Sealing Jaws - Dura-Therm Archives - Greener Corporation

Optimizing Pressure + Heat + Time on Flow Wrappers and Vertical Baggers

Michael Wojtech — Wed, 25 Feb 2026 11:55:45 +0000

A Tech Bite from Greener Vice-President & co-owner Matt Wojtech

This Tech Bite topic was recommeded on our Suggest a Topic page by one of our Technical Resource Blog subscribers. In return for using his suggestion, he will receive a collection of Greener Corporation merchandise.

Pressure + Heat + Time

Whether you are running a familiar flexible packaging material or converting to a new traditional or sustainable structure, Pressure + Heat + Time is the foundation for producing quality heat seals.

This Greener Tech Bite compares how the Pressure + Heat + Time sealing equation affects the setup of flow wrappers and vertical baggers and explains how these sealing factors are influenced by your specific packaging material and conditions.

A typical vertical bagger or long dwell flow wrapper might run at 60-80 packages per minute. A typical rotary flow wrapper runs faster, around 200-250 packages per minute, with shorter dwell times that make optimizing pressure and heat levels more crucial.

Pressure

Rotary Sealing Jaws

Sealing pressure applied by rotary sealing jaws is adjusted with springs or compression washers, but it is also affected by the clearance setting, sealing jaw serration design and alignment, and by the knife and anvil adjustment.

Pressure levels must be high enough to initiate a seal and to caulk off leakers by forcing melted sealant layer into gaps at the corners, along the fold of the fin seal or gussets, and at package wrinkles, but not so high that the seal is crushed or split.

Reciprocating Sealing Jaws

The application of pressure by the flat, reciprocating sealing jaws on most vertical baggers is simpler, with fewer variables. Sealing jaw serration design and alignment still have a big effect on pressure, but there is no clearance adjustment to fine tune and the fly-thru style knife does not create impact that alters pressure levels.

Even with the longer dwell times on vertical baggers, problems with leakers often stem from issues in the package formation process. Wrinkles and pleats create varying thicknesses in the package that can be difficult to seal across without damaging the package.

Heat

Heat is important on all machines, and becomes more crucial with the typically shorter dwell times on rotary flow wrappers. The optimum sealing jaw temperature setting depends on your flexible packaging material, the model, condition, setup, and running speed of your wrapper or bagger, and the design of your sealing jaws.

To ensure that your jaws are providing consistent heat across the package, check the temperature at multiple points along the sealing face with a contact pyrometer. (Non-contact pyrometers are less accurate.) You may find temperature variations between the middle and the ends, especially with larger, longer jaws on vertical baggers.

You can make this heat profile more consistent by coating heaters and thermocouples with heat sink compound, which fills in air gaps to improve heat transfer and sensing accuracy; by switching to preferentially wound heaters, which are hotter near the ends to compensate for typical heat loss there; and by utilizing sealing jaws made from a more thermally conductive material.

Temperature Window

It’s important to know the accurate temperature setting window for your flexible packaging material. The temperature window provided by your material supplier is a general guide, typically determined on a lab sealer with flat, non-serrated jaws, that can’t account for your specific conditions such dwell time, setup, and sealing jaw design.

You likely have standard sealing jaw temperature settings for each packaging material you run. But if you are experiencing problems, it’s a good idea to recalibrate this temperature window.

And if you are converting to a new structure, determining the material’s temperature window for your application is a vital step for setting up your wrappers or baggers.

Start by running packages at production speed and make needed adjustments until seal quality meets your standards.
Run additional tests, dropping the temperature by increments of 5° F, or 3° C, until seal integrity is unacceptable.
Then add back 5° F (or 3° C) to this number—this is your minimum temperature setting.

Return to your original temperature setting, and make incremental increases of 5° F, or 3° C, until the package is distorted or damaged.
Subtract 5° F, or 3° C to get your maximum temperature setting.
The span between seal failure and seal distortion is your seal temperature window.

Time

Thermal Transfer Efficiency

During the sealing process, Thermal Transfer Efficiency affects the dwell time required to transfer heat from the sealing jaws to the sealant layers of the packaging material. Improving levels of pressure and heat applied by the jaws can improve Thermal Transfer Efficiency and reduce the time required to produce a quality seal.

Greener’s XR™ Sealing Jaws utilize unique serration geometry to increase the pressure that can be applied to move sealant into gaps and seal off leaks without crushing or splitting the seal.

