DESIGN AND FABRICATION OF MULTI-PURPOSE MACHINE
ABSTRACT
The aim of our project is to design and fabricate a multipurpose device. With this device a number of operations can be performed. They are as follows: 1. Drilling 2. Grinding 3. Boring By means of this machine various operations can be performed using same power. So this multipurpose device is used for various operations with a less amount of investment.
INTRODUCTION
The project work subject is one, in which actually we are leaning the theoretical concepts in practical way. Also the practical experience is one of the aims of this subject. For a developing industry these operating performed and the parts or components produced should have its minimum possible production cost, then only the industry runs profitably. There are a number of units having used in industries for various purposes.
Drilling is a cutting process that uses a drill bit to cut or enlarge a hole of circular cross-section in solid materials. The drill bit is a rotary cutting tool, often multipoint. The bit is pressed against the workpiece and rotated at rates from hundreds to thousands of revolutions per minute. This forces the cutting edge against the workpiece, cutting off chips from what will become the hole being drilled. Exceptionally, specially-shaped bits can cut holes of non-circular crosssection; a square cross-section is possible. Process Drilled holes are characterized by their sharp edge on the entrance side and the presence of burrs on the exit side (unless they have been removed). Also, the inside of the hole usually has helical feed marks. Drilling may affect the mechanical properties of the workpiece by creating low residual stresses around the hole opening and a very thin layer of highly stressed and disturbed material on the newly formed surface. This causes the workpiece to become more susceptible to corrosion at the stressed surface.A finish operation may be done to avoid the corrosion.Zinc
plating or any other standard finish opertion of 14 to 20 microns can be done which helps to avoid any sort of corrosion. For fluted drill bits, any chips are removed via the flutes. Chips may be long spirals or small flakes, depending on the material, and process parameters.[3] The type of chips formed can be an indicator of the machinability of the material, with long gummy chips reducing machinability. When possible drilled holes should be located perpendicular to the workpiece surface. This minimizes the drill bit's tendency to "walk", that is, to be deflected, which causes the hole to be misplaced. The higher the length-to-diameter ratio of the drill bit, the higher the tendency to walk. The tendency to walk is also preempted in various other ways, which include: Establishing a centering mark or feature before drilling, such as by:
Casting, molding, or forging a mark into the workpiece
Center punching
Spot drilling (i.e., center drilling)
Spot facing, which is facing a certain area on a rough casting
or forging to establish, essentially, an island of precisely known surface in a sea of imprecisely known surface
Constraining the position of the drill bit using a drill jig with drill bushings
Surface finish in drilling may range from 32 to 500 microinches. Finish cuts will generate surfaces near 32 microinches, and roughing will be near 500 microinches. Cutting fluid is commonly used to cool the drill bit, increase tool life, increase speeds and feeds, increase the surface finish, and aid in ejecting chips. Application of these fluids is usually done by flooding the workpiece or by applying a spray mist. In deciding which drill(s) to use it is important to consider the task at hand and evaluate which drill would best accomplish the task. There are a variety of drill styles that each serve a different purpose. The subland drill is capable of drilling more than one diameter. The spade drill is used to drill larger hole sizes. The indexable drill is useful in managing chips.
