Castle and Black Label film problems
When the belt was replaced, I stood watching the operation. 6 Non-returnable bottles on the white transport belt, are covered with a printed film before the 6 pack moves into an oven where the plastic is heated causing it to shrink around the bottles.
As the bottles move into the Packer on the white transport belt, an arm sweeps the printed plastic over the top of the bottles and down the back where the film is cut to length before the 6 pack moves into the oven.
I noticed that sometimes the bottles would fall over just as the plastic film was pulled over the leading edge bottles. When the bottles fall over, they would occasionally nick the white belt which then over time becomes a tear rendering the belt useless. The operator reported that the bottles would fall consistently while he was running Castle or Black Label. This only started happening about a week ago. OK so this could be the reason for the torn white belt. We will need to examine both the replaced belts so see if we could verify this possibility.
Why would only the Castle and Black Label bottles fall over. Obviously there must be something different or unique about them compared to any other brand that is shrink wrapped. So what is different? Caps and the colour printed film. So what? All the brands are different.
Let’s dig a little deeper. While playing with a handful of different caps, I noticed that the Castle and Black Label caps felt a bit rougher than the other brands. They contain gold and black pigment in the printers ink that is a bit rougher than the other colours used. When I felt samples of the plastic film, I noticed the same thing.
A few more questions led to the discovery that an additional supplier of film had been added to the vendor list. A quick friction test by the lab confirmed that the pigmentation on the new film was out of spec. With the added friction of the film, it caught the bottle caps and pulled the bottles over.
Many years later, I facilitated a problem solving session at the Alrode Brewery. The problem statement read that Castle and Black Label caps were sticking in the crown [cap] chute. Bottle caps are stored in a hopper and fed to the bottle crowner via the crown chute. The crown chute makes a twist where the crowns were sticking. The pigmentation problem on the shrink wrap film in Newlands came to mind. The lab examined the caps and confirmed that the pigmentation on the Castle and Black Label caps was out of spec.
Being to course, the added friction would cause the caps to stick in the crown chute. The crown manufacturer started using paint supplied by a new supplier just before the problem manifested itself.
Learning points:
1. Engineering and production personnel must keep careful track of all problems experienced and their verified causes.
2. Communicate problems and their causes to stakeholders.
3. Keep track of all supplier, material and process changes.