MAN 547_Reverse Engineering-Hardware and Software.pptx
1. MAN 547
Reverse Engineering in Mechanical Design
Dr. Mohamed Badran
Department of Mechanical Engineering
Reverse Engineering-Hardware and Software
2. Reference
• Raja, Vinesh and Kiran J. Fernandes. “Reverse
Engineering: An industrial Perspective”
Springer, 2008.
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3. Introduction: RE Hardware
RE Hardware is used for RE data acquisition
Collection of geometric data that represent a physical object.
RE data acquisition technologies:
– Contact
– Noncontact
– Destructive
RE data acquisition output:
– 2-D cross-sectional images
– Point clouds
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4. Introduction: RE Software
RE Software is used to transform the RE data acquired
into 3-D geometric models.
Two types of 3-D data are generated which are:
– Polygons
STL , VRML, or DXF format (RP, laser milling, 3-D graphics,
simulation and animation)
– NURBS (non-uniform rational B-splines)
Surface or solids (CAD, manufacturing and engineering CAD-CAM-
CAE)
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5. Contact Methods
Contacts methods digitizes a surface employing:
– Sensing devices with mechanical arms
– Coordinate measurement machines (CMM)
– Computer numerical control (CNC) machines
Data collection techniques:
– Point to point sensing
with touch-trigger probes.
– Analogue sensing with
scanning probes.
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6. Contact Methods: Point to point
sensing
A touch trigger probe is used that is installed on a CMM or on an
articulated mechanical arm.
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8. Contact Methods : Analogue sensing
• Scanning probe provides continuous deflection output combined
with the machine position to derive the location of the surface
• Scanning speed > 3 times Point to point
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10. Contact Methods
Advantages:
• High accuracy
• Low cost
• Ability to measure deep slots and pockets
• Insensitivity to color or transparency
Disadvantages:
• Slow data collection
• Distortion of soft objects by the probe
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11. NonContact Methods
Project energy source onto an object, then either the transmitted or
the reflected energy is observed.
Calculation of geometric data by:
• Triangulation
• Time of flight
• Wave interference information
• Image processing algorithm
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12. NonContact Methods
Advantages:
• No physical contact
• Fast digitizing of substantial volumes
• Good accuracy and resolution for common applications
• Ability to detect colors
• Ability to scan highly detailed objects
Disadvantages:
• Limitations for colored, transparent or reflective surfaces
• Lower accuracy
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19. NonContact Methods: Optical
Passive methods
• Shape from shading
• Shape from stereo
• Shape from motion
• Shape from focus/defocus
• Shape from Silhouette, and volumetric reconstruction
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22. NonContact Methods: Transitive
Computerized tomography (CT)
Computerized axial tomography (CAT)
Computerized transaxial tomography ( CTAT)
Digital axial tomography (DAT)
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23. Destructive Method
• 2-D slice images of the part are gathered by destroying the part
layer by layer.
• Applicable for small and complex objects (internal and external
features)
• Components:
CNC milling + CCD Camera
• Acceptable accuracy
• layer thickness 0.0127-0.254 mm
• repeatability ±0.0127 mm
• Any machinable object
• Destruction of part (disadvantage)
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24. Destructive Method
• 2-D slice images of the part are gathered by destroying the part
layer by layer.
• Applicable for small and complex objects (internal and external
features)
• Components:
CNC milling + CCD Camera
• Acceptable accuracy
• layer thickness 0.0127-0.254 mm
• repeatability ±0.0127 mm
• Any machinable object
• Destruction of part (disadvantage)
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