Engineerig Project-Paper Cutting

HI-TECH POLYTECHNIC AURANGABAD

Project Report On

PAPER CUTTING & RE-WOUNDING MACHINE

SUBMITTED BY

DEPARTMENT OF MECHANICAL ENGINEERING

HI- TECH POLYTECHNIC COLLEGE, AURANGABAD.

2008-2009

Hi-Tech PolyTechnic

AurAngAbAd

Certificate

This is to certified that Mr. ---------------------------------------------- has successfully completed his project on Paper Cutting And Wounding Machine during academic year 2008-2009 with all respect. Project Guide H.O.D. Prof. A. P. Golhar Prof. G. S. Dhage

Principal Prof. A. V. Waware

Department Of Mechanical Engineering

Hi- Tech Polytechnic College, Aurangabad.

Declaration

This project report has been completed, edited, written and complied by me and is submitted to Hi-Tech Polytechnic Collage, Aurangabad. In

partial fulfillment of the Diploma in mechanical engineering, As per the

syllabus of course, I declare that no part(s) or any content(s) of the project

has been used anywhere by anybody from the purpose of degree or

diploma course in any institution or university level of learning. Hence

every thing is original and conclusion drawn is my own view.

Dept. Of Mechanical Engineering

Hi-Tech Polytechnic, Aurangabad.

Acknowledgement

I am very glad to represent project report on PAPER CUTTING

AND WOUNDING MACHINE. I have tried my level best to focus upon each and every parameter. In concern with this topic the detail, necessary figure, definition, tabular analysis has been enumerated in very easy, simple, compact and lucid manner.

I have been able to achieve this task by the dynamic guidance of honorable ------------------------------ sir; I have no wards to express my gratitude towards his kind and outstanding treatment while clarifying my confusion. Because of his reference to the Sun-Shine engineering works, we able to fabricate our idea as a machine.

I also extend my sincere thanks to our esteemed H.O.D. -------------------------- whose guidance and constant inspiration where a great use in working of this project.

I am also grateful to our honorable Principal PROF. ------------------ for providing numerous facilities and guidance due to which this difficult task turned in a convenient task.

Also I am grateful to ----------------------------------------------------------- for helping us in our project with his experience in designing SPM. Also thanks to them who directly or indirectly co-operated and contributed me during work.

Last but not least, I am very thankful to my project partners without whose kind cooperation it was difficult and impossible to go through the leaps and bounds while preparing this project.

2009 Paper Cutting And Re-wounding Machine

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Index

Chapter I 8-10.

INTRODUCTION 1. Definition of project 2. Procedure for design of machine elements 3. Background of project

Chapter II 11-12.

CHARACTERISTICS OF MATERIAL AND WELDING PROCESS 1. Plain carbon steels 2. Strength of welded joints 3. Advantages of welded joints compared with other joints 4. Stress reliving of welded joints

Chapter III 13-28.

STRUCTURE FABRICATING PROCESS

SELECTION OF MATERIAL FOR ROLLS

1. Design of hollow shaft 2. Calculation for dimensions of welded solid shaft journal 3. Steps in machining of roll

ROLL FOR CUTTER MOUNTING

1. Steps In Machining Of Grooved Bush And End Plates 2. Cutter clamping modification

Chapter IV 29-34.

MOTOR MOUNTING ADJUSTMENT

1. Driving mechanism

BRAKE ADJUSTMENT

WORKING OF MACHINE

1. Advantages And Disadvantages 2. Specifications of machine

Chapter V 35-38.

MATERIAL REQUIREMENTS


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TROUBLE SHOOTING

1. Belt drive troubles and their remedies 2. Defects and their prevention in lathe operation

Chapter VI 39-43.

TECHNICAL DATA

Chapter VII 44.

FUTURE MODIFICATIONS

Chapter VIII 45.

CONCLUSION

Chapter IX 46.

BIBLIOGRAPHY

Introduction


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Definition Of Project

A project is a group of unique, inter-related activities that are planned and executed in a certain sequence to create a unique product or service, within a specific time frame, budget and the clients specifications. Some of the characteristics of the task that qualify to be projects are:

1) Unique Activities 2) Attainment of a specific goal 3) Sequence of activities 4) Specified time 5) Interrelated activities

The success of the project is depend on the ability to strike a balance between the

following interrelated variables or constraints, that are: 1) Scope of product 2) Quality of product 3) Cost(design cost, material cost, Service cost & Transportation charges) 4) Time (lead time, manufacturing time) 5) Resources

According to this Chart given below the Project characteristics will come to know

that in small projects level of risk is very little and small projects are also less complex. Project class

Class I

Class II

Class III

Class IV

Project characteristics

Time span 18 months or more

Between 9 to 18 months

Between 3 to 9 months

3 months or less

Level of risk High Medium Low Very low

Level of complexity

High Medium Low Very low

Technology Breakthrough Contemporary Best Practical

Probability of problems 100% (certain) 50% (likely) 10% (low) No risk

Procedure For Design Of Machine Elements:

The design of machine element is the most important step in the complete

procedure of machine design. In order to ensure the basic requirement of machine elements, calculation are carried out to find out the dimensions of the machine element. These calculation form an integral part of the designing of machine elements. The basic procedure of the design of element is as follows:


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Background Of Project At the time of deciding the subject of the project, there was a auction of one paper

mill named Maharudra Paper mill Pvt. Ltd. And unfortunately we saw that add and as it is near to our college we go there to see how was the setup of any paper mill. That time first we saw the paper re-winding machine And wanting someone to explain working. So by some reference We got the address of Mr. V.D. Zirmire, The chairmen of Sun-Shine Engineering Works. We discussed with him and convinced him to guide us to Modify the machine. So he says yes to not only guide us but also to give us free machining charges. It look like dream come true that we got the help of such experienced person and our Sir also.

