Mechanotechnics N4

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Mechanotechnics N4

This document includes important informa on about the revised curriculum for Mechanotechnics N4. In the table that follows, we explain what has changed between the old curriculum and the new one. The fi rst column summarises the old curriculum, the second column explains what has changed in the 2021 curriculum so that you can directly compare the two, and the third column has addi onal comments by the author. For best results, use TVET First Mechanotechnics N4. This is the weigh ng for each module in the Mechanotechnics N4 curriculum which is being implemented from 2021.

Modules Weigh ng

1. Workshop Layout 5

2. Metal Protec on 5

3. Lubrica on 5

4. Precision measuring of machine parts 15

5. Gear drive 15

6. Belt drive 5

7. Hydraulic systems 20

8. Bearings 15

9. Metal cu ng machines 15

TOTAL 100

Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

Module 1 Organisa on and layout of workshops Objec ve The student should be able to: Plan the layout of a workshop with due considera on of all the principles, advantages and disadvantages, factors, types of construc on and various diff erent types of processes Module 1 Workshop layout (weigh ng 5/100) General aim Plan the layout of a workshop with due considera on of all the principles, advantages and disadvantages, factors, types of construc on and various diff erent types of processes. Content stayed the same (old weigh ng 10/100).

Content stayed the same.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

1.1 Advantages of a good layout 1. Introduc on to workshop layout Learning Outcome The student must be able to: List the advantages and disadvantages of good workshop layout.

Content stayed the same. 1.2 Principles of a good layout Content changed for 1.2

1.3 Factors which have to be taken into considera on in the layout of a workshop

1.4 Types of produc on and the most important requirements of each type: 1.4.1 Mass produc on 1.4.2 Batch produc on 1.4.3 Individual produc on 1. Introduc on to workshop layout Learning Outcome The student must be able to: List the factors that should be considered in the design of workshop layout. 2. Types of produc on Learning Outcome Explain the diff erences between mass, individual and batch produc on. Content stayed the same.

Content stayed the same.

1.5 Product layout 3. Factory layout Learning Outcome Draw diagrams to illustrate the diff erences between the following processes of layouts – Product, Fixed and Process.

Content stayed the same. 1.6 Process layout On the fi xed layout, drawing has been added as well as advantages and disadvantages.

1.7 Layout of machines: Special requirements 4. Graphic layout techniques Learning Outcome Draw two-dimensional and threedimensional models.

5. Considera on when placing machines in a factory Learning Outcome Explain how materials are handled in the workshop. Explain what is meant by each of the following requirements of process layout: a) Economic placing of various sec ons Content stayed the same.

There have been changes in this sec on -see a), b), c) and d) in the middle column.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

b) Highly skilled workers c) Adaptability of inspec on methods d) Thorough planning of produc on. 1.8 Layout procedures Incorporated into Module 1. Module 2 Calcula ons: Flat, vee and conveyor belt drives (centrifugal forces included) Module 6 Belt drives (weigh ng 5/100) Content changed: Conveyor belts are only men oned in passing in the new curriculum. The rest of the content stayed the same. (old weigh ng 15/100). The old Module 2 has become Module 6 in the new curriculum.

Objec ve The student should be able to: Do calcula ons with fl at, vee and conveyor belt drives 2.1 Flat belts (open and crossed drives) Aim Apply calcula ons of fl at, vee and conveyor belt drives.

1. Introduc on to belt drives Learning Outcomes Explain concepts and terminology. Draw and explain belt drives – fl at, open, crossed and vee belt drives. 2.1.1. Velocity ra o of the pulleys 2. Belt drive 2.1.2 Maximum tension in the belt Learning Outcomes Calculate the following on belt 2.1.3 Ra o of tensions: tension drives: ght side of belt to tension slack a) Eff ec ve diameter side of belt b) Velocity ra o 2.1.4 Eff ec ve tension in the belt c) Belt velocity d) Belt length2.1.5 Power transmi ed by fl at e) Angle of contactbelt drives f) Tensions in the belt 2.1.6 Length of open belt g) Torque transmi ed by the belt 2.1.7 Length of crossed belt h) Power transmi ed by the belt i) Force on bearings to all types of belt drives. Content stayed the same.

Content stayed the same.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

2.1.8 Force exerted on the sha bearings 2.2 Vee belts (as for fl at belts, crossed belts excluded) 2.2.1 Finding the number of belts 2.2.2 Force exerted on the sha bearings 2.3 Conveyor belts Nothing in new curriculum referring specifi cally to conveyer belts as such.

