ABSTRACT
ABSTRACT
A concave attachment attachment is a versatile one one to cut concave-convex profiles. profiles. A set of rotating plates have have T-slots for the T-bolts T-bolts that hold the boring boring bar. These plates are rotated by a train of gears. The bar is held roughly yet free free enough to rotate. rotate. When the tool is built, the boring bar is first clamped with both pivots at lead centre. So, the tool describes describes a zero radius radius when the crank crank is turned. turned.
At this time, one set up pin hole is drilled in each of the rotating plates, as indicated so that the pin touches the boring boring bar. Then to set the tool, tool, for a desired radius, it is merely necessary to place a piece of flat stock the same thickness as the desired radius between the bar and the set up pins while securing the bar in position. At this point, point, data the flat stock stock and set up pin pin can be removed. removed.
ABSTRACT
A concave attachment attachment is a versatile one one to cut concave-convex profiles. profiles. A set of rotating plates have have T-slots for the T-bolts T-bolts that hold the boring boring bar. These plates are rotated by a train of gears. The bar is held roughly yet free free enough to rotate. rotate. When the tool is built, the boring bar is first clamped with both pivots at lead centre. So, the tool describes describes a zero radius radius when the crank crank is turned. turned.
At this time, one set up pin hole is drilled in each of the rotating plates, as indicated so that the pin touches the boring boring bar. Then to set the tool, tool, for a desired radius, it is merely necessary to place a piece of flat stock the same thickness as the desired radius between the bar and the set up pins while securing the bar in position. At this point, point, data the flat stock stock and set up pin pin can be removed. removed.
INTRODUCTION
INTRODUCTION
The concave attachment is fixed to the carriage of the Shaper. The compound rest that is locked solid with its base is removed and the attachment is fixed on the cross lied of the carriage with its axis parallel to the Shaper bed. The work is secured rigidly in a chuck. By the concave-convex movement of the boring bar, the material is being removed. This attachment is used to produce contour profiles and round balls.
NEED FOR ATTACHMENT
In recent years, new fabrication techniques have been developed to satisfy the technological demands. Moreover, emphasis is stressed on attachments. Attachments are used in various fields and machines depending upon the needs to be fulfilled and mode of operation. An attachment eliminates the purchasing of a new unit which serves the same purpose. For example, a Shaper occupies a place opposite to that of a milling machine, the ten machines mainly used to produce cylindrical and plain surfaces respectively. By implementing an attachment to a unit, the capacity of the unit can be increased which is very economical.
LITERATURE REVIEW
LITERATURE REVIEW
AN ATTACHMENT FOR TURNING APPROXIMATELY SPHERICAL SURFACES OF SMALL CURVATURE ON A LATHE By I. C. Gardner This device replaces the compound rest on a lathe and was particularly designed for the production of the convex or concave surfaces of lens-grinding tools although it is well adapted for the production of such surfaces for any purpose. It is intended to be used only for the production of surfaces of which the radius of curvature is too great to permit the use of a tool mounted on the end of a radius rod. The mathematical theory underlying the design and a detailed description of the instrument as built are given in detail. The attachment, as constructed, permits disks under 300 mm in diameter to be faced and any radius of curvature, greater than 500 mm may be obtained. The surfaces produced are not accurately spherical, but for many purposes the approximation is entirely satisfactory. The approximation becomes pooreras either the curvature or diameter of the surface is increased. For a surface 200 mm in diameter with a radius of curvature of 1,000 mm the maximum departure from
sphericity is 0.02 mm. If the diameter of the tool is 300 mm and the radius of curvature is 500 mm, the departure from sphericity is approximately 0.3 mm. This last value is the maximum departure for any surface lying within the working range of the instrument.
