Masking of Cooling Holes

[gshejale]

Hi,

Any ideas/ thoughts on the effective way of masking the cooling holes of gas turbine nozzle segments while plasma spraying.

Regards,

Girish

[Gordon]

Hi Girish

Not too sure on this, but I think these holes are not normally masked. The holes are either machined oversize to counteract reduction in size when coated or are resized after spraying.

[gshejale]

Hi Girish

Not too sure on this, but I think these holes are not normally masked. The holes are either machined oversize to counteract reduction in size when coated or are resized after spraying.

Thanks a lot Gordon. We are trying to find out a way to avoid the resizing after spraying. I thought probably a liquid masking solution will be available.

Regards,

Girish

[Gordon]

Hi Girish

Problem with masking or plugging a small hole is that the coating bridges and covers the hole completely. Raising the plug above the surface level reduces this effect, but then you get shadowing problems

[plasmajet1990]

Try conic washers.
What are the diameters oj the holes?

Hi,

Any ideas/ thoughts on the effective way of masking the cooling holes of gas turbine nozzle segments while plasma spraying.

Regards,

Girish