Machining Metal Plasma Spray

[hansjoi001]

I have a client using metal plasma spray for reconditioning turbine housings...once sprayed, he machines with TPG432 carbide inserts (uncoated). Does anyone have experience with machining metal plasma spray..interrupted cut? Any suggestions for improved tool life..other insert geometry?

 

[EdDanzer]

What material is being sprayed?

 

[hansjoi001]

the turbine housings are cast iron

 

[EdDanzer]

What is the material that is being sprayed on to the cast iron?

 

[Capntom]

The problem with machining plasma sprayed coatings is the ratio of interface tensile strength (bonding)and the hardness of the coating. Grinding is much more desirable because the chip size is much smaller. The coating will separate from itself easier then de-laminate off of the base metal. If grinding is not an option use the smallest radii on the insert to reduce the chip load.

 

[richardgb]

why not ask the plasma gun manufacturer for recommendations?

I am sure they will be more than helpful

each may have their own alloys/mixtures they spray

otherwise:

experiment using different qualities and the cheapest inserts should be given a chance as well, try anything

personally, I would sharpen inserts on a diamond grinding wheel by hand and get a sharp corner that can penetrate the material, the corners on the inserts are often rounded, and even sharp-corner inserts can be improved upon

I used to simply grind the top flat and get three times the tool life as well as excellent finish


Taking the inserts out of a box and using them ? Not me. Not for delicate work like that. Roughing may be ok if you have enough horsey power.