Protecting Coated airfoils?

[Watash]

Hello,
I am looking for a way to protect a coated airfoil from chips and dings during machining of the shroud end and root end of a rotor blade. If anyone can help me it would be of great help.
Thanks you in advance,
Watash

 

[knobhead]

If it comes off that easily, would it maybe be simpler just to strip it off first, and then reapply? I'm assuming this is a rework job, but if not, why not just do the coating as the last op?

 

[butelja]

How about using some high-tech masking tape?

 

[Watash]

Knobhead,
We are receiving these parts from a OEM, they already have some machining operations done on them, We are doing the final maching and EDM work on the blade.
Each blade weights around 60LBS, and I am looking for a solution to stop the airfoil from being chipped or dinded. I am thinking about using plastic mesh around the airfoil .

 

[knobhead]

Hmm, I'd say you have a problem! What actually causes the marking though,is it swarf, locating points or handling? What is the coating? (I shouldn't really be trying to help you here, you obviously work for one of our competitors!)

 

[OldestToolDesigner]

Back in the 60's when we designed most of the tooling for PWA's small rocket engine, we set it in a matrix to hold and protect it while machining the bosses ,etc. The engine was located into a shuttle then the liquid matrix was poured in and solidified to hold the engine in an accurate location with respect to the shuttle. When finished the matrix was melted out and the engine removed. The temperature required was low. I am testing my memory here but I think the matrix was "Cerrobend" or something like that. You may be able to adapt it to your application if it doesn't prove to be too expensive.

Al Kirby
askkkf@avci.net

 

[MortenDK]

Perhaps you could have a jig made, which is fittet to the part from your supplier and detached and reused after your processing. This is something you often do, when machining smaller parts in difficult operations and when it is impossible to fix the part in a normal vice or clamp it down. The jig, of cause, should stay on the part as long as possible.


Morten Morten K. Thillemann

 

[knobhead]

We used to use cerrobend and cerrotrue here, but we can't anymore because of environmental concerns. There is a wax/plastic type material version called rigidax, but encapsualtion is messy and expensive to set up. I'd call that as a last resort.
If swarf damage is the problem, could you use some sort of sheild on the fixture, or perhaps play around with the cutter geometry to alter the way the chip flys off?