2.3.1 Slanted and horizontal drives

2.3.2 Calcula ng the power required 2.3.3 Tension in the ght side and slack side of the belt

Module 3 Metal cu ng machines: Forces ac ng on the cu ng tools (including shaping, drilling, milling and surface grinding machines) Module 9 Metal cu ng machines (weigh ng 15/100)

Objec ve The student should be able to: Do calcula ons regarding forces ac ng on machine cu ng tools and also determine machine effi ciency and power. General aims Do calcula ons regarding forces ac ng on machine cu ng tools. Calculate power, speed, torque, forces and effi ciency of cu ng machines.

3.1 Calcula ng machine effi ciency 1. Introduc on to metal cu ng machines Learning Outcomes List the diff erent types of cu ng machines and iden fy their uses. The rest of the contents stayed the same (old weigh ng 15/100) The old Module 3 has become Module 9 in the new curriculum.

Contents stayed the same.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

3.2 Calcula ons regarding forces ac ng on cu ng tools 2. Calcula ons for cu ng machines Learning Outcomes Calculate power, moment of force, circumferen al speed, and torque, and effi ciency, coeffi cient of fric on, cu ng pressure and cu ng area.

Contents stayed the same.

3.3. Power exerted by cu ng tools Contents stayed the same.

Module 4 Metal protec on Module 2 Metal protec on (weigh ng 5/100)

Objec ve The student should be able to: Defi ne the various types of corrosion, tes ng for corrosion and the relevant processes for preserving metal. General aim Compare various types of corrosion, tes ng for corrosion and the relevant processes for preserving metal.

4.1 Causes of corrosion 1. Introduc on of corrosion and its preven on Learning Outcome Describe corrosion as the destruc on of a material as a result of chemical, electrochemical or metallurgic interac on between the material and the environment.

2. Classifi ca on of corrosion Learning Outcome Explain the two main classes of corrosion. The contents stayed the same (old weigh ng 10/100). The old Module 4 has become Module 2 in the new curriculum. Galvanising has been removed from the new curriculum.

Contents stayed the same.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

3. Diff erent forms of corrosion Learning Outcome Explain the following forms of corrosion: Surface corrosion: a) Stress corrosion b) Galvanic corrosion c) Inter-crystalline corrosion d) Pi ng corrosion. 4.2 Corrosion tes ng 4. Corrosion test 4.2.1. Salt spray test Learning Outcome Explain the most common types of 4.2.2 Humidity test corrosion tests. 4.2.3 Sulphur dioxide test 4.3 Metal protec on processes 5. Metal protec on process 4.3.1 Cathodic protec on Learning Outcome Describe what each of the 4.3.2 Electropla ng following metal protec on 4.3.3 Anodising involves: a) Cathodic protec on 4.3.4 Galvanising b) Electropla ng 4.3.5 Phospha ng c) Anodising d) Phospha ng.

4.4 Surface prepara on for pain ng 4.4.1 Sand and shot blas ng 4.4.2 Descaling 4.4.3 Grease removal 6. Surface prepara on for pain ng Learning Outcome Describe the following processes that we use to prepare steel for spray pain ng: Sandblast cleaning, Descaling and Grease removal.

4.5 Pain ng processes 7. Pain ng process 4.5.1 Air-spray pain ng Learning Outcome Explain the following pain ng 4.5.2 Airless spray pain ng processes: Air spray pain ng, 4.5.3 Electrosta c pain ng Airless spray pain ng, Electrosta c spray pain ng and Dip pain ng.4.5.4 Dip pain ng List advantages and disadvantages of using each of the pain ng processes. Contents stayed the same.

Contents stayed the same.

Contents stayed the same.

Contents stayed the same.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

Module 5 Precision measuring of machine parts Module 4 Precision measuring of machine parts (weigh ng 15/100)

Objec ve The student should be able to: The precision measuring of, and relevant calcula ons on machine parts by means of precision measuring instruments. 5.1 Measuring of tapers: balls, rollers and sine bar Aim Apply precision measuring of machine parts and relevant calcula ons on machine parts by means of precision measuring instruments.

1. Basic principles Learning Outcomes Describe the concepts and terminology of precision measuring machines. 2. Determining tapers using balls Learning Outcome Explain how to measure tapers with balls, sine bars and rollers.

3. Determining tapers of taper plugs Learning Outcome Explain how to use precision balls to determine the taper of a small ring gauge and internal tapers. Analyse how to use balls and slip gauges to determine the taper of a taper plug. Most of the content stayed the same (old weigh ng 15/100) The old Module 5 has become Module 4 in the new curriculum. The following have been removed from the 2021 curriculum: • Measuring of threads: three-wire method, thread micrometer and adjustable slip gauges. • Measuring of gear teeth: the constant chord method.

