Resource Blog Archive - Greener Corporation

Adjusting Knives: Causes and Solutions for Excessive Shimming on Flow Wrappers & Rotary Vertical Baggers

Michael Wojtech — Tue, 28 Apr 2026 12:16:33 +0000

A Tech Bite from Greener Technical Service Manger Jeff Fouche

At times a client inquires why they need so much shim to get a new knife to cut on their flow wrapper or rotary vertical bagger, and our Technical Specialists have encountered this same issue during service visits. Excessive shimming of knives causes cutting problems that delay production, reduce knife and anvil life, and create sealing troubles.

This Greener Tech Bite identifies the optimal limits for shim thickness when adjusting knives and explains the reasons why excess shims may be required to get a knife to cut.

How Much Shim Should Be Required?

Greener Corporation sets and holds tight manufacturing tolerances on sealing jaws, knives, and anvils, so that the knife and anvil extend between the root and the mid-point of the serrations. The anvil does not require adjustment, and shims totaling no more than five to ten thousandths of an inch, or .12 to .25 millimeters, should be needed when setting up a new knife.

Problems Caused by Excessive Shims

Instability

With greater amounts of shim, the base under the knife becomes less solid and unstable.

Overadjustment

To overcome this instability the knife must be overadjusted to achieve the force necessary to cut against the anvil.

Premature Failure of Knives and Other Components

The heavy impact of an overadjusted knife—often conspicuous by the banging sound it makes as it strikes the anvil—causes knives, sealing jaws, springs, bearings, and other critical components to fail prematurely, increasing both downtime and spare part costs.

Poor Seal Quality

Overadjusted knives also create sealing problems, where the impact of the knife causes the sealing jaws to bounce apart, reducing the sealing pressure and seal quality on the leading end of the next package.

8 Conditions That Create the Need for Excessive Shims

1. The Knife and Anvil Are Worn and Need to be Replaced

When running sealing jaws, knives, and anvils from Greener, if a total shim thickness of more than fifteen or sixteen thousandths of an inch, or .38 to .4 millimeters, is needed under the knife, then a new knife and anvil should be installed.

2. A New Knife Was Installed With the Old, Used Anvil

With this practice, much greater force is required to achieve a cut and knife life can be reduced up to 50%.

3. Springs or Compression Washers Are Worn or Too Weak

Worn or weak springs or compression washers on the cutting and sealing head are failing to provide adequate cutting force.

4. Shims Have Burrs or Are Too Soft

Shims with burrs on their edges, or shims made from brass or another soft material, are flattening and compressing over time and failing to properly support the knife.

Greener can provide precut, high quality stainless steel shims that produce accurate, consistent knife adjustments.

5. Many, Thin Shims Instead of Fewer, Thicker Shims

The use of many, thinner shims instead of fewer, thicker shims has failed to provide a solid seat for the knife and reduced the available cutting force.

6. Clearance Set Too Wide

Clearance between the sealing jaws is set too wide, effectively deepening the slots in the jaws and requiring extra shims for the knife to cut.

If the clearance adjustment is incorrect, sealing problems will also be present.

7. Resharpened Knives and/or Anvils

Knives and/or anvils have been resharpened and need excess shim to compensate for their reduced height. Greener does not recommend resharpening knives and anvils unless it’s an emergency, where a new knife and anvil are not available to keep the machine running.

The price difference between a new and a resharpened knife is minuscule compared to the thousands of dollars in extra downtime costs required to setup and troubleshoot a resharpened knife.

8. Sealing Jaws With Deeper Slots – Shorter Knives and Anvils

Sealing jaws with deeper slots and/or knives and anvils with shorter heights are provided by some machine manufacturers and part suppliers. With these components, more than fifteen thousandths of an inch, or .38 millimeters, of shims may be needed to get a knife to cut—sometimes significantly more.

We don’t typically recommend shimming a new anvil. But if the anvil sits below the root of the sealing jaw serrations, it should be shimmed up to the mid-point of the serrations to reduce the shim thickness under the knife.

If the anvil sits too deeply, the knife will need to protrude above the tops of the serrations. The package is not supported as it spans between the edges of the anvil slot and can be fractured when the knife pushes it downward to meet the anvil.

