SYNOPSIS
SYNOPSIS
In this project we are fabricate the cam vice. It works in the principle
or ecce eccent ntri ricc cam cam mech mechan anis ism m. The main main feat featur ures es of the the cam cam vice vice are are
promotes mass production, can hold irregular jobs, more rigidity, 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 fiture.
This type of fiture is useful for mass production where only similar
si!e 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 #ithout 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. 'ther kinds of vise include( % hand vises )hand*held+, % machine vises * drill vises )lie flat on a drill press bed+. ises of the same general form are used also on milling machines and grinding machines. % compound slide vises are more comple machine vises. They allow speed and precision in the placement of the work.
% cross vises, which can be adjusted using leadscrews in the - and aes/ 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 supported from the ground so as to be stable under the very heavy use imposed by a blacksmith&s work. WOODWORKING VISES
0or 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 etension 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
0or metalworking, the jaws are made of metal which may be hardened steel with a coarse gripping finish. 1uick 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. 2etalworking bench vises, known as engineers& or fitters& vises, are bolted onto the top surface of the bench with the face of the fied 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 user when standing upright. #here 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. 2any 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. ise 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 C3C machines may perform operations on an array of vises. To assist this, there are several machine*shop specific vises and vise accessories.
4ard 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. 'ne 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. 0or rectangular parts being worked at 56 degree angles, prismatic hard jaws eist with grooves cut into them to hold the part. 7ome vises have a hydraulic or pneumatic screw, making setup not only faster, but more accurate as human error is reduced. 0or 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& fied jaws are aligned by means of a dial indicator so that there is a common reference plane for the C3C machine.
0or multiple parts, several options eist, and all machine vise manufacturers have lines of vises available for high production work.
% The first step is a two clamp vise, where the fied jaw is in the center of the vise and movable jaws ride on the same screw to the outside. % The net step up is the modular vise. 2odular 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 hori!ontal machining centers. They have one vise per side, and come in single or dual clamping station varieties. A dual clamping tower vise, for eample, will hold eight relatively large parts without the need for a tool change. % Tombstone fitures 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 C3C pallet. The surface of the tombstone has holes to accommodate modular vises across all four faces on a pallet that can rotate to epose those faces to the machine spindle. % 3ew work holding fitures are becoming available for five*ais 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 eample, or an eccentric disc or other shape that produces a smooth reciprocating )back and forth+ motion in the follower which is a lever making contact 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. 'n the other hand, some cams are made with a hole eactly 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 86 and 9:;, with higher pitch screws tending to be more efficient. A higher performing, and more epensive, 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.
=eadscrews 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. 0or multi*start screws the mechanical advantage is lower, but the traveling speed is better.
>acklash 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 heli 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 bron!e nut will back drive when the heli angle of the thread is greater than 8:@.
ADVANTAGES & DISADVANTAGES
The advantages of a leadscrew are(
=arge load carrying capability
Compact
7imple to design
asy to manufacture/ no speciali!ed machinery is required
=arge mechanical advantage
Brecise and accurate linear motion
7mooth, quiet, and low maintenance
2inimal number of parts
2ost are self*locking
The disadvantages are that most are not very efficient.
They also have a high degree for friction on the threads, which can wear the threads out quickly.
0or square threads, the nut must be replaced/ for trape!oidal threads, a split nut may be used to compensate for the wear.
3.3. FRAME STAND
0rame 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 fied 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 fied one corner of the lead screw.
3.. FI!ED "AW & MOVING "AW The fied 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. #e 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 <7ID3 A3< 0A>EICATI'3 '0 CA2 ICF consists of the following components to full fill the requirements of complete operation of the machine.
Cam arrangements
=ead screw
0rame stand
=ever
4andle
0ied jaw
2oving jaw
4.2. DRAWING FOR DESIGN AND FA#RICATION OF CAM VICE
CHAPTER V WORKING PRINCIPLE
CHAPTER V WORKING PRINCIPLE
The cam vice consists of fied jaw, moving jaw, lever, lead screw, handle, cam mechanism and frame stand. The fied jaw is fied on the frame. The moving jaw is arranged parallel through the fied 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 si!e specimens on it. This vice is used in mass production. The specimen is placed between the fied 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. 3ow we can easily clamp and unclamp the same si!e of specimens in this equipment very easily.
CHAPTER VI MERITS & DEMERITS
CHAPTER VI MERITS & DEMERITS
MERITS
Idle time of the machine is reduced
#hen compared with the mechanical vices, it continues less time for clamping and unclamping the job
It reduces the clamping time
4ence, production rate is higher
DEMERITS
=imited si!e 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
Bhysical
2echanical
0rom manufacturing point of view
Chemical
The various physical properties concerned are melting point, thermal Conductivity, specific heat, coefficient of thermal epansion, specific gravity, electrical conductivity, magnetic purposes etc. The various 2echanical 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
#eld ability
7urface properties
7hrinkage
2. MANUFACTURING CASE
7ometimes 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. 0or eample, 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. AVAILA#ILITY OF MATERIAL
7ome 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
7ometimes high strength materials have to be selected because the forces involved are high and space limitations are there. . COST
As in any other problem, in selection of material the cost of material plays an important part and should not be ignored.
7ome times factors like scrap utili!ation, appearance, and non* maintenance of the designed part are involved in the selection of proper materials.
CHAPTER I! COST ESTIMATION
CHAPTER I! COST ESTIMATION
1. MATERIAL COST 2. LA#OUR COST =athe, drilling, welding, drilling, power hacksaw, gas cutting cost
3. OVERGHEAD CHARGES The overhead charges are arrived byF manufacturing costF 2anufacturing Cost
G 2aterial Cost H =abor Cost G G
'verhead Charges
G 8:;of the manufacturing cost G
4. TOTAL COST Total cost
G 2aterial Cost H=abor Cost H'verhead Charges
G G Total cost for this project G
CHAPTER ! CONCLUSION
CHAPTER ! CONCLUSION
This project is made with pre planning, that it provides fleibility in
operation.
This innovation has made the more desirable and economical. This
project <7ID3 A3< 0A>EICATI'3 '0 CA2 ICF 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.
#I#LIOGRAPHY
#I#LIOGRAPHY
.
*B.7.D.Tech.
8. 2achine tool design handbook JCentral machine tool Institute, >angalore.
K. 7trength of 2aterials * E.7.Lurmi
5. 2anufacturing Technology * 2.4aslehurst.
6.