Machining Process Lecture 1

7/31/2019 Machining Process Lecture 1

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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


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?


. .

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.


than scheduled in the lab agenda. No late reports are allowed unless an official justification letter is submitted

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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.


)( 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


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.


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.


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


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.


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.


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


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.


Cutting Abrasion


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Machining by Cutting

Singlepoint

Multi point

Classification of cutting processes


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


Workpiece

Depth of cut

Cut surface

Tool


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WorkpieceTool

Stationary Linear Rotary Spiral

Shaping

Broaching

Drilling

Tool and workpiece motions


Planing Milling

Turning

Hobbing


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General aspects of machining technology


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)


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.

Alexandria University, 2011 Dr. Islam Shyha 21/28


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Milling machinesMilling cutteris a multi-tooth cutter rotates along various axes with respect to the

workpiece.


(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


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


Schematic illustration of a horizontal-spindle surface grinder


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Grinding operations


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


Schematic illustrations of internal-grinding operations

Machining Process Lecture 1

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