20.<br />
32<br />
d<br />
0.<br />
0255 cm and f <br />
2<br />
400<br />
0.<br />
0508 cm/rev
Ex) Turn<strong>in</strong>g<br />
Solution<br />
Material-removal rate is<br />
The torque and cutt<strong>in</strong>g <strong>for</strong>ce is<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
MMR <br />
3<br />
1. 24450.<br />
02550.<br />
0508400<br />
2.<br />
02586 cm / m<strong>in</strong><br />
15.<br />
24<br />
Actual time taken to cut is t <br />
0.<br />
75 m<strong>in</strong><br />
0. 0508400<br />
Amount of power dissipated is<br />
3 410 Power 2. 02586<br />
135<br />
W<br />
82597<br />
T 32.<br />
8643 kg - cm and Fc<br />
<br />
4002 <br />
60<br />
32. 86432<br />
1. 2445<br />
<br />
52.<br />
8153<br />
kg
Mill<strong>in</strong>g<br />
• Cutt<strong>in</strong>g tool is rotated and traversed along 3 axes of<br />
motion to produce from simple rectangular plane, slot,<br />
hole and complex contour.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Mill<strong>in</strong>g<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Mach<strong>in</strong><strong>in</strong>g center (CNC Mill<strong>in</strong>g)<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
C Type<br />
Horizontal M/C<br />
Bridge Type<br />
Vertical M/C<br />
http://www.youtube.com/user/GlacernMach<strong>in</strong>eTools<br />
5AX M/C
3+2 axis mach<strong>in</strong><strong>in</strong>g (5면가공기)<br />
• Huge 3+2 axis mill<strong>in</strong>g has additional rotation BC axis on<br />
head.<br />
• Used <strong>for</strong> automobile door panel and bumper mold.<br />
http://ma.gnu.ac.kr/vod/mach<strong>in</strong><strong>in</strong>g/Huge_mach<strong>in</strong>e_tools.AVI<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
http://ma.gnu.ac.kr/vod/mach<strong>in</strong><strong>in</strong>g/Huge_5axis.AVI<br />
© 2012 Su-J<strong>in</strong> Kim GNU
5-axis mach<strong>in</strong><strong>in</strong>g (5축가공기)<br />
• Has 2 t<strong>in</strong>t<strong>in</strong>g A C or B C axis on table or head.<br />
Rotary table: http://ma.gnu.ac.kr/vod/Mach<strong>in</strong><strong>in</strong>g/Rotaty_table.MP4<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
Impeller : http://ma.gnu.ac.kr/vod/Mach<strong>in</strong><strong>in</strong>g/5axis_mach<strong>in</strong><strong>in</strong>g_impeller.MP4<br />
© 2012 Su-J<strong>in</strong> Kim GNU
Automatic Tool Changer (ATC)<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Changer Arm<br />
Tool<br />
Sp<strong>in</strong>dle
Automatic Pallet Changer (APC)<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Pallet #1<br />
Pallet #2
Work hold<strong>in</strong>g Vise, Clamp (치구)<br />
• Work is fixed by vise or clamp on the table with T-slot<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
http://www.youtube.com/user/GlacernMach<strong>in</strong>eTools#p/u/5/J1VtofzVG24<br />
Flex clamp: http://ma.gnu.ac.kr/vod/Mach<strong>in</strong><strong>in</strong>g/Clamp.MP4
Tool holder, Tools<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Holder + Collet + Solid Endmill Insert Endmill<br />
http://www.youtube.com/watch?v=IPWGV_EGAHw&feature=related
Tool holder, Tools<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Mill<strong>in</strong>g operations<br />
• Face cutter<br />
• Endmill : Flat, Ball, Rounded<br />
Face Cutter<br />
Basic: http://www.youtube.com/watch?v=j0vRYe9uvnI<br />
Face: http://www.youtube.com/watch?v=9OsNUi_o6C4<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
Endmill: http://www.youtube.com/user/GlacernMach<strong>in</strong>eTools#p/u/1/HfIaISnqHOk<br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Flat endmill (Slott<strong>in</strong>g)
Math <strong>for</strong> mill<strong>in</strong>g<br />
• Cutt<strong>in</strong>g speed(mm/m<strong>in</strong>) = 3.14 x Diameter x Sp<strong>in</strong>dle<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
V = π D S<br />
• Feed per tooth = Feed / (Sp<strong>in</strong>dle x Number of teeth)<br />
F / Sn<br />
• MMR = Depth x Width x Feed<br />
f t<br />
MRR = d w F<br />
<br />
f t<br />
F (mm/m<strong>in</strong>)<br />
