CAD/CAM/CIM
CAD/CAM/CIM
ABSTRACT
Computer-aided technologies (sometimes abbreviated as CAx[1]) is a broad term describing the use of computer technology to aid in the design, analysis, and manufacture of products.
Advanced CAx tools merge many different aspects of the product lifecycle management (PLM), including design, analysis using finite element analysis (FEA), manufacturing, production planning, product testing using virtual lab models and visualization, product documentation, product support, etc. CAx encompasses a broad range of tools, both those commercially available and those which are proprietary to the engineering firm.
The term CAD/CAM (computer-aided design and computer-aided manufacturing) is also often used in the context of a software tool covering a number of engineering functions.CAD/CAM software uses CAD drawing tools to describe geometries used by the CAM portion of the program to define a toolpath that will direct the motion of a machine tool to machine the exact shape that was drawn.
CONTENTS
· NC MACHINES BEFORE CAD/CAM
· INVENTION OF CAD/CAM
· COMPUTER-AIDED DESIGN (CAD)
· OVERVIEW TO CAD
· USAGE OF CAD
· 3D PARAMETRIC SOLID MODELING
· IMPLEMENTATION OF CAD
· COMPUTER INTEGRATED MANUFACTURING (CAM)
· TYPICAL AREAS OF CONCERN
· OVERCOMING HISTORICAL SHORTCOMINGS
· CAM SOFTWARE PROVIDERS
· AREAS OF USAGE OF CAM
· CONCLUSION
NC MACHINES BEFORE CAD/CAM:
Well before the development of Computer-aided design, the manufacturing world adopted tools controlled by numbers and letters to fill the need for manufacturing complex shapes in an accurate and repeatable manner. During the 1950's these Numerically-Controlled machines used the existing technology of paper tapes with regularly spaced holes punched in them to feed numbers into controller machines that were wired to the motors positioning the work on machine tools. The electro-mechanical nature of the controllers allowed digital technologies to be easily incorporated as they were developed.
By the late 1960's Numerically-Controlled machining centers were commercially available, incorporating a variety of machining processes and automatic tool changing. Such tools were capable of doing work on multiple surfaces of a workpiece, moving the workpiece to positions programmed in advance and using a variety of tools - all automatically. What is more, the same work could be done over and over again with extraordinary precision and very little additional human input. NC tools immediately raised automation of manufacturing to a new level once feedback loops were incorporated.
NC technology was successful by the development of the universal NC programming language called APT (Automatically Programmed Tools).APT allowed programmers to develop postprocessors specific to each type of NC tool so that the output from the APT program could be shared among different parties with different manufacturing capabilities.
INVENTION OF CAD/CAM:
The development of Computer-aided design had little effect on CNC initially due to the different capabilities and file formats used by drawing and machining programs. However, as CAD applications such as SolidWorks and AutoCad incorporate CAM intelligence, and as CAM applications such as MasterCam adopt sophisticated CAD tools, both designers and manufacturers are now enjoying an increasing variety of capable CAD/CAM software. Most CAD/CAM software was developed for product development and the design and manufacturing of components and molds, but they are being used by architects with greater frequency.
Today, over three-quarters of new machine tools incorporate CNC technologies. These tools are used in every conceivable manufacturing sector, including many that affect building technologies. CNC technology is related to Computer Integrated Manufacturing (CIM), Computer Aided Process Planning (CAPP) and other technologies such as Group Technology (GT) and Cellular Manufacturing. Flexible Manufacturing Systems (FMS) and Just-In-Time Production (JIT) are made possible by Numerically-Controlled Machines.
COMPUTER-AIDED DESIGN (CAD):
Computer-Aided Design (CAD) is the use of computer technology to aid in the design and particularly thedrafting (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 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.
OVERVIEW TO CAD:
Current Computer-Aided Design software packages range from 2D vector-based drafting systems to 3Dsolid 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 used in the design of tools and machinery and in the drafting and design of all types of buildings, from small residential types (houses) to the largest commercial and industrial structures (hospitals and factories).
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.
USAGE OF CAD:
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.
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 word 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 parametric solid modeling (programs incorporating this technology include Pro/ENGINEER, NX, the combination of UniGraphics and IDeas, CATIA V5, Autodesk Inventor, Alibre Design, TopSolid,T-FLEX CAD, SolidWorks, and Solid Edge) require the operator to use what is referred to as "design intent". The objects and features created are adjustable. Any future modifications will be simple, difficult, or nearly impossible, depending on how the original part was created. One must think of this as being a "perfect world" representation of the component. If a feature was intended to be located from the center of the part, the operator needs to locate it from the center of the model, not, perhaps, from a more convenient edge or an arbitrary point, as he could when using "dumb" solids.