And by reducing temperature variation, XR™ and other jaw designs made from Dura-Therm material transfer more heat to the sealant layer without distorting or damaging the package.

By improving Thermal Transfer Efficiency, Greener’s advanced sealing jaw technology reduces dwell times to improve seal quality and allow faster machine speeds.

To learn more about optimizing Pressure + Heat + Time on your packaging application, contact Greener Corporation. We provide integrated parts and technical service solutions worldwide.

The post Optimizing Pressure + Heat + Time on Flow Wrappers and Vertical Baggers appeared first on Greener Corporation.

How to Determine the Optimum Machine Speed on Flow Wrappers and Vertical FFS Baggers

Michael Wojtech — Sun, 25 Jan 2026 19:58:53 +0000

A Tech Bite from Greener Vice-President & co-owner Matt Wojtech

“The Tortoise and the Hare” and “Slow is Smooth, and Smooth is Fast” are just two of many adages promoting the advantages of a slower, steady pace for solving problems and accomplishing goals. Does this strategy apply to your packaging lines?

This Greener Tech Bite explains how you can use the seal range of your flexible packaging material to determine the optimum machine speed on your flow wrappers and vertical baggers.

Sealing Jaw Temperature Cycles

During steady production, sealing jaw temperatures dip as they transfer heat to the package and then recover. These temperature cycles typically range within a few degrees.

When product feed rate fluctuates and production slows or is interrupted, sealing jaw temperatures cycle more widely.

Setup for Maximum Machine Speed

Flow wrappers and vertical baggers are often set up to run at maximum speed, with the intent to increase output. To maintain seal quality with the resulting shorter dwell times, sealing pressure is increased just short of the point where seals are crushed or split.

Steady Production Rate

Temperature is set to the highest possible level that keeps temperature cycles within the packaging material’s seal range—the span between the seal initiation temperature and distortion temperature. The seal range narrows as machine speed increases and dwell time is reduced.

Variable Production Rate

With machines set up for maximum speed, any fluctuation in product feed rate that slows production creates wider temperature cycles that can exceed the seal range.

This results in damaged and distorted packages with poor seal integrity.

Downtime accumulates as operators stop the machine to clean melted packaging material and product from the sealing jaws and fin wheels.

Maximum vs. Slower, Steady Machine Speed

Let’s look at some examples that compare scrap rate, downtime, and output levels for a flow wrapper and a vertical bagger set up to run at different speeds.

Flow Wrapper

A. Setup for Maximum Machine Speed

In situation A, a flow wrapper is set up to run at the maximum speed of 300 packages per minute. Over a ten hour production run, the wrapper only maintains this top speed for a cumulative total of five hours, or half the run.

During the other five hours, machine speed ramps up and down and occasionally pauses as the product feed rate fluctuates. With the wrapper set up to run at maximum speed, sealing jaw temperature cycles frequently exceed the seal range, increasing the scrap rate and downtime and limiting production to an average of 200 packages per minute.

Potential total output for the run is 150,000 packages, but actual output is limited to 117,000 packages.

B. Setup for Slower, Steady Machine Speed

In situation B the wrapper is set up to run at 225 packages per minute, which provides a broader seal range to accommodate wider temperature cycles when the product feed rate fluctuates.

This machine speed is maintained for most of the ten-hour run, with low scrap and downtime rates, and 129,600 packages are produced.

**A: Maximum vs. B: Slower, Steady Machine Speed**

Setting up for and running at this slower, steady speed improves seal quality and produces higher actual output than the setup for maximum speed.

Vertical Bagger

**A: Maximum vs. B: Slower, Steady Machine Speed**

Similar outcomes occur on vertical baggers where the product feed rate fluctuates. The setup for slower, steady machine speed produces more packages with better seal quality.

Slow is Smooth, and Smooth is Fast

To optimize setup on your flow wrappers and vertical baggers, use seal range and temperature cycles to determine what machine speed produces the highest output and best seal quality.

For cold seal applications where temperature and dwell time are not issues, setting machine speed to the maximum product feed rate can still cause problems that decrease output, such as frequent starting and stopping, empty packages, and product registration issues.

Dura-Therm and XR™* Sealing Jaws

You can increase the optimum machine speed on your flow wrappers and vertical baggers by updating to advanced sealing jaw designs.

