(08-19-2010, 11:05 AM)LEN WOOD Wrote: Hi Sam,
Yes, as you realised some parts size and geometries won't allow the ideal of a 90 degree 'attack'. As the angle becomes more severe the coating quality and deposit efficiency (DE) deteriorates. Investing in an F1 (or other system compatible small inner diameter gun) will allow you to apply better quality and less waste coatings. The ID guns do have slower feed rates but this is the compromise.
I don't know which mark/model of F4 (MB?) you have but the earlier guns have wide diameter plastic exterior gun shells. With these you can consider machining them down a little to allow you to lessen the angle on some parts. OK you may have to fabricate a new smaller 'secure ring' or clamp collar. I have found that a jubilee type clamp or plasma tape works just fine. Ironically the hand based F4-HB & F4-HBS offer more versatility and processing of a greater diversity of work pieces than the F4-MB!
Hi len,
First of all ,thank you very much for your honest reply.
Sorry for I didn't describe the gun type clearly. We use only F4-MB gun. As you know ,there is a big plastic exterior shell for the gun. I don't know exactly the function of it.(protect the gun from dusty and tough condition? )But a friend of mine from suzler told me that some company even don't use the shells at all.
Fabricate a new small shall is not practical for me at present. May be I can try the plasma tape. (just enlace the gun with the tape for several cycles?)
There is a fixed distance form the nozzle to the part surface for every powder. In our production, the distance is between 120mm to 140mm. some parts(diameter less than 120mm e.g.)can not avoid to spray at a severe angle. In such circumstances , I could not ensure the quality of the coating.
I wanna know how does people check the quality of the coating in plasma process normally.
Thank you.
Sam
p.s. we supervise the coating's quality by checking samples which has the same powder coating with the part.