Now shaping machine is much more primitive even more primitive than lathe central lathe and which is almost going to be obsolete but even then atleast earlier some attachments were used to enhance the processing capability of shaping machine. Some unstipulated work which are not supposed to be done in shaping machine, could be done 14 by some attachments. One example, first example is that double cut attachment. You remember that in shaping machine, this cutting tool cuts in the forwards stroke alright and in the return stroke it does not cut. That is called idle stroke. It is a waste of time and loss of productivity. So if it can cut in the forward stroke as well as in the return stroke then productivity will be double. Keeping these views keeping this idea in mind attachment has been developed. Here you see that this is a rectangular piece which is hinged over here on a block, this block this block is rigidly fixed on the ram which ram reciprocation shaping machine. So this is connected with the ram. So this reciprocates; when it
reciprocates in this moves forward this cutting tool removes the material like this and this one is arrested you can see clearly. This one is arrested along this surface of this block. So because the force is going there cutting force and this is the hinge it cannot rotate further because it is arrested here in the return stroke. When this will reach at the extreme end then this one will move forward this lever will move forward this spring loaded and then this will go in this direction and you see the orientation previously this surface was along this surface. Now this here, it will contact here and this may be moving in this direction force is force will act in this direction but this will be arrested hinged over here arrested over here. So this cannot move so it is cutting in the both the strokes. So this way you can enhance the productivity, this was also attempted in planing machine but not that required not successful.
DESCRIPTION OF EQUIPMENTS
DESCRIPTION OF EQUIPMENTS
SPUR GEAR
A gear or cogwheel is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part to transmit torque, in most cases with teeth on the one gear being of identical shape, and often also with that shape on the other gear.Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine. Geared devices can change the speed, torque, and direction of a power source. The most common situation is for a gear to mesh with another gear; however, a gear can also mesh with a non-rotating toothed part, called a rack, thereby producing translation instead of rotation.
The gears in a transmission are analogous to the wheels in a crossed belt pulley system. An advantage of gears is that the teeth of a gear prevent slippage. When two gears mesh, and one gear is bigger than the other (even though the size of the teeth must match), a mechanical advantage is produced, with the rotational speeds and the torques of the two gears differing in an inverse relationship. In transmissions with multiple gear ratios — such as bicycles, motorcycles, and cars — the term gear, as in first gear, refers to a gear ratio rather than an actual physical gear. The term describes similar devices, even when the gear ratio is continuous rather than discrete, or when the device does not actually contain gears, as in a continuously variable transmission.
LEVER The lever is used to lock and unlock the cam arrangements in this device. The liver is an easily operatable device in this equipment.
BEARINGS
A bearing is a machine element that constrains relative motion and reduces friction between moving parts to only the desired motion. The design of the bearing may, for example, provide for free linear movement of the moving part or for free rotation around a fixed axis; or, it may prevent a motion by controlling the vectors of normal forces that bear on the moving parts. Many bearings also facilitate the desired motion as much as possible, such as by minimizing friction. Bearings are classified broadly according to the type of operation, the motions allowed, or to the directions of the loads (forces) applied to the parts.
The term "bearing" is derived from the verb "to bear";[1] a bearing being a machine element that allows one part to bear (i.e., to support) another. The simplest bearings are bearing surfaces, cut or formed into a part, with varying degrees of control over the form, size, roughness and location of the surface. Other bearings are separate devices installed into a machine or machine part.
SHAFT
A drive shaft, driveshaft, driving shaft, propeller shaft (prop shaft), or Cardan shaft is a mechanical component for transmitting torque and rotation, usually used to connect other components of a drive train that cannot be connected directly
because of distance or the need to allow for relative movement between them. As torque carriers, drive shafts are subject to torsion and shear stress, equivalent to the difference between the input torque and the load. They must therefore be strong enough to bear the stress, whilst avoiding too much additional weight as that would in turn increase their inertia.
SINGLE POINT CUTTING TOOL
The single point cutting tool has only one cutting point or edge. These tools used for turning, boring, shaping or planning operations. These tools used on lathe, boring and shaper machines.