* patent pending

Dura-Therm sealing jaws and XR™* Serration Technology reduce sealing jaw temperature variation, resulting in narrower temperature cycles that provide two types of opportunities:

Increase Output

To increase production output, you can increase machine speed and still keep temperature cycles within your material’s seal range to maintain seal integrity.

Convert to Sustainable and Less Expensive Packaging Materials

With Dura-Therm and XR™* sealing jaws, you can convert to sustainable or less expensive packaging materials with a narrower seal range without reducing machine speed or seal quality.

Slower and Steady Wins the Race

Setting up your packaging machines for slower, steady production and updating your sealing jaws can optimize production output and quality.

For help determining your optimum machine speed, or to learn how Dura-Therm and XR™* Sealing Jaws can improve your results, contact Greener Corporation.

We provide integrated parts and technical service solutions worldwide.

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XR™* Sealing Jaws Improve Thermal Transfer Efficiency to Provide Better Seals, Faster

Michael Wojtech — Fri, 29 Nov 2024 19:15:52 +0000

What if a new, unique design for sealing jaws could provide better seals, faster than you thought were possible on vertical baggers and long dwell flow wrappers?

This Tech Bite explains how Greener Corporation’s XR™* Sealing Jaws dramatically improve Thermal Transfer Efficiency to:

Improve Package Quality
Increase Machine Speed
Run Sustainable Materials & Hard to Seal Packages
Reduce Flexible Packaging Costs

The Sealing Process

Seal Range and Temperature Cycles

The seal range for your packaging material and conditions spans between the seal initiation temperature and the distortion temperature. The seal range must allow for sealing jaw temperature cycles as the jaws transfer heat to the package and then recover, and for wider temperature cycles when production slows down or is interrupted.

Machine Speed

The effective seal range narrows as machine speed is increased and dwell time is reduced. Machine speed is limited by the need to keep normal temperature cycles within the effective seal range.

Thermal Transfer Efficiency

During the sealing process, Thermal Transfer Efficiency determines the dwell time required to transfer heat from the sealing jaws to the sealant layers of the packaging material.

Force

Increasing the force that closes the sealing jaws improves Thermal Transfer Efficiency by increasing the surface contact between jaws and the packaging material.

But the ability to increase force is limited on most vertical baggers and long-dwell wrappers.

XR™* Sealing Jaws

1. Improve Package Quality

Utilizing unique serration geometry and Dura-Therm material, Greener Corporation’s XR™* Sealing Jaws distribute a machine’s existing sealing force more effectively to increase Thermal Transfer Efficiency and improve package quality.

2. Increase Machine Speed

The improved Thermal Transfer Efficiency yields wider seal ranges at shorter dwell times to allow increased machine speeds.

3. Run Sustainable Materials & Hard to Seal Packages

XR™* Sealing Jaws increase seal quality and machine speed where the need for longer dwell times has previously created limitations, such as with thicker and stiffer materials, wider packages, gusseted applications, mono PE and other materials with narrow seal ranges, and poorly conducting materials like paper.

4. Reduce Flexible Packaging Costs

By increasing Thermal Transfer Efficiency, XR™* Sealing Jaws enable users to decrease sealant thickness or utilize less expensive sealants with higher seal initiation temperatures to reduce flexible packaging material costs without sacrificing seal quality or productivity.

To learn how XR™* Sealing Jaws can:

Improve Package Seal Quality
Increase Machine Speeds
Run Sustainable Materials and Hard to Seal Packages
Reduce Material Costs

on your vertical baggers and long dwell flow wrappers, contact Greener Corporation. We provide integrated parts and technical services worldwide.

* patent pending

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Sealing Jaws Optimize Package Quality & Productivity on Flow Wrappers

Michael Wojtech — Sun, 23 Jun 2024 16:00:51 +0000

Sealing jaws on flow wrappers are not standard, universal components; they should be designed according to the unique features of your packaging operation. When you work with Greener Corporation, we integrate your machinery design and condition, packaging materials, seal integrity requirements, and other circumstances to design and manufacture sealing jaws that optimize package quality and productivity.

Custom Designed Sealing Jaw Designs

We have developed a wide variety of sealing features and will recommend customized designs that solve current packaging problems, prevent future issues, and create production efficiencies you may not have thought possible.

Serration Pattern

The serration pattern on your sealing machines should be designed for your seal packaging conditions. Greener corp can match your current serration profile or update serration geometry to improve results.

