Reverse Engineering: Imagine being asked to supply customers with accurate drawings of their parts. This may sound ironic, but many companies do not have up-to-date drawings of their parts and some have never had part drawings of any kind. Precision manufacturers can offer part drawings to their customers using a process called reverse engineering. Reverse Engineering (RE) is the process of capturing the geometry of existing physical objects and then using the data obtained as a foundation for designing something new. The new design can be duplicate of the original or an entirely new adaptation. Need of reverse engineering: Reverse engineering is an ideal process to use in the following situations: · A physical model of a product has been produced, but no drawings exist. · Drawings have been created, but working prototypes have been modified. · Worn or broken parts, for which there are no drawings, must be replaced and there is no source of supply. · 3D CAD is introduced to a company, & all existing products must be loaded into the system. · A disaster destroys parts records. · It is easier to develop drawings of an existing product and modify them in a 3D CAD system than create drawings from scratch. This is especially true for complex shapes that can be difficult to conceptualize. Process of reverse engineering: 1. Digitizing of component or molds 2. Working on Point cloud data 3. Creation of Surface of desired quality 4. Modifications to suit requirement 5. Creation of Surface or solid Model 6. Analysis for model properties 7. Creation of Molds & Dies for product 8. Analysis of the Molds 9. CNC Programming on CAM Package 10. CNC Machining of Molds 11. Trial Sample on Injection Molding Machine Acquiring cloud Data: Two major methods are, 1. Contact type: The simplest reverse engineering process is manual measurement and data collection of a physical model's dimensions. In this process, hand tools such as micrometers, vernier calipers and gages are used to capture the critical dimensions needed to generate a part drawing. A more sophisticated approach is to use a hard probe and a manual coordinate measuring machine (CMM). The CMM operator maintains contact between the hard probe and the surface being measured to record as many dimensions as possible. 2. Non-contact type: In non-contact type laser scanning is used, pulsed laser is directed at the object and the reflections are measured. The time lag between emitting a pulse and receiving it by the detector after reflection from the surface point is the measure of its distance. Before digitizing or 3D scanning, planning & partitioning of the surfaces should be done meticulously because we cannot scan complete object in one pass with the required accuracy, Hence following are the key points to be remembered, · Partition the object into small, discrete sections. · Separate Discontinuities in the surface. · Separate Discontinuities in the surface edges. · Scan each region meticulously. Constructing 3D Model: Key point to be remembered while building 3d model, · Data Orientation: If the part is symmetrical, the point cloud is oriented such that the mirror plane is defined. Once orientation is complete, all data exported to CAD software will be located correctly for easier model creation. · Data Manipulation: The final product is a variation of the part that was digitized. Therefore, data manipulation is required to reflect the desired changes. Scaling data is the most common manipulation. · Data Separation: Separate the data with high curvature difference, build surfaces on the cloud data extracted with similar curvature with in specified tolerance. · Replacing scanned data with Geometric features: Points that make up a flat surface, cylinder, or sphere are isolated, and a best-fit surface is created. · Verification of final surfaces: Software is used for verification of the CAD model. Surfaces are exported several times during CAD model creation and compared, vis. a color variance plot, to the point cloud. Applications : Some important applications of reverse engineering are as follows :- · Product Design / Rapid Prototyping: Engineering components can sometimes be styled rather than engineered. Typical examples include the shapes of cars, kettles or telephones. These parts may be as clay or plasticine models. Rather than recreating them in the computer, it is possible to scan them and generate geometric CAD models of them. This styled part can be manufactured using any of the RP processes early in the design cycle. · Quality Control: One part of quality control is to compare the manufactured shape to the required shape. For simple-shaped products, this can be done by means of simple measurement. However this is infeasible for complex, large parts. Using scanning and surface fitting techniques, it is possible to capture and recreate the manufactured shape and compare it with the required shape. · Simulation: Simulation of parts using numerical methods is only possible when a computational model of the object exists. This is usually not the case for natural objects. These objects can be scanned and a computational object can be created for them. This makes subsequent numerical analyses possible. · Medicine: To manufacture orthopedic shoes it is necessary to wrap the patients foot into plaster, let the plaster harden then remove it. This is a time consuming process, it is easily possible to generate a computer based image of patients foot. From this, the orthopedic shoe can be manufactured using CNC machining. Advantages of Reverse Engineering : Some of the benefits of using advance reverse engineering techniques are · Product reaches market quickly · No time spent in Concept design stages · No R & D & Analysis costs involved · A proven Product in the market Thus Higher reliability · Lower market price · Ability to modify product as per requirement · Reduce time & efforts for transferring CAD information from shop floor to Parent CAD systems. · Reverse Engineering products and tools for which incomplete data is available. · Improve Quality of the products by doing virtual to physical part comparison and doing modification thus achieve zero defects. · Finger print the dies and moulds so as to maintain uniformity between shop floor and CAD models. · Reduce the complete cycle time within the Design and R & D department. · Using software as Data Bridge for transferring and cleaning the electronic files from different CAD systems.