Precise knife adjustment on your flow wrappers and rotary vertical baggers plays a vital role in optimizing package quality and productivity.

If you’d like input with establishing knife setup procedures, training, or troubleshooting chronic cutting problems, contact Greener Corporation. We provide integrated parts and technical services worldwide.

The post Adjusting Knives: Causes and Solutions for Excessive Shimming on Flow Wrappers & Rotary Vertical Baggers appeared first on Greener Corporation.

Seal Integrity Objectives and Obstacles to Achieving Them on Flow Wrappers and Vertical FFS Baggers

Michael Wojtech — Mon, 30 Mar 2026 13:27:38 +0000

A Tech Bite from Greener Packaging Technology Engineer Steve Tucker

How do you define a successful seal on packages from your flow wrappers or vertical baggers? What obstacles can prevent you from achieving these standards?

This Greener Tech Bite helps you evaluate your seal integrity objectives and explores the limitations of your flexible packaging material and production output requirements that can prevent you from achieving these objectives.

Seal Integrity Objectives

Each product has different needs for barrier protection from oxygen, moisture, and/or light, and has different shelf life requirements. These criteria dictate both the structure of the flexible material the product is packaged in and the levels of seal strength and hermiticity that are required.

It’s important to clearly understand the protection requirements of your product.

For nonperishable products that only need a dust cover or containment, such as plastic cutlery, there’s no need to spend money or waste time and effort attempting to achieve hermetic seals. But for some baked goods and other products that need more protection to extend their shelf life, maintaining a quality seal with the properly specified packaging material is vital. Most packaging applications fall somewhere between these two extremes and require some careful consideration.

If you can’t clearly state the reasons for your current seal integrity requirements, it’s a good idea to reevaluate your criteria—you could be wasting money on overly stringent goals or be losing market share by sending out packages that don’t keep your product fresh.

Flexible Packaging Material

Once you are satisfied that your seal integrity objectives address the protection needs for your product, you can re-examine your flexible packaging material choice to make sure the structure can achieve these standards..

Requirements for puncture resistance, tear resistance, and for specific graphics, colors, and glossiness also much be considered.

Production Output Goals

The production output goals you have for your flow wrappers or vertical baggers will also influence the packaging material structure that you need.

On heat seal applications, sealing jaw temperatures typically cycle up and down as they transfer heat to the package and then recover.

Maximum production speeds are limited by the need to maintain these temperature cycles within the seal range of the packaging material—the span between the seal initiation temperature and distortion temperature. The seal range narrows as machine speed increases and dwell time is reduced.

Flexible packaging materials with limited seal ranges may be utilized to reduce costs or to achieve sustainability goals.

Improvements to sealing jaw design and machine setup can reduce temperature cycles and broaden the seal range to help you achieve success with these materials.

But a seal range that is too narrow can reduce machine speed and prevent you from reaching your production output requirements.

Conversely, an overqualified material with a wider-than-required seal range adds unnecessary expense to your operation.

Your packaging material should meet, but not exceed, your requirements for product protection, machinability, and production output levels.

Seal Integrity Testing

Your method for testing seal strength and hermeticity levels of packages should align with, but not exceed, your seal integrity objectives.

For a product that simply needs a dust cover, any testing more elaborate than a simple hand squeeze test might be a waste of time and effort. But a product that requires a moisture and oxygen barrier to stay fresh necessitates a more reliable, accurate test such as Pressure Decay or Gas Flow Detection.

If you’d like guidance with evaluating your seal integrity objectives, specifying and trialing packaging materials, seal testing, and setting up your flow wrappers and vertical baggers for success, consult with Greener’s Technical Specialists.

We provide integrated parts and technical service solutions worldwide.

The post Seal Integrity Objectives and Obstacles to Achieving Them on Flow Wrappers and Vertical FFS Baggers appeared first on 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.

The post How to Determine the Optimum Machine Speed on Flow Wrappers and Vertical FFS Baggers appeared first on Greener Corporation.

Maintain Efficiency on Flow Wrappers with Systematic Preventative Maintenance

Michael Wojtech — Tue, 11 Nov 2025 16:46:06 +0000

A Tech Bite from Greener Technical Service Manger Jeff Fouche

Due to production demands and a shortage of experienced mechanics, maintenance on flow wrappers is often reduced to immediate problem solving. In the rush to restore production, this reactive maintenance relies on short-term fixes that don’t fully resolve the underlying cause of the problem and fail to restore peak efficiency. Repeat problems require additional quick fixes and further erode efficiency.

