This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.
In order to compete with the ever-growing competent market, it is indispensable for an industrialist to aim for higher production coupled with the enhanced quality with an objective of reduction in cost potential. This necessitates to automation and usage of Tooling aids such as "Jigs and Fixtures" which involve comparatively much lower initial investments and higher productivity.
The main factor of automation and utility at modernization of the tool design adopts tooling aids, such as Jigs and Fixtures. As sequel to this observation and aiming at higher productivity, It is proposed to study the performance parameters of modeling and assembly of drill Jigs using the software package Solid Works at "CADD Centre Training Services Pvt Ltd"
Jigs and Fixtures are defined as devices used in the designing and manufacturing of the various parts of machines and intended to make interchangeable work, at reduced cost as compared with the cost of producing each machine detail individually.
The modern manufacturing requires companies to reduce product development time and capitalize their know-how so that they can respond quickly to customer needs. In order to make it happen, they must expand their ability to innovate by automating redundant tasks and focusing on innovative projects.
Solid Works is an interactive CAD/CAM system, a fully 3-D double precession system that allows accurate description of almost any geometric shape. Solid Works modeling provides capabilities to help the design engineer to perform conceptual and detailed deigns. It is a feature and constrained based solid modeler that allows users to create and edit complex solid models interactively.
Literature and Survey
Jigs and Fixtures
Types of Jigs
Types of Fixtures
Classification of fixtures
Difference between Jigs and Fixtures
Materials used in Jigs and Fixtures
Considerations in Designing of Jigs
Introduction to modeling
Implementation of Modeling
Introduction to Computer-Aided-Engineering(CAE)
Different fields in CAE
Introduction to FEM/FEA
Finite Element Analysis
List of Figures
3. - 3.01 , 3.02
3.1 - 3.1.1 , 3.1.2 ,3.1.3 , 3.1.4 , 3.1.5 , 3.1.6 , 3.1.7, 3.1.8 , 3.1.9 ,3.1.10,
3.1.11 , 3.1.12
3.2 - 3.2.1 , 3.2., 3.2.3 , 3.2.4 , 3.2.5 , 3.2.6
3.4 - 3.4.1 , 3.4.2
3.8 - 3.8.1
Over the past century, manufacturing has made considerable progress. New machine tools, high-performance cutting tools, and modern manufacturing processes enable today's industries to make parts faster and better than ever before. Although workholding methods have also advanced considerably, the basic principles of clamping and locating are still the same.
Eventually, they found the secret of mass production: standardized parts. Standard parts not only speeded production, they also ensured the interchangeability of parts. The idea may be obvious today, but in its time, it was revolutionary.
These standard parts were the key to enabling less-skilled workers to replicate the skill of the craftsman on a repetitive basis. The original method of achieving consistent part configuration was the template. Templates for layout, sawing, and filing permitted each worker to make parts to a standard design. While early templates were crude, they at least gave skilled workers a standard form to follow for the part. Building on the template idea, workers constructed other guides and workholders to make their jobs easier and the results more predictable. These guides and workholders were the ancestors of today's jigs and fixtures.
Past workholders had the same two basic functions as today's: securely holding and accurately locating a workpiece. Early jigs and fixtures may have lacked modern refinements, but they followed many of the same principles as today's workholder designs.
Production devices are generally work holders with/without tool guiding/setting arrangement. These are called jigs and fixtures.
A jig is any of a large class of tools in woodworking, metalworking, and some other crafts that help to control the location or motion (or both) of a tool. Some types of jigs are also called templates or guides.
Jigs are provided with tool guiding elements such as drill bushes. These direct the tool to the correct position on the workpiece.Jigs are rarely clamped on the machine table because it is necessary to move the jig on the table to align the various brushings in the jig with the machine spindle. The primary purpose for a jig is for repeatability and exact duplication of a part for reproduction. An example of a jig is when a key is duplicated; the original is used as a jig so the new key can have the same path as the old one. In the advent of automation and CNC machines, jigs are not required because the tool path is digitally programmed and stored in memory.
