NATIONAL CERTIFICATE (VOCATIONAL) FITTING AND TURNING NQF LEVEL 4

[Pages:9]NATIONAL CERTIFICATE (VOCATIONAL)

FITTING AND TURNING

NQF LEVEL 4

NOVEMBER EXAMINATION

(6011044) 25 November 2014 (Y-Paper)

13:00 ? 16:00

This question paper consists of 9 pages.

Copyright reserved

Please turn over

(6011044)

-2-

TIME: 3 HOURS MARKS: 100

NC1260(E)(N25)V

INSTRUCTIONS AND INFORMATION

1.

Answer ALL the questions.

2.

Read ALL the questions carefully.

3.

Number the answers according to the numbering system used in this question

paper.

4.

ALL drawings must be neat and in good proportion

5.

ALL work you do not want to be marked must be clearly crossed out.

6.

Write neatly and legibly.

Copyright reserved

Please turn over

(6011044)

-3-

NC1260(E)(N25)V

QUESTION 1: DIAGNOSE AND REPAIR FAULTS ON EQUIPMENT AND MACHINES

1.1

Choose a description from COLUMN B that matches a statement or activity in

COLUMN A. Write only the letter (A?E) next to the question number

(1.1.1?1.1.5) in the ANSWER BOOK.

1.1.1

COLUMN A The replacement of heavy plant equipment

COLUMN B A requires the proper ventilation of

the working area

1.1.2 1.1.3

The quality and manufacture of products

Scheduling of repairs on production machines and equipment

B requires a list with specifications of all the parts that need to be repaired

C requires the use of heavy duty lifting equipment

1.1.4

Planning a major shutdown of a milk-bottling plant

D requires proper monitoring and inspection of the production equipment

1.1.5 The maintenance and repair of gas equipment

E requires the dismantling and assembly of the equipment (5 ? 1) (5)

1.2

Predictive maintenance analysis methods are used to determine the condition

and life span of machines and equipment.

State THREE methods that can be used.

(3)

1.3

One of the four V-belts breaks on the water pump pulley on a milk production

plant. The machine operator decides to remove the broken belt and continues

with the production process.

1.3.1 Do you think that was a good decision? Answer YES or NO.

(1)

1.3.2 Motivate your answer by giving THREE reasons.

(3)

1.4

The early detection of faults in machines and equipment is essential to

prevent breakdowns and damage to the machine parts at a canning factory.

Excessive vibration on a flange coupling between an electrical motor and a

pump is detected.

Name FIVE possible areas that you would check for the cause of this

problem.

(5)

Copyright reserved

Please turn over

(6011044)

-4-

NC1260(E)(N25)V

1.5

The breakdown of machines and equipment is a direct result of poor

maintenance and improper use.

Identify THREE examples of activities you would put in place to prevent the

slippage of belts.

(3)

[20]

QUESTION 2: MAINTAIN FLUID POWER AND PNEUMATIC SYSTEMS

2.1

Why would you consider using a pneumatic instead of a hydraulic system on

machines used in the food industry?

(2)

2.2

Name FOUR areas that you would check for excessive air leaks in a

pneumatic system.

(4)

2.3

The four basic components of any hydraulic system are identified as:

? Pump

? Valves

? Reservoir

? Actuator (cylinder)

Make a neat labelled drawing of the above-mentioned system showing it in

the symbolic format.

(8)

2.4

Name TWO factors that determine the operation of any hydraulic or

pneumatic system.

(2)

2.5

List FOUR of the requirements for a hydraulic fluid to function effectively.

(4)

[20]

QUESTION 3: PRODUCE COMPLEX COMPONENTS USING LATHES

3.1

Various options are given as possible answers to the following questions.

Choose the answer and write only the letter (A?D) next to the question

number (3.1.1?3.1.5) in the ANSWER BOOK.

3.1.1

Bruno wants to measure the inside length of a bush. Which tool should he use?

A Outside micrometer B Vernier calliper C Vernier height gauge D Dial gauge

3.1.2

Copyright reserved

Which ONE of the following tools would you use if you are required to machine a 60 mm internal diameter on a brass bush?

