foundry tech practical

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YEAR 2- SEMESTER 4

PRATICAL

Version 1: December 2008

UNESCO-NIGERIA TECHNICAL &

VOCATIONAL EDUCATION

REVITALISATION PROJECT-PHASE II

NATIONAL DIPLOMA IN

MECHANICAL ENGINEERING TECHNOLOGY

FOUNDRY AND FORGING OPERATIONS

COURSE CODE: MEC215


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TABLE OF CONTENTSWORKSHOP TASK 11.0 Safety Precaution

1.1 Observation of Workshop SafetyThe need for safety

Hazards1.2 General rules for safety

Behavior1.3 Personal safety

WORKSHOP TASK 2Identify and use of foundry tools

Objective:- Skills acquisition in use and handling of foundry tools

Tools:- Moulding Boxes, Cores Box, Rammer, Trowel, Bellows, Turned Spiral pins, pattern.

Procedure:

WORKSHOP TASK 3

Selecting material for pattern makingObjective: Design & manufacture a pattern for a given product.

Tools: wood, measuring tools, working tools.

Procedures

WORKSHOP TASK 4Major types of pattern objective

Objective: identifying various types of pattern

Tools:a. Single (loose pattern)

b.

Gated patternc. Cope & drag.

d. Match platee.

Follow board (special pattern)

Procedure:

WORKSHOP TASK 5Determination of grain size of sand.

Objectives:To Determine the Percentage Distribution

Tools: Sand (50g) Sieve Shaker.

Procedure:

WORKSHOP TASK 6Determination of the amount of clay in foundry sand

Objective:-Clay content determination

Tools: 50g clay sample, distilled water caustic soda washed bottle

Procedures:-


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WORKSHOP TASK 7Mixing & moulding operations

Objective: green sand mixing and moulding procedures

Tools: Sand, clay, water, binders additives moulding box rammer, trowel, pattern, spring pinsbellows

Procedures:

WORKSHOP TASK 8Moulding and preparation of cores

Objectives :Core MakingTools:Sand, organic Binders, core boxes, core plates

Procedure:

WORKSHOP TASK 9Sand Testing Methods

Objectives:-moisture content determination

Tools: Weighing machine, reheating furnace, timer, sand heapProcedures:-

Activitiesi.

Why should 50g only be taken from the heap of sand?

ii.

Explain the reason for the weight loss?

iii. Why should moisture be regarded as detrimental to the sand moulding properties?

WORKSHOP TASK 10Sand testing methods

Objective:- mould hardness

Tools:mould hardness tester, spring waded steel ball mould specimenActivities

i. Compare this method with an indentation method in hardness test

WORKSHOP TASK 11Macro examinations of castings

Objective:-Deformation lines in steel castings

Tools: Casting specimen, cupric acid, hydrochloric acid, water, furnace, timer, porcelain dish

WORKSHOP TASK 12Demonstration of basic heat treatment on steelObjectives:Hardening Operations

Tools:Furnace, Steel specimen, Timer Oil Baths

WORKSHOP TASK 13Demonstration of basic heat treatment on steelObjectives :Tempering Operations


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Tools:Furnace, Cold work steel specimen, timer

Activities1.

Test for Ductility in the three cases above

2. Carry out the hardness test on each

3. Check also the strengths in 3 above

4.

Draw your conclusion.

WORKSHOP TASK 14Fetling operation

Objectives:Knocking off of casting, from previous week is ready for inspection.Tools:Hammer, Sledge. Hacksaw, Cating

WORKSHOP TASK 15Basic heat treatment operation

Objective:-Annealing operations

Tools:Reheating furnace, specimen, clockQuestions

a. Test the above bar for mechanical proper test.

b.

Explain why the above heat treatment is carried out.


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MECHANICAL ENGEERING DEPARTMENT

FOUNDRY & FORGING OPERATIONS

MEC. 215

PRACTICAL CONTENT

WEEK. 1.