Easy Seal™️ Jaws

Easy Seal™️ jaws for heat seal and cold seal applications feature QUICK-CHANGE inserts that reduce sealing jaw changeover times, improve seal quality, and decrease parts costs.

Optional Easy Seal™️ FLEX jaw inserts accommodate the extra thickness at the fin seal fold to resolve problems with leakers and crushed or split seals.

Fracture Elimination Design (FRED)

Fracture Elimination Design (FRED) alleviates pressure on the leading edge of the seal, where the upper and lower sealing jaws first make contact, to prevent cutting and splitting of the package.

Seal Reduction Profile

Our Seal Reduction Profile reduces seal width to decrease film costs without sacrificing seal quality.

Sealing Jaw Materials

Greener corporation will recommend specialized materials to optimize performance or to provide other desired functional characteristics that are not available with basic steel sealing jaws.

High Durability Stainless Steel sealing machines resist wear and damage to help maintain quality seals.

Dura-Therm sealing jaws provide exceptional heat transfer and thermal consistency across the sealing face, and also provides flexibility and durability on our Easy Seal™️ FLEX jaws.

Kevlar® Composite sealing jaws provide a flexible, resilient sealing face on Easy Seal™️ FLEX for cold seal.

Project Development

Greener corp’s project development experts will help you create customized sealing jaw designs for packaging projects such as new film qualifications, changes in package size, and cross-platform sealing jaw standardization.

To learn how custom sealing jaws and technical support can improve your package quality and productivity, contact Greener Corporation. We provide integrated parts and technical services worldwide.

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Sealing Leaks at the Triangle of Death on Flow Wrappers and Vertical Baggers

Michael Wojtech — Fri, 12 Apr 2024 15:06:28 +0000

Are you consistently meeting your standards for package seal integrity and production speeds on your flow wrappers and vertical baggers? This Greener Tech Bite explains causes and solutions for a common package sealing problem where high integrity seals are required—the unsealed gap where the lap seal or fin seal intersects the end seal, sometimes referred to as the “Triangle of Death.”

For anyone who has struggled to seal these gaps, this nickname is no exaggeration.

Package Geometry

On a typical package, the end seal thickens from two to three layers where the vertical sealing overlaps, or from two to four layers where the fin seal folds over. On packages with gussets this transition occurs multiple times, creating, in effect, a series of plateaus and abrupt valleys.

Packaging Material Structure

To consistently seal the gaps created at these transition points, the structure of your flexible packaging material must be appropriate for your package geometry, required machine speeds, and other conditions.

The Sealing Process

But limitations within the seal packaging process can cause leaks at the Triangle of Death to persist.

Temperature Cycles

As explained in our previous Tech Bite, sealing jaw temperatures fluctuate as each package is sealed, and temperatures vary more widely if production slows down or is interrupted.

Seal Range

Machine speeds are limited by the need to keep these temperature cycles within the seal range of your packaging material.

Heat, Pressure, and Time

With adequate heat, pressure, and dwell time, sealant layers designed with the necessary mass and flow properties—shown here in yellow—can flow into and seal off the Triangle of Death.

But sealing jaw temperatures must remain below the point where they distort or melt the exterior packaging material layers, shown here in blue.

Sealing pressure helps to move sealant into these gaps, but too much pressure can crush or split the seal, especially at thicker sections where the lap seal, fin seal, or gussets intersect

It can be difficult to sustain the balance of heat and pressure required to seal these gaps while also maintaining required machine speeds.

Sealing Jaw Design and Setup

Here’s where improving the design and setup of your sealing jaws can help you seal the Triangle of Death.

Dura-Therm

Jaws made from Dura-Therm, a highly conductive alloy, reduce temperature cycles so you can maintain seal quality at higher speeds.

Serration Pattern

Sealing jaw serration patterns are not universal; your sealing jaw serrations should be designed to optimize sealing pressure and heat transfer for your specific packaging conditions.

XR™* Sealing Jaws

Greener’s XR™* Sealing Jaws combine the benefits of Dura-Therm and our unique serration geometry to seal leaks at the Triangle of Death and:

Improve Package Quality
Increase Machine Speed
Run Sustainable Materials & Hard to Seal Packages
Reduce Flexible Packaging Costs

Easy Seal™ FLEX

Easy Seal™ FLEX Jaws accommodate the extra thickness at the fin seal fold to further optimize sealing pressure and heat.