A Thread cutting tool B Parting tool C Drill bit D Boring bar

Please turn over

(6011044)

-5-

NC1260(E)(N25)V

3.1.3

Which ONE of the following lathe attachments would you use when you are required to work with a long thin shaft?

A Carriers B Face plate C Mandrel D Compound slide

3.1.4

A work piece is put in the chuck of a lathe between centers for machining so that no setting-up is required.

Which attachment is needed?

A Tailstock B Face plate C Carrier D Mandrel

3.1.5 You have to machine a taper of 60? onto a shaft.

Which part of the lathe would you adjust to the required angle?

A Carriage B Cross slide C Compound slide D Tailstock

(5 x 1) (5)

3.2

A line must be marked off on a piece of metal by using a vernier height gauge

on a surface table.

Briefly describe the procedure to be followed to ensure the accuracy of the

marked-off line.

(4)

3.3

Calculate the rotational speed in r/s when turning aluminum round a bar with

a diameter of 40 mm. The cutting speed for aluminum is given as 90 m/min.

(3)

Use S = x D x N

3.4

Ivy must machine a shaft on the lathe.

Indicate FOUR aspects that Ivy must check before operating the machine.

(4)

3.5

A shaft needs to be machined over its entire length in a centre lathe.

Describe what preparation needs to be done before the shaft can be mounted

between the headstock and the tailstock centres.

(3)

3.6

Why is it recommended that the operator wear a hair-net when working on

machines?

(1)

[20]

Copyright reserved

Please turn over

(6011044)

-6-

NC1260(E)(N25)V

QUESTION 4: PRODUCE COMPLEX COMPONENTS USING MILLING MACHINES

4.1

FIGURE 1 below shows the profile of a flat plate that needs to be milled. Only

the top and the side profiles need to be machined.

FIGURE 1

4.1.1 Name TWO types of milling cutters you will use for the milling

process.

(2)

4.1.2

The plate needs to be quality assured and checked that the top and bottom faces are parallel to each other.

Briefly explain how you would check the workpiece by using a dial

test indicator on the marking-off table.

(3)

4.2

A slot drill is used to machine a mild steel workpiece with a diameter of

12 mm.

The cutting speed used is 80 m/min and the feed rate is 0,47 mm per tooth.

If given that feed/min = feed/tooth x number of teeth x r/min, what is the feed rate required for the operation?

NOTE: The slot drill has 2 teeth and S = x D x N (5)

Copyright reserved

Please turn over

(6011044)

-7-

NC1260(E)(N25)V

4.3

Calculate the indexing required to machine a number of grooves into a shaft

when the angle measured between the grooves is 50?.

INDEXING = or 40 9N

DIVIDING HEAD

CINCINNATI INDEX PLATES

SIDE 1 24 25 28 30 34 37 38 39 41 42 43

SIDE 2 46 47 49 51 53 54 57 58 59 62 66

(3)

4.4

An artisan is doing a job on a milling machine and the cutter breaks.

Explain TWO precautions that the artisan must take to avoid the cutter from

breaking.

(2)

4.5

A plain helical milling cutter is fitted centrally on the milling machine arbor.

The machine vibrates during the machining process. You observe that the

cutter chatters onto the work piece.

What are TWO possible causes of this problem and also recommend a

solution for each.

(2 x 2)

(4)

4.6

The cutter of a horizontal milling machine must be mounted on the ...

A overarm

B knee

C spindle

D arbor

(1)

[20]

Copyright reserved

Please turn over

(6011044)

-8-

NC1260(E)(N25)V

QUESTION 5: PRODUCE COMPLEX COMPONENTS BY PERFORMING INTERNAL AND EXTERNAL GRINDING OPERATIONS

5.1

When working on the grinding machine, the operator must make sure that

he/she knows the rules regarding safety.

State any FIVE safety rules the operator must follow to operate a grinding

machine.

(5)

5.2

Explain what you understand by the following:

5.2.1 Orbital grinding

5.2.2 Face grinding

(2 x 1) (2)

5.3

Bruno is working on a grinding machine and notices problems with the work

piece.

Describe what Bruno should do to stop the following problems from occurring:

5.3.1 Burn marks

5.3.2 Chatter marks on the work piece

5.3.3 Scratches on the work piece

(3 x 1) (3) [10]

Copyright reserved

Please turn over

 ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download