The conventional paper re-winding machine was 9-10 feet in length, 5 feet in

width and almost 6 feet in height. It also facilitate complex mechanisms. Thus after

Specify Function of Element

Determine Forces Acting On Element

Select Suitable Material For Element

Determine Failure Mode Of

Determine Geometric Dimensions Of Element

Modify Dimensions For Assembly and Manufacturing

Prepare Working Drawing of Element


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discussing with Golhar sir and Mr. Chirmule we decided to give some minor modifications to the machine.

The floor space acquired by the machine is too large thus we decided to cut the

length of machine up to 6 feet and also height up to 4.5 feet and put the width as it is because it is the size of standard paper. (But as our project is a demo project we decided to take the width 3 feet.)

Then they have also used the complex mechanism for mounting the roll which is

to be re-winded. So we decide to use the Self aligning bearing with extended inner ring for easy mounting and un-mounting.

Then we see there a cutter and roll adjustment for cutting paper Which add

extremely high wt. to machine and decided to give some new design which is also discussed .

Then as they are using the motor mounting outside the structure it consumes

much more floor space and also create difficulties in operating the break. So we are Giving the motor mounting adjustment within the structure itself. Above and other modifications are explained in sequence with the structure fabricating process in the report.

Characteristics of materials and welding process


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Plain Carbon Steels:

Depending upon the percentage of carbon. plain carbon steels are classified into following three groups:

a) Low carbon steel b) Medium carbon steel c) High carbon steel

Low carbon steel: they contain less than 0.3% carbon. It is popular as mild steels. Low carbon steels are soft and very ductile. They can be machined and welded easily. however, due to low carbon content, they are unresponsive to heat treatment. So we are using M.S.

Strength Of Welded Joints:

Welded joints are classified into following two categories:

a) Where strength of weld is more than the strength of parts joined together. b) Where strength of weld is less than strength of parts joined together.

In first category the failure occur in the parts joined together by weld while in second one it will occur in the weld deposit. Strength of weld deposit is more than the strength of connected parts under the following conditions:

a) The components are mead up of mild steel with less than 0.3% of carbon. b) The welding electrode contain 0.15% carbon. c) Electrode are coated resulting in shielded wilding.

During the welding process coating on the electrode gives off an inert gas which

acts as a shield, protecting the arc from the surrounding atmosphere. Coating also forms the slag on the molten metal and protects it during cooling process. When components are mead up of material such as high carbon steel or alloy steel the weld deposits is weaken than the strength of connected components.

Welded Joints Offer Following Advantages Compared With Other Joints:

a) Riveted joints required additional cover plates, gusset plates, straps, clip angles

and a large number of rivets that increase weight. b) due to elimination of these components cost of welded assembly is lower than that

of riveted assembly. c) Welded structures are lighter than corresponding iron casting by 50% and steel

casting by 30%. d) Welded structure has smooth and pleasant appearance, the projection of rivet head

adversely affects the appearance of riveted structure.


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e) Strength of welded joint is high, very often the strength of weld is more than the

strength of the plates that are joined together. f) machine components of certain shape such as circular steel pipe find difficult in

riveting, However they can be easily welded.

Stress Reliving Of Welded Joints: Welded joints are subjected to residual stresses due to non-uniform heating of

parts being joined. There is always possibility that localized thermal stresses may result from uneven heating and cooling during fusion and subsequent cooling. This is also results in distortion. The magnitude of residual stresses cannot be predicted with any degree of certainty. This is the major disadvantage of welded joints. Following two methods can reduces the residual stresses.

a) Preheating of the weld area to retarded cooling of the metal in the vicinity of the

joint. b) Stress reliving of weld area by using proper heat treatment such as normalizing

and annealing in temperature range of 550O C to 675O C.

One of the method of stress reliving is hand peening. It consist of hammering the weld along the length with peen of hammer while joint is hot. It reduce residual stress and induced residual compressive stress on surface. This improves fatigue strength of joint.

Manufacturing process


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Structure Fabricating Process:

For structure fabrication we are using the c-channel of size 75 X 40 mm. The approximate wt. of it per meter is 6.8 kg. Steps in fabrication of structure are given below:

Step One: First cut the c-channel in pieces of length 71 (i.e. 6 feet two pieces) and in 36 ( i.e. 3 feet three pieces). Then Put the two lengths of 6 feet parallel to each other at a distance of 3 feet from each other. Then put the lengths of 3 feet on either end of two parallel lengths and weld them as shown below. The two diagonals Must be same.

Step Two: Then cut four pieces of c-channel of length 24 (i.e. 2 feet) and weld two of them on one end of rectangular structure vertically using engineers block. Then weld remaining two pieces vertically at a distance of 30 from previous pieces. Step Three: Then brought the two pieces of flat of size 75 X 12 X 760 mm and weld them on the top of four columns as shown. Step Four: Then cut another two pieces of length 48 (i.e. 4 feet) and weld them vertically at a distance of 16 from previously welded columns. Afterwards weld the previously cut piece of 36 on top and in between the upper ends of these columns.


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Step Five: Then cut two pieces of c-channel of length 15. and four pieces of 4 length. Then at a distance of 4.5 from nearest end weld them to form a frame as shown below.