Spot drilling The purpose of spot drilling is to drill a hole that will act as a guide for drilling the final hole. The hole is only drilled part way into the workpiece because it is only used to guide the beginning of the next drilling process. Center drilling The purpose of center drilling is to drill a hole that will act as a center of rotation for possible following operations. Center drilling is typically performed using a drill with a special shape, known as a center drill. Deep hole drilling Deep hole drilling is defined as a hole depth greater than five times the diameter of the hole. These types of holes require special equipment to maintain the straightness and tolerances. Other considerations are roundness and surface finish. Deep hole drilling is generally achievable with a few tooling methods, usually gun drilling or BTA drilling. These are differentiated due to the coolant entry method (internal or external) and chip removal method (internal or external). Using methods such as a rotating tool and counter-
rotating workpiece are common techniques to achieve required straightness tolerances. Secondary tooling methods include trepanning, skiving and burnishing, pull boring, or bottle boring. Finally a new kind of drilling technology is available to face this issue: the vibration drilling. This technology consists in fractionating chips by a small controlled axial vibration of the drill. Therefore the small chips are easily removed by the flutes of the drill. A high tech monitoring system is used to control force, torque, vibrations, and acoustic emission. The vibration is considered a major defect in deep hole drilling which can often cause the drill to break. Special coolant is usually used to aid in this type of drilling. Gun drilling Another type of drilling operation is called gun drilling. This method was originally developed to drill out gun barrels and is used commonly for drilling smaller diameter deep holes. This depth-to-diameter ratio can be even more than 300:1. The key feature of gun drilling is that the bits are self-centering; this is what allows for such deep accurate holes. The bits use
a rotary motion similar to a twist drill; however, the bits are designed with bearing pads that slide along the surface of the hole keeping the drill bit on center. Gun drilling is usually done at high speeds and low feed rates. Trepanning Trepanning is commonly used for creating larger diameter holes (up to 915 mm (36.0 in)) where a standard drill bit is not feasible or economical. Trepanning removes the desired diameter by cutting out a solid disk similar to the workings of a drafting compass. Trepanning is performed on flat products such as sheet metal, granite (curling stone), plates, or structural members like I-beams. Trepanning can also be useful to make grooves for inserting seals, such as O-rings. Microdrilling Microdrilling refers to the drilling of holes less than 0.5 mm (0.020 in). Drilling of holes at this small diameter presents greater problems since coolant fed drills cannot be used and high spindle speeds are required. High spindle speeds that exceed 10,000 RPM also require the use of balanced tool holders.
Vibration drilling of an aluminum-CFRP multi-material stack with MITIS technology The main principle consists in generating axial vibrations or oscillations in addition to the feed movement of the drill so that chips could be fractionated and easily removed from the cutting zone. One can find two main technologies of vibration drilling: self-maintained vibrations systems and forced vibrations systems. Most of vibrations
drilling technologies are still at a research stage. It is the case of the selfmaintained vibrations drilling: the eigen frequency of the tool is used in order to make it naturally vibrate while cutting; vibrations are selfmaintained by a mass-spring system included in the tool holder. Other works use a piezoelectric system to generate and control the vibrations. These systems allow high vibration frequencies (up to 2 kHz) for small magnitude (about a few microns); they particularly fit drilling of small holes. Finally vibrations can be generated by mechanical systems
the
frequency is given by the combination of the rotation speed and the number of oscillation per rotation (a few oscillations per rotation), the magnitude is about 0.1 mm. This last technology is a fully industrial one (example: SineHoling® technology of MITIS). Vibration drilling is a favoured solution in order to face issues like deep hole drilling, multi-material stacks drilling (aeronautics) or dry drilling (without lubrication). Generally it allows increasing the reliability and the control of the drilling operation. Material
Drilling in metal
High speed steel twist bit drilling into aluminium with methylated spirits lubricant Under normal usage, swarf is carried up and away from the tip of the drill bit by the fluting of the drill bit. The cutting edges produce more chips which continue the movement of the chips outwards from the hole. This is successful until the chips pack too tightly, either because of deeper than normal holes or insufficient backing off (removing the drill slightly or totally from the hole while drilling). Cutting fluid is sometimes used to ease this problem and to prolong the tool's life by cooling and lubricating the tip and chip flow. Coolant may be introduced via holes through the drill shank,
which
is
common
when
using
a
gun
drill.