Jigs or templates have been known long before the industrial age. There are many types of jigs, and each one is custom-tailored to do a specific job. Many jigs are created because there is a necessity to do so by the tradesmen. Some are to increase productivity, to do repetitious activities and to do a job more precisely. Because jig design is fundamentally based on logic, similar jigs used in different times and places may have been created independently.
To accommodate several components at one setting in order to take advantage of multiple machining. Instead of making a hole in one thin flat piece at a time, 10 such pieces can be stacked in a jig and the hole can be drilled in one go.
Jigs and fixtures are production tools used to accurately manufacture duplicate and interchangeable parts. Jigs and fixtures are specially designed so that large numbers of components can be machined or assembled identically, and to ensure interchangeability of components.
The economical production of engineering components is greatly facilitated by the provision of jigs and fixtures. The use of a jig or fixture makes a fairly simple operation out of one which would otherwise require a lot of skill and time.
A jig or fixture is designed and built to hold, support and locate every component (part) to ensure that each is drilled or machined within the specified limits.
The correct relationship and alignment between the tool and the work piece is maintained. Jigs and fixtures may be large (air plane fuselages are built on picture frame fixtures) or very small (as in watch making). Their use is limited only by job requirements and the imagination of the designer.
The jigs and fixtures must. be accurately made and the material used must' be able to withstand wear and the operational (cutting) forces experienced during metal cutting.
To position a component and to guide the drill or cutter so that every component will be uniform. In machining we perform operations and create surfaces, flat or curved or round holes, which must bear some definite relations in terms of distance or angle with others. In mass production, this must be essentially uniform. This uniformity is achieved by use of jigs and fixtures.
Jigs and fixtures must be clean, undamaged and free from swarf and grit Components must not be forced into a jig or fixture.
Jigs like fixtures are designed to hold, locate and support a work piece. However, they also guide the working tool in to work piece through out the cutting cycle, which is important, for example in small diameter and/or long drilling situations.
2. LITERATURE AND SURVEY
All washer machines work by using mechanical energy, thermal energy, and chemical action. Mechanical energy is imparted to the clothes load by the rotation of the agitator in top loaders, or by the tumbling action of the drum in front loaders.
Since their introduction in the late 1930s/mid 1940s, automatic washing machines have relied on mechanical timers to sequence the washing and extraction process. Mechanical timers consist of a series of cams on a common shaft. At the appropriate time in the wash cycle, each cam actuates a switch to engage/disengage a particular part of the machinery (e.g. drain pump motor). The timer shaft is driven by a small electric motor via a reduction gearbox.
On the early mechanical timers the motor ran at a constant speed throughout the wash cycle, although it was possible for the user to truncate parts of the program, by manually advancing the control dial. However, by the 1950s demand for greater flexibility in the wash cycle led to the introduction of electronic timers to supplement the mechanical timer. These electronic timers enable greater variation in such functions as the wash time. With this arrangement, the electric timer motor is periodically switched-off to permit the clothing to soak, and is only re-energized just prior to a micro-switch being engaged/disengaged.
Despite the high cost of automatic washers, manufacturers had difficulty in meeting the demand. In automatic washing machines, any changes in impeller/drum speed were achieved by mechanical means or by a rheostat on the motor power supply.
Modern washing machines are available in two configurations: top loading and front loading.
In top loading washers, if the motor spins in one direction, the gearbox drives the agitator; if the motor spins the other way, the gearbox locks the agitator and spins the basket and agitator together.
The front loading design or H-axis clothes washer mounts the inner basket and outer tub horizontally, and loading is through a door at the front of the machine.
Front loading washers are mechanically simple compared to top-loaders, with the main motor normally being connected to the drum via a grooved pulley belt and large pulley wheel, without the need for a gearbox, clutch or crank. But front-load washers suffer from their own technical problems, due to the drum lying sideways.
Mechanical washing machines appeared in the early 1800s, although they were all hand-powered. Early models cleaned clothes by rubbing them, while later models cleaned clothes by moving them through water. Steam-powered commercial washers appeared in the 1850s, but home washing machines remained entirely hand-powered until the early 1900s, when several companies started making electric machines.
