PATTERN ALLOWANCES

After drawing figures of patterns and writing few lines about patterns.I would like to add about pattern allowances as laid under.

1.Shrikage or contraction allowance
2.Machining or finish allowances
3.Draft or Taper allowance
4.Distortion or camber allowance
5.Shake or rapping allowance
6.Mould wall movement allowance
As explained in the class write few lines with figures.

I have already dictated the following in the class.
Classification of sand.
Preparation of moulding sand.
Preparation of core sand.
Riser,Runner and Gating.
Engineering Materials-Metal, Non-metal, Ferrous & Non-ferrous metals etc.

Plant Layout contd.

Dear Students,
Kindly make layouts i.e. Product and Process layouts. The objectives of a good plant layout are laid down.

1.Minimising & efficiently control of material handling and transportation.
2.Bottlenecks and congestion to be eliminated for smooth and continuous flow.
3.Movement of persons to be minimised for effective utilisation of equipment & space.
4.Working place to be safe,well ventilated, and free from dust,noise, fumes & odour.
5.Waiting time for semifinished product should be minimised.
6.Cubic space should be utilised in effective manner.
7.To increase productivity with reduced capital investment.
8.To provide flexibility of manufacturing and management.
9.To allow the movement of material with desired speed and lowest cost.
10.To promote job satisfaction and good relation between management & employees.

FOUNDRY.........FORGING..........FORMING

FOUNDARY: Foundary is a place, where casting is done.Casting is a process of pouring molten metal in a cavity called MOULD.When this mould is filled with molten metal, it solidifies and produces a casting.

PATTERN:Pattern is a model of desired product(casting)i.e. constructed in such a way that it can be used for forming an impression called mould.Pattern is replica of casting.

Pattern Materials:
* Wood
* Metal(Cast Iron, Brass, Aluminium alloys & White Metal etc)
* Plaster
* Plastic Compound
* Wax

The following factors are to be considered for selection of pattern material.
1. Design of casting
2. Quality and quantity of casting
3. Shape and size of casting
4. Types of moulding
5. Types of process of casting
6. Moulding material
7. Possibility of design changes
8. Chances of repeat orders
9. Pattern material should be light in weight, easily worked, shaped and joinable.
10.It should be durable,strong, hard, resistant to wear abrasion, corrosion and chemical reaction.
11. Dimensionally stable,unaffected by variation in temprature and humidity.
12. Low cost, easily repairable and re-usable.
13. Ability to take a good finish.

Refer Casting processes figure at my site 9262k and draw of your own and write basic steps taken in a casting process as explained in the class i.e. from pattern making to dispatch of the cast product.
Main shops in the FOUNDRY.
Pattern Shop, Moulding shop and melting shop( Furnace).
Name the types of patterns and draw the figures. Write why & where are these used.
Types: Solid and single piece, Split(two Pieces), Multi-piece,Match plate, Gated, Skeleton,Sweep, Pattern with loose pieces, Cope & drag pattern, Follow board pattern and Segmental pattern.

Types of Plant Layouts

a) PRODUCT LAYOUT
Machines are arranged according to sequence of operations. This type of layout is preferred for mass production with less variety-normally used in assembly shop of automobiles, mass production of plastic goods and still mills etc.

Advantages:
-Minimizing material handling due to straight flow.
-Product completes in lesser time.
-Continuous flow of work.
-Better coordination in planning & control of production.
-Less floor area for same volume of work.
-Less skilled worker.
b) PROCESS LAYOUT
Machines performing similar operations are arranged in groups at one location not according to sequence of operation. For examples all lathe m/cs are placed at one place and all milling m/cs are placed at another place. Generally used for low volume of production needed at regular interval.

Advantages:
-Lower initial investment
-General purpose m/cs may serve the purpose
-Greater flexibility in utilisation.
-Optimum use of m/cs.
-At the time of breakdown, transferring of work to other m/cs may easily be done.
-Variety of parts make the work interesting and challanging.
-Better productivity,as supervisor and worker attend one type of m/c.

