When sealing problems kept a packager of energy bars from meeting their production requirements, they contacted Greener to see if we could help develop a solution. They explained to one of our technical experts that rejects and downtime due to split or unsealed packages had reached the point of crisis.
Mechanics were constantly monitoring and readjusting their horizontal flow wrappers and struggling to keep them running. He recommended a line evaluation and training as the fastest and most effective way to diagnose the causes of their problems and implement lasting solutions. The client agreed, and arranged for him to visit their facility.
WHAT is the Problem?
Once on site, he learned more about the split and unsealed packages that were delaying production.
WHERE do Problems Occur?
Problems occurred on both the leading and the trailing seals, with all the heat seal and cold seal films that they ran, and on all wrappers, which were the same make and model.
WHEN do Problems Occur?
The split and unsealed packages occurred intermittently but repeatedly. Even after set up was adjusted and production was restored, the problems returned.
Sealing Jaws – He discovered that the serration pattern on the sealing jaws, which was the same on all wrappers, was too sharp. It was difficult to apply adequate sealing pressure without splitting the film. Reducing spring pressure to eliminate splits often caused poor seal quality. The serration design, he determined, must be updated to solve this problem.
Mechanics had to overly rely on spring pressure adjustments on these machines. Accurately setting the clearance between the jaws was difficult, since it required the bearing blocks to be shimmed.
The one-piece design of the current, drum-style jaws made them difficult to set up, since the head had to be disassembled to install or remove them from the shafts.
WHAT has Changed?
He also found that variations in product size had a larger impact on seal quality than the client realized. The sealing jaws clipped the edges of bars that were too tall and pushed product into the seal area, resulting in poor seal quality and unsealed packages.
They had ordered new processing equipment to eliminate the oversized bars, but it had not yet been delivered.
He recommended that the client purchase new, redesigned sealing jaws for one wrapper and evaluate the results. But their packaging problems were urgent, and they decided to convert all eight machines right away.
Sealing Jaw Design
For each wrapper, Greener would manufacture and return to install:
• New shafts that remained on the machine when jaws were changed, along with new bearings and pressure springs
• Easy Seal™ bases
• Easy Seal™ jaw inserts
The new sealing jaw design, with QUICK-CHANGE inserts, an updated serration profile, and FLEX sealing faces, would improve seal quality, provide fast, accurate set-up, and reduce lead times for replacement parts.
Also included were custom, stainless steel shim kits to improve the ease and accuracy of clearance adjustments. The currently used brass shims were malleable and often had burred edges.
After he returned and installed the new sealing jaws, problems with split seals caused by sealing jaw design were eliminated. Mechanics no longer needed to monitor each wrapper and fewer adjustments were needed. Production levels increased.
Product contamination from oversized bars still caused some problems, but this issue will be resolved when the new processing equipment is online.
Mechanics reported that the training helped them better understand why problems were occurring and how to correct them.