Many models with many varying features are now available; however, with a few exceptions, only the controls are different. The only difference between the washers in our home and the top-load washers in the laundromat is the ruggedness of construction.
2.2 Working Principle
The washing machine operates by a motor, which is connected to the agitator through a unit called a transmission. The motor and transmission are near the bottom of the machine, while the agitator extends up through the middle of the machine. The transmission is similar to the transmission in automobile, in that it changes the speed and direction of the agitator. In one direction (agitate), the transmission changes the rotation of the agitator and spin tub-the inside tub with small holes in it-into a back-and-forth motion. When the motor is reversed by the controls (spin), the transmission locks up and the agitator, transmission, and spin tub all rotate as a unit. Without the transmission changing the speed or direction, the unit uses centrifugal force to remove as much water from the clothes as possible. The motor is also connected to a pump. When the motor is moving in the spin direction, the pump removes the water from the tub and discards it through the drain pipe.
3. JIGS and FIXTURES
Jigs and fixtures are most often found where parts are produced in large quantities, or produced to complex specifications for a moderate quantity. With the same design principles and logic, workholding devices can be adapted for limited-production applications.
The economical production of engineering components is greatly facilitated by the provision of jigs and fixtures.
A jig is a special device that holds, supports or is placed on a part to the machine. It is a production to make so that it not only locates and holds the work piece but also guides the cutting tool as the operation is performed. Jigs are usually fitted with hard and steel bushing for guiding drill or other cutting tools.
A fixture is a work holding device which holds and positions the workplace, but does not guide or locate or position the cutting tool. A fixture should be securely fastened to the table of the machine upon which the work is done. Though largely used on milling machines fixture are also designed to hold work for various operation on most of the standard machine tools.
CLASSES OF JIGS
Jigs may be divided into two general classes:
1)Boring jigs 2)Drill jigs
Boring jigs are used to bore holes that either are too large to drill or must be made an odd size.
Drill jigs are used to drill, ream, tap, chamfer, counterbore, countersink, reverse spotface, or reverse countersink .The basic jig is almost the same for either machining operation.The only difference is in the size of the bushings used.
3.1 TYPES OF JIGS
Drill jigs may be divided into two general types, open jigs and closed jigs.
Open jigs are for simple operations where work is done on only one side of the part.
Closed or box jigs are used for parts that must be machined on more than one side. The names used to identify these jigs refer to how the tool is built.
Template jigs are normally used for accuracy rather than speed. This type of jig fits over, on, or into the work and is not usually clamped .Templates are the least expensive and simplest type of jig to use. They may or may not have bushings. When bushings are not used, the whole jig plate is normally hardened.
Plate jigs are similar to templates.The only difference is that plate jigs have built-in clamps to hold the work. These jigs can also be made with or without bushings, depending on the number of parts to be made.
Plate jigs are sometimes made with legs to raise the jig off the table for large work. This style is called a table jig.
Sandwich jigs are a form of plate jig with a back plate. This type of jig is ideal for thin or soft parts that could bend or warp in another style of jig. Here again, the use of bushings is determined by the number of parts to be made.
Angle-plate jigs are used to hold parts that are machined at right angles to their mounting locators (Figure 1). Pulleys, collars, and gears are some of the parts that use this type of jig.
A variation is the modified angle-plate jig, which is used for machining angles other than 90 degrees (Figure 2). Both of these examples have clearance problems with the cutting tool. As the drill exits the product being drilled, it has little or no room for the drill point to clear the product completely, produce a round hole all the way through the part wall, and avoid drilling the part locator. This is most noticeable in (Figure 2), where an angled hole requires additional clearance to the relieved portion of the part locator. Additional clearance here would allow the drill to complete the hole and avoid drilling the relieved portion of the locator. The part locator will most likely be hardened and the drill will be lost as a result of any attempted drilling. Additional clearance on the relieved diameter of the part locator may be possible. A larger clearance hole in the locator could also be added if the relieved diameter cannot be reduced. The additional design consideration added to the locator would include the feature to provide the correct orientation of this clearance hole or machined relief to line up with the bushing location.
