PARUL POLYTECHNIC INSTITUTE - Weebly · PARUL POLYTECHNIC INSTITUTE ESTIMATING, COSTING AND CONTRACTING MECAHNICAL ENGINEERING 3351905 ~ 4 ~ DATE:- Experiment No. 1 Title: Preparatory

PARUL POLYTECHNIC INSTITUTE ESTIMATING, COSTING AND CONTRACTING MECAHNICAL ENGINEERING 3351905

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PARUL POLYTECHNIC INSTITUTE

(IIND SHIFT)

MECHANICAL ENGINEERING

DEPARTMENT

ESTIMATING, COSTING & CONTRACTING (3351905)

LAB MANUAL

LAB INCHARGE: HARSHIL SHAH LECTURER


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INDEX

Sr. No. Experiment Title Date Page

No. Sign Remark

1 Preparatory Activity

2 Collection of Parts

3 Estimate welding cost

4 Calculate Pattern making and Foundry shop cost

5 Estimate forging cost

6 Estimate Machine Shop Cost

7 Estimation of Process cost

8 Mini project presentation

9 Prepare a list of elements of cost

10 Justify inclusion of overhead allocation or depreciation in cost

11 Estimate Material cost

12 Construct Break Even Chart & Break Even Analysis

13 Cost reduction techniques


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CERTIFICATE

This is to certify that student Mr./Ms._________________________

Enroll. No. ______________ of branch ______________________

Division _______ of batch ________ has satisfactorily completed the

course in the subject “ESTIMATING COSTING AND CONTRACTING”;

Subject code 3351905; Within the Laboratory Premises of the P.P.I.

(2ND SHIFT), Limda during the academic year _______. Date of Submission ________________________

Signature of the staff in Charge ________________________

Name of the Staff in Charge ________________________

Head of the Department ________________________


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DATE:-

Experiment No. 1 Title: Preparatory Activity.

A. Write various equations to calculate area and volume of commonly

used shapes.

B. List densities of commonly used materials.

SR. NO. MATERIAL DENSITY

gm / cc SR. NO. MATERIAL DENSITY

gm / cc

1 CAST IRON 7.2 5 MILD STEEL 7.87

2 ALUMINIUM 2.685 6 TEAK WOOD 0.657 - 0.882

3 BRASS 8.081 7 TIN 7.42 4 BRONZE 8.496 8 COPPER 8.9

C. Machining process parameters of various manufacturing processes for

commonly used materials.

(1) Specification of Drilling Machine: - Capacity to drill holes in steel - 50 mm ϕ - Capacity to drill holes in C.I. - 62 mm ϕ - Morse taper in spindle - 5 - Distance between spindle & column - 350 mm - Spindle transverse - 240 mm - Minimum distance between table and spindle - 510 mm - Minimum distance between base and spindle - 900 mm - Working surface table - 560 mm - Table diameter - 650 mm ϕ - Availability of speed variation - 28 to 2000 R.P.M. - Feed range per revolution - 0.2 to 0.5 mm - Motor speed - 1400 R.P.M. - Required power - 3 kW - Gross weight - 1200 kg - Dimension of packing case - 750 x 450 x 2700 mm


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(2) Specification for Milling Machine: - Working surface - 1000 x 275 mm - No. of Tee-slots - 3 - Top width of key slot - 225 mm - Automatic longitudinal transverse - 590 mm - Vertical motion - 494 mm - Left & right table swivel - 45° Spindle: - No of spindle - 9 - Speed range - 45 to 710 R.P.M.

- Distance between top surface of table & spindle centre - 495 mm

- Distance between bottom surface of table & spindle centre - 135 mm

- Distance from spindle nose to bearing - 460 mm - Space between column sliding face and bearing - 565 mm Feed and rapid transverse: - Longitudinal & cross feed per minute - 15 to 225 mm - Rapid transverse per minute - 1750 mm General: - Power of spindle drive motor - 3 kW - Power of table motor - 0.5 kW - Nett weight - 1500 kg

(3) Specification of Shaping Machine: - Machine size (maximum stroke length) - 500 mm - Stroke length (extreme) - 525 mm - Table cross motion - 675 mm - Minimum height between table and ram - 90 mm - Maximum height between table and ram - 470 mm - Travel of table sleeve - 200 mm - Size of table top - 525 x 410 mm - Depth of table - 400 mm - Feed change - 15 - Range of feed change - 0.3 to 4 mm - Speed of ram - 3 - Stroke per minute - 10 to 133 - Motor horse power - 5 - Nett weight - 2300 kg

(4) Specification of Planning Machine: - Width of job work - 1000 mm - Height of job work - 1000 mm


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- Length of job work - 2000 mm - Width of table - 900 mm - Depth of bed - 56 mm - Motor speed - 1100 - Total height - 2.5 meter - Vise - centre - 600 mm - Length of bed - 4000 mm - Down feed of tool box - 280 mm - Horse power - 13 - Counter shaft pulley - 38 x 14 cm - Counter shaft speed - 400 RPM - Nett weight - 6000 kg - Gross weight - 7000 kg

(5) Specification of centre lathe: (i) Capacity: - Height of centre - 260 mm - Type of bed - Straight - Swing on bed - 575 mm - Swing on carriage wing - 545 mm - Swing over cross slide - 350 mm - Swing over gap - 800 mm - Distance between two centres - 1500 mm

(ii) Head stock: - Spindle nose bore - A-2/6-53 mm - Spindle socket - 60/53 mm bore Table (metric) Speed range: - Forward - 40 to 2000 RPM - 16 steps - Reverse - 60 to 2375 RPM - 8 steps

(iii) Feed and thread:

- Longitudinal feed range - 60-0.04 to 2-24 mm/rev.