Setup Procedures and Training

Once you determine the optimal sealing jaw design for your application, establish proper sealing jaw setup procedures and provide training to consistently produce high-quality seal packaging.

If you experience sealing problems at the Triangle of Death, consult with our experts at Greener corp about packaging material specifications, sealing jaw designs, and setup procedures for your flow wrappers and vertical baggers.

Greener Corporation provides integrated parts and technical service solutions worldwide.

* patent pending

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Sustainable Packaging Materials 2: Running Mono Polyethylene & Mono Polypropylene on Flow Wrappers & Vertical FFS Baggers

Michael Wojtech — Thu, 08 Feb 2024 14:51:49 +0000

Most traditional flexible packaging is made from multiple layers of different materials that can’t be easily separated. Mono polyethylene (PE) and mono polypropylene (PP) are produced from the same or similar materials, and are the most common polymer-based sustainable packaging materials we’ve encountered so far.

Segment 2 in our Sustainability Series explores the properties that can make mono PE and mono PP more challenging to form, cut, and seal, and presents solutions for maintaining package quality and machine speeds when running these materials on flow wrappers and vertical FFS baggers.

FORMING Mono PE & Mono PP Packaging Materials

During the forming process, the thicker, stiffer nature of mono PE and mono PP structures creates greater tension in the web. On both flow wrappers and vertical baggers, a power film drive will help keep these structures tracking properly.

Specially designed formers are often required to maintain consistently sized packages that are free from creasing and scoring.

CUTTING Mono PE & Mono PP Packaging Materials

The mechanical properties of these thicker and stiffer structures can also make cutting more challenging.

Knives designed for your specific packaging material will improve cutting performance.

Special features such as an extreme angle zig zag knife can improve openability for the consumer.

SEALING Mono PE & Mono PP Packaging Materials

As explained in our previous Tech Bite, the effective seal range of a packaging material is defined as the difference between the seal initiation temperature and the distortion temperature.

With all flexible packaging materials, machine speeds are limited by the need to fit normal sealing jaw temperature cycles within the seal range.

Many current mono PE and mono PP structures have a lower distortion temperature, which decreases their seal range.

And since these mono structures tend to be thicker and stiffer, higher sealing jaw temperatures are needed for heat to reach and activate the sealant layer. This further reduces the seal range.

With sealing jaw temperature increases limited by the lower distortion point, reductions to machine speed may be necessary to provide adequate dwell time for seal initiation.

Sealing Solutions

Advanced sealing jaw designs can help mitigate sealing issues encountered with mono PE and mono PP materials. Sealing jaws made from Greener Corp’s proprietary Dura-Therm alloy provide more responsive and consistent thermal conductivity across the sealing face to reduce temperature cycle fluctuations and help maintain seal quality and machine speeds.

Temperatures don’t spike as high when the machine idles, or drop as far when the line restarts.

Customized sealing jaw serration patterns and options such as Easy Seal™ FLEX jaws can also reduce temperature cycles by optimizing thermal transfer and sealing pressure.

In addition to sealing jaw design, optimized adjustment procedures and training are critically important for maintaining seal quality and machine speeds on flow wrappers and vertical baggers.

To learn more about sustainable flexible packaging materials, advanced part designs, machine adjustments, and training, contact Greener Corporation.

We provide integrated parts, industrial packaging solutions and technical services worldwide.

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Easy Seal™️ QUICK-CHANGE Jaws: Fast, Accurate Changeovers on Flow Wrappers

admin — Thu, 09 Feb 2023 22:44:16 +0000

Damaged or poorly performing sealing jaws on flow wrappers can cost you hours of lost production time. Greener Corporation’s Easy Seal™️ QUICK-CHANGE Jaws decrease changeover times from hours to minutes, and at the same time improve seal quality, reduce part replacement costs, and create opportunities for standardization.

Decrease Downtime

The initial Easy Seal™ installation includes bases, QUICK-CHANGE inserts, knives, and anvils.

When jaws are replaced the heaters and thermocouples, if utilized, stay in the bases, which remain accurately positioned on the shafts. New Easy™️ Seal QUICK-CHANGE inserts fit precisely into the bases, so the serrations are already aligned. Making the packaging equipment installation quick and consistently accurate.

New knives and anvils can then be adjusted to cut, and you can be back up and running in less than an hour total.