This Greener Tech Bite details systematic preventative maintenance practices for flow wrappers that sustain peak efficiency and production levels.

If you and your team don’t have the required time or experience to implement preventative maintenance, Greener’s Technical Specialists can provide regularly scheduled onsite visits to perform line evaluations, make necessary updates, and provide training on these procedures.

Systematic Preventative Maintenance

The following flow wrapper components and adjustments—from the product feed through to the package discharge—should be evaluated and updated at least every three months.

Product Infeed

On the product infeed, stretched or worn components cause product misalignment and create timing problems. Replace worn or stretched infeed flight chains. Inspect the belts—even those with automatic tensioners—and replace them if they are stretched, worn, or frayed and can’t hold the proper tension.

The product infeed should be level and aligned with the flow wrapper.

Rails – Deck Plates – Forming Box

Check the rails, deck plates, and the forming box for misalignment or damage and readjust, repair, or replace them as needed.

When not level, smooth, or properly positioned, these components inhibit movement of the product and packaging material, causing malformed packages that delay production.

Packaging Material Unwind

Replace the bearings of shafts and rollers on the packaging material unwind that don’t spin freely; they create excess tension that causes tracking problems.

Adjust rollers to create the proper tension on the packaging material as it moves throught he forming process.

Fin Wheels

Fin wheel issues can cause slippage, poor tracking, and seal problems. Make sure that the tension between the fin wheels is correct and adjust their tilt to prevent slippage and create tighter packages.

Replace fin wheels that are worn, damaged, or have sharp edges. Check the condition of the fin wheel bearings and replace them if needed.

Cutting and Sealing Head

The cutting and sealing head requires frequent inspection and updating.

Backlash

Check for and remove backlash between the upper and lower sealing jaws.

Gears

Inspect the gears and replace them if necessary.

Springs or Compression Washers

Assess the condition of the springs or compression washers and adjust or replace them as needed.

Bearings

Worn bearings cause chronic problems that can be difficult to diagnose. To determine if new bearings are needed, follow this bearing evaluation process.

Carbon Impression

Next, remove the knives and anvils and, with the sealing jaws at operating temperature, run carbon impressions to evaluate their condition and setup.

Sealing Jaws and Adjustments

Replace worn or damaged sealing jaws. Check and, if needed, readjust the clearance, phasing, serration alignment, and pressure.

Clean the slots to ensure that knives and anvils can be firmly and accurately seated. To prevent cutting problems, always replace the anvil when installing a new knife.

After adjusting the knife with shims or adjustment screws, re-check your sealing setup with another carbon impression.

Cleaning

At any point in the packaging process, insufficient cleaning can degrade efficiency.

Clean components such as belts, formers, deck plates, fin wheels, and both the upper and lower sealing jaws during scheduled production breaks and whenever time allows—before problems occur.

Regularly Scheduled Preventative Maintenance with Greener Corporation

Relying on reactive maintenance erodes package quality and output levels.

If you don’t have a systematic preventative maintenance program for your flow wrappers, consider partnering with Greener Corporation for regularly scheduled Technical Service visits. Our Technical Specialists will perform line evaluations, make necessary updates, and provide training to keep your flow wrappers running at peak efficiency.

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

The post Maintain Efficiency on Flow Wrappers with Systematic Preventative Maintenance appeared first on Greener Corporation.

QUICK TIPS: Troubleshooting Forming Problems on Vertical FFS Baggers

Michael Wojtech — Tue, 07 Oct 2025 16:13:42 +0000

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

This Greener Tech Bite, in partnership with Kenray Forming, provides QUICK TIPS for troubleshooting three common forming problems on vertical baggers: torn or broken packaging material, wrinkled and scored packages, and open back seals.

Former Design and Precision

Both proper design and consistently precise fabrication of formers are critical to their proper function.

Shoulder Geometry

Incorrect shoulder geometry can tear or break the packaging material, create wrinkles, and cause open back seals.

Crossover Point

Tearing and breakage are also caused by sharp edges or by inadequate clearance at the crossover point on the former.

