machining process lecture 1
TRANSCRIPT
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Machining processes (PE 131)
First year
Production Engineering Department(Lecture notes)
Alexandria University, 2011Dr. Islam Shyha 1/28
Lecture 1: Introduction to machining processes
Prepared by:
Dr. IslamDr. Islam ShyhaShyha
Assistant Professor, Faculty of Engineering, Alexandria UniversityAssistant Professor, Faculty of Engineering, Alexandria University
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Course details/assessment
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Midterm exam : 20.0
Homework/Labs : 10.0
Oral examination : 10.0Final examination : 60. 0
Total marks : 100.0
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At the end of this course student should be aware of the following:
Course objectives
What is your main objective?
Do you know what my objective is?
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. .
2. Machining system components.
3. Selection of appropriate tool materials and geometries.
4. Economics of machining.
5. Effect of the different variables on the process behavior.
6. Selection of the proper machining procedure for various workpieces.
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Lab/lecture instructions
Your behaviour during lectures and labs must be in the most acceptable way. You should come early (5 minutes) before the scheduled time, NO LATE ENTRY.
A paper notebook must be with you all the time and labelled with your personaldetails.
You must put on your WHITE lab coat (from the first week, 19/03/2011). All of your electronic devices such as mobile phone, MP4, etc. should be switched
off during the entire labs or lectures.
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than scheduled in the lab agenda. No late reports are allowed unless an official justification letter is submitted
)( .
No gossip during lectures or labs )( .
You are not allowed to borrow any basic equipment during lectures or labs (pen,pencil..) ) (
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Lab/lecture instructions
Attendance will be only considered for your scheduled time (DO NOT change yoursection)
Follow the full instructions for submitting your lab/lecture reports (blank A4 coverand core..)
You are only allowed to submit your lab/lecture report if you have already attendedthe associated lab/lecture.
DO NOT COPY your reports, all copied versions will be seriously punished.
Assignments/reports should be only submitted at the scheduled time.
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)( NO FOOD during lectures/labs/tutorial (DRINKS are ok but not cans).
All prerequisites (such as lectures notes, lab sheet, calculators, ..........) should becarefully checked before coming to your lab/lecture.
You will be exempted from the FINAL EXAM ifyour absence exceeds 25%
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Benefits of following the instructions
Attending the maximum number of lectures and labs/tutorial
Easy to pass your exams
Get bonus marks during labs and lectures
Gain more knowledge in the field of study (machining)
Trainin chances durin summer vacation
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Satisfy your educational requirements
Enhance your ability to learn, know and practice
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Introduction: Manufacturing processThe time span between the original concept and the marketing of a product may
range from a few months to many years, depending on the complexity of the productand the type of materials used.
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Various steps involved in designing and manufacturing a product
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Introduction: What is manufacturing?
Manufacturing is the process of converting raw materials into products.
Manufacturing represents 20-30% of the value of all goods and services produced inindustrialized countries.
Machining activities constitute ~ 20% of the manufacturing activities in the USA.
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Classification of manufacturing processes
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Introduction: Shapes & manufacturing process
Shape or feature Production methodFlat surfaces Rolling, planing, broaching, milling, grinding
Parts with cavities End milling, electrical discharge machining, electrochemical
machining, ultrasonic machining, casting, forging, extrusion,
injection molding
Tubular shapes Extrusion, drawing, roll forming, spinning, centrifugal casting
Square edges Fine blanking, machining, shaving
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Shapes and some common methods of production
Small holes Laser or electron-beam machining, electrical-dischargemachining, electrochemical machining
Threaded parts Thread cutting, thread rolling, thread grinding, injection molding
Very large parts Casting, forging, assembly
Very small parts Investment casting, etching, powder metallurgy, nanofabrication,micromachining
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Introduction: Methods of manufacture Casting: expandable mould and permanent mould.
Forming and shaping: rolling, forging, extrusion, drawing, sheet forming, powdermetallurgy and moulding.
