machining fundamentals
TRANSCRIPT
BACHELOR OF ENGINEERINGBACHELOR OF ENGINEERING
MANUFACTURING TECHNOLOGIESMANUFACTURING TECHNOLOGIES
MACHINING FUNDAMENTALSMACHINING FUNDAMENTALS
by Endika Gandarias
2by Endika Gandarias
Dr. ENDIKA GANDARIAS MINTEGI
Mechanical and Manufacturing department
Mondragon Unibertsitatea - www.mondragon.edu(Basque Country)
www.linkedin.com/in/endika-gandarias-mintegi-91174653
Further presentations: www.symbaloo.com/mix/manufacturingtechnology
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CONTENTS
BIBLIOGRAPHYCHIP FORMATIONCUTTING TEMPERATURESCUTTING FORCES AND POWERGLOSSARY
by Endika Gandarias
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BIBLIOGRAPHY
BIBLIOGRAPHY
by Endika Gandarias
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The author would like to thank all the bibliographic references and videos that
have contributed to the elaboration of these presentations.
For bibliographic references, please refer to:
• http://www.slideshare.net/endika55/bibliography-71763364 (PDF file)
• http://www.slideshare.net/endika55/bibliography-71763366 (PPT file)
For videos, please refer to:
• www.symbaloo.com/mix/manufacturingtechnology
BIBLIOGRAPHY
by Endika Gandarias
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CHIP FORMATION
CHIP FORMATION
by Endika Gandarias
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Oblique cuttingOrthogonal cutting
by Endika Gandarias
CHIP FORMATION
VIDEO
Faxial
Fradial
Faxial
λ
λ = 0º λ 0º
Introduction
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CHIP FORMATION
More realistic view of chip formation, showing shear zone rather than shear
plane.
t0 : depth of cut (mm)tc : chip thickness (mm)
Orthogonal cutting model
VIDEOVIDEO
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CHIP FORMATION
by Endika Gandarias
λ
λ
λ = 0º
λ = 15º
λ = 30º
Oblique cutting model
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VIDEO
by Endika Gandarias
CHIP FORMATION
Discontinuous chip Continuous chip Continuous chip with Built-Up Edge
Serrated or segmented chip
VIDEO VIDEO VIDEO VIDEO
It depends on: Workpiece material Tool geometry Cutting conditions
Chip formation types
11by Endika Gandarias
CHIP FORMATION
Chip formation types
Chip formation and cutting temperatures in different workpiece materials:
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CUTTING TEMPERATURES
CUTTING TEMPERATURES
by Endika Gandarias
13by Endika Gandarias
CUTTING TEMPERATURES
The maximum heat generated during cutting is close to the cutting edge, in the chip breaker. This is where the maximum pressure from the material is, and, with the friction between chip and carbide, causes these high temperatures.
Severe temperature gradients within the tool and the chip occurs, and the workpiece remains relatively cool. Heat distribution is:
80% through the chip. 10% through the workpiece. 10% through the tool.
VIDEO
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CUTTING FORCES & POWER
CUTTING FORCES & POWER
by Endika Gandarias
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N = spindle speed (rpm)
Davg = average diameter (mm) Davg = (D0-Df)/2
Vc = cutting speed (m/min)
fn = feed per revolution (mm/rev)
ap = radial cutting depth (mm)
Kc = specific cutting force (N/mm2)
ηm = machine efficiency (0.7-0.8)
Fc = cutting force (N)
Pc = net power (kW)
Pc =Fc × Vc
60 × 103 × ηm
N
CUTTING FORCES & POWER
Fc = kc × ap × fn
[kW]
[N]
TURNING
Q = Vc × ap × fn [cm3/min]
by Endika Gandarias
Mc =Fc × Davg
2[N*m]
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CUTTING FORCES & POWER
TURNING
by Endika Gandarias
N = spindle speed (rpm)
F = feed rate (mm/min)
Fc = cutting force (N)
Ft = thrust or feed force (N)
Fr = radial force (N)