If the crossover point is mispositioned, open back seals can result.

Clearance Between the Tube and Shoulder

The clearance between the forming tube and forming shoulder must be the proper dimension and must remain consistent around this intersection.

Improper clearance, often created by imprecise former geometry and misalignment between the tube and shoulder, is a common cause of chronic forming issues.

Pinch points where this clearance is too narrow create excess tension that can tear or break the packaging material.

These pinch points also create score marks that degrade package appearance and can reduce the material’s barrier capacity.

Kenray’s unique manufacturing process allows them to fabricate formers with precise, constant clearance between the shoulder and the tube, so they can provide narrower clearance widths, without pinch points, that produce more accurate, consistent bag sizes.

Formers without Kenray’s unique level of precision must have wider clearance between the tube and shoulder to avoid pinch points, which can result in more variable bag sizes, wrinkles, and other issues.

Former Condition

Former condition is also important. Over time, the packaging material wears the lip of the forming shoulder as it moves across it and can eventually create an uneven edge, often referred to as shark’s teeth.

This rough edge creases the material and creates jagged score marks down the outside surface of the package.

Formers should be regularly inspected and replaced or refurbished when the shoulder begins to wear.

Former Adjustment

Former misadjustments are another cause of forming problems.

Rollers that are adjusted too far back can cause score marks on the inside and outside of the bag.

Formers that are not correctly positioned can cause open back seals.

Troubleshooting Forming Problems on Vertical FFS Baggers

The design, precision, condition, and adjustment of the formers on your vertical baggers—even the seemingly smallest details—can have a big impact on package quality and productivity.

Do you need to troubleshoot forming problems on your vertical baggers? Contact Greener Corporation and Kenray Forming. We provide integrated parts and technical service solutions worldwide.

The post QUICK TIPS: Troubleshooting Forming Problems on Vertical FFS Baggers appeared first on Greener Corporation.

Why Trials of New Flexible Packaging Materials Fail When They Don’t Need To

Michael Wojtech — Sun, 21 Sep 2025 13:41:42 +0000

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

The failed trial of a new flexible packaging material may have more to do with the trial process than the structure of the material.

Problems often occur when new materials are trialed on machines that retain adjustments and components designed for the previous material. This is especially true for new sustainable structures, with increased heat sensitivity and narrower seal ranges that often require specialized sealing jaws and optimized machine setup to run properly.

This Greener Tech Bite compares two different trial processes for flexible packaging materials on flow wrappers and vertical baggers that often yield contrasting results.

The Circular Trial Process

Packagers, material suppliers, and converters often get caught in the following Circular Trial Process:

New Flexible Packaging Material Specified

A material supplier or converter works with the packager to specify a material that will help them reach their corporate goals and provides material for a trial.

Factory Trial with Current Sealing Jaws & Minor Adjustments

The packager trials the new material in one of their factories, utilizing existing sealing jaws and only making minor adjustments to their flow wrapper or vertical bagger.

Factory Trial Fails

The trial is unsuccessful. They are unable to meet seal integrity and/or machine speed requirements, and the new material is deemed a failure.

Modified Version of New Material Specified

The packager’s process returns to stage 1, and the material supplier or converter provides a modified version of the new material.

Factory Trial with Modified Material

A second factory trial is run with the modified material, again using the existing sealing jaws.

Factory Trial with Modified Material Fails

Results improve slightly, but seal quality fails to meet quality standards at the machine speeds necessary to meet production requirements.

Circular Trial Process Repeats

The process again repeats, and may do so multiple times before a successful trial occurs or the project reaches an impasse.

The cost is high not just monetarily, but also for the long time it takes to develop and approve a new material. When forced to rely on this Circular Trial Process, packagers often don’t meet their goals in the desired timeframe or are forced to settle for substandard package quality and/or productivity.

The Expedited Trial Process

With Greener’s Expedited Trial Process, we partner with packagers, material suppliers, converters, and OEMs to prevent the repetitive efforts and failed results of the typical Circular Trial Process and reduce the time required to move from project inception to successful trials.

Through our Expedited Trial Process:

New Flexible Packaging Material Specified

The packager works with the material supplier or converter, often with input from Greener, to specify a material that will help them reach their corporate goals.

