Design And Fabrication Of Cam Vice Report 4t5m5f

SYNOPSIS

SYNOPSIS In this project we are fabricate the cam vice. It works in the principle or eccentric cam mechanism. The main features of the cam vice are promotes mass production, can hold irregular jobs, more rigidity, reduce fatigue, etc. Cam was designed to hold the job at high pressure. The other parts were designed to hold the job in rigid condition. Cam vice is suitable for mass production. It is possible to hold irregular components also, and similar components can be very quickly.

CHAPTER I INTRODUCTION

CHAPTER I INTRODUCTION

Cam vice is one of the clamping devices used to hold the job in rigid condition. Cam vice is operated by eccentric cam mechanism. There is a cam lever. The job can be held tightly in between the jaw. In this, first the job is place in between jaws, and movable jaw is adjusted by adjusting the screw rod to maintain according to the eccentricity of the cam with cam profile. After that, cam lever at the top is operated so that the job is held tightly in the fixture.

This type of fixture is useful for mass production where only similar size of jobs is to be held. It reduces operator’s fatigue and also reduces stetting time and cost of production.

CHAPTER II LITERATURE REVIEW

CHAPTER II LITERATURE REVIEW

TYPES OF VISES Without qualification, "vise" usually refers to a bench vise with flat, parallel jaws, attached to a workbench. * A woodworker's bench vise is a more or less integral part of the bench. * An engineer's bench vise is bolted onto the top of the bench. Other kinds of vise include: * hand vises (hand-held), * machine vises - drill vises (lie flat on a drill press bed). Vises of the same general form are used also on milling machines and grinding machines. * compound slide vises are more complex machine vises. They allow speed and precision in the placement of the work.

* cross vises, which can be adjusted using leadscrews in the X and Y axes; these are useful if many holes need to be drilled in the same workpiece using a drill press. Compare router table. * off-center vises, * angle vises, * sine vises, which use solving triangles and gauge blocks to set up a highly accurate angle, * rotary vises, * diemakers' vises, * table vises, * pin vises (for holding thin, long cylindrical objects by one end), * jewellers' vises and by contrast, * leg vises, which are attached to a bench but also ed from the ground so as to be stable under the very heavy use imposed by a blacksmith's work. WOODWORKING VISES

For woodworking, the jaws are made of wood, plastic or from metal, in the latter case they are usually faced with wood to avoid marring the work piece. The top edges of the jaws are typically brought flush with the bench top by the extension of the wooden face above the top of the iron moveable jaw. This jaw may include a dog hole to hold a bench dog. In modern metal woodworkers' vises, a split nut is often used. The nut in which the screw turns is in two parts so that, by means of a lever, it can be removed from the screw and the moveable jaw can be quickly slid into a suitable position at which point the nut is again closed onto the screw so that the vise may be closed firmly onto the work. METALWORKERS' VISES For metalworking, the jaws are made of metal which may be hardened steel with a coarse gripping finish. Quick change removable soft jaws are being used more frequently to accommodate fast change-over on set-ups. They are also kept for use where appropriate, to protect the work from damage. Metalworking bench vises, known as engineers' or fitters' vises, are bolted onto the top surface of the bench with the face of the fixed jaws just forward of the front edge of the bench. The bench height should be such that

the top of the vise jaws is at or just below the elbow height of the when standing upright. Where several people use the one vise, this is a good guide. The nut in which the screw turns may be split so that, by means of a lever, it can be removed from the screw and the screw and moveable jaw quickly slid into a suitable position at which point the nut is again closed onto the screw. Many fitters prefer to use the greater precision available from a plain screw vise. The vise may include other features such as a small anvil on the back of its body. Vise screws are usually either of an Acme thread form or a buttress thread. Those with a quick-release nut use a buttress thread. METALWORKING VISES IN MACHINE SHOPS In high production machine work, work must be held in the same location with great accuracy, so CNC machines may perform operations on an array of vises. To assist this, there are several machine-shop specific vises and vise accessories.

Hard and soft machine jaws have a very important difference between other metalworking vise jaws. The jaws are precision ground to a very flat

and smooth surface for accuracy. These rely on mechanical pressure for gripping, instead of a rough surface. An unskilled operator has the tendency to over-tighten jaws, leading to part deformation and error in the finished workpiece. The jaws themselves come in a variety of hard and soft jaw profiles, for various work needs. One can purchase machinable soft jaws, and mill the profile of the part into them to speed part set-up and eliminate measurement. This is most commonly done in gang operations, discussed below. For rectangular parts being worked at 45 degree angles, prismatic hard jaws exist with V grooves cut into them to hold the part. Some vises have a hydraulic or pneumatic screw, making setup not only faster, but more accurate as human error is reduced. For large parts, an array of regular machine vises may be set up to hold a part that is too long for one vise to hold. The vises' fixed jaws are aligned by means of a dial indicator so that there is a common reference plane for the CNC machine.