Box jigs or tumble jigs, usually totally surround the part .This style of jig allows the part to be completely machined on every surface without the need to reposition the work in the jig.
Channel jigs are the simplest form of box jig.The work is held between two sides and machined from the third side. In some cases, where jig feet are used, the work can be machined on three sides.
Leaf jigs are small box jigs with a hinged leaf to allow for easier loading and unloading .The main differences between leaf jigs and box jigs are size and part location. Leaf jigs are normally smaller than box jigs and are sometimes made so that they do not completely surround the part. They are usually equipped with a handle for easier movement.
Indexing jigs are used to accurately space holes or other machined areas around a part. To do this, the jig uses either the part itself or a reference plate and a plunger. Larger indexing jigs are called rotary jigs.
Trunnion jigs are a form of rotary jig for very large or odd-shaped parts.The part is first put into a box-type carrier and then loaded on the trunnion. This jig is well suited for large, heavy parts that must be machined with several separate platetype jigs.
Pump jigs are commercially made jigs that must be adapted by the user . The lever-activated plate makes this tool very fast to load and unload. Since the tool is already made and only needs to be modified, a great deal of time is saved by using this jig.
There are several other jigs that are combinations of the types described. These complex jigs are often so specialized that they cannot be classified. Regardless of the jig selected, it must suit the part, perform the operation accurately, and be simple and safe to operate.
Although these are usually more permanent, complex and dedicated and often fastened down, some may be simple. Often they are accessories for hand or machine tools. Probably the most common are vises and clamps, which may be highly specialized.
A fixture is a work-holding device that is bolted or otherwise fastened to the machine; a fixture does not provide for the guiding of the processing tool. Instead, the tool is moved to the point of operation, as in the case of a radial drill, or the table is moved under the processing tool, as in a milling machine. Provisions are usually made for setting up the tool in relation to a specific surface, called the rest surface, on the part. The device used for this purpose is called a set block. Rest surfaces or locating pins on the set block allow each duplicate part to be positioned and clamped to the fixture in the same manner so that the operation taking place will always be within the same dimensional tolerances.
The names are used to describe various type of fixtures are determined mainly by how the tool is built. Jigs and fixtures are basically the same way as far as the locators and petitioners are concerned because of the increased tool forces the fixtures are build stronger and heavier than a jig.
3.2.1 Types of Fixtures
Plate fixtures are the simplest form of fixture The basic fixture is made from a flat plate that has a variety of clamps and locators to hold and locate the part. The simplicity of this fixture makes it useful for most machining operations. Its adaptability makes it popular.
The angle-plate fixture is a variation of the plate fixture. With this tool, the part is normally machined at a right angle to its locator. While most angle-plate fixtures are made at 90 degrees, there are times when other angles are needed. In these cases, a modified angle-plate fixture can be used.
Vise-jaw fixtures are used for machining small parts .With this type of tool, the standard vise jaws are replaced with jaws that are formed to fit the part. Vise-jaw fixtures are the least expensive type of fixture to make. Their use is limited only by the sizes of the vises available.
Indexing fixtures are very similar to indexing jigs. These fixtures are used for machining parts that must have machined details evenly spaced.
The parts shown below are the examples of the uses of an indexing fixture.
Multistation fixtures are used primarily for high-speed, high-volume production runs, where the machining cycle must be continuous.
Duplex fixtures are the simplest form of multistation fixture, using only two stations . This form allows the loading and unloading operations to be performed while the machining operation is in progress. For example, once the machining operation is complete at station 1, the tool is revolved and the cycle is repeated at station 2. At the same time, the part is unloaded at station 1 and a fresh part is loaded.
Profiling fixtures are used to guide tools form machining contours that the machine cannot normally follow. These contours can be either internal or external. Since the fixture continuously contacts the tool, an incorrectly cut shape is almost impossible. The operation shows how the cam is accurately cut by maintaining contact between the fixture and the bearing on the milling cutter. This bearing is an important part of the tool and must always be used.