Improve Seal Quality

Easy Seal™️ QUICK-CHANGE Jaws also improve seal quality by providing more consistent, accurate set-ups, and through options such as Easy Seal FLEX, which helps eliminate leaks and reduce end seal fracturing by automatically compensating for extra film layers at the fin seal, and Dura-Therm material, which provides more consistent, responsive heat transfer.

Reduce Parts Costs

Easy Seal™ also reduces parts costs, since QUICK-CHANGE Jaw inserts are less expensive to replace than standard jaws.

Standardization

And Easy Seal™ creates opportunities to standardize jaw and knife designs and set-up procedures across different flow wrapper makes, models, and lines to further improve seal quality, decrease parts inventories, and reduce costs.

Greener will engineer Easy Seal™ QUICK-CHANGE Jaws to match your specific packaging requirements for heat and cold seal applications.

To learn more contact Greener Corporation. We provide integrated parts and technical services worldwide.

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Sealing Over Extra Layers of Film at the End Seal (part 4 of 4): Optimizing Crimper & Sealing Jaw Design

Matt Wojtech — Tue, 16 Jan 2018 00:16:24 +0000

There is no one-size-fits-all solution for the design of crimpers and sealing jaws on horizontal flow wrappers and vertical baggers; they should be specified according to the packaging film, products, and conditions of your packaging operation.

This post, the last in our four-part series, reviews design options for crimpers and jaws. The optimal combination of serration patterns, materials, and special features can dramatically improve seal quality and productivity when sealing across extra film layers at the end seal.

Transitions on the end seal between varying thicknesses of film created by the fin seal, lap seal, gussets, and wrinkles make it more difficult to maintain the operating window necessary for quality seals:

Too little pressure leaves gaps, or leakers, at these transition zones.
Excess pressure can easily crush or split the end seal.
Overheating distorts the seal and can cause poor hot tack, where the film springs back open at transition zones or “moons,” before the seal can set.

The end results can be packages that fail to protect the product or have little appeal to consumers, as well as lost production time spent attempting to meet package quality standards.

Crimper and Sealing Jaw Design Options

What combination of serrations patterns, special options, and materials will perform best for your packaging application? Start by identifying problem areas and unmet goals. Your objectives might include:

Reducing or eliminating end seal leaks
Preventing crushing or splitting at the end seal
Improving package appearance
Increasing line speeds
Decreasing downtime associated with package quality issues
Achieving quality seals where different package sizes and styles, or different films, are run on the same machine

Crimper and sealing jaw design, as well as the consistency and quality with which they have been manufactured, have a major impact on the distribution of the pressure and heat necessary to achieve quality end seals across varying thickness of film. The optimal design depends upon the unique combination of variables of your packaging operation, such as equipment design and condition, product, packaging film, and line speeds.

Serration Pattern

Sealing pressure is applied by the force of the crimpers or jaws coming together with the film between them, and controlled through machine adjustments. In addition, as the film is drawn across and stretched over the serrations, the resulting “shearing” action helps push the inner sealant layer into gaps that would otherwise cause leaks.

The precise geometry of the serration pattern should be matched to the structure and thickness of the film in use, the presence of a lap or fin seal, gussets, persistent wrinkles, and other factors such as machinery design and condition and line speeds.

Special Design Features

A number of special designs for crimpers and sealing jaws work in combination with the proper serration pattern to provide more consistent, controlled pressure across end seals by accommodating extra layers from a fin or lap seal, gussets, or unavoidable wrinkles.

Flexible Sealing Faces

Easy Seal™ FLEX Inserts conform to extra film layers, allowing crimpers to apply the consistent pressure and heat (where applicable) required to effectively seal gaps at transition zone between varying thicknesses of film without distorting the package. These flexible, durable sealing faces can be provided for heat seal or cold seal applications.

Easy Seal ™ QUICK-CHANGE Inserts facilitate the precision serration alignment necessary to apply sufficient pressure across multiple thicknesses of film at the end seal without crushing or splitting the package, and at the same time reduce crimper changeover time from hours to minutes.

Fin Seal Relief

A precision relief in the serration pattern can be provided to accommodate the extra layers of film from the fin seal. A fin seal relief works best on applications where the fin seal size and tracking is consistent.

Fracture Elimination Design (FRED)

With Fracture Elimination Design, a special serration profile on the leading edge of the crimper sealing face helps eliminate excess pressure that can damage or cut through the packaging film.