For multiple parts, several options exist, and all machine vise manufacturers have lines of vises available for high production work.

* The first step is a two clamp vise, where the fixed jaw is in the center of the vise and movable jaws ride on the same screw to the outside. * The next step up is the modular vise. Modular vises can be arranged and bolted together in a grid, with no space between them. This allows the greatest density of vises on a given work surface. This style vise also comes in a two clamp variety. * Tower vises are vertical vises used in horizontal machining centers. They have one vise per side, and come in single or dual clamping station varieties. A dual clamping tower vise, for example, will hold eight relatively large parts without the need for a tool change. * Tombstone fixtures follow the same theory as a tower vise. Tombstones allow four surfaces of vises to be worked on one rotary table pallet. A tombstone is a large, accurate, hardened block of metal that is bolted to the CNC pallet. The surface of the tombstone has holes to accommodate modular vises across all four faces on a pallet that can rotate to expose those faces to the machine spindle. * New work holding fixtures are becoming available for five-axis machining centers. These specialty vises allow the machine to work on

surfaces that would normally be obscured when mounted in a traditional or tombstone vise setup.

CHAPTER III DESCRIPTION OF EQUIPMENTS

CHAPTER III DESCRIPTION OF EQUIPMENTS

3.1. CAM A cam is a projecting part of a rotating wheel or shaft that strikes a lever at one or more points on its circular path. The cam can be a simple tooth, as is used to deliver pulses of power to a steam hammer, for example, or an eccentric disc or other shape that produces a smooth reciprocating (back and forth) motion in the follower which is a lever making with the cam. The reason the cam acts as a lever is because the hole is not directly in the centre, therefore moving the cam rather than just spinning. On the other hand, some cams are made with a hole exactly in the centre and their sides act as cams to move the levers touching them to move up and down or to go back and forth.

3.2. LEAD SCREW A lead screw also known as a power screw or translation screw, is a screw designed to translate radial motion into linear motion. Common

applications are machine slides (such as in machine tools), vises, presses, and jacks. A lead screw nut and screw mate with rubbing surfaces, and consequently they have a relatively high friction and stiction compared to mechanical parts which mate with rolling surfaces and bearings. Their efficiency is typically between 25 and 70%, with higher pitch screws tending to be more efficient. A higher performing, and more expensive, alternative is the ball screw. The high internal friction means that leadscrew systems are not usually capable of continuous operation at high speed, as they will overheat. Due to inherently high stiction, the typical screw is self-locking (i.e. when stopped, a linear force on the nut will not apply a torque to the screw) and are often used in applications where backdriving is unacceptable, like holding vertical loads or in hand cranked machine tools. Leadscrews are typically used well greased, but, with an appropriate nut, it may be run dry with somewhat higher friction. There is often a choice of nuts, and manufacturers will specify screw and nut combinations as a set.

The mechanical advantage of a leadscrew is determined by the screw pitch and lead. For multi-start screws the mechanical advantage is lower, but the traveling speed is better. Backlash can be reduced with the use of a second nut to create a static loading force known as preload; alternately, the nut can be cut along a radius and preloaded by clamping that cut back together. A lead screw will back drive. A leadscrew's tendency to backdrive depends on its thread helix angle, coefficient of friction of the interface of the components (screw/nut) and the included angle of the thread form. In general, a steel acme thread and bronze nut will back drive when the helix angle of the thread is greater than 20°. ADVANTAGES & DISADVANTAGES The advantages of a leadscrew are:  Large load carrying capability  Compact  Simple to design

 Easy to manufacture; no specialized machinery is required  Large mechanical advantage  Precise and accurate linear motion  Smooth, quiet, and low maintenance  Minimal number of parts  Most are self-locking The disadvantages are that most are not very efficient.  Due to the low efficiency they cannot be used in continuous power transmission applications.  They also have a high degree for friction on the threads, which can wear the threads out quickly.  For square threads, the nut must be replaced; for trapezoidal threads, a split nut may be used to compensate for the wear.

3.3. FRAME STAND

Frame stand in this device is made up of combination of sheet metal or flat rods welded together. The frame stand is used to hold the fixed jaw, moving jaw, and lever, lead screw, handle and cam arrangements in this device.

3.4. LEVER The lever is used to lock and unlock the cam arrangements in this device. The liver is an easily operateable device in this equipment.

3.5. HANDLE The handle is used to adjust operate the lead screw in this equipment. The handle is fixed one corner of the lead screw.

3.6. FIXED JAW & MOVING JAW The fixed jaw is stable; the jaw is mounted on the frame stand in this equipment.

The moving jaw is easily adjustable by the lead screw arrangement. We can easily move the moving jaw on this equipment by rotating the lead screw by handle and operating the lever in cam arrangement.