WORKSHOP TASK 1

1.0 SAFETY PRECAUTION

1.1 OBSERVATION OF WORKSHOP SAFETY

The need for safety

Almost everyone working in a factory/school workshop has at some stage in his or her careersuffered an injury requiring some kind of treatment or first aid. It may have been a cut finger or

something more serious. He cause may have been carelessness by the victim or a colleague,defective safety equipment, not using he safety equipment provided, the true cause was mostlikely a failure to think ahead. You must learn to work safely. Your workplace will have its own

safety rule so obey them at all times. Ask if you dont understand any instruction and do report

anything which seems dangerous, damaged or faulty.

Hazards

Accidents result most commonly for the following reason:

Careless or hurried movement about the workshop causing collisions or knocking over of toolsor materials. Careless movement is particular dangerous near machinery.

Loose clothing or long hair becoming caught in revolving parts f machines, particularly the

drilling spindle.Failing to secure work properly before commencing machining.

Lack of care in handling hot metal

1.2 GENERAL RULES FOR SAFETY

All injuries, no matter how slight, should be reported immediately.

Breakages and all damage to equipment should be reported.

A file should never be used without a handle.

The correct size and dye of smiths tongs should be used when foxing short work.Hot work being transferred from forge to anvils should be held downwards close to the ground,

to minimize danger of burns resulting from accidental collisions with other students.

When preparing the pickle bath for cleaning copper and gilding metal, the acid must be added to

the water never vice versa.

Behavior

It is very important to study all the safety instructions and regulations for the work in hand, but

the craftsman should be aware of safe pratice all the time. He must study the work to be done,

the environment in which it is to be done, the tools to be used and the best method to be used. He


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must realties what the dangers will be I he adopts a wrong and thoughtless approach. He must

always have a thoughtful and positive approach to safety for his own sake and the sake of his

workmate

Fig .1 The Correct Way of dressing in the Workshop.

1.3 PERSONAL SAFETY

To avoid injuries to yourself and your workmates on the shop floor, the following points must

form part of the general code of behavior:

1.

Do not act foolishly on the shop floor.

2.

Do not operate machines that you have not used before without learning about them.

3.

Always tidy in the workshop

4.

Always protect your eyes

5.

Do not wear loose clothing

6.

Do not lift heavy loads

7.

Always protect your feet

8. Do not use hand tools that are not in good condition


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9. Make sure all moving machinery is fenced

10.Do not run in workshops

11.Do not throw tools or materials about the shop floor

12.Remember to place warning notice on faulty machines

13.Always keep away from suspended loads

14.Always cooperate with your colleagues

15.Always protect your hands.

Fig. 1 The types of Safety goggles in the Workshop.


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g. 1.2. Safety footwear and dangers in use of hand

tools.

Safety rules for particular tools, machine tools and

processes

Files:- File must not be used without handles. The tang

can cause injury to the wrist. Files with chipped tips are

also dangerous.

Spanners:- Spanners of the correct sizes must be used

for nuts to avoid injury to the user when the spanner

slips. Over size spanner also round off the edges of the

nuts. Do not extend spanner with pieces of tube becausethis strains the spanner and the fastening.

Socket Wrenches:- Allen key of the correct size must be used for socket screws (allenscrews). Worn socket wrenches must never be used as they can slip and injure the user.

Hammer:- Hammers Must be securely fixed to the handles before use. Badly fixed head can

fly off while in use and injure co workers.

Chisels:- Chisel with mushroomed heads must not be used as the sharp edges can causeinjury to the user for the protection.


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WORKSHOP TASK 2

IDENTIFY AND USE OF FOUNDRY TOOLS

OBJECTIVE:

SKILLS ACQUISITION IN USE AND HANDLING OF FOUNDRY

TOOLS

TOOLS.Moulding Boxes, Cores Box, Rammer, Trowel, Bellows Turned Spiral pins, pattern.