A single point cutting tool consists of a sharpened cutting part and the shank and main parts or elements which are: 1: Shank It is the main body of the tool. 2: Flank: The surface or surfaces below the adjacent to the cutting edge is called flank of the tool. 3: Face The surface on which the chip slides is called the face of the tool. 4: Heel It is the intersection of the flank and the base of the tool. 5: Nose It is the point where the side cutting edge and end cutting edge intersect. 6: Cutting Edge It is the edge on the face of the tool which removes the material from the work piece. The cutting edge consists of the side cutting edge(major cutting edge) and cutting edge(minor cutting edge) and the nose.
WORM GEAR
A worm drive is a gear arrangement in which a worm (which is a gear in the form of a screw) meshes with a worm gear (which is similar in appearance to a spur gear, and is also called a worm wheel). The terminology is often confused by imprecise use of the term worm gear to refer to the worm, the worm gear, or the worm drive as a unit.
Like other gear arrangements, a worm drive can reduce rotational speed or allow higher torque to be transmitted. The image shows a section of a gear box with a worm gear being driven by a worm. A worm is an example of a screw, one of the six simple machines.
DESIGN OF EQUIPMENT AND DRAWING
DESIGN OF EQUIPMENT AND DRAWING
SIDE VIEW
TOP VIEW
FABRICATION
FABRICATION
The stand (or) base carries the whole machine. The rod is vertically fixed on the stand by means of welding.
TIG WELDING
TIG Welding is a manual welding process that requires the welder to use two hands to weld. What separates TIG welding from most other welding processes is the way the arc is created and how the filler metal is added! When TIG Welding one hand is used for holding the TIG torch that produces the arc and the other hand is to add the filler metal to the weld joint. Because two hands are required to weld; TIG welding is the most difficult of the processes to learn, but at the same time is the most versatile when it comes to different metals. This process is slow but when done right it produces the highest quality weld! TIG welding is mostly used for critical weld joints, welding metals other than common steel, and where precise, small welds are needed.
Knowing alternative names and abbreviations for TIG welding is important for anyone who is interested in getting a job as a TIG welder. Many companies may use alternative names when placing ads in the classifieds. Sometimes they may use alternative name on a written test to test your knowledge of the welding process. Besides that the alternative name means something to the process. As of today TIG welding is the slang term that is widely accepted and used. TIG stands for Tungsten Inert Gas Welding. TIG welding’s proper name is Gas Tungsten Arc Welding or “GTAW”. This is the name the American Welding Society and other welding organizations refer to this process on their welding procedures. GTAW is also the abbreviation that welding engineers use to specify the welding process that is to be used on blue prints. On top of that; when working on high pressure piping you could get sent home for a few days for not using proper terminology! When TIG welding was introduced around the 1940’s Helium gas was the primary shielding gas used in process. The term Heliarc welding was the common phrase used back in the day and now is a registered trademark “GENUINE HELIARC”, from what I know, it now owned by ESAB welding equipment! Why would this matter when you are job hunting or working in a shop? Most old timers and veteran welder’s refer to TIG welding as Heliarc welding. I learned this very
early on when I started to weld. I did not know Heliarc was also TIG welding! I thought when I went to welding school TIG welding was a new process I was going to learn. Wrong! Just like my former boss called the refrigerator the “ice box”, they are both the same thing. When someone reefers to TIG welding as heliarc, it’s pretty safe to assume either they have a lot of experience, or apprenticed under a journeyman welder who has been around. Since the name includes the term “Tungsten” and tungsten is what makes TIG welding possible, it is good to know what tungsten is! Tungsten is a very hard, slightly radioactive, and brittle metal. Its uses are limited compared to other metals. In TIG welding the tungsten is made into a non consumable electrode that is used to create the arc for TIG welding. Typical other uses for tungsten are in light bulbs, heating elements, and rocket engines. Basically any place that requires a very high melting point or the need to pass electricity at a high temperature is needed. In the case of TIG welding the tungsten metal properties allows an arc to maintain a temperature up to 11,000 degrees Fahrenheit. A high melting point and excellent electrical conductivity keeps the tungsten electrode from burning up! The unique properties of tungsten allow welding with a hotter arc then the actual melting point of the tungsten. The tensile strength of tungsten is an extremely high up to 500,000 lbs per square inch! Comparing it to commonly used steel with 36,000 lbs of tensile strength per square inch, tungsten is very strong! Although the metal is very
strong it is also brittle! It is not hard to break a tungsten electrode with just a tap of a hammer.