Content stayed the same.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

4. Determining angles of dovetails Learning Outcomes Explain how balls or rollers are used to determine angles of dovetails.

5.2 Measuring of threads: threewire method, thread micrometer and adjustable slip gauges 5.3 Measuring of gear teeth: the constant chord method

Module 6 Bearings 5. Sine bars Learning Outcomes Draw and label a taper plug gauge with a sine bar. Calculate an inclined and included angle using sine bars.

Module 8 Bearings (weigh ng 15/100)

Objec ve The student should be able to: Defi ne the various types and applica ons of bearings, the advantages and disadvantages of each type and the moun ng and maintenance of diff erent types. Aim To compute bearing loads on the forces which act on the sha being supported by the bearing.

1. Load ac ng on sha s Learning Outcome Explain diff erent types of loads which act on a sha including dead load of the rotator, load produced when the machine performs work, and load produced by transmission of dynamic force. Calculate loads ac ng on a parallel sha gears and cross-sha gears. Content removed from new curriculum.

Content removed from new curriculum.

The content of this module are en rely new (old weigh ng 5/100). The old Module 6 has become Module 8 in the new curriculum.

The content of this module is en rely new.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

2. Bearing load distribu on Learning Outcome Calculate applied bearing loads. 3. Mean load Learning Outcome Explain the concept of mean load. Draw graphs to depict fl uctua ng stepped load, con nuously fl uctua ng load, linear fl uctua ng load, sinusoidal fl uctua ng load. 4. Equivalent load Learning Outcome Discuss the following types of equivalent load: a) Dynamic equivalent radial load b) Dynamic equivalent axial load c) Sta c equivalent axial load. Compare the following types of sta c equivalent axial load: a) Sta c equivalent axial load b) Sta c equivalent radial load. Calculate the load for angular contact ball bearing and tapered ball bearings. Calculate bearing ra ng life and load.

6.1 Sliding bearings (journal bearings) 6.1.1 Radial, thrust and guide bearings 6.1.2 Fric on and hydrodynamic lubrica on Content removed from new curriculum.

See Module 3 Lubrica on This part of Module 6 is part of Module 3 in new curriculum.

6.1.3 Bearing metals 6.1.4 Surface fi nishing and running in of bearings 6.1.5 Lubrica ng holes and grooves See Module 3 Lubrica on

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Exis ng curriculum (1989) New curriculum For implementa on 2021

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6.1.6 Reasons for bearing failure 6.1.7 Various types of lubrica ng devices See Module 3 Lubrica on

6.2 An -fric on bearings Content removed from new curriculum.

6.2.1 Radial, axial and combined loads

6.2.2. Types of bearings: ball bearings, roller bearings, tapered bearings, needle bearings and selfaligning bearings 6.2.3 Applica ons of the various types 6.2.4 Installa on and maintenance of bearings Content removed from new curriculum.

Module 7 Gear drives Module 5 Gear drive (weigh ng 15/100)

Objec ve The student should be able to: Do elementary calcula ons in respect of spur gear systems, as well as epicyclic gear systems Apply elementary calcula ons in respect of spur gear systems, as well as epicyclic gear systems.

7.1 Spur gears 1. Introduc on to gear drives Learning Outcomes List advantages and disadvantages of gear drives when compared with v–belt drives and chain drives. The content stayed the same (old weigh ng 15/100). The old Module 7 has become Module 5 in the new curriculum.

Content stayed the same.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

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7.1.1 Gearing terms and dimensions: pitch circle, pitch circle diameter, module, addendum, dedendum, centre distances, etc.

7.1.2 Elementary calcula ons in respect of the: pitch circle diameter, module, number of teeth, approximate and actual centre distances 2. Gear terminology Learning Outcomes Draw and label the following gear parts: a) Involute b) Module c) Line of ac on and pressure angle d) Pitch circle diameter e) Circular pitch f) Tooth thickness g) Addendum h) Dedendum i) Clearance j) Whole depth k) Working depth l) Blank or outside diameter m) Centre distance between gears on parallel sha s. 3. Simple and compound gear trains Learning Outcomes Explain the working principles of simple and compound gear trains. Calculate the following on simple compound gear trains: a) Module b) Pitch circle diameter c) Circular pitch d) Tooth thickness e) Addendum, Dedendum f) Clearance, Whole depth g) Working depth h) Blank or outside diameter i) Centre distance between sha s.

7.1.3 Velocity ra os of simple and compound drives Content stayed the same.

Content stayed the same.