When
cutting aluminum in particular, cutting fluid helps ensure a smooth and accurate hole while preventing the metal from grabbing the drill bit in the process of drilling the hole. For heavy feeds and comparatively deep holes oil-hole drills can be used, with a lubricant pumped to the drill head through a small hole in the bit and
flowing out along the fluting. A conventional drill press arrangement can be used in oil-hole drilling, but it is more commonly seen in automatic drilling machinery in which it is the workpiece that rotates rather than the drill bit. In computer numerical control (CNC) machine tools a process called peck drilling, or interrupted cut drilling, is used to keep swarf from detrimentally building up when drilling deep holes (approximately when the depth of the hole is three times greater than the drill diameter). Peck drilling involves plunging the drill part way through the workpiece, no more than five times the diameter of the drill, and then retracting it to the surface. This is repeated until the hole is finished. A modified form of this process, called high speed peck drilling or chip breaking, only retracts the drill slightly. This process is faster, but is only used in moderately long holes otherwise it will overheat the drill bit. It is also used when drilling stringy material to break the chips. Drilling in wood Wood being softer than most metals, drilling in wood is considerably easier and faster than drilling in metal. Cutting fluids are not used or needed. The
main issue in drilling wood is assuring clean entry and exit holes and preventing burning. Avoiding burning is a question of using sharp bits and the appropriate cutting speed. Drill bits can tear out chips of wood around the top and bottom of the hole and this is undesirable in fine woodworkingapplications. The ubiquitous twist drill bits used in metalworking also work well in wood, but they tend to chip wood out at the entry and exit of the hole. In some cases, as in rough holes for carpentry, the quality of the hole does not matter, and a number of bits for fast cutting in wood exist, including spade bits and self-feeding auger bits. Many types of specialised drill bits for boring clean holes in wood have been developed, including brad-point bits, Forstner bits and hole saws. Chipping on exit can be minimized by using a piece of wood as backing behind the work piece, and the same technique is sometimes used to keep the hole entry neat. Holes are easier to start in wood as the drill bit can be accurately positioned by pushing it into the wood and creating a dimple. The bit will thus have little tendency to wander.
Grinding Machines Grinding Machines are also regarded as machine tools. A distinguishing feature of grinding machines is the rotating abrasive tool. Grinding machine is employed to obtain high accuracy along with very high class of surface finish on the workpiece. However, advent of new generation of grinding wheels and grinding machines, characterised by their rigidity, power and speed enables one to go for high efficiency deep grinding (often called as abrasive milling) of not only hardened material but also ductile materials. Conventional grinding machines can be broadly classified as: (a) Surface grinding machine (b) Cylindrical grinding machine (c) Internal grinding machine
(d) Tool and cutter grinding machine Surface grinding machine: This machine may be similar to a milling machine used mainly to grind flat surface. However, some types of surface grinders are also capable of producing contour surface with formed grinding wheel. Basically there are four different types of surface grinding machines characterised by the movement of their tables and the orientation of grinding wheel spindles as follows: • Horizontal spindle and reciprocating table • Vertical spindle and reciprocating table • Horizontal spindle and rotary table • Vertical spindle and rotary table Horizontal spindle reciprocating table grinder A disc type grinding wheel performs the grinding action with its peripheral surface. The grinding operation is similar to that of face milling on a vertical milling machine. In this machine a cup shaped wheel grinds the workpiece over its full width using end face of the wheel. This brings more grits in
action at the same time and consequently a higher material removal rate may be attained than for grinding with a peripheral wheel. In principle the operation is same as that for facing on the lathe. This machine has a limitation in accommodation of workpiece and therefore does not have wide spread use. However, by swivelling the worktable, concave or convex or tapered surface can be produced on individual
Vertical spindle rotary table grinder The machine is mostly suitable for small workpieces in large quantities. This primarily production type machine often uses two or more grinding heads thus enabling both roughing and finishing in one rotation of the work table. Creep feed grinding machine: This machine enables single pass grinding of a surface with a larger down feed but slower table speed than that adopted for multi-pass conventional surface grinding. This machine is characterised by high stiffness, high spindle power, recirculating ball screw drive for table movement and adequate supply of grinding fluid. A further development in this field is the creep feed grinding centre which carries more than one wheel with provision of automatic wheel changing. A number of operations can be performed on the workpiece. It is implied that such machines, in the view of their size and complexity, are automated through CNC. High efficiency deep grinding machine:
The concept of single pass deep grinding at a table speed much higher than what is possible in a creep feed grinder has been technically realized in this machine. This has been made possible mainly through significant increase of wheel speed in this new generation grinding machine. Cylindrical grinding machine This machine is used to produce external cylindrical surface. The surfaces may be straight, tapered, steps or profiled. Broadly there are three different types of cylindrical grinding machine as follows: 1. Plain centre type cylindrical grinder 2. Universal cylindrical surface grinder 3. Centreless cylindrical surface grinder Plain centre type cylindrical grinder The machine is similar to a centre lathe in many respects. The workpiece is held between head stock and tailstock centres. A disc type grinding wheel performs the grinding action with its peripheral surface Universal cylindrical surface grinder Universal cylindrical grinder is similar to a plain cylindrical one except that it is more versatile. In addition to small worktable swivel, this machine
provides large swivel of head stock, wheel head slide and wheel head mount on the wheel head slide. This allows grinding of any taper on the workpiece. Universal grinder is also equipped with an additional head for internal grinding. Roll grinding is a specific case of cylindrical grinding wherein large workpieces such as shafts, spindles and rolls are ground. Crankshaft or crank pin grinders also resemble cylindrical grinder but are engaged to grind crank pins which are eccentric from the centre line of the shaft Cam and camshaft grinders are essentially subsets of cylindrical grinding machine dedicated to finish various profiles on disc cams and cam shafts. The desired contour on the workpiece is generated by varying the distance between wheel and workpiece axes. The cradle carrying the head stock and tail stock is provided with rocking motion derived from the rotation of a master cam that rotates in synchronisation with the workpiece. Newer machines however, use CNC in place of master cam to generate cam on the workpiece. External centreless grinder
This grinding machine is a production machine in which outside diameter of the workpiece is ground. The workpiece is not held between centres but by a work support blade. It is rotated by means of a regulating wheel and ground by the grinding wheel. In through-feed centreless grinding, the regulating wheel revolving at a much lower surface speed than grinding wheel controls the rotation and longitudinal motion of the workpiece. The regulating wheel is kept slightly inclined to the axis of the grinding wheel and the workpiece is fed longitudinally
Centreless through feed grinding
The grinding wheel or the regulating wheel or both require to be correctly profiled to get the required taper on the workpiece. Tool post grinder A self powered grinding wheel is mounted on the tool post or compound rest to provide the grinding action in a lathe. Rotation to the workpiece is provided by the lathe spindle. The lathe carriage is used to reciprocate the wheel head. Internal grinding machine This machine is used to produce internal cylindrical surface. The surface may be straight, tapered, grooved or profiled. Broadly there are three different types of internal grinding machine as follows: 1. Chucking type internal grinder 2. Planetary internal grinder 3. Centreless internal grinder Chucking type internal grinder
The workpiece is usually mounted in a chuck. A magnetic face plate can also be used. A small grinding wheel performs the necessary grinding with its peripheral surface Planetary internal grinder Planetary internal grinder is used where the workpiece is of irregular shape and cannot be rotated conveniently does not rotate. Instead, the grinding wheel orbits the axis of the hole in the workpiece. Centreless internal grinder This machine is used for grinding cylindrical and tapered holes in cylindrical parts (e.g. cylindrical liners, various bushings etc). The workpiece is rotated between supporting roll, pressure roll and regulating wheel and is ground by the grinding Tool and cutter grinder machine Tool grinding may be divided into two subgroups: tool manufacturing and tool resharpening. There are many types of tool and cutter grinding machine to meet these requirements. Simple single point tools are occasionally sharpened by hand on bench or pedestal grinder. However, tools and cutters with complex geometry like milling cutter, drills, reamers
and hobs require sophisticated grinding machine commonly known as universal tool and cutter grinder. Present trend is to use tool and cutter grinder equipped with CNC to grind tool angles, concentricity, cutting edges and dimensional size with high precision.