GEAR MACHINING
Gear manufacturing refers to the making of gears. Gears can be manufactured by a variety of processes, including casting, forging, extrusion, powder metallurgy, and blanking. As a general rule, however, machining is applied to achieve the final dimensions, shape and surface finish in the gear. The initial operations that produce a semifinishing part ready for gear machining as referred to as blanking operations; the starting product in gear machining is called a gear blank.
Selection of materials The gear material should have the following properties:
High tensile strength to prevent failure against static loads
High endurance strength to withstand dynamic loads
Low coefficient of friction
Good manufacturability
Gear manufacturing processes
There are multiple ways in which gear blanks can be shaped through the cutting and finishing processes.
Gear forming
In gear form cutting, the cutting edge of the cutting tool has a shape identical with the shape of the space between the gear teeth. Two machining operations, milling and broaching can be employed to form cut gear teeth.[3]
Form milling
In form milling, the cutter called a form cutter travels axially along the length of the gear tooth at the appropriate depth to produce the gear tooth. After each tooth is cut, the cutter is withdrawn, the gear blank is rotated, and the cutter proceeds to cut another tooth. The process continues until all teeth are cut...
Broaching
Broaching can also be used to produce gear teeth and is particularly applicable to internal teeth. The process is rapid and produces fine surface finish with high dimensional accuracy. However, because broaches are expensive and a separate broach is required for each size of gear,this method is suitable mainly for highquantity production.
Gear generation In gear generating, the tooth flanks are obtained as an outline of the subsequent
positions of the cutter, which resembles in shape the mating gear in the gear pair.
There are two machining processes employed shaping and milling. There are several modifications of these processes for different cutting tool used.
Gear hobbing
Gear hobbing is a machining process in which gear teeth are progressively generated by a series of cuts with a helical cutting tool. All motions in hobbing are rotary, and the hob and gear blank rotate continuously as in two gears meshing until all teeth are cut.
Finishing operations
As produced by any of the process described, the surface finish and dimensional accuracy may not be accurate enough for certain applications. Several finishing operations are available, including the conventional process of shaving, and a number of abrasive operations, including grinding, honing, and lapping.
WORKING PRINCIPLE
WORKING PRINCIPLE
The worm wheel is rotated with the help of a worm shaft. Rotating plates with Tslots that hold the boring are screwed to the worm wheel. The worm wheel in turn is screwed to its base with a simple gear train. The rotary motion is imported to the blank through two spur gears and an intermediate gear namely “Idler Gear”.
The idler gear serves to keep the rotation of rotating plates in the same direction.
The worm shaft is rotated in clockwise direction, the boring bar
machines a contour profile in the clockwise direction and vice versa. Thus a concave-convex profile is machined by boring bar by simultaneous engagement of the two plates.
WORKING OF THE UNIT
When the worm shaft is rotated in a clockwise direction, the worm wheel rotates in the clockwise direction and vice versa. Idler gears are used to rotate the rotating plates in the same direction. When the boring bar is bolted to only one of the ‘I’ slots in the rotating plate and when the crank is turned, the material is removed at a certain radius depending on the
extension of the boring bar. When the boring bar is bolted to the T-slots provided in the rotating plates and when the worm is rotated, the boring bar described a concave-convex profile. This movement of the bar is used to produce spherical balls also.
ADVANTAGES
ADVANTAGES
The unit is compact in size. Less maintenance is essential The unit gives long life with proper alignment of gears. Jobs can be easily handled in this unit.
APPLICATION
APPLICATION
Concave and convex profiles of desired radius can be easily turned. Round balls can be produced.
CONCLUSION
CONCLUSION
Working in this area has provides a lot of practical knowledge regarding,
planning, purchasing, assembling and machining. This innovation has made the
more desirable and economical. This project “CONCAVE ATTACHMENT FOR
SHAPER ” 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.
