B024409 - REVERSE ENGINEERING AND ADDITIVE MANUFACTURING

italian

-R.E. motivations, processes and technologies
-Processing of scanned data
-Geometry reconstruction from scanned data
-Practical demonstration of 3D scanners
-Practical demonstration of geometry reconstructions from 3D scanned data
-Practical examples and applications of R.E. techniques
-R.P. motivations and technologies
-The STL file format
-Polymeric materials
-R.P. Techniques
-Rapid Tooling
-Rapid Manufacturing

No reference books are available for the subjects of the course.
Support material consists of a set of slides used by the teacher during the lessons. Students will be provided with such material.

AQUIRED SKILLS
Part A: Reverse Engineering
Ability to cope with the issue of 3D model reconstruction of a real object by means of:
-choice of the most suitable 3D scanning device;
-definition of the necessary procedures for simplify/process the scanned data
-definition of the characteristics of the 3D model to be reconstructed and choice of the most suitable reconstruction technique.
Part B: Rapid Prototyping
Ability of pre-processing the CAD model of the starting object, in order to make it “usable” by the prototyping system.
Knowledge of the R.P. machines, techniques and of the respective usable materials.
Ability to define, for a given object to be built, the optimal R.P., rapid tooling and/or rapid manufacturing process.Knowledge and understanding:cc3. Knowledge, understanding and use of scientific (computer and other) tools specific to the field of mechanical engineering design.cc6. In-depth knowledge and understanding of production systems and technologies. Understanding the advantages and limitations of technologies and process choices in different application contexts. Knowledge of methods for the representation of mechanical components and systems, and for their reconstruction from artifacts, deepening the aspects strictly connected with production systems and technologies.Applying knowledge and understandingCa1. Applying knowledge and understanding related to problem identification and formulation of solutions, in the field of mechanical engineering, to set up, design, implement and verify systems and apparatus, even of high functional complexity, taking into account the implications related to environmental, economic and ethical aspects, employing well established methods.Ca3. Applying knowledge and understanding related to the choice and application of appropriate analytical and modelling methods, based on mathematical and numerical analysis, in order to better simulate the behavior of components and plants in order to predict and improve their performance.Ca5. Applying in-depth knowledge and understanding related to the choice and use of appropriate equipment, tools, procedures and methods, knowing their limits and potential; in particular the ability to conduct even complex experiments, manage and employ advanced instrumentation and software, with appropriate analytical capabilities.Ca10. Applying advanced knowledge and understanding to operate effectively, individually and as members of a group, having a clear understanding of the context of engineering problems and of the interdisciplinary implications that characterize mechanical engineering.Ca11. Applying improved knowledge and understanding to present in written, verbal and, if necessary, multimedia form, their arguments and the results of their own study or work, with characteristics of organic and technical rigour.Ca14. Applying knowledge and understanding to learn and update autonomously and continuously in a constantly evolving context, such as the industrial engineering one.

Base knowledge of Computer Aided Design and manufacturing technologies

Part A: Reverse Engineering
The first part of the program is dedicated to theory and practice of devices and techniques for R.E.; the second deals with practical demonstrations of 3D scanning machines and real case studies.

Part B: Rapid Prototyping
Most of the lessons are dedicated to the presentation of R.P. technologies (machines and processes); afterwards some practical demonstrations, about the CAD model processing and the definition of process parameters, will be provided.

In order to take the exam, please register to:
http://sol.unifi.it/prenot/prenot

The learning verification test consists of a written test with open questions and exercises. In particular, 2 questions/exercises relating to additive manufacturing processes (description of technologies, problems, processes); 4 questions/exercises relating to reverse engineering processes (description of technologies, processes, problems encountered). The student will have to demonstrate good knowledge of 3D additive manufacturing and scanning technologies (cc3, cc6, ca5); good knowledge of the preparation processes of 3D models for physical realization (cc3, cc6, ca5); good knowledge of the general process of Reverse Engineering (cc3, cc6, ca4; sufficient knowledge of the procedures for extracting geometric parameters from the measured raw data (cc3, cc6, ca7); sufficient knowledge of the procedures for the extraction of geometric parameters from the measured raw data (cc3, cc6, cc6, ca7); sufficient knowledge of the sources of error that characterize additive manufacturing and reverse engineering (cc3, cc6, ca9, ca15).

Part A: Reverse Engineering
1. R.E. motivations and application fields
2. R.E. process definition
3. Introduction to R.E. technologies
4. Classification of 3D scanning methodologies
5. Contact systems
a. general characteristics
b. active systems
c. passive systems
d. point mode and scanning mode acquisition
e. scanning strategies and possible error sources
6. No contact systems
a. general characteristics
b. optical systems
i. introduction to cameras and epipolar geometry
ii. calibration of a set of cameras
iii. passive optical systems
1. passive stereo-vision
2. shape from shading
3. shape from texture
4. shape from focus-defocus
5. shape from silhouette
iv. active optical systems
1. laser-camera triangulation
2. active stereo-vision (laser and structured light)
3. time of flight scanning
7. Pre processing of scanned data
a. overlapping and oversampling
b. simplification and registration of point clouds
i. techniques for scan lines
ii. techniques for 2.5 D point clouds
iii. techniques for 3D point clouds
c. error sources and dimensional assessment
8. 3D modeling: geometry reconstruction starting from scanned data
a. tessellation and triangulation
b. reconstruction by means of primitives and features
c. reconstruction by means of sections
d. reconstruction by means of surface patches
9. Practical demonstrations of a series of 3D scanners
10. Practical demonstrations of geometry reconstructions of objects starting from scanned data
11. Case studies

Part B: Rapid Prototyping
1. R.P. Motivations and application fields
2. Introduction to R.P. technologies
3. R.P. techniques classification
4. The STereoLithography Interface Format (STL)
a. file content description
b. geometry errors management and dedicated software packages
5. Polymeric materials
6. R.P. Techniques; processes, machines, materials
a. Stereolithography (SLA)
b. Solid Ground curing (SGC)
c. Fused Deposition Modelling (FDM)
d. Laminated Object Manufacturing (LOM)
e. Selective Laser Sintering (SLS)
f. Polyjet method
g. Three Dimensional Printing (3DP)
h. Multi Jet Modelling (MJM)
i. Ballistic Particle Manufacturing (BPM)
l. Drop On Demand (DOP)
h. R.P. with metal material
i. Selective Laser Melting (SLM)
ii. Electron Beam Melting (EBM)
iii. Laser Engineered Net Shaping (LENS)
7. Rapid Tooling