- Cross feed range - 60-0.02 to 1-12 mm/rev.

- Lead screw pitch - 6 mm - Metric thread - 40-05 to 28 mm - Inch thread - 60 to 56 to 1 Tpi - Module thread - 40 - 0.25 to 14 mm

(iv) Carriage: - Cross slide travel - 300 mm - Top slide travel - 1500 mm - Tool side travel - 24 mm x 25 mm


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(v) Tail - stock: - Sleeve diameter - 90 mm - morse taper - Sleeve travel - 200 mm

(vi) Motor capacity: - Power - 11 kW

(6) Specification of Cylindrical Grinding Machine: (i) Capacity: - Height of centre - 150 mm - Swing over table - 300 mm - Distance between two centres - 450 mm - Maximum grinding length - 400 mm

(ii) Grinding wheel: - Maximum diameter - 300 mm - Minimum diameter - 200 mm

(iii) Work head: - Taper bore of spindle - MT2

(iv) Tail stock: - Centre - MT2

- Quill movement - 25 mm (v) Table head: - Maximum table travel - 400 mm - Table swill in both the direction - 7°

(vi) Wheel head: - Cross travel of wheel head - 150 mm - Rotation of hand wheel or wheel feed - 1.27 mm - Wheel spindle speed (single) - 225 mm - Speed steps for table transverse - 4

(vii) General: - Wheel head motor - 3 H.P., 1420 R.P.M. - Work head motor - 1 H.P., 920 R.P.M. - Table drive motor - 1 H.P., 920 R.P.M.

- Overall dimension of machine - 1525 x 1020 x 1320 mm

- Weight of machine - 1450 kg

(7) Specification of CNC high vertical lathe: (i) Capacity: - Table diameter - 1250 mm - Maximum swing - 1600 mm - Maximum turning dia. - 1350 mm - Maximum turning height - 1140 mm - Maximum weight of job - 5000 kg


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- Maximum cutting force - 2500 kgf - Table speed - range - 2 x stepless

(ii) Speed rage: - Low - 284 RPM - High - 8350 RPM

(iii) Cross rail: - Maximum height of cross rail - 1455 mm - Minimum height of cross rail - 455 mm - Cross rail steps - 200 mm - 6 step

(iv) Tool head: - Vertical travel - 90 mm - Tool size - 480 m - Tool holder shank size - 32 mm x 32 mm

(v) Horizontal travel: - Towards right of table centre - 1170 mm - Feed - stepless - Feed rate - 0.01 - 500 mm/rev.

(vi) Traverse rate: - Rapid traverse - 10,000 mm/min. - Elevating speed of cross rail - 300 mm/min

D. Various equations used to calculate different machining process time

with figure.

1) Turning Operation:

Turning time, T = min

Where L = Length of cut in cm. F = Feed cm / revolution N = Job revolution / min. - RPM

2) Knurling Operation:

Knurling time, T = min


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Where L = Knurling length - cm F = Feed mm / rev.

N = RPM D = Job diameter - cm S = Knurling speed - m / min

3) Facing Operation:

Facing time, T = min

Where L = cm

4) Drilling Operation:

Drilling time, T = min

Where L = Depth of hole - cm F & N have same meaning as above

5) Reaming Operation:

Reaming time, T = min

Where L = Depth of bored hole - cm F & N have same meaning as above

6) Threading Operation:

Threading time, T = min / cut

Where Pitch = for Single start threads


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Lead = for multi start threads

7) Tapping Operation:

Tapping time, T = min / cut

Where L = Length of cut in cm

D / 2 = Approach & over travel in cm P = Thread pitch - cm N & S as per turning operation

8) Chamfering Operation:

Chamfering time, T = min

Where L = Length of chamfer- cm 0.3 to 0.4 cm

F & N as per turning operation


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DATE:-

Experiment No. 2 Title: Collection of Parts.

a. Collect the finished parts from industries/market/scrap merchants

consisting:

I. Welded parts.

II. Casted parts.

III. Forged parts.

IV. Parts having five to six machining operations like cutting, turning,

threading, grinding, milling, shaping, drilling, etc.

b. Measure and prepare production drawings of all the parts using A4

size paper (Manually).


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DATE:

Experiment No. 3 Title : Estimate welding cost. Introduction :

Welding is very much important in the field of fabrication, reconditioning of worn parts, and has become the main joining process.

Welding Welding Technology is gaining importance in the field of fabrication, reconditioning of worn parts, and has become principal joining process of numerous metal products of different sizes and shapes. The welded joints give the strength equal to that of original metal. With the increase in the importance of welding, estimation of welding cost has also become important, and therefore estimation of the welding cost is being discussed below.

Welding is the process of joining two or more metal pieces by heating them up to the desired temperature with or without the application of pressure and with or without the use of filler metal.