3.3 CLASSIFICATION OF FIXTURES
Fixtures are normally classified by the type of machine on which they are used. Fixtures can also be identified by a sub classification . For example, if a fixture is designed to be used on a milling machine, it is called a milling fixture. If the task it is intended to perform is straddle milling, it is called a straddlemilling fixture. The same principle applies to a lathe fixture that is designed to machine radii. It is called a lathe-radius fixture.
3.4 Difference between Jigs and Fixtures
From the construction point of view, jigs are lighter in weight.
Jigs hold the work piece, locate and guide the tool.
They are used for particularly drilling, taping operations.
The fixtures hold the work and position the work but do not guide the tool.
They are generally heavier and are bolted rigidly on the machine table.
They are utilized for holding the work in milling, grinding, planing or turning operation
A jig guides the cutting tool, in this case with a bushing.
A fixture references the cutting tool, in this case with a set block
3.5 Materials used in Jigs and FixturesÂ
Jigs and fixtures are made from a variety of materials, some of which can be hardened to resist wear.
It is sometimes necessary to use nonferrous metals like phosphor bronze to reduce wear of the mating parts, or nylons or fiber to prevent damage to the workpiece. Given below are the materials often used in jigs, fixtures, press tools, collets, etc.
High Speed Steels (HSS)
Collet Steels (Spring Steels)
Oil Hardening Non-Shrinking Tool Steels (OHNS)
Case Hardening Steels
High Tensile Steels
Nylon and Fiber
3.6 Applications for Jigs and Fixtures
Typically, the jigs and fixtures found in a machine shop are for machining operations. Other operations, however, such as assembly, inspection, testing, and layout, are also areas where workholding devices are well suited.
There are many distinct variations within each general classification, and many workholders are actually combinations of two or more of the classifications shown below:-
External Machining Applications :-
Shaping fixtures Cylindrical-Surface Machining
Cylindrical-grinding fixtures Irregular-Surface Machining
Internal Machining Applications :-
Cylindrical- and Irregular-Hole Machining
Non Machining Applications :-
Mechanical-assembly fixtures (Riveting, stapling, stitching, pinning, etc.)
3.7 Considerations in Designing of Jigs:
The design of a jig should depend altogether on the character of the work to be done, the number of pieces to be drilled, and the degree of accuracy necessary in order that pieces drilled may answer the purpose for which they are intended. When jigs are to be turned over and moved around on the drill press table they should be designed to insure ease and comfort to the operator when handling, and should be made as light as is consistent with the strength and stiffness necessary. Yet, we should never attempt to save a few ounces of iron, and thereby render the jig unfit for the purpose we intend to use it for. The designer should see that the jig is planned so that work may be easily and quickly placed in and taken out, and that it can be easily and accurately located in order to prevent eventual mistakes.
As it is necessary to fasten work in the jig in order that it may maintain its correct position, fastening devices are used; these should allow rapid manipulation, and yet hold the work securely to prevent a change of location. Yet, while it is necessary to hold work securely, we should not use fastening devices which spring the work, or the holes will be not only improperly located, but they will not be true with the working surfaces or with each other. When finishing the surfaces of drill jigs and similar devices used in machine shops, the character of the finish depends entirely on the custom in the shop, for while in some shops it is customary to finish these tools very nicely, removing every scratch, and producing highly finished surfaces, in other shops it is not required, neither is it allowed, as it is considered a waste of time and an unnecessary item of cost.
3.8 TIMERS :-
A timer function allows you to set up the device to automatically cook for a certain amount of time without having to manually turn it on and off. A timer is a specialized type of clock. A timer can be used to control the sequence of an event or process. Timers can be mechanical, electromechanical, electronic (quartz), or even software as most computers include digital timers of one kind or another.
Mechanical timers used typical clockwork mechanisms, such as an escapement and spring to regulate their speed.
Electromechanical timers have two types. A thermal type has a metal finger comprised of two metals with different rates of thermal expansion sandwiched together; steel and bronze are common. An electric current flowing through this finger causes heating of the metals, one side expands less than the other, and an electrical contact on the end of the finger moves away from or towards an electrical switch contact.
Another type of electromechanical timer (a cam timer) uses a small synchronous AC motor turning a cam against a comb of switch contact.
