There are practical references. For example, in penetration electro discharge machining, when the electrode material is graphito, the TWR is the 0,5% of MRR.

OK sir. Thank you.. Is it applicable all tool materials.. of course with different percentages?

Not, is a practical reference ONLY for graphito electrode and penetration EDM.

In the book Manufacturing technology by Kalpakjian, it has been provided the theoretical equation for tool wear rate. You can refer it. However lot of empirical modelling equations are available for calculating TWR based on the process parameters and tool materials. Kindly refer the following work for your reference, if it will suit your need.

T Muthuramalingam, S Vasanth, T Geethapriyan, “Influence of Energy Distribution and Process Parameters on Tool Wear in Electrical Discharge Machining,” International Journal of Control Theory and Applications, 9(37), 353-359, 2016.

Regards,

Muthuramalingam

Of course, the question can not be answered so easily because the solution depends on many parameters and application specifications. This makes it easier to calculate simple holes in wear than more complex shapes. So the current amplitude is not always decisive, but the current increase. Then it must also be distinguished whether I work with a relaxation generator or a static pulse generator. The often stated "solutions" are very limited in their reuse and should be considered with care. Anyway, the solutions are not as easy as described here.

Thank you Prof Muthuramalingam Thangaraj and Prof H.-P. Schulze ..valuable information..

You can use microscope method to measure the size or dimension of crater wear which appearance on tool during machining by EDM process.

best regard,Dr.Saad Shather

Thank you sir..

The question is so involved that It is practically not possible to prescribe a general solution. It can at best be approximately estimated on a case to case basis. For example for a particular tool-work material combination, dielectric fluid and as a case of EDM drilling that too for particular type of power source characteristic (which includes type of power source).

Thank you Professor Arshad..

There is not a simple answer to this question. Several aspects (already discussed above by our colleagues) and their mutual interaction must be considered. In practice, each EDM operation becomes a project itself. Try to define clearly the wear objectives of your operation. Refer to the recent research work by WZL Aachen, in which very interesting results about heat transfer to the electrode are presented.

Thank you Prof Sanchez..

There is one simple approach to find out the tool wear rate without calculating the tool weight i.e. calculating the eroded volume of the tool electrode and dividing that with the machining time. This approach is not used for the intricate shapes of the tool electrode. However, for the exact value of the tool wear rate, the calculation of eroded corner volume needs to be considered, which is little difficult as the shape of the worn out corner is always curvy, but, that can be calculated easily by using a digital microscope. The below article may be useful-

Ravinder Kumar and Inderdeep Singh. Productivity improvement of micro EDM process by improvised tool. Precision Engineering. 2017, 51, 529-535.

Thank you Prof Ravindra Kumar for your response and reference..

Calculate the change of the tool shape.