15

750 mm 120 mm 120 mm

do = 89 mm

38 mm

Selection Of Material For Rolls: It is observed that torsional shear stress as well as bending stresses are zero at the

shaft centre (r = 0, y = 0) and negligibly small in the vicinity of shaft centre, where radius is small. As the radius increases the resisting stresses due to external bending and torsional moments increases. Therefore outer fibers are more effective in resisting the applied moments.

In hollow shaft the material at centre is removed and spread at large radius.

Therefore hollow shafts are stronger than solid shafts having same weight. Compared with solid shaft, hollow shaft offer following advantages:

a) The stiffness of hollow shaft is more than that of solid shaft with same weight. b) The strength of hollow shaft is more than that of solid shaft with same weight. c) Natural frequency of hollow shaft is higher than that of solid shaft with same

weight.

Design Of Hollow Shaft:

Design of hollow shaft consist of determining the correct inner and outer diameters from strength and rigidity consideration. Such shafts are subjected to axial tensile force, bending moment, torsional moment or combination of these loads. For hollow shaft we are using low carbon steels because strength of weld is higher in case of low and medium carbon steels. Material of shaft is plain carbon steel 40C8 (Syt = 380 N/mm2

Roll A, B, C & D are the combination of hollow pipe and solid shaft journal. We

are using this type of roll because of the reasons listed above. Roll A, C &D has to bear load of 3000 N on them, which we suppose acts centrally for calculation purpose. Permissible shear stress is given by:


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S sy 0.5 S yt max = = F

( f s ) (3)

0.5(380) = F (3)

max = 63.33 N/mm2 As we are going to wound paper of weight 300 kg on roll, Assume that load of 3000N is acting centrally on shaft. Bending moment Mb = 3000 x 375 = 1.125 x 106 N-mm 60 x P 60 x (746) Torsional moment Mt = F = F 2n 2x (541.35)

= 13159.27 N-mm Shafts can be designed on the basis of ( i ) Max. shear stress theory and ( ii ) Max. principle stress theory. But, we are not going to use Max. principle stress theory. Because, experimental investigations suggest that this theory gives good predictions for brittle materials. Shafts are made of ductile materials like steel and therefore this is not applicable for shaft design. Instead of this theory we use Max. shear stress theory because it is more logical to apply this theory to ductile material. During calculations it is also recommended that bending and torsional moments to be multiplied by Shock factor ( Kb ) and fatigue factor ( Kt ), to account for shocks and fatigue in operating conditions. Now, di C = F do Where, di = Inner diameter of hollow shaft do = Outer diameter of hollow shaft C = Ratio of inner diameter to outer diameter of hollow shaft Lets assume that ratio of inner diameter to outer diameter i.e. C = 0.90 When shaft is subjected to bending moment, bending stresses are given by:


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Mb y b = F 9(a) I

For hollow circular cross section ( do4 di4 ) ( do4 C4 d4 ) I = F = F

64 64 do4 (1 C4 ) (b) I = F 64 And, do y = F (c) 2 Substituting eqn. (b) & (c) in eqn. (a) 32 Mb b = F [ I ] do3 (1 C4) When shaft is subjected to pure torsional moment, torsional shear stress is given by: Mt r F (d) J For hollow circular cross section (do4 di4) (do4 C4 do4) J = F = F 32 32 do4 (1 C4 ) J = F (e) 32 do And, r = F (f ) 2 Substituting eqn. (e) & (f ) in eqn. (d)


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16 Mt F [ II ] do3 (1 C4 ) There are two conditions for calculating principle stress i.e. x i) Shaft subjected to combination of axial forces, bending and torsional moments. x = t + b ii) Shaft is subjected to a combination of bending and torsional moments only, without axial force. x = b Substituting eqn. [ I ] & [ II ] in following fundamental eqn. design = x ( F)2 + ( )2 2 = b ( F)2 + ( )2 as x = b 2 = 16 Mb 16 Mt { }2 + { }2 do3 (1 C 4 ) do3 (1 C 4 ) 16 = } ( ( Mb )2 + ( Mt )2 do3 (1 C4 ) Also, allowable shear stress for shaft material is: Ssy 0.5 ( Syt ) 0.5 (380) max = F = F = F = 63.33 N/mm2 f s f s 3 we are considering combined shock & fatigue factor for bending = Kb = 1 and combined shock & fatigue factor for torsion= Kt = 1.2


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16 design = } ( Kb x Mb )2 + ( Kt x Mt )2

do3 (1 C4 ) From the design point of view & requirement we are going to take value of outer diameter do = 89mm. Substituting these values in above eqn. 16 design = } (1 x 1.125 x 106)2 + ( 1.2 x 13159.27)2 (89)3 ( 1 0.904 ) design = 23.63 N/mm2 So the induced shear stress in design is much more less than allowable shear stress in shaft material, and design is safe.

Calculation For Dimensions Of Welded Solid Shaft Journal :

The roll has 3000 N load on it, so there will be reaction of 1500 N on both the side shafts. By the design point of view length of shaft must not be less than 100mm. And diameter we are taking is 38mm because of having that size of pedestal bearing blocks. So we have to find what should be the thickness & height of weld.