Boring
In machining, boring is the process of enlarging a hole that has already been drilled (or cast), by means of a single-point cutting tool (or of a boring head containing several such tools), for example as in boring a gun barrel or an engine cylinder. Boring is used to achieve greater accuracy of the diameter of a hole, and can be used to cut a tapered hole. Boring can be viewed as the internal-diameter counterpart to turning, which cuts external diameters. There are various types of boring. The boring bar may be supported on both ends (which only works if the existing hole is a through hole), or it
may be supported at one end (which works for both through holes and blind
holes). Lineboring (line boring,
line-boring)
implies
the
former. Backboring(back boring, back-boring) is the process of reaching through an existing hole and then boring on the "back" side of the workpiece (relative to the machine headstock). Because of the limitations on tooling design imposed by the fact that the workpiece mostly surrounds the tool, boring is inherently somewhat more challenging than turning, in terms of decreased toolholding rigidity, increased clearance angle requirements (limiting the amount of support that can be given to the cutting edge), and difficulty of inspection of the resulting surface (size, form, surface roughness). These are the reasons why boring is viewed as an area of machining practice in its own right, separate from turning, with its own tips, tricks, challenges, and body of expertise, despite the fact that they are in some ways identical. Boring and turning have abrasive counterparts in internal and external cylindrical grinding. Each process is chosen based on the requirements and parameter values of a particular application.
Machine tools used
A horizontal boring mill, showing the large boring head and the workpiece sitting on the table.
Boring head on Morse taper shank. A small boring bar is inserted into one of the holes. The head can be shifted left or right with fine gradation by a screw, adjusting the diameter of the circle that the cutting tip swings
through, thus controlling the hole size, even down to within 10 micrometres if all machining conditions are good. The boring process can be executed on various machine tools, including (1) general-purpose or universal machines, such as lathes (/turning centers) ormilling machines (/machining centers), and (2) machines designed to specialize in boring as a primary function, such as jig borers and boring machines or boring mills, which include vertical boring mills (workpiece rotates around a vertical axis while boring bar/head moves linearly; essentially a vertical lathe) and horizontal boring mills (workpiece sits on a table while the boring bar rotates around a horizontal axis; essentially a specialized horizontal milling machine). Boring mills and milling machines The dimensions between the piece and the tool bit can be changed about two axes to cut both vertically and horizontally into the internal surface. The cutting tool is usually single point, made of M2 and M3 high-speed steel or P10 and P01 carbide. A tapered hole can also be made by swiveling the head.
Boring machines come in a large variety of sizes and styles. Boring operations on small workpieces can be carried out on a lathe while larger workpieces are machined on boring mills. Workpieces are commonly 1 to 4 metres (3 ft 3 in to 13 ft 1 in) in diameter, but can be as large as 20 m (66 ft). Power requirements can be as much as 200 horsepower (150 kW). Cooling of the bores is done through a hollow passageway through the boring bar where coolant can flow freely. Tungsten-alloy disks are sealed in the bar to counteract vibration and chatter during boring. The control systems can be computer-based, allowing for automation and increased consistency. Because boring is meant to decrease the product tolerances on pre-existing holes, several design considerations apply. First, large length-to-borediameters are not preferred due to cutting tool deflection. Next, through holes are preferred over blind holes (holes that do not traverse the thickness of the work piece). Interrupted internal working surfaces—where the cutting tool and surface have discontinuous contact—are preferably avoided. The boring bar is the protruding arm of the machine that holds cutting tool(s), and must be very rigid.