Custom Designs

New design solutions can be created to match your production needs or for special projects such as new film qualifications, changes in package size, and cross-platform crimper standardization.

Materials

Optimizing the materials that crimper and sealing jaw materials are made from helps produce the consistent pressure and heat transfer (where applicable) necessary to achieve quality seals.

Durability

Wear and damage to the sealing faces of crimpers and sealing jaws can make it challenging or even impossible to transfer the proper pressure and heat across the end seal. This wear may not be readily visible on the sealing face, but becomes obvious when crimpers or jaws are evaluated using carbon paper (as shown). For more details see Assessing Crimper and Sealing jaw Set-Up.

Crimper and sealing jaw materials that resist wear and damage can be specified to match the variables of your packaging operation, for flexible or standard sealing faces and for heat seal or cold seal applications. There is no need to sacrifice durability in order to achieve quality seals.

Heat: Consistency and Responsiveness

On heat seal applications, heat and pressure work together with time to produce quality seals. Consistent, responsive heat transfer across the length of the sealing face eliminates the need to increase temperature and pressure settings to the point where the film is distorted or crushed in order to seal gaps between varying thicknesses of film on the end seal. The crimper and sealing jaw set-up required for achieving quality seals and meeting production goals becomes much easier to establish and maintain.

Crimpers and jaws made from Dura-Therm provide the consistent temperature profiles and the long-term durability necessary for sealing across extra layers of film at the end seal. (For more details see our post on Heat.)

Optimizing Crimper and Sealing Jaw Design

The best design for your crimpers or sealing jaws depends on the operational goals of your packaging operation. Taking a little time to evaluate your needs is a worthy endeavor that can significantly improve package quality and productivity.

Greener’s technical experts can help you refine your goals and determine the solutions that will accomplish your objectives. If you would like assistance with this process or have questions, please contact us and visit the Solutions page of our website.

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Troubleshooting Intermittent Seal Quality Issues

Mark Green — Thu, 08 Dec 2016 00:02:36 +0000

When end seal issues such as leakers or splitting occur, an important initial step is to determine where, and how often, the trouble shows up. For problems that occur inconsistently—perhaps leakers on every other package, or splits only on the top or trailing end seals of the package—you need to determine if the bad seals show up randomly or according to a pattern. Do the problems occur on every package? On both ends of the package?

Start out by collecting a series of packages produced by the machine during production conditions. Number the packages sequentially and mark the machine flow direction. If you are working on a horizontal wrapper with multiple crimpers, label each pair (ex: A, B) and mark each seal according to the set of crimpers it came from. Now you can trace the problem seals back to the place they occur.

Following is a list of procedures that will help you troubleshoot intermittent seal problems. You can find additional details by clicking on the links or images in each section:

• Clean the crimpers or sealing jaws. Product build-up can cause random, hard to trace problems by preventing the sealing faces from applying adequate pressure and heat.

Learn about custom scrapers and other methods to clean product build-up without damaging serrations.

• Look for backlash on rotary crimper heads. When problem seals can’t be consistently traced back to a particular location on the sealing face or to a specific pair of crimpers, backlash is often the culprit. You should not be able to move the upper shaft independently of the lower shaft. It only takes a little movement to cause a problem, especially if the crimpers have horizontal serrations (parallel to the knife slot).

Get more details on diagnosing and eliminating backlash.

• Assess the condition and set-up of the crimpers or sealing jaws. Use carbon or carbonless paper to make sure the crimpers or jaws are providing even pressure across the sealing face and that the serrations are properly meshed. Problems may be isolated to just one part of the seal or to only one pair of crimpers (where multiple pairs are used).

Discover how carbon or carbonless paper help reveal hidden wear, damage, and set-up issues.

Review clearance and pressure adjustments on horizontal wrappers.

• Check the temperature of all sealing faces along their entire functional length with a pyrometer, making sure that all heaters are functioning properly.

Learn how to achieve more consistent, responsive heat transfer.

• Check the knife set-up. On horizontal wrappers a knife that that is adjusted too far out can, especially at higher speeds, push the crimpers apart as they rotate through such that the pressure applied to the leading seal of the following package is reduced and leakers develop. You can often hear, or put your hands on the machine and feel, when a knife is striking the anvil with excessive force.

Explore methods to optimize knife and anvil set-up.