Bending moment Mb = 1500 x 100 = 150 x 103 N-mm Torsional moment Mt = 19760.26 N-mm Primary shear stress in weld is given by: P P 1500 12.56 F F F ( ) N/mm2

A D t (38) t t

38

100 mm

1500 N


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Consider the elemental section of area A. It is located at an angle & subtends an angle d (Ixx ) = (A ) ( y2 )

= ( r dt ) ( r sin 2 ) = t r3 sin2 .d

Moment of inertia of annular fillet weld is obtained by integrating above Eqn

Ixx = 2 t r3 sin2 d 0 = 2t r3 sin2 d 0 cos 2 = 2t r3 [ ] d 0 2 = 2t r3 ( ) 2 Or, Ixx = t r3 By symmetry, Iyy = t r3 For given welded joint, Ixx = t ) (19)3 Bending stress is given by:

y = t sin X X

Y

Y


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Mb y (1500 x 100) (19) b = F = F I t ) (19)3

132.26 = ( ) N/mm2 9(a) t Max. shear stress in weld is given by: max = b ( )2 + ( ) 2 132.26 12.56 = ( )2 + ( )2 2 t t 67.31 = ( ) N/mm2 9(b) t Since we are assuming permissible shear stress in weld is 25N/mm2. from eqn ( b ) we get: 67.31 25 = ( ) t t = 2.69 mm t 2.69 h = ( ) =( ) = 3.80 mm 0.707 0.707 But we are taking the value of ( t ) = 4mm & ( h ) = 5.5mm So by giving this size of weld, 1) The primary shear stress in weld will be: P P 1500 F F F 3.14N/mm2

A D t (38) (4) 2) Max. shear stress in weld will be:


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max = b ( )2 + ( ) 2 132.26 12.56 = ( )2 + ( )2 2(4) (4) = 16.82 N/mm2

Steps In Machining The Roll: Roll is mead up of hollow pipe, solid circular plates & solid shaft journal. So we have to manufacture each part as per required size and then assemble it as a roll. Steps in this task are Step one: First brought the hollow pipe of required dimensions i.e. of required outer, inner diameters and length. If not available then cut it on hacksaw machine

750 Step two: Then brought two circular plates of 10 mm thickness, face them from both sides by holding them on lathe machine. and turn out to the diameter as equal to inner diameter of hollow pipe so they can fit into pipe for welding purpose. Step three: Take solid bar of M.S. of 50 mm diameter cut it to length 110 mm. Hold this bar on lathe chuck and turn it out up to the diameter 38 mm so that it can be fit in pedestal self-aligning bearing block. Step four: Now, weld the turned solid bar to each of two solid circular plates axially by using engineers square. for minimizing the residual stresses induced in shaft and plates, perform hand pining operation before it get cool.


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Grove for welding the bars at centre

Step five: Now, weld these plates in the bore of hollow pipe and do the same hand pining operation in welded area.

Step six: The roll is completed, but because of welding different parts it need to be turned again using lathe machine. Hold the journal on one side in chuck and turn the other journal as well as hollow pipe part of roll. do the same operation by holding other journal in chuck so the roll will rotate along its axis accurately. 120 750

120

Steps In Machining Of Grooved Bush And End Plates: (A) Steps in machining of grooved bush


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Step One: First take the round bar of 100 mm diameter. Then cut it using Hacksaw or bend saw machine at thickness 22 mm. Take the piece of bar 55X20 and weld it at the centre of that plate as possible.

5 3 3 5 89 75 50 36

Step Two: Then hold that piece on lathe machine using three jaw self centering chuck. And face it from one side. Then turn it out to diameter 89 mm (as this is the diameter of core pipe). Step Three: Then turn out the step of diameter 75 mm up to the thickness 5 mm. so that it will fit in the bore of core pipe. Step Four: Then fix the drill of 14 mm on the tail stock and drilled out the through bore in the plate. Then by using boring bar make through bore in the plate of dia. 36 mm.. Step Five: Then take the parting tool and fix it on the tool post. Then make the groove on periphery of 89 mm diameter area at the distance of 3 mm from its edge . Step Six: Then take out the job and again fix it by taking the un-machined side to front for machining. perform the operations above turn out the step of diameter 75 mm up to thickness 5 mm. then turn out the welded piece to dia. 50 mm. Step Seven: By using drill machine make the through holes of dia. 10 mm on two sides of welded piece. And then using tap of 10 make the taping operation. (B) Steps in machining of end plates: Step One: First take the round bar of 100 mm diameter. Then cut it using Hacksaw or bend saw machine at thickness 15 mm. Take the piece of bar 55X25 and weld it at the centre of that plate as possible.

Grooved bush


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Step Two: Then hold that piece on lathe machine using three jaw self centering chuck. And face it from one side. Then turn it out to diameter 89 mm.( for endplates of rewinding roll turn out this step to 89 mm dia. ) Step Three: Then turn out the step of diameter 75 mm up to the thickness 5 mm. so that it will fit in the bore of core pipe. And make the step of 89 mm dia. of thickness 8 mm. Step Four: Then fix the drill of 20 mm on the tail stock and drilled out the through bore in the plate. Then by using boring bar make through bore in the plate of dia. 36 mm.( for end plates of rewinding roll instead of 36 mm drill use the 28 mm drill) Step Five: Then take out the job and again fix it by taking the un-machined side to front for machining. Then turn out the welded piece to dia. 50 mm. 5 8 22 89R 75R 28R 50R

End Plate


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Cutter Clamping Modification:

In conventional machine they are using bar of 30-36 mm diameter an fix it on the column and then by suitable bolting mount cutter on it as shown in photo (8).But using solid M.S. bar of 30-36 mm dia. will increase wt by 5.13 kg.-7.8 kg.