PROCEDURE:

(1)

THE ABOVE TOOLS HAVE BEEN CLEARLY EXPLAINED TO THESTUDENTS AFTER CLOSELY BEING EXAMINED

(2)

EACH FO THE STUDENT WAS ASKED TO DRAW THE ITEM.

(3) THEY ARE THEN TOUGHT HOW TO HANDLE EACH OF THEM.

(4) THEY ARE THEN OBSERVED ON HOW THE HANDLING OF EACH ITEMWAS MADE WHERE CORRECTIONS ARE OBSERVED MADE.


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WORKSHOP TASK 3

Selecting material for pattern making

Objective: design & manufacture a pattern for a given product.

Tools: wood, measuring tools, working tools.

PROCEDURES

1.

MAKING OF THE FULL SIZE DRAWING OF A PATTERN TOGETHER WITH

CORE PRINTS.

2. MUNUFACTURE OF THE PATTERN BLACKS AND THEIR MACHINING

(MILLING GRINDING)

3. ASSEMBLING OF THE PATTERN PARTS BY (GLUEING, PINS, TONGUE &

GROOVE JOINTS)

4. CONTROL, ACCEPTANCE & PAINTING OF THE PATTERN


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WORKSHOP TASK 4

MAJOR TYPES OF PATTERN OBJECTIVE

OBJECTIVE: IDENTIFYING VARIOUS TYPES OF PATTERN

TOOLS

f.

SINGLE (LOOSE PATTERN)

g.

GATED PATTERN

h.

COPE & DRAG.

i.

MATCH PLATE

j.

FOLLOW BOARD (SPECIAL PATTERN)


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PROCEDURE

1.

The above patterns were on display to the students by the lecturer.

2.

A careful study of each is made on each.

3.

The differences of each is noted

4.

Activity of different set of design, the above were display and the

student were asked the following questions.

1.

identify each of a, b, c, d,& e above.

2.

what is the difference between and

3.

outline the differences of a and b

4.

outline also the differences between c& d.

5.

why is e called special pattern


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WORKSHOP TASK 5

DETERMINATION OF GRAIN SIZE OF SAND.

Objectives :To Determine the Percentage Distribution

Tools: Sand (50g) Sieve Shaker.

Procedure:

1.

A 50g sample of washed and dried sand with all the day substances removed.

2.

The sample placed in the sieve shaker a set of grad ed greens numbered according to

their fineness of their mesh.

3.

The shaker is started for 10-15 minutes vibration.

4.

The shaker is then switched off and vibrations slipped.

5. The screens are discharged one after the other.

6.

The sand is distributed based on the size of the meshes as well as the gram size of the

sand


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7. Each screen is weighed to obtain the grain fineness =

screeninretainnedsamdofpercentagetotal

producttotal

......

.

S/No Sieve no. Opening mm Amount gm Retained %

1 6

2 12

3 20

4 30

5 40

6 50

7 70

8

9

10


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S/No Sieve no. Opening mm Amount gm Retained % Multiplier

1 6 3.353 0 0 3 0

2 12 1.651 0 0 5 0

3 20 0.8533 0 0 10 0

4 30 0.590 0 0 20 0

5 40 0.414 1.5 3.0 30 90

6 50 0.295 0.3 0.6 40 24

7 70 0.208 2.5 5.0 50 250

8 100 0.147 0.5 1.0 70 70

9 140 0.104 8.20 16.40 100 1640

10 200 0.074 13.00 26.0 140 3640

11 270 0.053 12.80 25.60 200 5120

12 Pan 5.60 11.20 300 3360

Total 44.40 88.80 14.194

AFS grain finess = 1608.88

14194=


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WORKSHOP TASK 6Determination of the amount of clay in foundry sand

Objective:-Clay content determination

Tools:50g clay sample, distilled water caustic soda washed bottle

Procedures:-1.Put 50g sample of dried clay in wash bottle

2.Add 475ml distilled water and 25ml of caustic soda solution

3.

Agitate 5mm with mechanical stirrer or shaker, dilute with water to a height of 6 (marker

bottle) and let settle 10 min

4.