w<br />
d
Drill<strong>in</strong>g<br />
• Drills produces deep holes.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Drill<br />
Drill<strong>in</strong>g mach<strong>in</strong>e<br />
Insert drill<br />
Max drill<br />
Drill: http://www.youtube.com/watch?v=ul20R32HJ3E<br />
Drill: http://ma.gnu.ac.kr/vod/Mach<strong>in</strong><strong>in</strong>g/Drill.MP4
Tapp<strong>in</strong>g<br />
• Tap produces thread <strong>in</strong>side the hold.<br />
• Tap Feed Rate = RPM x Pitch<br />
Ex) M6 x 1 at 2000 RPM = 2000 mm/m<strong>in</strong><br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Tapp<strong>in</strong>g Tapp<strong>in</strong>g holder and tool<br />
http://www.youtube.com/watch?v=vCHQLFZHHJc
Ream<strong>in</strong>g, Bor<strong>in</strong>g<br />
• Reamer enlarges an hole to the diameter of the tool.<br />
• Bor<strong>in</strong>g produce precise circular <strong>in</strong>ternal profiles.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Ream<strong>in</strong>g<br />
Bor<strong>in</strong>g<br />
Drill<strong>in</strong>g, Tapp<strong>in</strong>g, Bor<strong>in</strong>g: http://vimeo.com/8642433<br />
http://www.youtube.com/user/GlacernMach<strong>in</strong>eTools#p/u/0/om6GQKfoS1g
Planer and Shaper<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Gear Hobb<strong>in</strong>g<br />
• A hob (cutter) is rotated one revolution to transfer each<br />
tooth profile onto a rotat<strong>in</strong>g gear blank.<br />
• Used very often <strong>for</strong> medium to high sizes of production<br />
runs.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
http://www.youtube.com/watch?v=DwFssm9trSc
Broach<strong>in</strong>g<br />
• L<strong>in</strong>ear broach<strong>in</strong>g: the broach is run l<strong>in</strong>early aga<strong>in</strong>st a<br />
surface of the workpiece to effect the cut.<br />
• Rotary broach<strong>in</strong>g: the broach is rotated and pressed <strong>in</strong>to<br />
the workpiece to cut an axis symmetric shape.<br />
Broach<strong>in</strong>g gear: http://www.youtube.com/watch?v=2K45B6tDqsg&p=9B6D9EAE75875D9D<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
Rotary broach<strong>in</strong>g: http://www.youtube.com/watch?v=gUEcagEmmZo&p=9B6D9EAE75875D9D<br />
© 2012 Su-J<strong>in</strong> Kim GNU
Design <strong>for</strong> mill<strong>in</strong>g<br />
• M<strong>in</strong>imize mach<strong>in</strong><strong>in</strong>g, use cast<strong>in</strong>g and <strong>for</strong>g<strong>in</strong>g.<br />
• M<strong>in</strong>imize the length to diameter ratio of the tools.<br />
• Design features to be mach<strong>in</strong>ed from one side.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU
Design <strong>for</strong> mill<strong>in</strong>g<br />
• The <strong>in</strong>side edges must have the radius of the end mill.<br />
• For outside corners, chamfers are preferable over fillet.<br />
• For flatness, bosses should be used.<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
Ⓒ http://www.efunda.com/processes/mach<strong>in</strong><strong>in</strong>g/mill_design.cfm
Economics of Mach<strong>in</strong><strong>in</strong>g<br />
Total cost per piece consists of four items:<br />
C<br />
<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU<br />
t<br />
p<br />
p<br />
m<br />
s<br />
C<br />
where<br />
C<br />
C<br />
C<br />
C<br />
total cost<br />
mach<strong>in</strong><strong>in</strong>g<br />
sett<strong>in</strong>g up, load<strong>in</strong>g & unload<strong>in</strong>g<br />
<br />
m<br />
tool<br />
C<br />
s<br />
C<br />
t<br />
Cost<br />
Sett<strong>in</strong>g up<br />
Total<br />
Cutt<strong>in</strong>g speed
References: Mach<strong>in</strong>e Tool Makers<br />
• www.doosan<strong>in</strong>fracore.co.kr<br />
• www.wia.co.kr<br />
• www.hwacheon.co.kr<br />
• www.mazak.jp (Japan)<br />
• www.haascnc.com (USA)<br />
• www.deckelmaho.com (EU)<br />
Mach<strong>in</strong><strong>in</strong>g<br />
<strong>Manufactur<strong>in</strong>g</strong> <strong>Processes</strong><br />
© 2012 Su-J<strong>in</strong> Kim GNU