Removal Processes

Question 1

Classification for removal processes

Answer 1

-Physical & chemical
Spark erosion (EDM)
(electro)chemical
-Ultrasonic machining
Ultrasonic machining
Precision- and ultra-precision machining
-Machining with beams with high power density
Shot peening
Abrasive jet machining
Water jet machining
Ion beam processes
Laser-beam machining
Electron-beam machining

Question 2

Temperature effects

Answer 2

Heat-affected zone
Surface structure changes (hardening)
Deformation
Oxidation
The higher the energy concentration: the less conductivity to rest of the product

Question 3

Describe the process of EDM

Answer 3

An electrode, that conducts electricity is placed a small distance from the material. Everything is immersed in a dielectric liquid (insulating). A pulse generator creates pulsating voltage between the electrode and the workpiece. If the voltage exceeds the breakdown voltage then a spark is produced. A pump ensures the spark gap is flushed with fluid in a controlled way.

The discharge takes place where the strength of the field is strongest and the distance is the shortest. It is thermal

Question 4

List 3 types of EDM

Answer 4

Orbital, wire, Contour

Question 5

Describe the process of ECM

Answer 5

The electrode is the negative of the workpiece. Its drilled through channels, through which electrolytic fluid is pumped. It is electrochemical with a conductive fluid

Question 6

How much voltage is required for EDM/ECM

Answer 6

EDM -100-300 V
ECM - 5-20 V

Question 7

Disadvantages of ECM

Answer 7

Accuracy is limited
Expensive