• Upgrade crimper and sealing jaw design. Sometimes inconsistent seal quality results when operating conditions such as line speed, machine condition, and the film in use combine to push the edge of what works and what doesn’t, leaving little room for variations that occur during production. In these cases alternative crimper and sealing jaw designs can create a larger, more forgiving operating window where consistent, quality seals are produced.

Crimpers and Sealing Jaws made from Dura-Therm material provide more consistent, responsive heat transfer without sacrificing durability.

Customized Serration patterns and sealing jaw designs such as FRED (Fracture Relief Design) can be matched to your specific product, film, and operating conditions to maximize seal quality and consistency.

FLEX sealing faces for heat seal and cold seal films accommodate extra film layers at the fin seal to help seal off leakers and prevent crushing and splitting without sacrificing durability.

Easy Seal™ QUICK-CHANGE crimper inserts for heat seal and cold seal films facilitate more precise set-ups and reduce change-over time from hours to minutes.

Contact Greener Corporation for help with troubleshooting any type of sealing, cutting, or forming problems that impact your package quality and productivity.

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HEAT: Improving Seal Quality and Consistency

Matt Wojtech — Wed, 22 Jun 2016 17:56:56 +0000

For heat seal applications, each packaging film structure has a Seal Initiation Temperature (SIT), at which the sealant layer is heated enough to flow into and seal off gaps in the end seal and provide a minimally acceptable seal, and a Maximum Temperature, beyond which the film distorts, fractures, or has inadequate hot tack (seal strength and integrity while the seal is still warm). The temperature range between the minimum and maximum is the film’s Operating Window.

For a number of reasons, regulating heat is not as straightforward as simply adjusting the temperature setting within the operating window for the film you are running.

♦ The sealing face of crimpers and sealing jaws is often hotter in the middle than at the ends, where heat dissipates more quickly. These inconsistencies are readily apparent in the thermal profile shown below:

If the package extends into the cooler areas of the sealing face, temperature settings high enough to seal the outer ends of the package can overheat the center and cause distorted, leaking seals and poor hot tack. These temperature inconsistencies are one reason why seal separation, or “mooning,” typically occurs at the center of the end seal.

♦ The temperature readout at the controller does not usually reveal heat inconsistencies across the length of the sealing face, since thermocouples read the temperature at only one point within the crimper or sealing jaw body. The best way to check for these heat issues is with a pyrometer, at multiple points across the sealing face:

♦ The temperature of the sealing face on crimpers or jaws at rest should remain fairly consistent, depending on the responsiveness of the temperature controller. At production speeds, however, there is limited dwell time for the crimpers or jaws to interface and transfer heat to the sealant layer, which can be especially problematic where there are extra layers of film from the fin seal, lap seal, gussets, or wrinkles. The sealing face loses heat as it seals each package and then has limited time to recover before the next package has to be sealed. Charted over time, the temperature of the sealing face rises and falls with each package.

Since dwell time and recovery time are limited, temperature must often be set higher than the actual operating window for the film structure. This differential can cause problems when the line slows down or temporarily stops; with additional time for heat transfer and thermal recovery the sealing face can overheat, causing distortion, splits, and leaks in the end seal.

To provide the most consistent, responsive heat transfer:

♦ Start by keeping your crimpers and sealing jaws free of product contamination—even minimal coatings can impede heat transfer. (See Cleaning to Improve Package Quality and Productivity.)

♦ Make sure you coat all heaters and thermocouples with a silicone based heat sink compound before installing them. This will ensure better surface contact between heaters and the crimpers or jaws, providing better heat transfer and more accurate temperature readings.

♦ Switch to preferentially wound heaters, which provide more consistent temperatures across the sealing face. They are hotter near the ends to compensate for typical heat loss there.

♦ Upgrade to Greener’s Dura-Therm crimpers and sealing jaws, which provide more consistent, responsive heat transfer without sacrificing durability. Users of Dura-Therm crimpers and jaws report temperature readings within +/- 3° F across the sealing face and have been able to lower their temperature settings by 10 – 15%, resulting in a decrease in leakers and cosmetically flawed packages caused by heat issues.

Test results of thermal profiles, illustrated below, clearly show the temperature consistency of Dura-Therm crimpers compared to the temperature variation of crimpers made from stainless steel:

In addition to heat and time, proper pressure is also necessary to achieve consistent, quality seals. For more details see our earlier post, Clearance and Pressure on Horizontal Wrappers: What’s the Difference?

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