Induction sealing is necessary for a variety of markets needing bottle sealing. Those in the pharmaceutical, chemical, food, beverage and other industries, rely heavily on Pillar’s induction sealers for carrying out their sealing operations. Induction sealing is the process of sealing bottles by applying an induction current to the specially manufactured metal liner located on the inside of caps. Because the liner contains the sealing material adhered to the foil layer, the induction current then heats the foil liner, ultimately melting the sealant onto the bottle – creating a crisp, perfectly-sealed bottle that’s ready for packaging. If your induction sealing operations are not set up and managed properly, you can experience an increase in unsealed products – resulting in lost money and time for your business.
Because of this, Pillar's team put together the following list of 10 ways to improve your induction sealing results:
Adjust the guide rails
Adjust the guide rails to insure the bottle passes beneath the coil on a consistent path. When insufficient sealing power is suspected as the primary cause for incomplete sealing, adjustment of the conveyor guide rails may be necessary to resolve the issue. It’s possible that the metal guide rails are located too close to the sealing head, but if the positioning of guide rails under the sealing head cannot be avoided, then the rail should be substituted for a non-metallic material (since metallic guide rails can distort the induced electromagnetic field).
Align the coil
The sealing coil located on your induction sealer must be properly aligned for achieving a successful seal. For proper alignment, refer to the alignment parameters located in your sealer’s manual to make sure they are all correct.
Set the gap
The distance between the foil, located on your bottle, to the bottom of the coil is known as the gap. Setting a consistent gap is critical for improving induction sealing. By eliminating variance in gap, you eliminate a variable that causes you to adjust the power output differently each time you run a particular package. As a rule of thumb, ensure a minimum of 3 mm clearance between your thickest cap (likely to be child-resistant) and the sealing head. Then remove the cap, measure the gap distance, and standardize on that gap distance for all cap designs.
Regulate the conveyor speed
By regulating the speed of your conveyor, and keeping it as consistent as possible, you are able to get an even seal across all of your products. To regulate the speed of your conveyor, calculate the Dwell Time, or the amount of the time your product spends under the coil being heated, from enter to exit (Dwell Time = Sealing Head Length/Speed of Line). By doing this, and managing to keep it as consistent as possible, you can ensure that all of your products are being sealed effectively and evenly.
Example: L = 0.5 meter (1.67 ft.) / 30 meters/min. (100 fpm) ; Dwell Time = 0.0167 minutes
Control your Operating Window
The Operating Window is the key to uptime, so it’s important that you accurately control it. This can be done by setting the desired conveyor speed and trialing power settings to “baseline” the minimum power required for the foil to completely seal around the bottle lip. Then, incrementally increase the power settings by 2% to ultimately “baseline” the maximum power required for the foil to completely seal around the bottle lip, without leaving evidence of burning/melting inside of the cap, and/or melting of the bottle lip under the foil. Finally, record and communicate the Operating Window parameters.
Ensure your seal is the right seal
For better sealing results, ensure that your seal is the right seal to be used. Determining the right induction seal is first dependent upon the product being packaged. If the product contains any potentially aggressive or volatile chemicals, ingredients, acids, solvents, alcohol, or vinegar, a protective layer may be needed. Next, the liner of the seal needs to be determined. A single-piece liner has a backing that is typically a board, foam, or layer of paper, while a two-piece liner is a wax-bonded material with backing that is usually a board, pulp, or foam bonded to the foil-seal structure with a temporary wax-bond. Finally, the removal characteristics must be determined to specify details about the unique application in order to ensure that all sealing needs are met.
Torque it
When sealing, the force that presses the seal against the bottle is known as the Torque, and without it, your products cannot be sealed. In order to determine the Torque required for your specific application, calculate your Application Torque (1/2 Diameter of the Cap +/- 10%).
Example: If you have a 28 mm cap, the recommended application torque would be 14 inch/pound +/- 10% = 1.4 inch/pounds
Application Torque Range = 12-16 inch/pounds
Set your alarms
Located on your induction sealer system will be an Alarm Fault, which lights up when the coil output has dropped below the threshold, set by the alarm set-point on the control panel. In order to avoid poor seal quality, make sure your under-seal and over-seal alarms are accurately set on the control panel. By doing so, you can ensure that optimum seal quality is obtained.
Inspect and reject
By taking the time to inspect and reject your sealed products thoroughly, you’re able to increase the likelihood of achieving a successful seal. With Pillar’s patented Sealing Unit Verification (SUV), a key factor for induction sealing reliability, you’re able to easily inspect your seals and discard any that aren’t properly sealed. Pillar’s SUV is a bundle of induction sealer features that when utilized, will add significantly to the quality of your seal. Features such as Missing Foil Detection, Overseal Alarm, Loss of Seal Alarm, and other SUV’s are critical for monitoring and verifying seal quality, while still ensuring product quality.
Confirm your results
Be sure to confirm your seal results with Thermal Imaging. Thermal Imaging indicates not only if a sealing issue occurs, but what caused it affording you the opportunity to correct the issue in real time. It does this by detecting emitted radiation of the electromagnetic spectrum (roughly 3,000– 14,000 nanometers or 3–14 μm), then translates this radiation data into images called thermograms.
Reduce Induction Sealing Rejects
When optimized and managed properly, the induction sealing process can offer effective solutions for tamper evidence, leak protection, freshness, and product protection. If not managed properly, your plant is at risk of experiencing increased product quality rejects due to over-sealing and under-sealing. By incorporating Pillar’s 10 tips for improving induction sealing results into your business’ sealing operations, you have the opportunity to reduce product rejects and save your business money, energy, time, and resources in the long run.
How can Pillar Help?
Pillar Technologies has been serving the packaging industry for over 40 years. Our team of experienced and talented Application Engineers and Sales Representatives have decades of experience working in the induction sealing and manufacturing arena. We will work alongside you to find, and build, the perfect induction sealer for your business, while also trying to reduce costs and energy usage. If you’re interested in Pillar’s induction sealers, or would like to learn more, email sealers@pillartech.com, or call (262) 912-7200. Get a quote from one of Pillar’s Application or visit our website.