Siphon off 5 water dilute again to 6 height and let settle for 10 min

5.

Siphon off 5 water dilute again to 6min height and let settle for 5 min

6.

Repeat step 5 enough times so that after standing 5min, the water is clear

7.Remove the remaining sand grains from the bottle, dry and weigh, the loss in weight of

the original 50g sample multiplied by 2 give the AFS clay percentage in the sand.


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WORK SHOP TASK 7

MIXING & MOULDING OPERATIONS

OBJECTIVE

GREEN SANDMIXING AND MOULDING PROCEDURES

TOOLS,

SAND, CLAY, WATER, BINDERS ADDITIVES MOULDING BOX RAMMER,

TROWEL, PATTERN, SPRING PINS BELLOWS

PROCEDURES:

(1)

Sand and clay both weighed accordingly are then mixed thoroughly

(2)

Binders (Bentouls) and Additive are also added on.

(3)

Water is also weighed accordingly and are mixed thoroughly.

(4) The mixing is then completed.

(5) Pattern is then placed on a moulding board with the flat face of the split female pattern

facing down.

(6) Moulding box (Drag) is placed on the moulding board with the pattern at the centre.


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(7) Facing sand (Charcoal dust) is dusted on the face of the pattern.

(8) Backing sand (sand, clay, water , Binder and Additives ) is filled in the moulding box.

(9) Rammer is used to compact the Backing sand, with addition of more where possible.

(10) Strike off bar (straight edge) is used to remove the excess sand on the

moulding box.

(11) The moulding box is now turnover with face of the female pattern facing upwards

(12) The 2nd

part (male) pattern is aligned on the female pattern

(13)

The cope (moulding) is guided on the Drag by the use of locating pins.

(14)

Procedures 7, 8, 9 and 10 are repeated while the spring pins and user pins were in

positioned.

(15)

Moulding completed the moulding box is now carefully opened for the extraction

of the pattern

(16)

Channels are then careful cut after pattern extraction. Loose san inside the cavity

are removed by the use of bellow

(17)

The cope and Drag part of the molding boxes are closed again by the help of the

guiding pins.

The cavity is ready for the molten metal.

This procedures is closely followed by each of the student.


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WORKSHOP TASK 8

MOULDING AND PREPARATION OF CORES

Objectives:Core Making

Tools:Sand, organic Binders, core boxes, core plates

Procedure:

1.

Core Box is filled with core mixtures

2. filled co re box is rimmed and struck off

3.

The core is transferred to a co re plate for baking


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4. The plate plus the core is placed in and oven for baking at 6500F to obtain the

strength of the organic binders

5. The baking time is 2-6hours

6.

Cleaning of the cores after baking

7.

The cores are Joined (halves) by the use of core paste (talk, mollases, dextruin flour

water etc.) can be used.

Question

1.

Outline properties of co re mixtures.

2.

Outline 5 different uses of cores in casting


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WORKSHOP TASK 9Sand Testing MethodsObjectives:-Moisture content determination

Tools: Weighing machine, reheating furnace, timer, sand heap

Procedures:-1. Weigh 50g of the sand heap with the weighing balance.

2. The reheating furnace is then switched on with the sand inside.

3.

The temperature of the reheating furnace is 220F for 2hrs or.

4. Until a constant weight is recorded of the sand.

5.

The reheating furnace is then switched off as allowed to cool.

6.

The sand is reweighted to find out the weight lost.

7.

The lost in weight multiplied by 2 gives the percentage of moisture in the sand.

Activitiesiv. Why should 50g only be taken from the heap of sand?

v. Explain the reason for the weight loss?

vi.

Why should moisture be regarded as detrimental to the sand moulding properties?


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WORKSHOP TASK 10Sand testing methodsObjective:- Mould hardness

Tools:Mould hardness tester, spring waded steel ball mould specimen

Procedures:-1. The specimen to be tested is placed under the mould hardness tester.