Thus we decided to give new clamping for cutter on the structure itself. So from all possibilities discussed, we make the c-clamp with the two bolts to clamp and one extended piece of flat for mounting of cutter.

Step One: First take the flat of 25 X 10 and cut it by bend saw in size of 90 mm, 65 mm, 60 mm and 40 mm. Step Two: Weld the pieces of 90, 65, and 60 mm to form C. Then take the piece of 40 mm in length and weld it on the 65 mm side of clamp. Step Three: Then using drill machine make the three through holes of 10.7 mm at the points shown below in complete assembly of cutter. Afterwards take the tap of size and perform the tapping operation.

Roll For Cutter Mounting:

In above way four rolls can be machined. In conventional machine either: (1) Grooved rolls are used which are made up of 6-7 mm thick pipe having

diameter of about 100-120 mm. Various equidistance grooves are made on periphery of that roll but it increase the weight tremendously. or

(2) A solid bar of 30-40 mm is used on which the aluminium bushes of diameter 60-70 mm and thickness of about 25-50 mm are used. the cutter is then fixed between any two consecutive bushes for cutting purpose. but it also increase the weight.

For weight loss, making operation easy, eliminate excess machining and give

freedom of cutting paper of any size we are design a bush having only one groove of 3 mm thickness and 5 mm depth on the periphery of bush. And on either side of bush there are the steps of 5 mm thickness and having diameter equal to inner diameter of core pipe.


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The core pipes are used to rewind paper. These are also made up of paper but are much tuff to sustain higher weight.

When paper being cut it is preferred that it must not be loosen between grooved

bush and end plate so firstly we think of using wooden blocks between end plates and grooved bush. But there is one problem that if you want to change the size of paper being cut, you have to change the distance between endplates and grooved bush and also size of wooden block accordingly. and it will take much time to machine the block so we decide to use core pipe. It is simple to use core pipe than any other option. Because one can adjust the bushes and cut the core pipe of required size within few minutes.

When using our new adjustment firstly we have to measure size of paper and

adjust the end plates, then decide the size of rolls have to be cut and adjust the grooved accordingly. Then measure the distance between grooved bush and each end plate and cut core pipe accordingly. then fix the one piece of core pipe between one end plate and one side of grooved bush, then fix second piece of core pipe between second end plate and other side of grooved bush. The bush and end plates have nuts to fix them with bar thus they will not move. Then take the roll and with the help of pillow block, bolted it on the column. But one precaution has to be taken that the cutter shaft must be parallel to the roll at bottom on which paper is to be rolled.

For the re-winding roll also we are going to use same type of arrangement, only

the difference is instead of using grooved bush in middle of end plates we are using an inner bush. This inner bush is bolted at middle and support one end of each core pipe.


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Then adjust the c-clamp connected with cutter as shown in fig. (a) and fix it with the help of nut bolts. then press the cutter and put it in the groove of bush as shown in fig. (b) then because of spring tension cutter remain pushed towards the edge of groove.

The complete cutter assembly is shown below.


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Motor Mounting Adjustment

In conventional machine the motor is mounted outside the structure of machine. It will not only increase the floor area occupied by machine but also create difficulties in operating the block brake. Because of the operator cannot get to break quickly they have to be given the additional feature i.e. steering like car to operate the break from distant.

To tackle these disadvantages we decided to give motor mounting arrangement within structure itself. First we take piece of angle of 45 X 45 and of length 30 cm. and weld it at the proper location, where the motor is to be mounted. Then we take two flats of size 25 X 10 X 40 mm and drilled out two holes on them to fix the lower end of motor mounting plate.

Then for adjusting the tension in belt we weld two flats with one through hole on

each to the neighboring column. And then by suitable bolting tie upper end of motor mounting plate to column. The complete assembly is shown below.

Thus by using motor mounting plate one can move motor horizontally and also

tight or loose the belt to adjust tension in belt with the help of nut-bolt given at the upper side of motor mounting plate.


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Driving Mechanism:

As our project as a demo and also designed for small weight we use the 1 Hp A.C. motor. It is having the 1440 rpm speed. We use two pulleys of 50 mm dia. One on the motor shaft and another is on the shaft of roll.

Now the numbers of belts required for given application is decided by following

equation: ( transmitted power in kW) X ( Fa) No. of belts = ) ( kW rating of single V-belt) X (Fc) X ( Fd) P X Fa = ) (A). Pr X Fc X Fd Where, P = drive power to be transmitted (kW) Fa = Correction factor for industrial service ( table 4) Pr = Power rating for single V-belt (table 5) Fc = Correction factor for belt length (table 6) Fd = Correction factor for arc of contact ( table 7) In this application we required a power of 0.746 kW for approximately 10 hours per day. From table 4 the correction factor according to service (Fa) is : Design power = Fa ( transmitted power) = 1.1 ( 0.746) P = 0 kW (B). Plot a point with coordinates kW and 1440 rpm speed in table 3 It is observed that the point is located in the region of A-section belt. Therefore for this application the cross-section of belt is A.