Electronic timers can achieve higher precision than mechanical timers because they are quart clocks with special electronics. Electronic timers can be analog (resembling a mechanical timer) or digital.
4. Introduction to Modeling
Computer-Aided Design (CAD) is the use of computer technology to aid in the design and particularly the drafting (technical drawing and engineering drawing) of a part or product, including entire buildings. It is both a visual (or drawing) and symbol-based method of communication whose conventions are particular to a specific technical field.
Drafting can be done in two dimensions ("2D") and three dimensions ("3D").
Drafting is the communication of technical or engineering drawings and is the industrial arts sub-discipline that underlies all involved technical endeavors. In representing complex, three-dimensional objects in two-dimensional drawings, these objects have traditionally been represented by three projected views at right angles.
Current Computer-Aided Design software packages range from 2D vector-based drafting systems to 3D solid and surface modellers. Modern CAD packages can also frequently allow rotations in three dimensions, allowing viewing of a designed object from any desired angle, even from the inside looking out. Some CAD software is capable of dynamic mathematic modeling, in which case it may be marketed as CADD - computer-aided design and drafting.
CAD is mainly used for detailed engineering of 3D models and/or 2D drawings of physical components, but it is also used throughout the engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies to definition of manufacturing methods of components.
CAD has become an especially important technology within the scope of computer-aided technologies, with benefits such as lower product development costs and a greatly shortened design cycle. CAD enables designers to lay out and develop work on screen, print it out and save it for future editing, saving time on their drawings.
Computer-Aided Design is one of the many tools used by engineers and designers and is used in many ways depending on the profession of the user and the type of software in question. There are several different types of CAD. Each of these different types of CAD systems require the operator to think differently about how he or she will use them and he or she must design their virtual components in a different manner for each.
3D wireframe is basically an extension of 2D drafting. Each line has to be manually inserted into the drawing. The final product has no mass properties associated with it and cannot have features directly added to it, such as holes. The operator approaches these in a similar fashion to the 2D systems, although many 3D systems allow using the wireframe model to make the final engineering drawing views.
3D "dumb" solids are created in a way analogous to manipulations of real world objects. Basic three-dimensional geometric forms (prisms, cylinders, spheres, and so on) have solid volumes added or subtracted from them, as if assembling or cutting real-world objects. Two-dimensional projected views can easily be generated from the models. Basic 3D solids don't usually include tools to easily allow motion of components, set limits to their motion, or identify interference between components.
3D modeling is the process of developing a mathematical, wireframe representation of any three-dimensional object (either inanimate or living) via specialized software. The product is called a 3D model. It can be displayed as a two-dimensional image through a process called 3D rendering or used in a computer simulation of physical phenomena. The model can also be physically created using 3D Printing devices.
Almost all 3D models can be divided into two categories.
Solid - These models define the volume of the object they represent (like a rock). These are more realistic, but more difficult to build. Solid models are mostly used for nonvisual simulations such as medical and engineering simulations, and for specialized visual applications such as ray tracing and constructive solid geometry.
Shell/boundary - these models represent the surface, e.g. the boundary of the object, not its volume (like an infinitesimally thin eggshell). These are easier to work with than solid models. Almost all visual models used in games and film are shell models.
Many number of Designing and Analysis softwares have been developed and developing as the technology is increasing day-by-day.
Some of the Design and Analysis Softwares are as follows:-
Computer Aided Design(CAD)
Computer Aided Manufacturing(CAM)
Computer Aided Engineering(CAE)
4.1 Solid Works
Solid Works (Computer Aided Three Dimensional Interactive Application) is a multi-platform CAD/CAM/CAE commercial software suite developed by the French company Dassault Systemes and marketed worldwide by IBM. Solid Works is the cornerstone of the Dassault Systemes product lifecycle management software suite.
The software was created in the late 1980s and early 1990s to develop Dassault's Mirage fighter jet, then was adopted in the aerospace, automotive, shipbuilding, and other industries.
