Vertical Form Film Sealing (VFFS) Manufacturing Process

Hi, We have a Vertical Form Film Sealing (VFFS) machine to pack off 7kg of resin sand into plastic foil laminate bags, for quality control we currently have a KPI to check Right First Time (RFT) daily by considering 1 hour as 1 batch and then we do visual seal inspection and pressure leak test in the lab to check for failures. Problem is how to quantify the visual inspection to calculate the correct RFT? We currently have issues on the machine with every bag failing visual inspection because of creases and wrinkles. Anyone with similar experience with VFFS. Any other KPI to capture seal quality?

We have sampling plan/size of less than 1% which is too low as well but considering this is enough with special inspection level S-3 according to ISO2859, acceptance number should be 0 and rejection number 1 , I am trying to make a case that because every bag is failing visual inspection for seal quality, we should not be running the production line until we fix the issues. Does this quality plan lean towards being excessively rigid?

We are looking to introduce automated reject system for sealing issues. But would love to hear about best demonstrated practices for such production lines & to learn from you experts!

Thanks!

What do you mean by saying "Problem is how to quantify the visual inspection to calculate the correct RFT?" There's defined formula to calculate this rate, which is: FTR = (number of usable products divided by the total number of products) x 100

Please clarify and then people here will try to help.

sorry I don't know why I wrote this, RFT is fine I know how to calculate it. But I am looking for any other KPI for this process. Because for this instance almost all the bags are failing because of bad seal quality, which means RFT is zero. But we don't reject the stock and it’s still being released to customers.

tariq18 said:

sorry I don't know why I wrote this, RFT is fine I know how to calculate it. But I am looking for any other KPI for this process. Because for this instance almost all the bags are failing because of bad seal quality, which means RFT is zero. But we don't reject the stock and it’s still being released to customers.

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This seems totally confusing to me, because you're sending out non-conforming products. Have you tried to perform root-cause analysis in order to identify why the seals are failing to perform as required by your specifications/customer requirements? To me it seems that you process has a lot of variation and is probably not capable of performing well. About the KPIs you define them on internal level and then you have your KPIs on external level. It is a good practice to turn your problems into KPIs as well in order to be on the way for continuous improvement. For example your RFT is almost 0% and for the next 6 months you can define KPI such as "Reach 50 % RFT on X product by X date". Btw why don't you reject the stock since is not according to specifications?

Well yeah this is confusing, because there is debate that visual inspection is not a major defect, & 2nd test - pressure leak test is more objective and is being passed with no issue, so visual inspection can be sanctioned etc. But for pressure leak test my sampling size is not that great it is less than 1% and this is destructive testing & its not practical to increase the sampling size.
& Then there is no clear customer requirement/specifications on the packaging sealing quality. Want to understand how food manufacturer and those work with VFFS machines, how do they handle such issues? Seen some videos, looks like most of the machines have automated rejected system.