Content stayed the same.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

7.2 Elementary calcula ons in respect of: 7.2.1 Simple epicyclic gearing 4. Epicyclic gear systems Learning Outcomes Explain basic working principle of epicyclic gear system. Explain the following: Speed increase with sun gear sta onary, Speed increase with annulus sta onary, Speed reduc on with sun gear sta onary, Speed increase and direc on reversal with planet sta onary. 5. Uses of epicyclic gears Learning Outcome List advantages and disadvantages of epicyclic gears. 6. Calcula ons of epicyclic gears Learning Outcomes Explain the method of calcula ng epicyclic gear drives. Calculate the following epicyclic gears: a) The number of teeth or the revolu ons per minute b) The number of teeth or the revolu on per minute of the input sha c) Intermediate sha or output sha , PCD.

Module 8 Hydraulic systems: Elementary calcula ons Module 7 Hydraulic systems (weigh ng 20/100)

Objec ve Student should be able to: Do elementary calcula ons on hydraulic systems, specifi cally of fl ow of water through pipes and Venturi meters Aim Apply elementary calcula ons on hydraulic systems, specifi cally of fl ow of water through pipes and Venturi meters. Content stayed the same.

The content stayed the same. (old weigh ng 15/100) The old Module 8 has become Module 7 in the new curriculum.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

8.1 Water fl owing through round orifi ces

8.2 The three coeffi cients of fl ow (Cv, Cc and Cd) 1. Basic principles of fl uid sta s cs Learning Outcomes Explain the following concepts and terms: a) Proper es of water b) Density c) Rela ve density d) Fluid pressure on a surface e) Pressure intensity f) Pressure head g) Atmospheric pressure. 2. Basic principles of fl uid dynamics Learning Outcome Explain the following: Flow rate (Q), Mass fl ow, Con nuity of fl ow. 3. Energy stored in fl uids Learning Outcome Explain the following concepts: Poten al energy, Kine c energy, Pressure energy.

8.3 Water fl owing through single pipes (constant diameter pipes only) 8.4 The theorem of Bernoulli and its applica on on piping installa ons 4. Bernoulli’s principle Learning Outcomes Describe Bernoulli’s Theorem. Calculate the Poten al, Kine c and Pressure energy. List the three varia ons of Bernoulli’s theorem.

8.5 Flow of water through single pipes from one reservoir to another with constant pipe diameters only Content stayed the same.

Content stayed the same.

Content stayed the same.

Content stayed the same.

Content stayed the same.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

8.6 Velocity of rate of fl ow of water fl owing through venturi meters and tapered pipes 5. Fric onal losses in pipelines Learning Outcomes Describe fric onal losses in pipelines. Darcy’s equa on for fric onal losses. Learning Outcome Apply Darcy’s formula to calculate the fl ow of fl uids in pipes. Chezy’s equa on for fric onal losses. Learning Outcome Apply Chezy’s formula to calculate the fl ow of fl uids in an open channel. 6. Measurement of fl ow Learning Outcomes Explain and calculate the following processes: a) Nozzles and orifi ces b) Theore cal velocity c) Theore cal area d) Theore cal quan ty e) Actual velocity f) Actual area g) Actual quan ty h) Coeffi cient of velocity i) Coeffi cient of contrac on j) Coeffi cient of discharge k) General formula l) Distance travelled by a waterjet m) Energy loss at orifi ce.

7. Venturi meters Learning Outcomes Explain how a Venturi meter is used to measure the fl owrate of fl uids through pipelines. Calculate energy loss on a Venturi meter. Draw and label a Venturi meter. Content stayed the same.

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Exis ng curriculum (1989) New curriculum For implementa on 2021

Addi onal comments by author

Part of bearings Module 6 6.1.2 Fric on and hydrodynamic lubrica on 6.1.5 Lubrica ng holes and grooves 6.1.7 Various types of lubrica ng devices Module 3 Lubrica on (weigh ng 5/100) Aim Iden fy types of lubricants, lubrica on method and explain uses of lubricants.

1. Classifi ca on of lubricants Learning Outcome List the diff erent classes of lubricants and give examples of each.

2. Fluid fi lm bearings Learning Outcome Describe in detail hydrodynamic and hydrosta c lubrica on. 3. Selec on of lubricants Learning Outcome List factors that should be considered when selec ng lubricants. 4. Lubrica on devices Learning Outcome Draw and label diff erent types of lubrica ng devices. 5. Uses of lubricants Learning Outcome List diff erent types of lubricants and their uses.

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P du Toit

Some of the content remained the same. (old weigh ng 5/100) Part of module 6 in the old curriculum has now become Module 3 in the new curriculum.