This ability may also include the additional ability to infer the correct relationships between selected geometry (e.g., tangency, concentricity) which makes the editing process less time and labor intensive while still freeing the engineer from the burden of understanding the model’s design intent history. These kind of non history based systems are called Explicit Modellers. The first Explicit Modeling system was introduced to the world at the end of 80's by Hewlett-Packard under the name SolidDesigner. This CAD solution, which released many later versions, is now sold by PTC as "CoCreate Modeling"
Draft views are able to be generated easily from the models. Assemblies usually incorporate tools to represent the motions of components, set their limits, and identify interference. The tool kits available for these systems are ever increasing; including 3D piping and injection mold designing packages.
IMPLEMENTATION OF CAD:
Some consequence that had been since the latest advances were often quite expensive, small and even mid-size firms often could not compete against large firms who could use their computational edge for competitive purposes. Today, however, hardware and software costs have come down. Even high-end packages work on less expensive platforms and some even support multiple platforms. The costs associated with CAD implementation now are more heavily weighted to the costs of training in the use of these high level tools, the cost of integrating a CAD/CAM/CAE PLM using enterprise across multi-CAD and multi-platform environments and the costs of modifying design work flows to exploit the full advantage of CAD tools.
The methods of lowered training costs can be split into three categories:
· Improved and simplified user interfaces. This includes the availability of “role” specifictailorable user interfaces through which commands are presented to users in a form appropriate to their function and expertise.
· Enhancements to application software. One such example is improved design-in-context, through the ability to model/edit a design component from within the context of a large, even multi-CAD, active digital mockup.
· User oriented modeling options. This includes the ability to free the user from the need to understand the design intent history of a complex intelligent model.
COMPUTER-AIDED MANUFACTURING (CAM):
Computer-aided manufacturing (CAM) is the use of computer-based software tools that assist engineers and machinists in manufacturing or prototyping product components. CAM is a programming tool that makes it possible to manufacture physical models using computer-aided design (CAD) programs. CAM creates real life versions of components designed within a software package. CAM was first used in 1971 for car body design and tooling.The first commercial applications of CAM were in large companies in the automotive and aerospace industries for example UNISURF in 1971 at Renault (Bezier) for car body design and tooling.
TYPICAL AREAS OF CONCERN:
l High Speed Machining, including streamlining of tool paths
l Multi-function Machining
l 5 Axis Machining
l Ease of Use
OVERCOMING HISTORICAL SHORTCOMINGS:
Over time, the historical shortcomings of CAM are being attenuated, both by providers of niche solutions and by providers of high-end solutions. This is occurring primarily in three arenas:
1. Ease of use
2. Manufacturing complexity
3. Integration with PLM and the extended enterprise
EASE IN USE
For the user who is just getting started as a CAM user, out-of-the-box capabilities providing Process Wizards, templates, libraries, machine tool kits, automated feature based machining and job function specific tailorable user interfaces build user confidence and speed the learning curve. User confidence is further built on 3D visualization through a closer integration with the 3D CAD environment, including error-avoiding simulations and optimizations.
MANUFACTURING COMPLEXITY
The manufacturing environment is increasingly complex. The need for CAM and PLM tools by the manufacturing engineer, NC programmer or machinist is similar to the need for computer assistance by the pilot of modern aircraft systems. The modern machinery cannot be properly used without this assistance. Today's CAM systems support the full range of machine tools including: turning, 5 axis machining and wire EDM. Today’s CAM user can easily generate streamlined tool paths, optimized tool axis tilt for higher feed rates and optimized Z axis depth cuts as well as driving non-cutting operations such as the specification of probing motions.
INTEGRATION WITH PLM AND THE EXTENDED ENTERPRISE
Today’s competitive and successful companies have used PLM to integrate manufacturing with enterprise operations from concept through field support of the finished product. To ensure ease of use appropriate to user objectives, modern CAM solutions are scalable from a stand-alone CAM system to a fully integrated multi-CAD 3D solution-set. These solutions are created to meet the full needs of manufacturing personnel including part planning, shop documentation, resource management and data management and exchange.
CAM SOFTWARE PROVIDERS:
The largest CAM software companies (by revenue 2005) are
· UGS Corp (now owned by Siemens and called Siemens PLM Software, Inc) and Dassault Systèmes, both with over 10% of the market.
· CAMWorks (From Geometric Ltd) is the first CAM package with Automatic Feature Recognition Technology.
· Tebis
· CATIA
· SolidCAM
· 35% is accounted for by other niche suppliers like T-FLEX,Dolphin CAD/CAM, MecSoft Corporation, SurfCAM, BobCAD, Metamation, GibbsCAM.
AREAS OF USAGE OF CAM:
l In machining
l In electronic design automation, CAM tools prepare printed circuit board (PCB) andintegrated circuit design data for manufacturing.
CONCLUSION
Therefore the softwares CAD and CAM being used in almost all recent developing industrial manufacturers finds its usage also in automation production field. The CAD and CAM softwares also get intervened with other soft wares like CIM, CAE etc thereby widening its application range. These softwares must be made availeble also with small scale industries to ultimately increase theirs turn over.
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