Sensor locates danger points

Glass is a packaging material that offers many clear advantages. It is pollutant-free, it can be recycled, and it provides excellent protection for its contents. However, glass has one intrinsic disadvantage that cannot be overlooked: if you grip it too hard, it can break or splinter. This often presents a dilemma for bottlers and filling plant operators in the food and beverage industry: reduce the belt speed on the bottling line so as to protect the containers, but reduce the filling rate? Or: operate at a higher belt speed with the risk of losing products that have to be separated out? Michael Waltl, Technical Customer Service Manager at Vetropack points out: "Technical optimisations on the line can solve the problem – but before you start, you must know which changes have to be made and where they are needed." One Swiss food manufacturer – a Vetropack customer – recently had to confront these issues. Small splinters of glass were noticed on the line of one filling plant, but there was no obvious glass breakage. So where and why were the jars getting damaged?

To shed light on the matter, our customer service team used the new addition to our toolbox for the first time: the ShockQC in-line sensor from Masitek of Canada. It measures the forces and loads acting on a glass container with maximum precision. As part of our service, we produced an exact replica of the glass container to be tested for our customer: in this case, a 390-ml European jar. 

This dummy made of highly resilient plastic was fitted with a ShockQC sensor calibrated by the manufacturer. It then began its journey along the filling line together with a batch of other jars. A total of four tests were performed, each at different belt speeds. The dummy and sensor passed through the entire line, starting with unpacking of the jars all the way to the final conveyor belt that carries the jars away in their finished cartons. The measured datasets were transmitted no less than 100,000 times per second to a tablet PC for visualisation on an easy-to-understand dashboard.

The result: the jars are conveyed along the line from the unpacking station to the filler and from the cooling tower to the cartoning and outbound transport stations at a rather leisurely pace, with sufficient minimum clearance. However, there is an impactzone between the filler and sealing station where the jars are subject to shocks that exceed Vetropack's guaranteed minimum impact strength by as much as 60 percent. This stress does not necessarily cause defects in a jar that has been processed without faults. But even if very minor faults or inclusions are present, an impact of this magnitude usually causes glass fragments to chip off. In this way, the cause of the problem was found and the basis for a targeted approach to eliminating it was established. Our customer is now able to optimise their filling line exactly where improvement is really needed. Michael Waltl is also satisfied: "Following on from the success of the first assignment, we have since used this service for several other interested parties – and we were able to provide rapid assistance every time. Now we're looking forward to helping the next customers optimise their lines – quickly and easily, with a results-oriented method that involves no unnecessary effort or expense."