ESL powder coating?

[alexberg]

I think laser cutting is the way to go to avoid sharp edges, after that etching might still help to make the square edges a bit round.

Laser cutting not only create sharp edge but additionally make the same kind sharp thin wall tube like protrusion as punching does. Moreover laser put really high stress (temperature related) on material.
So the mill router is the way to go with deburring as well.
One of the reasons of having arc shaped ESLs - as mentioned earlier - is thin sheet stabilty...

 

[JBdV]

I agree milling is better, however even in that case some rework afterwards like etching might be necessary

 

[markusA]

I have some numbers now, straight from the manufacturer.
This coating was recommended to me. (Base coat)
Specific surface resistivity: >10^13 ohm cm
Dielectric strength: >30kV/mm
Dielectric constant (100Hz, MHZ): 4.0

Plus a black top-coat for looks and corrosion resistance.

 

[bolserst]

I have some numbers now, straight from the manufacturer.
This coating was recommended to me. (Base coat)
Specific surface resistivity: >10^13 ohm cm
Dielectric strength: >30kV/mm
Dielectric constant (100Hz, MHZ): 4.0

Plus a black top-coat for looks and corrosion resistance.

Hi MarkusG,

Based on those numbers, the base coat recommended to you should work fine for ESL stator coating if it will coat the sharp edges of the holes properly. Do you know the electrical properties of the top-coat? It probably has much higher resistance, so try to minimize its thickness.

 

[markusA]

The topcoat is usually added for corrosion resistance even though it too will have similar qualities. Maybe not just as good.
And yes, exactly what I was thinking, a thick basecoat and a thin top coat.

 

[markusA]

The base coat has a recommended film thickness of 100-300um and the top coat 35-120um.

125+45um should do the trick or what do you think? With 40% edge coverege it should take at least 1.5kV (not counting the top coat at all) peaks before dielectric break down. (only counting one stator now, double it for both stators.)