Calculating Surface Area of a drill

[weirdo]

I am performing some electro-chemical etch tests on drills and it would be beneficial for me to be ble to determine the actual surface area of a 1/4" Jobber drill. I suppose that I could look up the drill dimensions and apply lots of geometry. Does anyone know of an easier/faster way to figure out the surface area?

Thanks in advance.

 

[butelja]

Model the drill bit in a 3D CAD system such as Pro/E, Solidworks, Inventor, or SolidEdge. These programs will easily give you the volume, mass properties, and surface area of any solid.

 

[IRstuff]

Since it's electro-chemical, you must be applying a voltage, which means there is a current, so a quick way would be to compare the current from the bit with a solid cylinder of the same material and diameter, such as the shank portion of the bit. The ratio of the currents should be roughly proportional to the current. There are lots of caveats, unfortunately, since the sharp edges change the electric field and current density, but at least it's a start.

You'll probably also need to agitate to ensure that fresh electrolyte is available continuously, since that will also change the current density.

TTFN

 

[GregLocock]

Weirdo - is that you, John Smith?

Anyway, if you have a drawing of the cross section then isn't the SA just the perimeter of the flutes *their length /cos(angle of twist)+ the obvious calculation for the lands?



Cheers

Greg Locock

 

[weirdo]

Problem is that all I have is the drill. No drawings, no dimensions, etc.

IRStuff is on the right track... Based on the power and current that is drawn from the drill I can get a rough idea of the surface area as compared to a stock cylinder and make comparisons.

I am trying to work this problem in the other direction. Based on the known surface area of the drill, I would like to understand the power and current draws of the tool. By comparing the amount that is etched from various drill sizes versus the surface area and power, I can determine if the current density is saturated at a given tool diameter, etc.

Thanks for your ideas.

 

[IRstuff]

While there is no drawing, you could possibly get something like Playdoh and make an impression of the groove and possibly measure that for surface area.

TTFN