CHAPTER IV DESIGN AND DRAWING

CHAPTER IV DESIGN AND DRAWING

4.1. MACHINE COMPONENTS The “DESIGN AND FABRICATION OF CAM VICE” consists of the following components to full fill the requirements of complete operation of the machine.  Cam arrangements  Lead screw  Frame stand  Lever  Handle  Fixed jaw  Moving jaw

4.2. DRAWING FOR DESIGN AND FABRICATION OF CAM VICE

CHAPTER V WORKING PRINCIPLE

CHAPTER V WORKING PRINCIPLE The cam vice consists of fixed jaw, moving jaw, lever, lead screw, handle, cam mechanism and frame stand. The fixed jaw is fixed on the frame. The moving jaw is arranged parallel through the fixed jaw. The cam arrangement is placed before the moving jaw. The cam arrangement consists of lever. The after the cam arrangement the lead screw is arranged. The lead screw is used to adjust the cam arrangement in the equipment. The main purpose of the cam vice is used to clamp and unclamp the same size specimens on it. This vice is used in mass production. The specimen is placed between the fixed jaw and moving jaw, and then the cam lever is operated by manually. The specimen is clamped at a perfect stage, and then the lead screw is used to fit the correct area in the cam arrangement. Now we can easily clamp and unclamp the same size of specimens in this equipment very easily.

CHAPTER VI MERITS & DEMERITS

CHAPTER VI MERITS & DEMERITS MERITS  Idle time of the machine is reduced  When compared with the mechanical vices, it continues less time for clamping and unclamping the job  It reduces the clamping time  Hence, production rate is higher

DEMERITS  Limited size of specimens only clamped in this vice

CHAPTER VII APPLICATIONS

CHAPTER VII APPLICATIONS

 Applicable in workshops  Applicable in small and medium scale industries

CHAPTER VIII LIST OF MATERIALS

CHAPTER VIII LIST OF MATERIALS

FACTORS DETERMINING THE CHOICE OF MATERIALS The various factors which determine the choice of material are discussed below. 1. PROPERTIES The material selected must posses the necessary properties for the proposed application. The various requirements to be satisfied Can be weight, surface finish, rigidity, ability to withstand environmental attack from chemicals, service life, reliability etc. The following four types of principle properties of materials decisively affect their selection  Physical  Mechanical  From manufacturing point of view  Chemical

The various physical properties concerned are melting point, thermal Conductivity, specific heat, coefficient of thermal expansion, specific gravity, electrical conductivity, magnetic purposes etc. The various Mechanical properties Concerned are strength in tensile, Compressive shear, bending, torsion and buckling load, fatigue resistance, impact resistance, elastic limit, endurance limit, and modulus of elasticity, hardness, wear resistance and sliding properties. The various properties concerned from the manufacturing point of view are,  Cast ability  Weld ability  Surface properties  Shrinkage  Deep drawing etc. 2. MANUFACTURING CASE Sometimes the demand for lowest possible manufacturing cost or surface qualities obtainable by the application of suitable coating substances may demand the use of special materials.

3. QUALITY REQUIRED This generally affects the manufacturing process and ultimately the material. For example, it would never be desirable to go casting of a less number of components which can be fabricated much more economically by welding or hand forging the steel. 4. AVAILABILITY OF MATERIAL Some materials may be scarce or in short supply, it then becomes obligatory for the designer to use some other material which though may not be a perfect substitute for the material designed. The delivery of materials and the delivery date of product should also be kept in mind. 5. SPACE CONSIDERATION Sometimes high strength materials have to be selected because the forces involved are high and space limitations are there. 6. COST As in any other problem, in selection of material the cost of material plays an important part and should not be ignored.

Some times factors like scrap utilization, appearance, and nonmaintenance of the designed part are involved in the selection of proper materials.

CHAPTER IX COST ESTIMATION

CHAPTER IX COST ESTIMATION

1. MATERIAL COST 2. LABOUR COST Lathe, drilling, welding, drilling, power hacksaw, gas cutting cost

3. OVERGHEAD CHARGES The overhead charges are arrived by” manufacturing cost” Manufacturing Cost

= Material Cost + Labor Cost = =

Overhead Charges

= 20%of the manufacturing cost =

4. TOTAL COST Total cost

= Material Cost +Labor Cost +Overhead Charges

= = Total cost for this project =

CHAPTER X CONCLUSION

CHAPTER X CONCLUSION

This project is made with pre planning, that it provides flexibility in operation.

This innovation has made the more desirable and economical. This project “DESIGN AND FABRICATION OF CAM VICE” is designed with the hope that it is very much economical and help full to workshops, small and medium scale industries.

This project helped us to know the periodic steps in completing a project work. Thus we have completed the project successfully.

BIBLIOGRAPHY

BIBLIOGRAPHY

1. Design data book

-P.S.G.Tech.

2. Machine tool design handbook –Central machine tool Institute, Bangalore.

3. Strength of Materials - R.S.Kurmi

4. Manufacturing Technology - M.Haslehurst.

5. Design of machine elements - R.S.Kurmi

PHOTOGRAPHY