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As we are using pulleys on both, the driver and driven shaft speed ratio is 2.66. d = 75 mm D = 200 mm From table 2 the preferred pitch length for A-section belts is 1100 and 1250 and 1430 . But from the design point of view we take the pitch length of belt is 1250 mm. Substituting this value of pitch length in following equation. ( D + d ) ( D d )2 L = 2C + + 2 4C ( 200 + 75 ) ( 200 75 )2 1250 = 2C + + 2 4C Simplifying the above expression, C2 409.01 C + 1953.125 =0 409.01 + (409.01)2 4 ( 1953.125) C = + 2 C = 404.17 mm Therefore the correct centre distance is 404.17 mm And Fa = 1.1 (C). From table 6 ( A-section and 1250 mm pitch length), Fc = 0.93 (D). Therefore the Arc of contact on pulley is: D d s = 180 2 sin -1 ( ) 2C 200 - 75 = 180 2 sin -1 ( ) 2 X 404.17 = 180 2 sin -1 (0.1546 )


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s = 162.200 Thus from table 7, Fd = 0.96 (E). From table 5 ( 1440 rpm, 75 mm pulley, A- section ) ( speed ratio 2.66) Pr = 0.91 + 0.17 = 1.08 kW (F). Therefore the numbers of belts: P X Fa = ) Pr X Fc X Fd (0.8206) (1.1) = ) (1.08) (0.93) (0.96) = 0.9361 or only one belt This application Required only one belt to transmit power . The decision of taking no. of belts is the first thing in any driving mechanism.

Brake Adjustment:

In conventional machine very complex design is used for break. They are used double band brake and it is having a wheel which is connected to break with the help of connecting rod for the ease in operation. But as we minimize the length of machine and also facilitate the motor inside the structure itself it is easy to operator to get at the break for adjusting pressure.

Thus we decided to use the single block brake. It is consist of the break drum of

dia. 110 mm which can be fixed on the journal of roll. Then quarter circular plate which is hinged at one end is fixed with one hole on other end. Through this hole one nut of


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suitable length is passed which fix with bolt welded at the bottom of plate. Thus when nut is being fitted it moves down and press the break linear against the drum. The total Single Block break assembly is shown below

Working Of Machine As we give number of modifications it is necessary to briefly explain working procedure of machine. When the paper being manufactured in paper mill it is not of standard size an also get torn out at the edges. And here is the need of re-winding machine. The roll of paper manufactured is mounted on the roll (A). In our machine we have given the self aligning bearing with inner extended ring for ease in mounting and um-mounting. Then paper is passed around roll (B) to ensure that paper remain straight and tight. Then it passed through the cutter and grooved bush on top of machine, where it is cut. Because of our modification to this cutter roll the wt. of machine is decreased. Then the paper which is cut is come to the two rolls at bottom, one of these two rolls powered by 1 Hp motor with 1440 rpm. This rotating roll make other roll to rotate and not only wound the paper but also pull the paper to make the operation going.

Hinged

Spring

Break drum

Break linear

Work plan and requirements


34

B

D

C

Specifications Of Machine

Length 6 feet ( 152.4 )

Width 0.914 feet ( 36 )

Height 4 feet ( 48 )

Consisting 4 Hollow rolls, One cutter roll 10 pillow blocks.

Motor 1 Hp, 3 phase, induction motor

A


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Material Requirements Sr. No

Description Qty. Rate Amount

1)

Pipe 80 m Swastic 4 meter. Rs. 362 per meter. 1448.00

2)

M.S. Bars

X 1500

50 X 1300

36 X 1500

80 X 400

100 X 120

7.245 kg.

20.03 kg.

11.05 kg.

12.150 kg.

7.847 kg

Rs. 55 per kg.

398.47

1101.65

607.75

668.25

431.58

3)

M. S. Flat

12 X 75 X 760 (2 no.)

10.79 kg

Rs. 57 per kg.

615.03

4)

C-channel

75 X 40 (12.2 meter )

82.96 kg

Rs. 36.50 per kg.

3028.04 5)

Pillow Blocks

No 206 i.e. 30 mm

No 208 i.e. 40 mm

Self aligning with extended inner ring

2 no.

4 no.

4 no.

Rs. 300 per block

Rs. 400 per block

Rs. 500 per block

600.00

1600.00

2000.00

6)

Pulleys 3 Pulley 8

1 no. 1 no.

Rs. 150 per pully Rs. 250 per pully

150.00 250.00

7)

V- Belt of A-47 1 no. 100.00

8) Paper 50 kg Rs. 14.50 per kg. 725.00

9) Motor 1 Hp - - -

Total

13,723.77

Technical data


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Belt Drive Troubles And Their Remedies :- As the driving mechanism is hart of our machine Because it dont have any other

Mechanism for operating and the pulling of paper is depend on the condition of driving mechanism. We have given some problem may occur in belt drive and their remedies. Sr. No.

Trouble Problem cause Remedies

1)

Belt slip in the drive.

a) Belt is over loaded i.e. being used to transmit more power than what it is designed for. b) The belt is too heavy for small pulley. c) The centre distance between two pulleys is too short. d) Ratio of diameter of two pulleys is too large (it should not exceeds 6:1 )

Reduce load or change the belt to suit the requirements. Replace the set of pulleys to suit the requirements. Increase the centre distance between two pulleys if possible. Sprinkle the small amount of powder of resin on to the inside surface of belt or use Jockey pulley.

2) Belt does not run properly and frequently goes off pulley.

a) Alignment of pulleys is wrong. b) Alignment of shafts is wrong. c) One or both pulleys are unbalanced. d) Belt is over loaded. e) Belt is running at excessively high speed. f) Belt ends have not been cut square for joining.

Check and correct. Check and correct. Check the balance of each pulley and rectify the defect. Check the load and belt capacity and adjust the load accordingly or change the belt. Check and reduce the speed. Check and correct.

3)

Belt wear badly at the edges.