Welding : Welding is defined as the process of joining two or more metal pieces by heating them up to desired temperature with or without the application of pressure and with or without use of filler metal. Types of Welding :

1. Pressure Welding : In this method, two metal pieces are heated up to plastic stage, pressure is applied and metal bond is obtained.

2. Fusion Welding ( Non Pressure Welding ) : In this method, two metal pieces are heated up to plastic stage ( fusion temperature ) and cooled to room temperature. Filler metal is added as per requirement. In this method pressure is not applied.


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Types of Welding Joints :

1. Butt Joint 2. Corner Joint

3. Tee Joint

4. Edge Joint

5. Lap Joint

Edge Preparation : Welding without edge preparation will not be strong enough because two metals may not be having uniform contact throughout the depth. Therefore edge preparation is very important for getting strong joint by welding. The surface should be cleaned so as so to make them free from foreign material and should not be oily.

Gas Welding

In case of gas welding following two welding techniques are adopted in practice:

(i) Leftward or Fore-hand welding.

(ii) Rightward or Back-hand welding.

Left-ward Welding

In this type, welding is started from right hand side of the joint and proceeds towards the left hand side. This method is suitable for welding plates up to 3 mm thickness without edge preparation.


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Right-ward Welding

In this type, welding is started from left hand side of the joint and proceeds towards the right hand side. This method is suitable steel plates which are of more than 5mm thickness. In plates up to 8mm thickness, edge preparation is not required beyond 8mm thickness plates should be beveled to about 30 0.

Gas welding can only be done on plates up to 25mm thickness.

Estimation of Welding Cost

For estimating the welding cost, following cost elements should be considered.

a. Preparation Cost: It includes the cost of edge preparation, proper fit up and other elements before actual starting of welding.

b. Actual welding Cost: This includes two costs.

(i) Cost of material used in welding process like O2H2C2 filer rod, and flux etc.

(ii) Labor Cost. It will be obtained from wages sheets.

(iii) Welding Finishing Cost. This includes, the expenditure made for finishing the welding joint after welding. Post welding treatment (such as heat treatment) cost can also be taken in to account.

(iv) On-cost. All the other overheads on the equipment and other facilities considered under on-cost heading.

Welding Techniques :

1. Left ward Welding : The welding is started from right hand side of the joint and proceeds towards the

left hand side. This method is suitable for welding plates up to 3mm thickness without edge preparation and up to 5 mm thickness with edge preparation.


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2. Right ward welding: The welding is started from left hand side of the joint and proceeds towards the right side. This method is suitable for welding the plates of thickness more than 5 mm. And edge, preparation is required beyond 8 mm thickness plates.

Estimation of Welding cost :

For estimation of the welding cost, following cost elements should be considered.

A. Preparation Cost: It includes the cost of edge preparation, proper fit up and other elements before actual starting of welding.

B. Actual welding cost: This includes two costs

i. Material Cost: Following are the examples of material cost : a. The cost of raw material e.g. sheet, plate stock, casting, etc b. Filler metal and electrode c. Spare parts like nut bolt, rivet, hinge, etc d. Scrape and primary packaging cost e. Oxygen, Acetylene gas etc.

ii. Labour Cost: Following are the examples of labour cost:

a. Labour cost for edge preparation, welding, cleaning etc b. Labour cost for stress removal process c. Painting, brushing, burnishing, anodizing etc labour charges.

C. Overhead Cost : This cost includes following :

i. inspection and quality control cost ii. packing and transportation cost

iii. tooling cost iv. administration cost v. factory overhead

vi. sells and distribution cost vii. energy cost ( e.g. electricity bill )

D. Welding Finishing Cost : This includes, the expenditure made for finishing the

welding joint after welding. Post welding treatment (e.g. heat treatment) cost is included.

E. Factors affecting the welding cost :

Following are the factors affecting the cost of different welding:

a. Gas Welding :

i. Cleaning time of welding plate. ii. Time for fitting work piece plates in fixtures

iii. Cost of base plate iv. Consumption of oxygen and acetylene gases.


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v. Filler rod and flux consumption vi. Labour cost

vii. Fatigue and personal allowances viii. Waste material etc.

ix. Direct expenses x. Time of welding

b. Arc Welding:

i. Cleaning time of welding plate

ii. Cost of base plate iii. Time for fitting work piece plates in fixtures. iv. Consumption of electrode v. Time of welding

vi. Labour cost vii. Power consumption

viii. Fatigue and personnel allowances ix. Cost of post welding processes like heat treatment etc x. Wastage of material, electrode etc

xi. Efficiency of the machine Procedure to find out the cost of welding :

a. Gas welding :

i. Cost of Oxygen: a. Consumption of Oxygen = Consumption rate of O₂ x Welding Time b. Cost of Oxygen = Consumption of 0₂ x Cost of 0₂ (Rs / m3 )

ii. Cost of Acetylene: a. Consumption of Acetylene = Consumption rate of C₂H₂ x Welding Time b. Cost of C₂H₂ = Consumption of C₂H₂ X Cost of C₂H₂ ( Rs. / m3 )

iii. Cost of Filler Rod : a. Filler rod ( length of filler rod ) consumed=Welding Length x

consumption rate of rod per meter length of welding (m/meter of welding )

b. Filler rod mass = Length of filler rod X c/s area of rod x density c. Cost of filler rod = Mass of filler rod X rate of filler rod (Rs. / kg )

iv. Total welding material cost = Cost of 02 + Cost of C2H2 + Cost of filler rod

b. Arc welding :

i. Welding consumable cost a. Consumption of electrode = Consumption rate of electrode per meter

length x total welding length b. Electrode cost = consumption of electrode x rate of electrode ( Rs. /

electrode length )


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ii. Labour cost : a. Welding time = Total length of welding in meter

Welding speed (in m / min)

If operating factor is considered then Actual Welding time = Total length of welding in meter Welding speed (in m / min) X operating factor

Examples: (Examples will be given by concerned lecturer)


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DATE :

Experiment No. 4

Title : Calculate Pattern making and Foundry shop cost.