OBJECTIVES OF GOOD PLANT LAYOUT

PLANT LAYOUT

Plant is a place, where persons, money, material, machinery, equipment and tools etc are brought together for producing/ manufacturing products. Layout means a plan/ method for arranging all these facilities/ things in an effective & perfect manner so that all the functions are carried out effectively and economically.

Layout is not restricted to plant only it is equally necessary for houses, buildings,schools, colleges, hospitals, malls and other such constructions.

Again plant layout does not mean of planning new plants only. It may involve:
1. Re-layout of existing plant i.e. relocation
2. Expansion of existing plant
3. Modification/ improvement of existing plant.
Plant layout may be divided mainly into two types.
a) Product Layout
b) process Layout

ME- 105F                               WORKSHOP TECHNOLOGY

L       T       P                                                                                  Class Work: 50 Marks

2       0       2                                                                                         Examinations: 25 Marks

                                                                                                                 Total: 75 Marks                                                                                                                                                        Duration of Exam:  3 Hrs.

NOTE: -

1. At least ten experiments/ jobs are to be performed/ prepared by students in the semester. 

2. At least 8 experiments/ jobs should be performed/ prepared from the above list, remaining two

 May either be performed/ prepared from the above list or designed & set by the concerned

 Institution as per the scope of the syllabus of the   ‘Manufacturing Processes’ as mentioned

 Below.

Manufacturing Processes:

Introduction to Manufacturing Processes and their Classification. Industrial Safety; Introduction, Types of Accidents, Causes and Common Sources of Accident, Methods of Safety, First Aid., Objectives of Layout, Types of Plant Layout and their Advantages.

Foundry, Forming and Wielding:          

Foundry: Introduction to Casting Processes, Basic Steps in Casting Processes. Pattern: Types of Pattern and Allowances. Sand Casting: Sand Properties, Constituents and Preparation. Mould & Core making with assembly and its Types. Gating System. Melting of Metal, Furnaces and Cupola, Metal Pouring, Fettling. Casting Treatment, Inspection and Quality Control. Sand Casting Defects & Remedies.

Forming Processes: Basic Principle of  Hot & Cold Working, Hot & Cold Working Processes, Rolling, Extrusion, Forging, Drawing, Wire Drawing and Spinning. Sheet Metal Operations: Measuring, Layout marking, Shearing, Punching, Blanking, Piercing, Forming, Bending and Joining.

Welding: Introduction to Welding, Classification of Welding Processes, Gas Welding: Oxy-Acetylene Welding, Resistance Welding; Spot and Seam Welding, Arc Welding: Metal Arc, TIG & MIG Welding, Welding Defects and Remedies, Soldering & Brazing.

 

 

 

 

List  of Experiments/ Jobs

1.            To study different types of measuring tools used in metrology and determine least counts of vernier calipers, micrometers and vernier height gauges.

2.            To study different types of machine tools ( lathe, shape or planer or slotter, milling, drilling machines )

3.            To prepare a job on a lathe involving facing, outside turning, taper turning, step turning, radius making and parting-off.

4.            To study different types of fitting tools and marking tools used in fitting practice.

5.            To prepare lay out on a metal sheet by making and prepare rectangular tray, pipe shaped components e.g. funnel.

6.            To prepare joints for welding suitable of r butt welding and lap welding.

7.            To perform pipe welding.

8.            To study various types of carpentry tools and prepare simple types of at least two wooden joints.

9.            To prepare simple engineering components/ shapes by forging.

10.         To prepare mold and core assembly, to put metal in the mold and fettle the casting.

11.         To prepare horizontal surface/ vertical surface/ curved surface/ slots or V-grooves on a shaper/ planner.

12.         To prepare a job involving side and face milling on a milling machine.