Notes On “Machining (1) Course 130/64” (Part 1) Prepared By: Dr. Samy Oraby

Notes On“Machining (1) Course 130/64”

(Part 1) Prepared By:

Dr. Samy Oraby (Associate Professor)

November 2008

04/19/2304/19/23 Deartment of Mechanical ProductiDeartment of Mechanical Production Technology - Machining (1) Coon Technology - Machining (1) Course 130/64urse 130/64

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Course Description & Goals Course Description: This is one of three consecutive courses for machining

being the backbone of manufacturing technology. This course provides students with basic theoretical and practical knowledge regarding the use of workshop hand tools and some conventional machining systems. Technical background is given regarding the general safety procedures in the workshop, the skills in manipulating hand tools and work layout. Also, the principle features and use of turning lathe and drilling of main importance.

INTRODUCTION

04/19/2304/19/23 Dept. Mech. Prod. Tech. - MachinDept. Mech. Prod. Tech. - Machining (1) Course 130/64 (New Prograing (1) Course 130/64 (New Program)m)

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Course GoalsUpon successful completion of this course the student

will be able to: Distinguish between hand and automatic machining tools

and machines. Demonstrate use of hand tools to assemble and

dissemble mechanical components. Produce simple components reflecting basic operations

using some conventional machine tools.


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Course Outline College :Technological Studies Department :Manufacturing Engineering Technology Program :Manufacturing Engineering Technology Course Title :Machining Processes (1) Course Code :64/130 Class Size: 20 Workshop: 10 Lab: 10 Semester: Second Credits: 3 Hours/Week:5 (2+2+1) Total Hrs: 70 Total Weeks: 14 Language :English Pre-requisite(s) :Workshop Technology (64/105) Co-requisite(s) :None


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Week No.

TOPIC

CLASS LAB WORKSHOP

1Introduction to machining

technology Course information and safety rules in shop.

Recognition of hand tools (Files-tabs-drivers, etc).

2 Layout tools and procedures.Definitions and manual skills in free-hand-

sketchingDisassembly of tailstock, vise, etc.

3 Hand tools and bench work. Group work on Exercise notebookAssembly of tailstock, vise, pulley and belts,

etc.

4

Sawing and cut off machines.

Audio/Video Presentation on Machining Processes

Sawing (Hand and power)

5Demonstration on Motion transmition using

belts and Pulleys

Recognition of centre-lathe parts (1): (assembly and disassembly of jaws - Tool setup.

6The lathe (lathe size – parts of the

lathe – lathe safety – cutting tools and holders).

Demonstration on Motion transmition using straight and bevel gears

Recognition of centre-lathe parts (2): (Quick-change Gearbox -Feed and screw shafts -Carriage and Apron parts - Manual and Power motion Beds and Tailstock).

Course Contents


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7 Mid-Term Exam. Group work on Exercise notebook

Exercise (1): Turning and Related operations (as specified in the provided PROCESS SHEET).

8Selection of the Appropriate cutting

conditions (cutting speeds, feeds and depth of cut).

Exercises, calculations and computer program on cutting conditions.

9 Machining time in turning).Exercises, calculations and computer program on

configuration of lathe tools

10The lathe (work holding attachments –

turning work between centres).Exercises, calculations and computer program on

machining time

11 The lathe (using chucks – taper truing). Exercises and calculations on taper turning

12 The lathe (drilling and boring – reaming).Audio/Video demonstration on special turning

operations

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The lathe (cutting screw threads on a lathe – knurling- grinding on a lathe – milling on a lathe – special lathe attachments).

Group work on Exercise notebookExercise (2): Drilling, boring,

countersinking, reaming and tabbing (as specified in the provided PROCESS SHEET).14 Drilling, boring, reaming and tapping.

Audio/Video on drilling operations – twist drill configuration – drilling calculations

Course Contents continue……


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Evaluation Strategy Exams 15% Lab 10% Workshop 25% Final 50% Total 100%


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References1. Machining Fundamentals, From Basic to

Advanced Techniques, By John R. WalkerPublisher Goodheart-WillcoxCo; Received edition (January 2000) ISBN: 1566376629

2. Technology of Machine Tools, By S. F. Krar and A. F. Check


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Practical Exercise No. 1 Turning & Related Processes


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Practical Exercise No. 2: Drilling, Boring, Reaming & Tabbing


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SAMPLE PROCESS SHEET

Seq.Operation Sketch Cutting Conditions Remarks

Speedm/min

Feedmm/rev

DOCmm

1

2

3


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Introduction to Machining Technology


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Manufacturing System


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Manufacturing Processes


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TURNING

MILLING


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Manufacturing by Machining


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Safety Procedures1. Machine Shop Safety

Safety Glasses Clothes and Hair Safe Conduct in the Shop Safety in Machining


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Safety Glasses

Even when you're not working on a machine, you must wear safety glasses. A chip from a machine someone else is working on could fly into your eye.

EVERYONE MUST WEAR SAFETY GLASSES IN THE SHOP.


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Clothes and Hair

IF YOU HAVE LONG HAIR OR A LONG BEARD, TIE IT UP.

