AboutJoe Martin Expertise I can answer questions about Quality Systems (AS9100, AS9103, Boeing D6-82479, etc.) Particular areas of expertise are Statistical Process Control (SPC), sampling inspection, design for Six Sigma, and Six Sigma tools in general.
Experience Quality engineer in aerospace for 20+ years. ASQ Certified Quality Engineer (#8920) since 1982.
I want to improve a tolerance for the width weld bead on the join of steel plate.Currently, the width bead tolerance is in range of (3-6mm) or (4.5 +- 1.5mm).
here i attached you a process capability sixpack that i've done using minitab as your reference.There are 3 points that i had measured which is at point A,B,C...
from the minitab software...i got the standard deviation, cp,cpk etc....and i know..the tolerance can be reduce...
but i don't know and not so sure about the method that need to be used.
the questions here are?
How to find the new tolerance?
what methods or formula need to be used and applied?
Can you recommend me a new tolerance?
Can't wait to see your answers?
thank you.
Answer When properly used, “Minitab” is wonderful tool. But like many other tools, it can cause a lot of damage if it’s used incorrectly. Obviously, I know nothing about the product or the weld process in question, and no “6 pack” by itself is going to give me—or anybody else—the answer to your problem. (By the way, the graphic is too small for me to really see clearly.)
I’m willing to help on this, but ultimately YOU have to come up with the answers. Let’s pretend that I am the chief engineer at your company. If you want me to approve any change in tolerance, you have to convince me it’s a good idea. Here are some basic questions that must be answered before we even think about making tolerance changes:
How is this going to save the company money? (If it doesn’t, what is your reason for seeking the tolerance change?)
Is this process automated or manual?
Is all the data from one machine?
Are multiple operators and/or part numbers involved?
What is the relationship between points A, B, and C?
Why did you choose these points?
What sort of measurement device was used?
Over what length of time was the data collected?
Regards,
Joe
PS—If you decide to go forward, I will ultimately need some raw data.
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