Introduction : Casting is done to produce intricate shaped terms, which are otherwise difficult and very costly if produced by any other methods. In casting, molten metal is poured into a cavity ( mould ) of the desired shaped form and allowed to solidify.

Mould is prepared by pattern. Metal contracts on solidification so the size of the casting will be slightly smaller than the size of cavity or pattern. So to overcome this problem, allowances are considered while making the pattern.

Pattern : Pattern is a model of the product to be casted. The dimension of the pattern includes the allowances i. e. shrinkage allowances, draft allowance and machining allowances.

Pattern Material : Wood, Metals, Plaster of Paris, Plastic, etc. and precision work wax is used as a pattern material.

Pattern Allowances : Following pattern allowances are added in the size of the work piece to be casted.

1. Shrinkage ( Contraction ) Allowances : As the temperature of the metal reduces it contracts. So when metal is poured in to the cavity ( mould ) then it contracts due to reduction in temperature. So it’s size reduces. This allowance is considered from the rate of contraction of the material. the rate of contraction is different for different materials.

2. Machining Allowances : After casting, machining is required to be done for achieving the finished shape and size of the work piece. This allowances depends on the nature and quality of the work.

3. Draft Allowances : This allowance is provided to facilitate the withdrawal of the pattern from the mould. For this purpose a slight taper is provided in the pattern.


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4. Distortion Allowances : This allowance is given for intricate shaped work piece like U or V shape. When possibility of distortion is more in any particular direction, this type of allowances are provided to overcome the distortion.

5. Shake Allowances : Before pattern is taken out from the cavity, hammering is done with wooden hammer so that it can be easily taken out. Therefore the size of mold cavity increases slightly. So negative allowance is provided to overcome this problem, which is known as shake allowances.

Estimation of Pattern Cost : The pattern cost can be divided in to the following :

1. Direct Material Cost : The sum of expenditure made on material required for pattern

making is known as direct material cost. Volume of material required for pattern making is calculated and different allowances are added.

Size of raw material = Size of finished job – pattern allowances + finishing and

cutting allowances

Raw material required ( weight ) = Volume of raw material x density

Cost of pattern material = Direct material cost x cost of pattern material per kg

2. Direct Labour Cost : This cost is calculated from labour rate of pattern makers.

3. Overheads : The expenditure other than direct material and direct labour is included

in overhead.

Examples : (Examples will be given by concerned lecturer)


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DATE:-

Experiment No. 5

Title : Estimate forging cost. Introduction :

Forging Forging is the process in which metal is heated at sufficiently high temperature to bring it to the plastic state. During this plastic state desired shape is given by applying sufficient force either by hand (manually) or by machine.

The shop in which forging is done is known as 'Forging shop'.

Type of forging

a. Hand forging. b. Machine forging.

Hand Forging

When forging is done by hand, the process is known as hand forging. In case of heavy jobs, smith is assisted by a hammer-man. Important hand forging operations are drawing down, upsetting, bending, punching, swaging and shearing etc.

Machine Forging

The processes, in which forging is done by machines are known as Machine Forging. Machine forging is useful for heavy and complicated jobs requiring large forces.

(i) Smith forging: In this process metal is heated in suitable forges and then shaping of the metal is carried out by power or steam hammers and hand tools. In this method accuracy depends upon the experience and skill of the smith.

With this method, similar pieces cannot be obtained and process requires too much time.

This method is used for large and simple types of products.

(ii) Drop forging: It is a process of hammering the metal during plastic state in impression dies. Die is used in two parts, one die is allowed to drop on the other, the hot metal in the plastic state is thus squeezed between the two dies and thus form the desired shaped of the forged product. Steam or power hammer can be used, instead of allowing the upper die to drop on the lower die from certain height. This process takes less time.This is generally used, where large numbers of identical shapes of good quality forgings are to be produced.


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(iii) Press Forging: Very heavy forgings are given proper shapes by the presses. This press can either be hydraulically operated or mechanically operated. Press forging method employs squeezing of plastic metal or metal in plastic condition and gives the required shape in the dies. Pressure is applied continuously and gradually. By applying gradual pressure excessive vibration can be avoided, which may otherwise disturb the machine alignment by rapid blows of hammer.

Forging Operations The shape of material can be transformed by forging with the aid of the following operations:

1. Drawing Down: It is also known as Drawing Out. This operation is performed to increase the length of the workpiece in forging by decreasing the cross-sectional area.

This process is performed by hammering the hot workpiece lengthwise to reduce cross-section.

2. Up Setting: This is the reverse of Drawing Down operation. In this operation, the cross-section of workpiece is increased at the expense of length.

This process is performed by hammering one end of hot workpiece while other end is supported against the anvil.

