Machining of thermal sprayed coatings
02-24-2012, 01:24 AM
|Machining of thermal sprayed coatings
Regarding the single point turning of thermal sprayed coatings, I am seeking the latest information available on methods, techniques and equipment.
At my shop, we predominately plasma spray Amdry 960, Metco 443NS, Metco 480NS, Amdry 718 and arc spray Tafa 73MXC and 75B. There are a few others but these are the heavy production materials.
While our success rate is good, I still get alot of calls to the floor to examine poor finishes, porosity in the thermal spray coating after turning, some chipping, small edge chips etc.
As usual, the coating process is blamed and not much accountability is held to the machine shop.
As I continue to develop our thermal spray processes, I believe the machine parameters should be examined in depth as well.
This leads me here to ask my fellow thermal sprayers what they would be willing to share in regards to finishing these coatings. Any information you can provide or point me to is greatly appreciated.
Thanks in advance.
02-28-2012, 06:50 PM (This post was last modified: 02-28-2012 06:57 PM by sreenuvundela.)
|RE: Machining of thermal sprayed coatings
(02-24-2012 01:24 AM)ServiceTech Wrote: Dear All;
(02-28-2012 06:50 PM)sreenuvundela Wrote:(02-24-2012 01:24 AM)ServiceTech Wrote: Dear All;
As you know that all thermal spray coatings will bond to substrate mechanically. So, it is always better to do grinding operation rather than carry turning on coating to get better surface finish and dimensional accuracy.
However, if you want to do machining only, then you have to concentrate much on metodology rather than on tooling.
During turning, you have to carry such that turner has to start from the middle of coating to one end so that cutting force will not act in opposite direction of mechanical bonding which will lead to peel off of coating at edges.
You have to take care about feed and depth of cut will be minimum.
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