Machining: turning, boring, drilling, milling, planning, shaping, broaching, grinding,ultrasonic machining, chemical, electrical and electrochemical machining.
Joining: welding, brazing, soldering, diffusion bonding, adhesive bonding and mechanicaljoining.
Finishing: honing, lapping, polishing, burnishing, deburring, surface treating, coating andplating.
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Various methods of making a simple part: (a) casting or powder metallurgy, (b)forging or upsetting, (c) extrusion, (d) machining, (e) joining two pieces
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Introduction: Scales in manufacture
Size, shape complexity andthickness of a part have a majorinfluence on the processselected to produce the part.
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Illustration of the range of commonsizes of parts and the capabilities ofmanufacturing processes in producingthese parts
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Introduction: Classification of machining processes
Cuttin
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Classification of machining processes
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Introduction: Classification of machining processes
Cutting: machining allowance is removed in the form ofvisible chips.
Abrasion: machining allowance is removed in the form of minute and invisible chips by hard,tiny, randomly oriented abrasive grit (bonded or loose) of indefinite number and shape.
Erosion: machining allowance is removed in the form of successive surface layers as aresult of dissolution, melting and vaporization of the material being machined.
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Cutting Abrasion
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Machining by Cutting
Singlepoint
Multi point
Classification of cutting processes
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TurningBoring
ShapingPlaning
DrillingReamingMilling
BroachingHobbing
SawingFiling
Classification of cutting processes based on number of cutting points/edges
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The tool is penetrated into the w.p by a depth of cut.
Cutting tools have definite number of cutting edges of a known geometry.
The machining allowance is removed in the form of visible chips.
The shape of the workpiece produced depends on the tool and workpiece
relative motions.
Machining by cutting
Chip
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Workpiece
Depth of cut
Cut surface
Tool
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WorkpieceTool
Stationary Linear Rotary Spiral
Shaping
Broaching
Drilling
Tool and workpiece motions
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Planing Milling
Turning
Hobbing
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General aspects of machining technology
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General aspects of machining technology
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Turning means that the part is rotating while it is being machined.
Lathe operations
(mm/rev) (mm)
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Terminology used in a turning operation on a lathe,where f is the feed (in mm/rev) and d is the depth of cut.
Centre lathe
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Lathe operations
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Drilling operationsDrilling is used to produce a hole which may be followed by tapping or boring to
improve the accuracy of the hole and its surface finish.
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Drilling: Twist drillThe conventional twin lipped twist drill (Chisel-point drill) is the most commonly used
tool when drilling various materials.
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Milling machinesMilling cutteris a multi-tooth cutter rotates along various axes with respect to the
workpiece.
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(a) Schematic illustration of a horizontal-spindle, column-and-knee-type milling machine forslab milling.
(b) Schematic illustration of a vertical-spindle, column-and-knee-type milling machine forface and end milling and drilling operations.
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(a) Illustration showing the difference between conventional milling and climb milling.(b) Slab-milling operation, showing depth of cut, d; feed per tooth, f; chip depth of cut,tc and workpiece speed, v.(c) Schematic illustration of cutter travel distance, lc, to reach full depth of cut.
Milling process
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Cutters for(a) Straddle milling;(b) form milling;(c) slotting; and(d) slitting operations.
Milling operations
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Face milling
Terminolo for face
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Face-milling operation showing (a)action of a single insert in face milling;
(b) climb (down) milling; (c)
conventional (up) milling; (d)dimensions in face milling.
milling cutter
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Grinding operations
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Schematic illustration of a horizontal-spindle surface grinder
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Grinding operations
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Schematic illustrations of surface-grinding operations. (a) Traverse grinding with ahorizontal-spindle surface grinder. (b) Plunge grinding with a horizontal-spindle surface
grinder, producing a groove in the workpiece. (c) Vertical-spindle rotary-table grinder.
G
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Grinding operations
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Schematic illustrations of internal-grinding operations