3. Bending: Bending is done by holding the workpiece between two fixtures and desired bend can be given by striking the workpiece with the help of hammer. This operation can also be carried out on the anvil break.

4. Punching and Drafting: Punching operation is performed by a tool called punch, for producing holes in the workpiece, when it is in the hot state; and drafting is an operation carried on by a special tool known as draft to enlarge the hole.

Forging Estimation Procedure

Estimation procedure varies from shop to shop and person to person but for a general procedure, following factors may be considered:

Estimation of Net Weight

For estimation of net weight of the forged component, following procedure is adopted:

a. Break up the job drawing into suitable geometrical section, whose volumes can easily be calculated by using mensuration.

b. Next, find the value of each section, neglecting rounded corners and taking suitable assumptions.

c. Now, find total volume of material required by subtracting volume of the hollow spaces.

d. Lastly, calculate the weight of the component by multiplying the total volume with its density.


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Estimation of Losses

Certain amount of material is lost during different forging operations. The exact estimation of losses is very difficult, but by practical experience, the losses can be calculated during forging as accurate as possible. Various losses in forging are:

(i) Tong Loss: While performing forging operations, some length of stock is required for holding the job in tong. This length is an extra length, which is removed after completion of the job. For estimation purposes, the weight of the extra length is also considered and is known as Tong loss. 2 to 3 cm of the stock length.

(ii) Scale Loss: The outer surface of the hot metal is generally oxidized, and when hammering is done oxidized film is broken and falls down in the form of scale. It reduces the dimensions of the job, and therefore, this loss must be considered for estimation purposes. Generally, it is taken as 6% of the net weight.

(iii) Flash Loss: It is the surplus metal, which comes out between the two meeting surfaces of the dies. For getting finished product, this surplus metal is required to be trimmed off.

This loss may be calculated by assuming it to be 20mm wide and 3mm thick all around the periphery of the dies.

Thus, volume of flash loss = periphery x 20x 3 cu mm nearly.

(iv) Shear Loss: The required sizes of workpiece for forging operations are obtained from long bars by sawing or shearing. In sawing operation, some material is always lost. If last piece of bar is not to be required length, it is rejected. This loss of material is taken as 5% of the net weight.

(v) Sprue Loss: The portion of metal between the length held in the tong and the material in the die is called sprue. This is also a metal loss and can be taken as 7% of the weight.

Thus we can see that nearly 15-20% of the net weight of metal is lost during forging. Therefore, in estimation their consideration is very essential and total weight will be net weight of job plus sum of the weight of different losses occurred during forging. Thus this gives the amount of weight of material required for forging.

Forging is the process, in which the heated at sufficiently high temperature to bring it to the plastic state desired shape is given by applying sufficient force either by hand ( manually ) or by machine. Types of Forging :

1. Hand Forging : When forging is done by hand ( manually ), the process is known as Hand Forging. In case of heavy jobs smith is assisted by a hammer man. Drawing down, upsetting, bending, punching, swaging and shearing are important hand forging operation.


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2. Machine Forging : The processes, in which forging is done by machines are known as Machine Forging. Machine forging is useful for heavy and complicated jobs requiring large forces.

Machine forging can be classified as :

I. Smith Forging : In this process metal is heated in suitable forges and then shaping of the metal is carried out by power or steam hammers and hand tools. In this method accuracy depends upon the experience and skill of the smith.

With this method, similar pieces cannot be obtained and process require too

much time. This method is used for large and simple types of products.

II. Drop Forging : It is the process of hammering the metal during plastic state in impression dies. Die is used in two parts; one die is allowed to drop on the other. The hot metal in the plastic state is thus squeezed between the two dies and thus forms the desired shape of the forged product. Steam or power hammer can be used, instead of allowing the upper die to drop on the lower die form certain height. This process takes less time.

This is generally used, where large number of identical shapes of good quality forgings are to be produced.

III. Press forging : Very heavy forgings are given proper shape by the presses. These presses can either be hydraulically operated or be mechanically operated. Press forging method employs squeezing of plastic metal or metal in plastic condition and gives the required shape in dies. Pressure excessive vibrations can be avoided, which may otherwise disturb the machine alignment by rapid blows of hammer.

Forging Operations : The shape of material can be transformed by forging with the aid of the following operations :

1. Drawing Down : It is also known as Drawing Out. This operation is performed to increase the length of the work piece in forging by decreasing the cross-sectional area.

This process is performed by hammering the hot work piece lengthwise to reduce

cross-section.

2. Up Setting : This is the reverse of Drawing Down operation. In this operation, the cross-section of the work piece is increased at the expense of length. This process is performed by hammering one end of hot work piece while other end is supported against the anvil.

3. Bending : Bending is done by holding the work piece between two fixtures and desired bend can be given by striking the work piece with the help of hammer. This operation can also be carried out on the anvil beak.


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4. Punching and Drafting: Punching operation is performed by a tool called punch, for producing holes in the work piece, when it is the hot state; and drafting is an operation carried on by a special tool known as draft to enlarge the hole.

5. Squeezing : The hot metal is hold between two dies and pressure is applied so the shape of the material will change as per the internal shape of the die.

6. Setting Down : It is the process of providing the neck to some portion of the work piece by reducing the cross sectional area.