Running belt rub against the flanges of pulley.

Discourage the use of flanged pulleys as far as possible.

4) There is a loss of power.

a) Belt is too tight to put excessive strain on bearings and belt. b) Excessive slip is there.

Adjust tension in belt. Adjust tension or take other measures to avoid slipping as described in no.1 above.


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Defects and their prevention in lathe operation

As our project was totally mechanical, we had to many problems during the machining of different components of our machine. Thus we have also facilitate the trouble shooting chart for different errors that may occur during operating the lathe machine.

Operation Defects in work Possible cause Method of prevention Cylindrical or plain turning

Certain portion of job remain un- machined.

a) Stock size not uniform and under size at different places. b) Machining allowance is not sufficient. c) The bar stock is not straight. d) Stock has not been set true. e) Live and dead centers are not properly aligned.

The job once made under these conditions cannot be corrected as it will become undersize on further machining. However after this defect is noted, the proper cause should be found out and necessary correction done accordingly.

Dimensions of work produced are incorrect.

a) Tool setting is in-accurate. b) Measurement taken during operation are incorrect.

Correct the tool setting and turn it a second time if it is oversized. If it is under sized it cant be helped.

The work produced has tapered surface.

Live and dead centers are not properly aligned.

Remove the misalignment of centers.

The work produced hasnt got a true circular cross section.

a) Spindle runs out of centre due to uneven wear of its bearings.

It should be checked frequently and repaired.

Surface finish is very poor.

a) Tool has been ground poorly. b) Tool overhang in the tool post is too much. c) Tool angles are not correct. d) Tool is clamped loosely. e) work vibrates while rotating due to either improper holding or worn out spindle bearing.

Locate the proper cause and remove the corresponding deficiency.


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Operation Defects in work Possible cause Method of prevention Facing

Certain portion of the face remains un-machined.

a) Machining allowance is not sufficient. b) Dimension of the stock bar are incorrect. c) Work has not been set concentric with the spindle. d) Tool has not been set at correct height.

Sufficient machining allowance should be provided. Check the dimensions of the bar stock Set the work true. Reset the tool properly.

The turned face is not square with the axis of the work.

a) Tool overhangs too much. b) Tool loosely clamped in tool post. c) Cross feed of tool is too much. d) Ways of the cross slide is inaccurate.

Reduce the overhang . Clamp the tool properly. Reduce the cross feed. Ways need reconditioning.

Surface finish is very poor.

a) tool is not properly clamped. b) Job is not properly clamped. c) Tool is not ground properly. d) Feed is too high. e) Tool is overhang too much. f) Tool has gone blunt. g) Spindle runs out.

Clamp the tool properly. Hold the job tightly. Take care in grinding. Reduce the tool feed. Reduce the overhang. Regrind the tool. Check the bearing and get them made true.

Grooving and parting off.

Width of the groove is larger or smaller than required.

Tool angles are incorrect or a wrong tool is used.

Check the angle of tool before using and select a proper tool.

Depth of groove is more or less than required.

Cross feed has not been given properly.

Control the feed properly.

Groove is not located correctly along the job length

Marking is not correct.

Mark properly and check before starting the operation.


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Table 1 Dimensions of standard cross-section Belt Section

Pitch width in mm.

Nominal top width in mm.

Nominal height in mm.

Recommended minimum pitch dia. of pulley in mm.

Permissible minimum pitch dia. of pulley in mm.

Z A B C D E

8.5 11 14 19 27 32

10 13 17 22 32 38

6 8 11 14 19 23

85 125 200 315 500 630

50 75 125 200 355 500

Table 2 Nominal pitch lengths for standard size of V-belts

Z A B C D E 405 447 530 625 700 780 920

1080 1330 1420 1540

630 700 790 890 990

1100 1250 1430 1550 1640 1750

930 1000 1100 1210 1370 1560 1690 1760 1950 2180 2300

1560 1760 1950 2190 2420 2720 2880 3080 3310 3520 4060

2740 3130 3330 3730 4080 4620 5400 6100 6840 7620 8410

4660 5040 5420 6100 6850 7650 9150 12230 13750 15280 16800

Table 3


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Table 4 Correction factor according to service factor (Fa) Service Type of driven machine Type of driving units

A.C. motor: normal torque, squirrel cage, synchronous, and split phase D.C. motor: shunt wound, multi cylinder I.C. engine over 600 rpm.

A.C. motor: high torque, induction, single phase. D.C. motor: series and compound wound, single cylinder I.C. engine, multi cylinder I.C. engine under 600 rpm.-line shaft.

Operational hours per day 0-10 10-16 16-24

Operational hours per day 0-10 10-16 16-24

Light duty

Blower, Exhauster, Centrifugal pump, Compressor and fan up to 7.5 kW

1.0 1.1 1.2

1.1 1.2 1.3

Medium duty

Belt conveyor, fans over 7.5 kW, Generator, Press,

1.1 1.2 1.3 1.2 1.3 1.4

Heavy duty

Bucket elevator, Hammer mill, Piston pump, Saw mill.