Because of the factors just mentioned, deep-hole drilling and deep-hole boring are inherently challenging areas of practice that demand special tooling and techniques. Nevertheless, technologies have been developed that produce deep holes with impressive accuracy. In most cases they involve multiple cutting points, diametrically opposed, whose deflection forces cancel each other out. They also usually involve delivery of cutting fluid pumped under pressure through the tool to orifices near the cutting edges. Gun drilling and cannon boring are classic examples. First developed to make the barrels of firearms and artillery, these machining techniques find wide use today for manufacturing in many industries. Various fixed cycles for boring are available in CNC controls. These are preprogrammed subroutines that move the tool through successive passes of cut, retract, advance, cut again, retract again, return to the initial position, and so on. These are called using G-codes such as G76, G85, G86, G87, G88, G89; and also by other less common codes specific to particular control builders or machine tool builders. Lathes
Lathe boring is a cutting operation that uses a single-point cutting tool or a boring head to produce conical or cylindrical surfaces by enlarging an existing opening in a workpiece. For nontapered holes, the cutting tool moves parallel to the axis of rotation. For tapered holes, the cutting tool moves at an angle to the axis of rotation. Geometries ranging from simple to extremely complex in a variety of diameters can be produced using boring applications. Boring is one of the most basic lathe operations next to turning and drilling. Lathe boring usually requires that the workpiece be held in the chuck and rotated. As the workpiece is rotated, a boring bar with an insert attached to the tip of the bar is fed into an existing hole. When the cutting tool engages the workpiece, a chip is formed. Depending on the type of tool used, the material, and the feed rate, the chip may be continuous or segmented. The surface produced is called a bore. The geometry produced by lathe boring is usually of two types: straight holes and tapered holes. Several diameters can also be added to each shape hole if required. To produce a taper, the tool may be fed at an angle to the axis of rotation or both feed and axial motions may be concurrent. Straight
holes and counterbores are produced by moving the tool parallel to the axis of workpiece rotation. The four most commonly used workholding devices are the three-jaw chuck, the four-jaw chuck, the collet, and the faceplate. The three-jaw chuck is used to hold round or hex workpieces because the work is automatically centered. On these chucks the runout faces limitations; on late-model CNCs, it can be quite low if all conditions are excellent, but traditionally it is usually at least .001-.003 in (0.025-0.075 mm). The fourjaw chuck is used either to hold irregular shapes or to hold round or hex to extremely low runout (with time spent indicating and clamping each piece), in both cases because of its independent action on each jaw. The face plate is also used for irregular shapes. Collets combine self-centering chucking with low runout, but they involve higher costs. For most lathe boring applications, tolerances greater than ±0.010 in (±0.25 mm) are easily held. Tolerances from there down to ±0.005 in (±0.13 mm) are usually held without especial difficulty or expense, even in deep holes. Tolerances between ±0.004 in (±0.10 mm) and ±0.001 in (±0.025 mm) are where the challenge begins rising. In deep holes with
tolerances
this
tight,
the
limiting
factor
is
just
as
often
the geometric constraint as the size constraint. In other words, it may be easy to hold the diameter within .002" at any diametrical measurement point, but difficult to hold the cylindricity of the hole to within a zone delimited by the .002" constraint, across more than 5 diameters of hole depth (depth measured in terms of diameter:depth aspect ratio). For highest-precision applications, tolerances can generally be held within ±0.0005 in (±0.013 mm) only for shallow holes. In some cases tolerances as tight as ±0.0001 in (±0.0038 mm) can be held in shallow holes, but it is expensive, with 100% inspection and loss of nonconforming parts adding to the cost. Grinding, honing, and lapping are the recourse for when the limits of boring repeatability and accuracy have been met. Surface finish (roughness) in boring may range from 8 to 250 microinches, with a typical range between 32 and 125 microinches. Sometimes a part may require higher accuracy of form and size than can be provided by boring. For example, even in optimized boring, the amount that the diameter varies on different portions of the bore is seldom less than 3 micrometre (.0001 inches, "a tenth"), and it may easily be 5 to 20
micrometre (.0002-.0008 inches, "2 to 8 tenths"). Taper, roundness error, and cylindricity error of such a hole, although they would be considered negligible in most other parts, may be unacceptable for a few applications. For such parts, internal cylindrical grinding is a typical follow-up operation. Often a part will be roughed and semifinished in the machining operation, then heat treated, and finally, finished by internal cylindrical grinding. The limitations of boring in terms of its geometric accuracy (form, position) and the hardness of the workpiece have been shrinking in recent decades as machining technology continues to advance. For example, new grades of carbide and ceramic cutting inserts have increased the accuracy and surface quality that can be achieved without grinding, and have increased the range of workpiece hardness values that are workable. However, working to tolerances of only a few microns (a few tenths) forces the manufacturing process to rationally confront, and compensate for, the fact that no actual workpiece is ideally rigid and immobile. Each time a cut is taken (no matter how small), or a temperature change of a few hundred degrees takes place (no matter how temporary), the workpiece, or a portion
of it, is likely to spring into a new shape, even if the movement is extremely small. In some cases a movement of a fraction of a micron in one area is amplified in lever fashion to create a positional error of several microns for a feature of the workpiece several decimetres away. It is factors such as these that sometimes preclude finishing by boring and turning as opposed to internal and external cylindrical grinding. At the extreme, no perfection of machining or grinding may be enough when, despite the part being within tolerance when it is made, it warps out of tolerance in following days or months. When engineers are confronted with such a case, it drives the quest to find other workpiece materials, or alternate designs that avoid relying so heavily on the immobility of part features on the micro or nano scales.