7. Swaging : Swage is used for shaping the metal in the required shape. Examples : (Examples will be given by concerned lecturer)


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DATE:-

Experiment No. 6

Title : Estimate Machine Shop Cost.

Introduction :

Machining is done to shape the product as per requirement There are certain machining operations and there are some methods to calculate the cost of machining cost

Terms :

1. Speed (N) : It is the speed at which job is rotating about in the chuck Unit is rpm ( Revolution per minute)

2. Cutting Speed (S) : The distance traveled by the tool along the material to be cut in

unit time is known as Cutting Speed (S) . Unit is m/min.

S = πDN m / min 100

N = Rotational speed of work piece in RPM D = Diameter of the work piece in cm.

3. Feed ( F ) : The distance through which the tool advances in to the work piece during one revolution of the work piece or the tool or cutter. Unit is mm/rev.

F = L

N x T

F = Feed in mm per revolution N = Rotational speed of work piece in RPM T = Time in min L = Cutting length. in mm

4. Approach ( A ) : The distance traveled by tool before it starts the cutting is known as approach distance. Unit is mm

5. Over Run / Over travel ( 0 ) : It is the distance traveled by the cutting tool after the cutting action is over. Unit is mm


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N rpm

d

Cutting Length L

A Methods to find out the time of machining of different operations on Lathe m / c :

1. Turning :

Cutting Speed S = πDN m / min 100

Machining Time T = L / F*N ( L = L’ + A + O )

2. Knurling : 3. Facing : 4. Drilling : 5. Reaming : 6. Boring : 7. Threading :

T = L + 0.7 where, p = pitch or lead and N = rpm

P x N Pitch = 1 / threads per cm… … … for single start thread Pitch = No of starts / threads per cm… … … for multi start thread

8. Tapping :

Machine Shop Estimating For estimation purposes, machining cost is calculated after finding the material cost. Machining is done on castings, forgings and bar stocks etc., for getting the exact size and shape of the product.

We shall discuss in the chapter on 'Estimation in Foundry Shop' that certain amount of material is added as machining allowance. For this purpose, we take slightly bigger dimensions than that shown on finished drawings on the sides which are o be machined.

Machine Shop Operations

Generally following operations are performed in the machine shop on different machines:


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1. Turning. 2. Knurling. 3. Facing. 4. Drilling. 5. Boring. 6. Reaming 7. Threading. 8. Tapping. 9. Milling. 10. Grinding. 11. Shaping. 12. Planning.

In estimating, our aim is to find out the time, which an operator takes for performing the machining operation, for calculating their wages. In addition to this machining time (also known as operation time), following time considerations are taken:

(i) Setting up the job and tool or cutters. (ii) Setting up the machine. (iii) Inspection of job. (iv) Fatigue allowance. (v) Tool changing and sharpening time. (vi) Machine cleaning and servicing time. (vii) Personal allowance.

In the study of machining time following terms are generally used:

Cutting Speed

It is the distance which tool travels along the material in one minute. Its unit is meters/min.

Let us consider an example, in which a job of D is revolving at a speed of N r.p.m. Then, distance travelled by the tool point in one min = Distance moved in one revolution x Revolutions performed in one min.

Therefore, Cutting Speed = 3.14D*N/100 m or min

Cutting speed depends on the following factors:

(i) Hard material requires a lower cutting speed than that of soft and ductile materials. (ii) High speed tools and tools of special cutting alloys can cut at higher cutting speeds than carbon steel tools. (iii) If the depth of cut and feed is more, then less cutting speed is taken and vice versa. (iv) By using good cutting fluids, cutting speeds may be increased.

An estimator should consider above factor while selecting a suitable cutting speed.

Table on next page gives the cutting speeds for different materials on different operations. The cutting speeds are with H.S.S. tools.

Note: (i) Cutting speeds for grinding in Table show the speed of the work at which it travels against the grinding wheel, while grinding wheel has its speed for external grinding at 1800 m/min, for internal grinding as 1200 m/min and for surface grinding as 1500 m/min. (ii) When the tungsten carbide tools are used, the cutting speeds are 2 to 3 times of these speeds.


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Feed

It is the distance, through which the tool advances into the workpiece during one revolution of the workpiece or the tool or cutter. Its unit is mm/rev.

As the feed depends on the depth of cut, cutting speed and power of the machine, hence no specific values for this can be mentioned.

Depth of Cut

It is the amount by which a tool or cutter is inserted into the metal during one cut. In other words, it is the thickness of the metal removed in one cut. It is generally measured in mm.



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DATE:-

Experiment No. 7

Title : Estimation of Process cost. Introduction: In an industry where standardized products are produced through a standard set of processes, the estimation becomes simple. Oil refining, chemical production, production activities of paper mill, flour milling, cement production etc. are the areas where this types of estimate is used. Its objective is to estimate the cost of each stage of production. This method of estimation indicates production cost estimation of the products by involving various stages of a production process. The estimate of time for production, material consumed, power, light and heating is prepared for each stage activities. For this purpose process cost estimation sheet is used.

Process Cost Estimation Sheet Estimating Period : ...........................................................................................................

Date Material Labour Hour

Over Head

Process stage - 1 Process stage - 2

Material Labour Hour O.H. Material Labour

Hour O.H.

