Unconventional Processes

Holders: Assist. Prof. Lebar Andrej, Assist. Prof. Orbanić Henri, Assoc. Prof. Valentinčič Joško

Subject description

Prerequisites:

It is recommended to have a basic knowledge on materials (metals), anorganic chemistry and conventional manufacturing technologies.

In order to pass and successfully execute the study obligations and participate in study work, the students are advised to regularly attend the lectures and to actively participate at the practical courses, covering the unconventional manufacturing processes and creation of CAM programs.

Content (Syllabus outline):

Unconventional processes, microtechnologies and their role in the production. The lectures are covering the following topics.

1. Introduction:

  • Definition of unconventional processes, comparison to conventional (mechanical) processe;
  • Development of unconventional processes;
  • The definition of a unit machining event;
  • The scale of specific energies and metal removal rates of unit events, and their reflection on the integrity of machined surface;
  • The classification of unconventional processes according to the energy form, physical foundations of processes and energy conversion models;
  • Thermal, electrothermal, electrochemical and mechanical processes with their technological characteristics

2. Electrical Discharge Machining processes

  • Electrical Discharge Machining processes:
  • Overview of technologies and trends;
  • Physical foundations:
  • thermal model of material removal,
  • Unit event,
  • process monitoring (voltage and current signal in the gap between the electrode and the workpiece),
  • types of discharges,
  • process control;
  • the role and types of dielectric liquids.
3. Die-sinking EDM – surface integrity:
  • Machine tools;
  • Selection and manufacturing of electrodes;
  • Surface roughness and influential machining parameters;
4. Die-sinking EDM – material removal rate:
  • Material removal rate, process stability and influential machining parameters;
  • CNC-control;
  • Usage in tool and die making – complementarity to high-speed milling
5. Wire EDM:
  • Machine tools;
  • Selection of wire type as a tool electrode;
  • Gap flushing;
  • The principle of controlling the position of wire;
  • Usage in tool and die making
6. Waterjet and abrasive waterjet machining – theoretical foundations:
  • The principles of abrasive water jet formation (injection, suspension);
  • Mechanical model of material removal mechanism;
  • Types of high pressure pumps and the influence to the cutting process;
  • Control of the cutting process.
7. Waterjet and abrasive waterjet machining – applications;
  • Overview of technologies and trends;
  • Using the water jet for cutting soft materials (medical, packaging, food industry etc.);
  • Using abrasive water jet for cutting hard materials (machine building, stonemasonry, machining of new materials etc.)
8. Laser beam machining – theoretical foundation:
  • Formation of laser beam (resonator, active medium, coherence);
  • Characteristics of continuous and pulse lasers;
  • The dependence of material type and laser wavelength on the laser beam absorption;
9. Laser beam machining – technology:
  • The fundamentals of laser cutting;
  • Machining parameters and their influence on process performances;
  • Fusion, sublimation, flame cutting;
  • Cutting and assist gases and their role in material removal process;
  • Material removal model in engraving and drilling;
  • Material removal model in laser cutting
10. Laser beam machining – applications:
  • The applications of laser technology;
  • Cutting materials and characteristics (geometry, surface integrity);
  • Process characteristics (accuracy, surface integrity, kerf, strations, anomalies).
11. Plasma arc machining:
  • Plasma – the fourth state of matter;
  • Plasma technologies for material removal;
  • The development of plasma cutting;
  • The principles of plasma cutting;
  • plasma cutting methods;
  • cutting and assist gases.
12. Comparison of contour cutting processes:
  • Wire EDM, waterjet and abrasive waterjet, laser and plasma cutting ;
  • Technology windows: material, thickness;
  • Selection criteria: accuracy, surface quality, economics
13. Rarely used unconventional processes (principles, properties, use):
  • Electrochemical machining;
  • Ultrasonic machining;
  • Abrasive air jet machining;
  • Abrasive flow machining
14. Micromachining processes:
  • Micro EDM milling; Micromilling;
  • Micro electrochemical milling;
  • Ablation by pico- and femto-second lasers;
  • Replication technologies, etching, lithography
  • Manufacturing chains: paradigm and examples from the practice
15. Additive manufacturing
  • Classification of additive manufacturing technologies according to standard ISO/ASTM52900-15.
  • Definition, historical development, challenges and opportunities;
  • General steps to create object by additive manufacturing;
  • Principles, characteristics and applications of vat photopolymerisation, binder jetting, material jetting, material extrusion, powder bed fusion, sheet lamination and direct energy deposition.

Objectives and competences:

Goals:

  • An in-depth knowledge of unconventional manufacturing processes from the viewpoint of physical foundations of processes and their technological capability.
  • To learn about the use/role of microtechnologies in modern manufacturing processes.

Competences:

  • Mastering unconventional processes and microtechnologies, and their fields of use.
  • The ability to find technological solutions in cases when the use of unconventional processes or microtechnologies is inevitable.

Intended learning outcomes:

Knowledge and understanding

Upon the completion of lectures and exercises, the students will:

  • comprehend the role of unconventional processes and microtechnologies in the production,
  • understand the specifics of unconventional technologies according to the product design,
  • learn the importance of automation and the methods of monitoring, modeling and optimisation,
  • learn to select the optimal technology according to the costs, quality and time of delivery,
  • comprehend the influence of specifics of micromachining from the viewpoints of material graininess and tool size (size effect)..

Usage

The students will use their knowledge in the industrial environment for:

  • product design from the viewpoint of unconventional technologies,
  • complementary introduction of unconventional technologies in addition to the conventional technologies,
  • the introduction of microtechnologies into production,
  • designing manufacturing chains in the production of microproducts.

Reflection

The theoretical knowledge acquired in the course and the experience gained at the exercises presenting concrete product designs, manufactured using different unconventional technologies and microtechnologies in the laboratory and industrial environment. The knowledge will be directly transferrable and useful for various industrial applications and research and development purposes in the field of design and manufacturing technologies.

Transferrable skills – related to more than one course

A good fundamental knowledge of unconventional processes and microtechnologies ensures the students can follow the lectures well and use the assimilated knowledge in manufacturing engineering and design.

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