Sketch and name the three surface layers structure. that caused by thermal damage in EDM
Which of the following is noted for high MRR ;EDM,PAC,LBM
EBM is limited to electrically conduction material ,true or false
false
in PAC ,state the two stages by which the gas is converted to plasma , how it is created and at what speed it exits .
Derive an equation for MRR in wire EDM to cut a plate of length (L) ,thickness (t) ,feed rate (fr) mm/min ,wire diameter (dw) ,spark length (s)
in EDM , how the wear ratio and melting point are related ,supply examples for an electrode and work
A 90mm diam through hole is to be cut in a steel plate of thickness 50mm by EDM .if the time taken to cut the hole was 75min , k=39 and the melting point of the steel is 1540°C ,calculate the discharge
current required to complete the cutting operation.
.23
MRR = K*I/T1
3/min 4243 mm /4)*50/75 =
MRR = VOLUME/TIME = (3.14* 902
T (melting point of steel plate) = 1540°C I = required
/K = to be calculated I= MRR*T1.23
Name the main physical property(ies) involved in workpiece material when used with EDM and LBM
Sketch the movement of the electron below surface until the heat is generated. State factors that affecting the total electron range (ᵟ).
sketch the relationship between MRR and spark gap. What are the consequences of allowing the spark gap to be too small or too large,
supply your comments
sketch the relationship between hardness and depth below surface for roughing EDM. Then, state the metallurgical transformations and
sketch the altered layers.
in a relative term, compare between EBM and LBM for;
1-speed, (faster at LBM) 2-power, (more at LBM) 3-l/d, (smaller at LBM) 4-HAZ (at EBM ONLY).