Summary : Stage - 1 Rs. Total Rs. Materials ............ Labour ............ Overhead ............ ............ Stage - 2 Materials ............ Labour ............ Overhead ............ ............ Estimated process cost. Rs. .......... Estimated production ........... (No. of units) Estimated cost per unit. Rs. .......... Process sheet is the summary of cost estimation for certain period say one month. The operating charges are noted in it partaining to the following details.

1. The transfer cost from the previous operation. 2. The cost incurred by each production operation showing materials, labour and

overhead in separate column.


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Procedure & Steps of Process Cost Estimation: The systems of diesel generating set are as under.

1. Fuel storage and supply system. 2. System for injecting fuel in a diesel engine. 3. Air supply system. 4. Cooling system. 5. Lubrication system. 6. Starting system. 7. Governing system.

The thermal efficiency of diesel generating set reduces with the increase in load on it and its specific fuel consumption is increase. Following costs are considered to estimate power generation cost of a diesel generating set.

1. Interest & depreciation of capital investment. 2. Fuel costs. 3. Cost of lubricating oil. 4. Fixed and running maintenance costs. 5. Labour costs. 6. Overhead costs.

Power produced at Thermal Power Plant: Following costs are considered to estimate the power cost in a thermal power plant. For thermal power station costs of land, building, equipments, transmission lines & distributor lines are considered. Again in sub-stations & other expenses needs capital investments. Fixed cost & running or variable cost is included in the total cost of power generation. Cost estimation per pouch for pouch packaging: Cost elements of pouch packaging are as under.

1. Cost of goods packed in the pouch. 2. Cost of pouch material. 3. Cost of packaging the pouch.

a. Labour cost. b. Interest & depreciation of packing machine. c. Power cost.

4. Overheads. Cost Estimation Per Unit Weight of Ice Production of an Ice Plant: Ice plant are popular for producing ice on commercial basis. Ice consumption has gone high as it is used in chemical industries, food preservation and day to day consumption. A commercial type of ice-plant is shown in fig. Ice-canes are used for producing ice. Pure water is filled in each ice canes. A tank is filled with brine-solution of solution chloride (Nacl), and water. The canes filled with pure water are placed in this tank. Freezing point of brine-solution is 0° C. This brine absorbs heat from the pure water and transform the pure water into ice. The heat from the brine solution goes to the


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evaporator. Ice plant operates as per vapour compression system uses Ammonia (NH3) as refrigerant. In 24 hours at 0° C, the cooling load or refrigerating effect transforming water into ice is called 1 ton refrigeration. 1 ton refrigeration = 211 kJ / min = 12660 kJ / hr. = 3.516 kw Cost Elements of an Ice Plant:

1. Power cost of brine-agitator motor. 2. Power cost of compressor motor. 3. Power cost of cooling water circulating motor. 4. Cost of pure water. 5. Cost of brine solution. 6. Labour cost. 7. Transportation cost of Ice delivery. 8. Plant maintenance cost. 9. Interest & depreciation of capital invested in ice plant.



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DATE:-

Experiment No. 8

Title : Mini project presentation.


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DATE:-

Experiment No. 9

Title: Prepare a list of elements of cost. Introduction:

In any factory, the cost of a product is calculated so that the exact idea of the amount of profit can be made. The total cost is divided in to different headings known as Elements of Cost.

Elements of Cost: The cost of the product manufactured can be divided in to three main ‘Elements’.

1. Material cost 2. Labour cost 3. Expenses

Costing Costing has been defined by the Institute of Cost and Works Accountants, England as:

"The technique and process of ascertaining costs". Whereas, Wheldon has defined the costing as: "Costing is the classifying, recording and appropriate allocation of expenditure for the determination of the costs of products or services; and for presentation of suitably arranged data for the purposes of control, and guidance of management".

Material Cost :

a. Direct Material Cost: This is the cost of the material on which, the processes or operations are done to achieve the final shape of the main product. E.g.

i. The cost of wood for making the furniture. ii. The cost of material (Aluminium, C.S., etc.) for manufacturing any

component (Piston, Cylinder, Connecting Rod, etc.) b. Indirect Material Cost: This is the cost of the material, which is not the part of

the main product but it is needed in various shops to manufacture the final product. E.g.

i. The cost of the coolant, fuel. ii. The cost of grease, lubricating oil, etc.

iii. The cost of kerosene oil, cotton waste, etc.

Labour Cost :

a. Direct Labour Cost: The worker, who actually work or process different materials manually or with the aid of machines is known as ‘Direct Labour Cost’. E.g.

i. The wages of turner, welder, milling operator, etc. ii. The wages of pattern maker, molder, painter, assembly worker, etc.


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b. Indirect Labour Cost: Any other labour, who helps the productive labour in performing their duties is known as Indirect Labour. Their wages can not be charged directly to a particular job but are charged on the total number of products produced in the plant during a particular period. E.g.

i. The wages of supervisors, inspectors, store keepers, crane driver, etc. ii. The wages of securities, gate keepers, helpers, etc.

Direct and Indirect Expenses In every industry there are several other expenditures, such as cost of advertisement, building rent, depreciation charges of plant and factory building, cost of packing, cost of transportation, salaries and commission to salesmen etc. All these expenditures are known as expenses. So, we can say that except direct material and direct labor cost, all other expenses, which are incurred in the factory are known as expenses.

The cost of indirect material and indirect labor is also included in the expenses.

