How do I measure variation in my process ?

M

MoldCrasher

Hello. We are manufacturing fuel injectors using additive 3d manufacturing, its become a low volume production job for us. I CMM the internal blades of the injector while the rest of the geometry is outsourced to 3d scan. I inspect 60 points on each of the 8 vanes/blades. I then profile it to the print which is a composite profile callout. .060" upper segment to A and B, and then the lower at .030 to itself.

I would like to start compiling the results into some sort of measurable. Im not sure if a capability is right for me and am a little shaky on all the variables. I have 8 different blades and a 2 profile results for each one on each part. I am using minitab.

I basically want to track how much variation we have in our entire process and be able to spot trends. Any input would be appreciated.
 
M

MoldCrasher

Would it be possible to capture two upper and lower specs (due to the callout) in one cap study?
 

Bev D

Heretical Statistician
Leader
Super Moderator
yes - but the math is a little different.

why do Cpk or Ppk at all tho?

if you really want to understand the variation I use a simple multi-vari chart. it will clearly show you the variation in all of its glory....
 
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