Question

Why positive polarity is commonly used for tool
electrode during Electro Discharge Machining?​

Answer 1

QUESTION:-

Why positve polarity is commonly used for tool electrode durinh ELECTRO DISCHARGE MACHINING?

ANSWER:-

SEE,

my first doubt over this is why we are calling it

positive polarity as it does mot indicate any electrode whether anode or cathode.

NOW,

The main reason behind this is,

About 70% of heat is liberated, near the anode in DC arc circuit.

Positive polarity improves METAL REMOVAL RATE. and negatovr polarity increase SURFACE FINISH.

So,

we actually use it due to metal removal rage as it will dissociate the metal with more speed and thus, the anionic transmission takes place under ELECTROCHEMISTRY.

now,

why we need for metal removing?

cause it will lead the transmission and flow of electron more rapidly, insistung the growth of other metal on cathode part.

SOME IMPORTANT POINTS:-

Normally positive workpiece polarity gives higher removal rate whereas negative workpiece polarity gives higher surface finish. Genearlly micro EDM is used for higher surface finish. Thats why negative workpiece polarity is utilized for MIcro EDM. Best wishes for your research.

Hope above explaination may get you!

in case of any other query do tell me, as it is important part for both physics and chemistry!

Answer 2

Answer:

Most recent answer

Due to the fact that, increasing the discharge time in plunge EDM, the erosion of Cathode is drastically increase whereas the Anode's erosion asymptotically die out. Thus, with sufficient discharge time. It is proven to use Positively charged Electrodes as tool, resulting lower wear.