Expenses may be of 2 classes,

1. Direct or chargeable expenses 2. Indirect expenses

Direct Expenses

These are those expenses, which can be charged directly to a particular job and incurred for that specific job only. For example, cost of special jigs and fixtures, cost of some special patterns and cost of experimental work on a particular job etc.

Indirect Expenses

These are also known as overhead charges, on cost, burden or indirect charges. These can be further classified as:

a. Factory expenses b. Administrative expenses c. Selling expenses d. Distribution expenses

Factory Expenses

These overheads include all the expenditures made on the actual operation of the product in the plant, such as indirect materials and indirect labor. It is also named as works on cost.


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Administrative Expenses

These overheads include all the expenditure made on the salaries of general office staff and executive staff, telegraph, fax, computer and telephone charges, depreciation of office building and equipment etc. This is also known as establishment on-cost or office expenses.

Selling Expenses

These overheads include all the expenditure made on the salaries of persons working in sales department, advertising expenses and agency expenses etc.

These overheads include all the expenses made on holding finished stock, dispatching them to the customer and packing cost etc.

Distribution Expenses

These overheads include all the expenses made on holding finished stock, dispatching them to the customer and packing cost etc.

Difference between Estimating and Costing Although estimating and costing both are required to decide the price of the product, even then the two are different as explained below:

1. Estimation is aimed to calculate the probable cost of the product before the manufacturing starts, and while costing is the determination of actual cost of the product by adding various elements of expenses incurred.

2. Estimation requires a highly technical knowledge hence an estimator is basically an engineer and costing requires the knowledge of accounts and therefore costing is done by accountants.

3. Estimation forecasts about the probable cost and hence one can know before the manufacture that the manufacturing of the product shall be profitable or not, and whether one should manufacture it or not, but costing tells after the manufacture about the profitability of the product.

Procedure for Costing

Actual expenditure incurred in various departments on different times are collected by the costing department. The expenditures are then categorized under the following main heads: 1. Direct material cost, 2. Direct labor cost, 3. Factory overheads, 4. Administrative overheads, 5. Selling overheads.


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Costing Methods Costing method to be followed in a particular enterprise depends upon: 1. Nature of industry 2. Class of products being manufactured 3. Quantity of goods products and 4. The wages of the workers employed and paid the system of payment.

However, the following may be considered to be the important methods of costing: 1. Multiple costs 2. Job costs 3. Departmental costs 4. Unit costs 5. Process costs 6. Operating costs

Overhead : 1. Fixed Overhead : These are those indirect expenses, which remain constant whatever may be the volume

of the production. e.g. i. Rent of the Building.

ii. Insurance and depreciation of building, plant machinery furniture etc. iii. Postage, telephone, internet, fax, etc. iv. Internet on capital invested. v. Salaries of officers, engineers, managers etc.

2. Variable Overhead : These are those indirect expenses, which vary with the volume of Production.e.g

i. Power and/or fuel consumption. ii. Tooling cost.

iii. Repairs and maintenance of the plant, machinery etc. iv. Indirect material & indirect labour cost. v. Service after sales.

vi. Packing, forwarding and transportation cost. vii. Trade discount.


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Component of Cost :

The various components of cost are : 1. Prime Cost : It consists of direct material cost, direct labour cost and direct

expenses. Prime cost = Direct Material Cost + Direct labour cost + Direct Expenses.

2. Factory Cost : It consist of Prime cost and Factory expenses.

Factory Cost = Prime Cost + Factory Expenses

3. Office Cost ( Production Cost ) : It consists of Factory cost and administrative overhead.

Office Cost = Factory Cost + Administrative Cost

4. Total Cost : It includes Office cost and sells and distribution cost. Total Cost = Office Cost + Sells and Distribution Expenses.

Examples : ( the examples will be given by concerned teacher of this chapter. )


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DATE:- Experiment No. 10

Title : Justify inclusion of overhead allocation or depreciation in cost. Introduction : After estimating the total on-cost, next step is the allocation of this on-cost over the production. To run the business in utmost economical way, it is necessary to know, the variation of on-cost with the variation of production. Overhead Allocation of Cost : Overheads are those expenses which, directly can not be charged to a particular product. There are some methods to charge these expenses over the product. The distribution of these overhead charges over the product is known as allocation of overhead cost.

A. Methods of Allocation of Overhead :

1. Percentage on Prime cost : This is very simple method and used in small industries.

This method is useful in the following two cases :

i. Only one type of product is being manufactured. And the cost of direct raw material is more. E.g. Casting industries, Forging industries, etc.

ii. Direct labour cost is nearly same as direct material cost.

This method is not useful in the following cases : i. When the labour charge varies as per the skill required in different

product. ii. There is no any relation between factory overhead and material cost in

this method.

2. Percentage on Direct Material cost : In this method, allocation of on-cost depends upon the total direct material cost.

Percentage on prime cost = Total overhead X 100 %

Prime cost

Percentage on Direct Labour Cost = Total overheads X 100 %

Direct Material cost

Documents

PARUL POLYTECHNIC INSTITUTE - Weebly · PARUL POLYTECHNIC INSTITUTE ESTIMATING, COSTING AND CONTRACTING MECAHNICAL ENGINEERING 3351905 ~ 4 ~ DATE:- Experiment No. 1 Title: Preparatory