1.2 1.3 1.4 1.4 1.5 1.6

Extra- heavy duty

Crusher, Mill, Hoist 1.3 1.4 1.5 1.5 1.6 1.8

Table 5


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Table 6 Correction factor for belt pitch length (Fc) Cross-section factor

Belt pitch length in mm. Z A B C D E

0.80 0.81 0.82 0.83 0.84 0.85 0.86 0.87 0.88 0.89 0.90 0.91 0.92 0.93 0.94 0.95 0.96

405

475

530

625

630

700

790

890

990

1100

1250

1430

930

1000

1100

1210

1370

1560

1760

1560

1760

1950

2190 2340 2490

2720 2800 3080

2740

3130 3330

3730

4080

4620

4660

5040

5420

6100 Table 7 Correction factor for arc of contact (Fd)

D d ) C

Arc of contact on smaller pulley (in degrees)

Correction factor

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50

180 177 174 171 169 166 163 160 157 154 151

1.00 0.99 0.99 0.98 0.97 0.97 0.96 0.95 0.94 0.93 0.93


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M.S. FLAT M.S. FLAT

Size in mm Wt. in kg. per meter Size in mm Wt. in kg. per meter 12 X 3 0.28 50 X 3 1.2 16 X 3 0.38 50 X 5 2.0 16 X 5 0.63 50 X 6 2.4 20 X 3 0.47 50 X 10 3.9 20 X 5 0.63 50 X 12 4.7 20 X 6 0.94 50 X 16 6.3 25 X 6 1.02 50 X 20 7.8 25 X 10111111 2.001111111111111 65 X 6 3.1 25 X 12 2.4 65 X 8 4.1 30 X 5 0.700 65 X 10 5.1 30 X 6 0.900 65 X 12 6.1 30 X 10 2.4 65 X 16 8.2 30 X 12 2.8 65 X 20 10.2 35 X 6 1.6 65 X 25 12.8 35 X 10 2.8 65 X 32 16.3 35 X 12 3.3 70 X 25 13.8 35 X 16 4.4 75 X 6 3.5 40 X 3 0.900 75 X 8 4.7 40 X 5 1.6 75 X 10 5.9 40 X 6 1.9 75 X 121111111111 7.111111111111111 40 X 10 3.1 75 X 16 9.4 40 X 12 3.8 75 X 20 11.8 40 X 16 5.0 75 X 25 14.7 45 X 6 2.1 75 X 32 18.8 45 X 10 3.5 80 X 25 20.1

M.S. CHANNEL Size in mm. Wt. in kg. per meter.

75 X 40111111111111111111 6.81111111 100 X 50 9.2 125 X 65 12.8 150 X 75 16.4 175 X 75 17.6 200 X 75 21.5 225 X 80 26.0 250 X 80 30.4 300 X 90 33.1


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MILD STEEL BRIGHT BAS Size in mm.

Wt. in kg. per foot.

Size in mm. Wt. in kg. per foot.

Size in mm. Wt. in kg. per foot.

3 0.017 16 0.486 32111111111 1.94611111 4 0.030 17 0.549 35 2.328 5 0.048 18 0.616 36111111111 2.46211111 6 0.063 19 0.685 40 3.040 7 0.093 20 0.760 45 3.848 8 0.122 21 0.850 50 4.750 9 0.154 22 0.920 55111111111 5.74811111 10 0.190 24 1.094 60 6.840 11 0.230 25 1.188 70 9.310 12 0.274 26 1.300 75 10.688 13 0.321 27 1.385 80 12.160 14 0.373 28111111111 1.490111111 90 15.390 15 0.428 30 1.710 10011111111 19.0001111

Future modifications and advantages


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Future Modifications In the Paper Re-winding machine there must be some weight on the roll that is being wounded after cutting. Because during demo we found that the paper is wounded loosely. Actually we suppose that because of self weight of paper it will going to wind tightly, But that stage comes after 50 kg of paper is wounded, before that the paper get wounded loosely. So in our future modification we want give one hinged roll which can add some weight on winding roll. As the complete idea is not clear, and also because of money problem we have only given the sketch of it. we also thinking to facilitate some weight counting and length counting gadgets. Because when the winding and cutting operation is going on there is no way to find that how much paper had been wound and how much is remained.

Advantages

1) It is more compact as compared with conventional one. 2) Operation is simple Because of eliminating complex mechanisms. 3) Saving of floor space as motor is adjusted inside the structure. 4) New cutter clamping assembly given by us will eliminate the biggest

disadvantage of machine i.e. high weight. Disadvantages

5) The main problem that we caught during demo that paper get winded loosely, but

for that we have given one suggestion in topic future modification.

Experiences and conclusions


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Experiences And Conclusion: During this wonderful project I have came across many difficulties but I have tackled them successfully. During this I have gained knowledge about various machines used in industries, The ideas and tricks that are used in industry. The project facilitate much more improved functions related with weight loss, simplifying operation, and other aspects. And more ever it will not add cost but we try to minimize the cost also. Even then we want to say that there is much space to improvement in the machine. The experience will be very useful for our future. Actually Mr. ------------------- said to us that It is not important that how much you improved machine, but that on your level you can manage to imagine and dare to express your ideas with your little knowledge. And after this small experience of industry we have to say that it is the key thing in industry. So we are happy that we get the experience of practical world beyond text book. During completing this projects we came to know the various problems occurring in any process. And if you want to success you have to manage each and every part of any task or project. Now we are more confident that we can also do something new and are interested to start our new carrier in mechanical engineering.

Bibliography


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Bibliography

1) Forbes Marshall- Engineering Data Book 2) Workshop Technology- B. S. Raghuwanshi (Vol. I & II) 3) Production Management- ICFAI University 4) Elements of machine design- V. B. Bhandari 5) Strength of materials- R. K. Bansal

Future modification1.bmp

Engineerig Project-Paper Cutting

Documents

Transcript of Engineerig Project-Paper Cutting