M
MSAFAI
Hi everybody,
Here is a case in SPC, that I try to describe below:
1- It is a process using a perishable tool with high Cpk (2 or more),
2- There is tool wear, that causes the part diameter to gradually increase (indiacted by a slow trend on the X-bar chart),
3- Change of part diameter cannot be helped by readjusting the machine/tool. The only way is to change the tool with a new one.
4- The production is typically a "short-run" production. Completion of each order takes one to maximum 3 days.
5- After completion of the first order the tool is NOT changed, but the production goes on using the same tool for another product having the same diameter, but maybe different length, until USL (upper tolerance) is reached.
Any idea about what kind of Control Chart to use in such a situation?
I thought maybe a Nominal Chart would be suitable?
Thanks
MSAFAI
Here is a case in SPC, that I try to describe below:
1- It is a process using a perishable tool with high Cpk (2 or more),
2- There is tool wear, that causes the part diameter to gradually increase (indiacted by a slow trend on the X-bar chart),
3- Change of part diameter cannot be helped by readjusting the machine/tool. The only way is to change the tool with a new one.
4- The production is typically a "short-run" production. Completion of each order takes one to maximum 3 days.
5- After completion of the first order the tool is NOT changed, but the production goes on using the same tool for another product having the same diameter, but maybe different length, until USL (upper tolerance) is reached.
Any idea about what kind of Control Chart to use in such a situation?
I thought maybe a Nominal Chart would be suitable?
Thanks
MSAFAI