Partnering with Greener Corporation

The packager and/or the material supplier or converter partner with Greener Corporation for the trial process. They send us rolls of the new material.

Trial of New Material in Greener’s Packaging Lab

Greener trials the new material in our Packaging Lab on a horizontal flow wrapper or vertical bagger. The optimal sealing jaw design and machine setup for the new material are determined and utilized for the trial.

Packages are tested to ensure they meet the packager’s quality standards. Testing methods include the Vacuum Decay Test for seal integrity, the Seal Strength/Burst Resistance Test, and Microscopic Evaluation.

A Seal Range Graph is created to determine optimal temperatures and machine speeds for the material. Seal Range can be used to identify potential modifications to the structure that could increase productivity or reduce material costs.

Using optimized sealing jaws and machine adjustments, the trial succeeds.

Recommendations are provided for sealing jaw designs and setup specifications for the packager’s flow wrappers or vertical baggers.

Factory Trial with Recommended Jaw Design & Setup

A factory trial utilizing the new sealing jaw and setup recommendations is run with the new material.

A Greener Technical Specialist attends the trial to help optimize packaging machine setup and ensure that factory trial results match those achieved in our Packaging Lab.

Factory Trial Succeeds

The factory trial produces successful results.

Greener’s Expedited Trial Process for Flexible Packaging Materials reduces costs by shortening the new material development process and by allowing packagers to maintain seal integrity standards and production levels.

Trials of new flexible packaging material often fail when they don’t need to.

If you are a packager, material supplier, or converter and want to improve your trial process to get faster, more accurate results, contact Greener Corporation. We provide integrated parts and technical service solutions worldwide.

The post Why Trials of New Flexible Packaging Materials Fail When They Don’t Need To appeared first on Greener Corporation.

How the Structure of Flexible Packaging Materials Impacts Their Sealability

Michael Wojtech — Wed, 23 Jul 2025 16:10:26 +0000

A Tech Bite from Greener Packaging Technology Engineer Steve Tucker

This Greener Tech Bite explains how the structure of a flexible packaging material effects its seal range and ultimately determines maximum machine speeds.

We examine legacy technologies as well as today’s sustainable materials, and discuss how Greener’s new sealing jaw technology expands the seal range to increase production speeds and improve package quality on flow wrappers and vertical FFS baggers.

In previous Tech Bites, we’ve defined seal range as the difference between the seal initiation temperature and seal distortion temperature during the packaging process. We’ve shown that the seal range must be wide enough to accommodate the normal temperature cycles of the sealing jaws.

Flexible Packaging Materials

Polymer Type & Thickness

To explain the impact of flexible packaging material structure on seal range, we will focus on the type and thickness of both the core layer polymers and the sealant layer.

Laboratory Melt Point Spread

One of the more important polymer attributes is the melt point of the core layers, which varies significantly between polymer types. The higher the melt-point, the more resistant the material becomes to heat-related damage at high temperatures.

The sealant layer is designed to have a lower melt temperature than the core layers.

We can refer to the spread between the sealant layer melt point and the core layer melt point as the laboratory melt point spread, which relates only to theoretical temperatures, without respect to the packaging conditions required for the material to reach those temperatures.

Seal Range

Melt Point Spread is not quite the same as seal range, which is a bit more complex. Rather than looking solely at a material’s theoretical melt points, seal range describes the machine settings necessary to achieve those melt points.

A true seal range study will describe the relationship between sealing jaw temperature, dwell time, and force, and will ultimately determine the optimized settings necessary to maintain seal quality.

Laboratory Melt Point Spread vs Seal Range

The seal initiation temperatures and distortion temperatures of a material’s seal range are always higher than the laboratory melt points. The difference is a function of a material’s thermal conductivity and thickness, along with the available dwell time and force.

Thermal Transfer Efficiency (TTE)

During the sealing process, temperatures are highest where the sealing jaws contact the package and then dissipate as heat travels through the core layers to the sealant. This heat transfer becomes a race against time.

The goal is to optimize Thermal Transfer Efficiency (TTE)—to reach seal initiation temperature at the sealant layer as quickly as possible, without heating the core layers to their distortion temperature.

Force, and the efficient distribution of that force, is the key driver of Thermal Transfer Efficiency.