2. The spring waded steel ball makes an indentation (mark) on the mould (specimen)

3.

If the steel ball sinks completely in the mould the reading indicates zero

4. If the steel ball makes no marks, the reading on the tester indicates 100.

5. Hardness reading are taken on the standard sand specimen as an additional test on the

specimen.

Activities

ii.

Compare this method with an indentation method in hardness test


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WORKSHOP TASK 11Macro examinations of castings

Objective:-Deformation lines in steel castings

Tools: Casting specimen, cupric acid, hydrochloric acid, water, furnace, timer, porcelain dish

Procedures:-1. The steel specimen is taken from steel casting

2. Wet the surface with a swab or solution containing cupric acid and hydrochloric acid

3.

The specimen is heated to 200-2500C in the furnace for hour

4. The etching time is 2-24 hours, until the structure is evident.

5. The specimen is removed, swilled in water then in methylated spirit and dried

6.

Success in etching depends on experience, largely, hence initial failures should not

discourage the examiner.


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WORKSHOP TASK 12

DEMONSTRATION OF BASIC HEAT TREATMENT ON STEEL

Objectives :Hardening Operations

Tools:Furnace, Steel specimen, Timer Oil Baths


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Procedure:

1. The Steel (specimen) is placed in the furnace and is switched on.

2.

The rise in temperature is carefully observed

3. Hardening temperature for Hypoeuletic steel is 30-500C above the upper critical

temperature while for Hypereulectic steel is 30-500 above the lower critical

temperature.

4. it is then held at tha6t temperature (soak) for some time to allow transformatic to

take place.

5.

The furnace is then opened and the specimen is drop in the oil Bath, to allow rapid

cooling to take place.

6.

This is allowed to cooled to room temperature.

Observation

All mechanical properties test for the steel can be carried

Try 1 or 2 tests and record your observations.


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WORKSHOP TASK 13

DEMONSTRATION OF BASIC HEAT TREATMENT ON STEEL

Objectives :Tempering Operations

Tools:Furnace, Cold work steel specimen, timer


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Procedure:

1.

The steel specimenis placed inside a reheating furnace and is then switched on

2.

The rise in temperature is carefully monitored.

3. Low temperature tempering is achieved at 2050C

4.

Medium temperature tempering is achieved at 350-5000C

5. High temperature temperiong between 5000680

0C

Territe- Cementite Mixtures

6. The heating time is about one hour

7. The furnace is then switched off

8.

The steel is either taken out or let in the furnace to cool down to room temperature.

Activities

5.

Test for Ductility in the three cases above


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6. Carry out the hardness test on each

7.

Check also the strengths in 3 above

8. Draw your conclusion.


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WORKSHOP TASK 14

FETLING OPERATION

Objectives:Knocking off of casting, from previous week is ready for inspection.

The following operations can be carried out

1.

Removal of gates and risers

2. Surface cleaning and interior of casting

3. Trimming, the removal of funs, wires and protuberances (extensions) at gates and

risers evocations

4. Finishing, final surface cleaning

5.

Inspection.

Tools:Hammer, Sledge. Hacksaw, Cating


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Procedure:

1. Gates and risers are removed by flogging in the case of Brittle material. For Ductile

material mechanical cut off, touch cutting

2. Surface cleaning is


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WORKSHOP TASK 15Basic heat treatment operation

Objective:-Annealing operations

Tools: Reheating furnace, specimen, clock

Procedures:-1.

The steel to be annealed is 1stplaced in the furnace with it switched on.

2.

The rise in temperature is moistured carefully.

3.

When the steel temperature in the furnace reaches 9100C, austenitic range, the furnace isthe

4.

The furnace at thus temperature is switched off.

5. The steel is then left inside the furnace till it cools down to worm temperature.

6. The steel bar can be taken and tested for mechanical properties

Activitiesc.

Test the above bar for mechanical proper test.

d.

Explain why the above heat treatment is carried out.


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