How to Create the Perfect Package Seal with Automated Packaging Machines
April 23, 2018
Inadequate seals mean that you incur additional costs for machine recalibration, rework, scrap, and clean up of spills. For perishable items, a bag with a compromised seal that slips past inspection can mean decreased shelf life, diminished product quality, increased contamination risk, and an inconvenient mess for the consumer.
Most flexible packaging machines create package seals by means of heat seal jaws or bars. These heated components close over the portion of the package receiving the seal, causing the sealant layers of the packaging material to melt and bond to one another. However, there are factors that can cause faulty package seals. Here are a few of the most important (and preventable) ones.
STRUGGLING WITH LESS THAN PERFECT PACKAGE SEALS? DOWNLOAD OUR FREE MACHINE PREVENTIVE MAINTENANCE CHECKLISTS:
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Inadequate sealing jaw construction & uniformity
The bonded strength of a package seal must be uniform for it to properly protect your product. This means the sealing jaws must operate with consistent force and temperature across the entirety of the sealing area. To ensure this, choose a packaging machine with sealing jaws forged from a single piece of metal. This ensures that temperature and pressure will not fluctuate, creating a strong package seal.
A packaging machine with sealing jaws comprised of multiple pieces of metal can have a tendency to create an inconsistent seam because of differences in temperature and pressure of individual components. At Viking Masek, we use Teflon-coated jaws forged from one solid piece of high-alloy steel. Our jaws rarely, if ever, fail.
Sealing jaw misalignment
If your package seals are routinely perfect on one side of your bag but weak on the other, your jaws are probably out of alignment. A 'quick fix' chosen by packaging machine operators and technicians is 'shimming' the jaws into alignment with a small piece of metal. However, this solution poses safety risks and is not feasible over the long term.
A better solution is to follow a machine preventive maintenance plan that includes making sure packaging machine jaws are aligned and in compliance at key points in the packaging machine's lifespan, including:
- Before machine startup
- After a material jam
- After changeovers
- After major maintenance or upgrades
Dust & debris in package seal area
When product is present in the bag seam during heat sealing, the areas where product is present will not properly adhere. This negatively affects package seal integrity and causes risk of leaking and contamination. In order to prevent dust from impeding the package seal, there are a number of solutions to employ, detailed in our article here.
Ignoring machine preventive maintenance
Each day, the packaging machine operator or technician should clean and inspect the sealing jaws as part of a comprehensive machine preventive maintenance plan. This ensures that any build up on the sealing bars will be removed proactively and will not impede proper package sealing. It also ensures that any small issues with sealing jaw alignment or function will be addressed early on before they have a chance to turn into a major catastrophe that causes unplanned machine downtime.
Keep on top of maintenance tasks for your VFFS machine with our free preventive maintenance checklist and planner:
Have an automatic pouch fill and seal machine instead? Download the preventive maintenance planner for pouch packing machines here.
Originally posted 6/12/2017, updated 4/23/2018.