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CUTTING FORCES & POWER
TURNING
EXERCISE: An external turning operation is accomplished for a 60mm rod steel CMC02.1 material using V c=400 m/min. Calculate for the following 2 cases:
by Endika Gandarias
Fc ? [N] Pc ? [kW] Q ? [cm3/min] Mc ? [N*m]
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ap = axial cutting depth (mm)
D = tool diameter (mm)
ae = radial cutting depth (mm)
F = feed per minute (mm/min)
kc = specific cutting force (N/mm2)
Fc = cutting force (N)
Pc = net power (kW)
Q = metal removal rate (cm3/min)
CUTTING FORCES & POWER
MILLING
Pc =Fc × F
60 × 106
Fc = kc × ap × ae
[kW]
[N]
Q =ap × ae × F
1000[cm3/min]
by Endika Gandarias
Mc =Pc × 30 × 103
π × N[N*m]
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Dc = 125 mm ap = 5 mm
ae = 100 mm F = 600 mm/min
EXERCISE: A face milling operation is accomplished for a CMC 02.1 material. It is known:
CUTTING FORCES & POWER
MILLING
Fc ? [N] Q ? [cm3/min]Pc ? [kW] Mc? [Nm]
by Endika Gandarias
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fn = feed per revolution (mm/rev)
vc = cutting speed (m/min)
Dc = drill diameter (mm)
r = positioning angle (º)
kc = specific cutting force (N/mm2)
Ff = feed force (N)
Pc = net power (kW)
Q = Metal removal rate (cm3/min)
CUTTING FORCES & POWER
DRILLING
Ff ≈
[kW]
[N]
Q =Dc × fn × Vc
4[cm3/min]
Pc =kc × Dc × fn × Vc
240 × 103
kc × Dc × fn× sen r
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by Endika Gandarias
Mc =Pc × 30 × 103
π × N[N*m]
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CUTTING FORCES & POWER
DRILLING
Dc = 12 mm fn = 0,21 mm/rev
r = 59º Vc = 105 m/min
EXERCISE: A drilling operation is accomplished for a CMC 06.1 material. It is known:
Ff? [N]Pc ? [kW]Q? [cm3/min]
by Endika Gandarias
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GLOSSARY
GLOSSARY
by Endika Gandarias
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GLOSSARY
by Endika Gandarias
ENGLISH SPANISH BASQUE
Alloy Aleación AleazioAxial cutting depth Profundidad de pasada axial Sakontze sakoneraBuilt-up edge Filo de aportación Ekarpen sorbatzChip Viruta TxirbilChip breaker Rompe virutas Txirbil hausleaContinuous chip Viruta continua Txirbil jarraiaContinuous chip with built-up edge Viruta continua con filo de aportación Txirbil jarraiko ekarpen sorbatzCool Fresco Hozkirri / FreskoCutting speed Velocidad de corte Ebaketa abiaduraDiscontinuous chip Viruta discontinua Txirbil ez jarraiaDrilling Taladrado ZulaketaEngagement Empañe LausotuaFeed per revolution Avance por vuelta Aitzinamendua birakoFeed per tooth Avance por diente Aitzinamendua hortzekoFeed rate Avance por minuto Aitzinamendua minutukoFlank Flanco / Lateral AlboHardness Dureza GogortasunaMilling Fresado FresaketaNet power Potencia neta Potentzi garbiaOblique cutting Corte oblicuo Ebaketa zeiharOrthogonal cutting Corte ortogonal Ebaketa ortogonalaPositioning angle Ángulo de posicionamiento Posizionamendu angeluPower Potencia PotentziaRadial cutting depth Profundidad de pasada radial / ancho de pasada Iraganaldi zabaleraRake Desprendimiento JaulkitzeRemoval rate Tasa de eliminación Eliminazio tasaRod Barra BarraSerrated or segmented chip Viruta escalonada o segmentada Txirbil mailakatu edo segmentatua
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GLOSSARY
by Endika Gandarias
ENGLISH SPANISH BASQUE
Shear strain zone Zona de deformación por cizalladura Ebakidura bidezko deformazio guneaShearing Cizallamiento Ebakidura / ZizailaduraSpecific cutting force Fuerza de corte específico Ebaketa indar espezifikoaSpindle Cabezal BuruSpindle speed Velocidad de giro Biraketa abiaduraSteel Acero AltzairuThickness Espesor LodieraThrust Empuje BultzadaTool Herramienta ErramintaTurning Torneado TorneaketaWear Desgaste HigaduraWorkpiece Pieza Pieza