NO LOOSE CLOTHING. NO GLOVES REMOVE JEWELERY WEAR APPROPRIATE SHOES


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Safe Conduct in the Shop Be aware of what's going on around you. Concentrate on what you're doing. Don't hurry. Don't rush speeds and feeds. Listen to the machine. Don't let someone else talk you into doing

something dangerous. Don't attempt to measure a part that's moving.


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Safety in Machining

Study the machine. Know which parts move, which are stationary, and which are sharp.

Remove chuck keys and wrenches. DO NOT LEAVE MACHINES RUNNING

UNATTENDED! CLEAN UP MACHINES AFTER YOU USE

THEM!


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Layout tools and Procedures

Laying out is the planning of the work on the surface of the material that is to be made into the finished part. It is the scribing of lines which indicates cuts to be made, the centerlines of holes to be drilled, and other details that guide the worker in completing the job.


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Figure 1. Part to be laid out.


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1. Locate and scribe base lines. 2. Locate all circle and arc centerlines.

3. Scribe in all circles and arcs. 4. Locate and scribe in angular lines.


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5. Complete all other object lines.


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Hand Tools and Bench Work


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Classificationof CuttingTools


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Sawing and Cut off Machines


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Metal Sawing - The first step in machining most metal working jobs is to cut the stock to the desired length. Many parts for machines of all kinds are cut from round, square, flat or hexagonal bar stock or tubing. Other parts may be made from structural shapes (such as I beams, channels and angles) cut off to the desired length.This cutting off operation should be done in the shortest possible time consistent with the desired quality. .The cutting action in the power sawing process is accomplished by the action of a continuous series of single point cutting tools as they pass over the work piece.Tool life on the various cutters, or blade (straight, circular or band) is extended because of the sharing of the wear on the individual teeth


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The cutting action in the power sawing process is accomplished by the action of a continuous series of single point cutting tools as they pass over the work piece.


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Metal Sawing Machines - power driven sawing machines are used for cutting off stock to the desired length. Such machines are classified according to the kind of motion used in the cutting action. These general types as explained below are in common use in industrial shops.

(a) Reciprocating saw-Manual hacksaw, -Power hacksaw.


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(b) Band saw

-Vertical cut off, -Horizontal cut off,-Combination cut off and contour, -Friction blade,-Band filing.

(c) Circular saw

-Cold saw,-Steel friction disk,-Abrasive disk.


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Reciprocating Saw Machines --The reciprocating power saw is the original and least expensive saw for the cutting off operation. It is perhaps the most common power saw found in most production, tool room and maintenance departments. It is considered to be the simplest of all power sawing machines.

A-CoolantB-Saw BladeC-ViceD-Round Stock


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- The speed of power saws may be from 30 strokes per minute - The speed of power saws may be from 30 strokes per minute for large cuts with heavy saws on difficult materials, up to 165 strokes per minute on carbon steels and non-ferrous materials. The hacksaw usually has 4 to 6 different speeds available.-Sawing capacity is expressed as the maximum diameter of metal bar capable of being cut. This is also known as the size of the power hacksaw. Typical sizes are 150x 150 mm to 600 x 600 mm. The motors used will vary from l. H.P. to 10 H.P.


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Circular Saw Machines --Circular sawing machines or cold sawing machines are used exclusively for cut off operations. Such machines differ from a power saw or a band saw in respect of the blade or cutter: Circular' sawing machines employ a toothed circular disk cutter which resembles a slitting saw (cutter) used on milling machine or the cutting blade used on a woodworking table saw.

A-SawB-WorkpieceC-FeedD-Rotation


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Abrasive Disk Cutting-Cutting by means of rotating abrasive disk is really not a sawing operation, but it frequently is classified as such and done on the same equipment,

A-OperatingB-Abrasive cutting wheelC-Vise Abrasive


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Saw Blades Types --Saw blades are the cutters used on different sawing machines for cut-off and other operations.

Saw blades are made in three basic configuration or types.

1-The first is straight, relatively rigid, and of limited length with teeth on one edge. These are commonly known as Hacksaw' blades.

2-The second type of saw blades is sufficiently flexible so that a long length can be formed into a continuous band with teeth on one edge; these are known as Band saw blades.

3-The third type is a rigid disc, having teeth on the periphery; these are circular saws.


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Various Band Saw Blade Tooth Forms-

(i)Regular(ii)Hook(iii) Skip(iv) Carbide insert.

-Regular or standard tooth form is used for all blades of 4 mm pitch. Such blades are most commonly used for all general purpose metal saving. The face of the tooth is straight to rake out chips.


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-The hook form is used for blades of 4 mm pitch and coarser. Blades with hook form are ideal for cutting large sections of steel, non-ferrous metals, wood, and plastics. Teeth are designed with a positive rake which gives a cutting action of digging out full chips instead of scraping. The rounded gullets permit chips to clear with ease.


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-Skip tooth blades use the same rake and clearance angles as regular tooth blades, but the teeth are shorter and spaced farther apart. Thus, skip tooth design prevents clogging when cutting soft, sticky materials such as aluminium and magnesium.


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Notes On “Machining (1) Course 130/64” (Part 1) Prepared By: Dr. Samy Oraby

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