Notable industries using Solid Works
Solid Works is widely used throughout the engineering industry, especially in the automotive and aerospace sectors. Solid Works Pro/ENGINEER, NX (formerly Unigraphics), and Catia are the dominant systems.
4.2 Implementation of modeling
In this project we have designed different components of drill jig and assembled them by using the software called Solid Works.
The following parts are designed :-
Jig Base Plate
Insert your fig..
5. Introduction to Computer-Aided Engineering (CAE)
Computer-aided engineering (CAE) is the use of information technology to support engineers in tasks such as analysis, simulation, design, manufacture, planning, diagnosis, and repair.
Software tools that have been developed to support these activities are considered CAE tools. CAE tools are being used, for example, to analyze the robustness and performance of components and assemblies. The term encompasses simulation, validation, and optimization of products and manufacturing tools. In the future, CAE systems will be major providers of information to help support design teams in decision making.
In regard to information networks, CAE systems are individually considered a single node on a total information network and each node may interact with other nodes on the network.
5.1 Different fields and phases in CAE
CAE areas covered include:
Stress analysis on components and assemblies using FEA (Finite Element Analysis);
Thermal and fluid flow analysis Computational fluid dynamics (CFD);
Mechanical event simulation (MES).
Analysis tools for process simulation for operations such as casting, molding, and die press forming.
Optimization of the product or process.
In general, there are three phases in any computer-aided engineering task :-
Pre-processing - defining the model and environmental factors to be applied to it. (typically a finite element model, but facet, voxel and thin sheet methods are also used)
Analysis solver (usually performed on high powered computers)
Post-processing of results (using visualization tools)
This cycle is iterated, often many times, either manually or with the use of commercial optimization software.
CAE in automotive industry:-
CAE tools are very widely used in the automotive industry. In fact, their use has enabled the automakers to reduce product development cost and time while improving the safety, comfort, and durability of the vehicles they produce. The predictive capability of CAE tools has progressed to the point where much of the design verification is now done using computer simulations rather than physical prototype testing. CAE dependability is based upon all proper assumptions as inputs and must identify critical inputs (BJ). Even though there have been many advances in CAE and it is widely used in the engineering field. Physical testing is still used as a final confirmation for subsystems due to the fact that CAE cannot predict all variables in complex assemblies (i.e. metal stretch , thinning).
5.2 Introduction to FEM/FEA
The finite element method (FEM) (sometimes referred to as finite element analysis) is a numerical technique for finding approximate solutions of partial differential equations (PDE) as well as of integral equations. The solution approach is based either on eliminating the differential equation completely (steady state problems), or rendering the PDE into an approximating system of ordinary differential equations, which are then numerically integrated using standard techniques such as Euler's method, Runge-Kutta, etcâ€¦
FEM was first developed for use in the aerospace and nuclear industries where the safety of structures is critical.Today, the growth in usage of the method is directly attributable to the rapid advances in computer technology in recent years.As a result, commercial finite element packages exist that are capable of solving the most sophisticated problems,not just in structural analysis,but for a wide range of phenomena such as steady state and dynamic temperature distriutions,fluid flow and manufacturing processes such as injection moulding and metal forming.
The finite-element method originated from the need for solving complex elasticity and structural analysis problems in civil and aeronautical engineering. Its development can be traced back to the work by Alexander Hrennikoff (1941) and Richard Courant (1942). While the approaches used by these pioneers are dramatically different, they share one essential characteristic: mesh discretization of a continuous domain into a set of discrete sub-domains, usually called elements.
5.2.1 Finite Element Method
Among the various numerical methods available, finite element method is most popular and widely used. Perhaps it serves as the most sophisticated tool for solving engineering problems. With the introduction of new materials, viz .composites, fiber reinforced materials etc. the conventional method fails to give solution in many cases, or it becomes quite uneconomical or time consuming. Moreover, many a structure or its components may have complicated shapes whose analysis by the conventional methods becomes very cumbersome and is a few cases almost impossible to analyze .Any structure having any shape and made of any material can be analyzed by the finite element method. Such an advantage is not available with other methods.
A Typical Analysis
In real world, no analysis is typical, as there are usually facets that cause it to differ from others. There is however a main procedure those most Finite Element investigations take. This procedure is explained in the following topics.