BLOCK DIAGRAM OF MULTIPURPOSE MACHINE
AC Power supply
AC Motor
Spindle
Boring operation
Counter shaft
Drilling operation
workpiece
Grinding operation
CONSTRUCTIONAL DETAILS
S.No
Components
Quantity
Material
1.
Grinding wheel
100 mm
Carborandum
2.
Drill bit
15 mm
HSS
3.
Cutter
1
Mild steel
5.
Belt and arrangement
pulley 1
Mild steel
6.
Base plate
1
Mild steel
7.
Electric motor
1 (900 RPM) Cast iron
WORKING PRINCIPLE
The multipurpose machine consists of an electric motor. Various machine tools such as boring drilling and grinding tools are attached to the motor spindle by means of pulley arrangement. When the motor gets rotated the mechanical power is transmitted to the spindle and the pulley arrangement and the grinding, boring and drilling tool also rotates. Thus by means of the single power we can perform three different operations. The shaft is supported in either and by bearings.
APPLICATIONS
This multipurpose device has a numerous applications in various fields.
In industries, this is used in assembly section.
The required
pressure is set and the operation is carried out. In automobile shops various operations are required frequently Drilling, boring, reaming, grinding etc. It is also used as a screw driver for tightening and loosening nuts and bolts. It is used. 1. In automobile workshops 2. In small scale industries 3. In such places where frequent changes in operations are required 4. In welding shops for grinding.
5. For performing operations in huge parts which can not be done in ordinary machines, since it is portable.
ADVANTAGES The pneumatically operated multi purpose device has many advantages. They are as follows: Low cost, so it can be used in small scale industries. Higher rate and quicker operations A number of operations like (drilling), screw driving, reaming etc., can be done. The nuts and bolts can be tightened to a particular pressure by operating the gate valve placed in the control unit and the pressure gauge. Both loosening and tightening is possible. Since there is air flow in both directions.
The weight of the unit is less and can be easily handled. Efficient operation.
Since if does not require any
electricity for running. The weight of the machine is concentrated towards the machining head to facilitate easy manipulation of the machining. The design is simple and there is no maintenance required. The control valve for allowing or restricting air may be placed on handle to make easier to control the speed of the machine. The maximum rpm of the unit of the unit is 7000 rpm. The speed provides a torque which is suitable for machining. The maximum pressure that can be used is 7 kg km². The rpm and torque can be varied by varying the pressure of the air inlet.
DISADVANTAGES 1. Initial cost is high 2. Spindle rotation is pneumatic power, so this machine having low torque 3. Need a separate compressor
CONCLUSION With the idea on view, we have completed the project titled “DESIGN AND FABRICATION OF MULTIPURPOSE MACHINE” By means of this machine various operations can be performed using same power. So this multipurpose device is used for various operations with a less amount of investment. This is one of the most reliable and simple machine in the machine shop in which many number of operations can be done.
REFERENCES 1.
Production technology by P.C. Sharma
2.
Todd, Robert H.; Allen, Dell K. Manufacturing Processes
Reference Guide
3.
Industrial Press Inc., ISBN 0-8311-3049-0,
4.
Colvin, Fred H. (1947), Sixty Years with Men and
Machines, McGraw-Hill, 5.
Floud, Roderick C. (2006) 1976, The British Machine Tool
Industry,
6.
Hounshell, David A. : The Development of Manufacturing
Technology in the United States, 7.
Noble, David F. (1984), Forces of Production: A Social
History of Industrial Automation
