Better to Reject a Few More: The Quality Math Behind the Huanghai MJ180 Reject Unit
The NG reject outlet and conveyor at the end of the Huanghai MJ180.
Key Takeaways
- The reject unit works from the system's log and removes each defective pouch automatically when it reaches the reject outlet.
- It usually removes the neighboring pouches too, which covers any timing error.
- Rejected pouches can be re-inspected by hand and the good ones recovered.
Customers watching the Huanghai MJ180 run for the first time often notice something: when the reject unit removes a defective pouch, a few pouches on either side go out with it. It looks like waste. In fact it is the most cost-effective choice a pharmaceutical packaging line can make.
How a Defective Pouch Is Tracked to the Reject Outlet
When film vision inspection or code vision inspection on the Huanghai MJ180 ODF cutting and packaging machine finds a problem, the system logs that pouch and calculates from the web speed when it will reach the reject outlet. At that moment the reject unit opens automatically and removes it, without stopping the line. See how the MJ180 finds, tracks and rejects every defective pouch.
Why the Neighbors Go Too
Between the inspection station and the reject outlet, the web passes through heat sealing, coding and die-cutting. To cover even a small timing error, standard practice in the industry is to remove the pouches immediately before and after a defective one along with it. Even if the timing is slightly off, the defective pouch is always inside the rejected group.
Doing the Math
Rejecting a few extra pouches costs a few films and a few lengths of packaging material. A defective pouch reaching the market brings complaints, investigations and possibly a recall. There is a saying in the industry: let one defective pouch slip through, and the compensation can wipe out a whole day's production.
Put the two side by side and the answer is clear: reject a few more rather than let one through. That is why pharmaceutical manufacturers widely accept conservative rejection.
Not Everything Rejected Is Scrap
Rejected pouches are collected together. A manufacturer that wants to save material can have staff re-inspect them, pick out the good ones and send them back to cartoning.
One More Check After the Good Pouches
Good pouches pass the reject outlet and run on the conveyor into a collection bin or bag, then on to cartoning. Many pharmaceutical manufacturers add a manual check before cartoning. With machine inspection of every pouch plus a manual check, two layers of protection stack up and a defect has a much harder time reaching the finished product.
Frequently Asked Questions
How does the reject unit know which pouch to remove?
From the vision inspection log. For each pouch that film vision inspection or code vision inspection marks as defective, the system calculates the arrival time from the web speed and the reject unit removes it automatically on time.
Why not remove just that one pouch?
To cover small timing errors and make sure the defective pouch is always removed, the pouches immediately before and after it are usually rejected too.
Can good pouches that were rejected be recovered?
Yes. Rejected pouches can be re-inspected by hand and the good ones returned to cartoning.
What does the reject unit work with?
The reject unit removes the pouches that vision inspection marks as defective, so it works together with film vision inspection or code vision inspection. With both, one reject unit is enough.
Next Step
See how the Huanghai MJ180 ODF cutting and packaging machine inspects and rejects on one line.