Planning the Finite Element Analysis
Planning the Finite Element Analysis
The planning of an analysis is the most important part of the finite element design process. It is usually the one step that is disregarded by the majority, even the most superlative analysts among us are guilty. Without careful planning, even the most trivial analysis would probably result in appropriate output. There are number of checks that should be carried out on the design approach and the model.
The preprocessor stage in general FE packages involves the following :-
Specifying the title
Setting the type of analysis to be used
Creating the model
Defining the element type
Applying a mesh
Applying Boundary conditions
This part is fully automatic. The FE solver can be logically divided into three main parts, the pre-solver, the mathematical-Engine and the post-solver. The pre-solver reads in the model created by the pre-processor and formulates the mathematical representation of the model. All parameters defined in the pre-processing stage are used to do this, so if you leave something out, chances are the pre-solver will complain and cancel the call to the mathematical-engine.If the model is correct the solver proceeds to form the element-stiffness matrix for the problem and calls the mathematically-engine which calculates the result. All these results are sent to a result file which many be read by the post-processor.
Here the results of the analysis are read and interpreted. They can be presented in the form of a table, a contour plot, deformed shape of the component or the mode shapes and natural frequencies if frequency analysis is involved. Other results for fluids, thermal and electrical analysis types. Most post-processor provide an animation service, which produces an animation and brings your model to life.
All post-processor now include the calculation of stress and strains in any of the x, y or z directions, or indeed in a direction at an angle to the coordinates axes. The principal stresses and strains may also be plotted, or if required the yield stresses and strains according to the main theories of failure.
A variety of specializations under the umbrella of the mechanical engineering discipline (such as aeronautical, biomechanical, and automotive industries) commonly use integrated FEM in design and development of their products. Several modern FEM packages include specific components such as thermal, electromagnetic, fluid, and structural working environments. In a structural simulation, FEM helps tremendously in producing stiffness and strength visualizations and also in minimizing weight, materials, and costs.
FEM allows detailed visualization of where structures bend or twist, and indicates the distribution of stresses and displacements. FEM software provides a wide range of simulation options for controlling the complexity of both modeling and analysis of a system. Similarly, the desired level of accuracy required and associated computational time requirements can be managed simultaneously to address most engineering applications. FEM allows entire designs to be constructed, refined, and optimized before the design is manufactured.
This powerful design tool has significantly improved both the standard of engineering designs and the methodology of the design process in many industrial applications. The introduction of FEM has substantially decreased the time to take products from concept to the production line.It is primarily through improved initial prototype designs using FEM that testing and development have been accelerated. Benefits of FEM include increased accuracy, enhanced design and better insight into critical design parameters, virtual prototyping, fewer hardware prototypes, a faster and less expensive design cycle, increased productivity, and increased revenue.
The Finite Element Method has been successfully applied in various fields.Few of them are listed below:
Finite element modeling is generally a cost-effective way to design a prototype. Although an empirical testing (e.g. modal analysis testing and dynamic response measurements) has to be performed to verify the results, a FEA model provides a fairly reliable account of how a structure or a component will behave under stress. Things as big as a building structure and as small as a component of a measurement device can be modeled with sufficient accuracy and with reasonable assumptions.
5.4 Results are as follows:-
High Speed Steel
Portable automation puts powerful tools into the hands of operators and provides them with an effective means to accomplish many drilling tasks.
Jigs are inexpensive and fairly easy to build. Moreover its simplicity and accuracy of its operation make it quite useful, particularly on those shows that require mass production.
The main aim of our project is to do the complete modeling of the Drill-Jig and analyzing the part of Drill-jig i.e locating plate by considering High Speed Steel and Aluminium and observing the deformation from the above figures it can be said that High Speed Steel (Stress= , Deformation= ) has got much less deformation when compared with Aluminium (Stress= , Deformation= . Hence , it can be concluded that ,High Speed Steel is best suited for the material of the locating plate of Drill-Jig when compared to Aluminium.
Introduction to Jigs and Fixtures
Production Technology by R.K Jain