Seal Range Factors

Dwell Time – Machine Speed

As machine speed increases and dwell time is reduced, the seal range narrows.

Flexible Packaging Material Thickness

Increasing a material’s thickness also narrows the seal range; the core layer distortion-point is raised, but the seal initiation temperature is raised even higher.

Temperature

Temperatures can be increased, but machine speed is limited by the need to keep normal sealing jaw temperature cycles within the seal range.

Flexible Packaging Material Structure

Compared to many other materials, polyester offers a broader seal range that enables excellent seal integrity even at high machine speeds.

Materials with a narrower seal range, including many sustainable structures, have often required slower machine speeds to maintain seal quality.

Increase Thermal Transfer Efficiency (TTE) to Expand Seal Range

Significant increases to the Thermal Transfer Efficiency of the sealing jaws can mitigate machine speed limitations. As Thermal Transfer Efficiency is improved, optimum heat will be transferred from the sealing jaws into the packaging material at a lower temperatures and/or in less time, allowing for a wider seal range that provides increased machine speed.

XR™* Sealing Jaws

Greener Corporation’s XR™* Sealing Jaws, utilizing unique serration geometry and Dura-Therm material, provide this increased Thermal Transfer Efficiency by distributing a machine’s existing sealing force more effectively.

Sustainable Materials & Difficult to Seal Packages

XR™* Sealing Jaws provide the broader seal range that can be especially critical with sustainable materials and difficult to seal packages, where the need for longer dwell times has previously created package quality and machine speed limitations.

Reduce Flexible Packaging Material Costs

Increased Thermal Transfer Efficiency can also maintain seal quality and machine speeds with thinner or less expensive sealant layers that reduce flexible packaging material costs.

Are you missing opportunities to expand your seal range to increase machine speed, improve seal quality, and reduce costs?

Contact Greener Corporation’s Technical Specialists. We provide integrated parts and technical service solutions worldwide.

The post How the Structure of Flexible Packaging Materials Impacts Their Sealability appeared first on Greener Corporation.

How to Adjust Knives with Adjustment Screws on Flow Wrappers

Michael Wojtech — Sun, 20 Jul 2025 15:11:35 +0000

A Tech Bite from Greener Technical Service Manager Mark Green

Learning how to set up knives with adjustment screws can require time consuming trial and error. This Greener Tech Bite presents a fast, dependable, 8-step method for adjusting knives with adjustment screws on flow wrappers.

1. Bring the Jaws to Operating Temperature

To start, remove the old knives and anvils and bring the sealing jaws to operating temperature.

2. Check Sealing Adjustments

Then make sure your sealing adjustments are correct. Run some trial packages—with product if possible. Cut the packages apart with scissors, test the seals with your standard method, and make any necessary readjustments.

Clearance, the narrow gap between the upper and lower sealing jaw serrations, should be adjusted when the jaws are set up and generally left unchanged. Never use clearance to adjust the knife.

3. Clean the Knife and Anvil Slots

Once your seals are set, clean the slots to ensure a stable base for the knife and anvil.

4. Install the Anvil

Install a new anvil with the radiused, working surface facing up. The bottom edges of the anvil will be chamfered, unless your anvils have a radius on both sides.

The height of the anvil should range between the root and the mid-point of the serrations.

Jaws from some manufacturers have deeper slots that require shims to raise the anvil up to this level.

Always replace the anvil along with the knife. A new knife paired with a worn, scored anvil requires excess pressure to cut and will fail prematurely and cause sealing problems.

5. Install the Knife

Before you install the knife, back the adjustment screws out at least halfway. Then insert the knife with the bottom angle facing the screws.

Snug the knife retaining screws lightly. Do not overtighten.

6. Adjust the Knife

A. Using only the two outside screws, over-adjust the knife so that it protrudes slightly from the sealing jaw face.

B. Then back the two outside adjustment screws out from under the knife. The light tension from the set screws should hold the knife in place.

C. Roll the upper and lower jaws together. The anvil will push the knife back into the knife slot so that it is flush and level with the anvil.

D. Now turn the outer adjustment screws inward, using two fingers, until you feel them contact the bottom of the knife. Then turn each outside screw in an additional one-eight of a turn.

E. Insert a single sheet of copy paper between the jaws and roll the jaws together. You should have two short cuts on the outside edges. With small, incremental adjustments to the outside screws, increase the knife height until the small cuts are about one inch, or 25mm, long.

F. Now turn the center adjustment screw in, using two fingers, until you feel it contact the bottom of the knife. Then turn this screw slightly more—less than one-sixteenth of a turn—and run another sheet of copy paper through the jaws.

At this point the knife should either either cut all the way across, or you will lose the cut completely.

If you lose the cut, turn in the outside screws in extremely small increments until the one-inch cuts on the outer edges return.

Then repeat the previous adjustment process with the center screw until you get a clean, smooth cut.

7. Reset Over Adjusted Knives

If the knife is hitting hard, such that you can hear it banging and feel the heavy impact with your hands, it has been over adjusted.

In this case, back out all adjustment screws counterclockwise for one-half a turn and roll the jaws together, using the anvil to once again level the knife.

Then return to step 6D and repeat the knife adjustment process.

If at any time during this process you adjust one side of the knife to get it to cut and it causes the opposite side to stop cutting, do not adjust the opposite side. This indicates that you have over adjusted the knife.

In this case, back out the adjustment screw you last adjusted one-half a turn counterclockwise. Then roll the jaws together, using the anvil to push that side of the knife back in.

On the same side, adjust the knife out in small increments until you get a smooth, clean cut without banging.

8. Lock the Set Screws

And as a final step, once a good cut is achieved, go back and lock the set screws.

Troubleshooting

If your knife fails to cut after following these procedures, you may need to address other conditions on your flow wrapper such as spring pressure adjustments, worn springs, damaged bearings, and damaged sealing jaws or shafts.

To learn more about the full range of adjustments on your flow wrappers and vertical baggers, or to discuss training programs for your packaging team, contact Greener Corporation.

We provide integrated parts and technical service solutions worldwide.

The post How to Adjust Knives with Adjustment Screws on Flow Wrappers appeared first on Greener Corporation.

Align Flow Wrapper Packaging Processes on the Centerline

Michael Wojtech — Wed, 18 Jun 2025 09:34:35 +0000

A Tech Bite from Greener Technical Service Specialist Jeff Fouche

As product moves along the infeed and through your flow wrapper, each packaging process should accurately align on the centerline. This Greener Tech Bite explains how to detect and fix even small, seemingly insignificant misalignment of flow wrapper packaging processes that degrade package quality and delay production.

Symptoms of Misalignment

Symptoms of centerline misalignment include loosely wrapped packages, uneven fin seals that easily pull free from the fin wheels, and package wrinkles and pleats that cause sealing problems.

Assess Your Alignment

1. Align the Product Feed

First, make sure the product infeed is inline with your wrapper. Infeeds often get moved out of position and deliver the product at an angle, causing a number of chronic problems.

2. Center the Forming Box

Forming box adjustments can often be improved, especially if they have been moved off-center to compensate for product entering the wrapper at an angle. Ensure that the forming box is level, centered, and aligned with the product feed.

The packaging material tube should form evenly around the product, without wrinkles or gaps, and should help maintain the inline spacing between products to prevent them from interfering with the cutting and sealing process.

3. Center the Fin Wheels

Also make sure each pair of fin wheels is on the centerline.

Misaligned fin wheels create loosely wrapped, wrinkled packages that are more difficult to cut and seal.

4. Center the Sealing Jaws

On some flow wrappers the shafts have multiple mounting hole options. Make sure both the upper and lower sealing jaws are installed on center in relation to the package.

5. Center the Packaging Material Roll

Now check the packaging material roll and align it on center. The material may have been mounted off center to compensate for misalignments in other areas of the packaging process.

Once the first four processes and the packaging material roll are centered, the edges of the fin seal should meet evenly and create a clean, parallel edge.

6. Center the Product Rails

With the material on the center line, you can center the product rails so that they guide the product correctly into the forming box.

Remember to align flow wrapper packaging processes on the centerline as part of your preventative maintenance program and to resolve packaging problems.

If you have questions about preventative maintenance or packaging problems on your flow wrappers or vertical baggers, contact Greener Corporation. We provide integrated parts and technical service solutions worldwide.

The post Align Flow Wrapper Packaging Processes on the Centerline appeared first on Greener Corporation.