Something has changed in carton sealing. Operations that ran the same tape on the same boxes for years are seeing more failures like lifts, pops, open flaps arriving at the customer's door. The tape hasn't changed. But the boxes have.
The rise of recycled corrugated content has quietly shifted the challenge. Boxes that meet spec on paper perform differently under tape. And when a seal fails in transit rather than at the line, by the time you know about it, the damage is already done.The answer is measurement, not guesswork. IPG's Adhesion Force to Kraft (AF2K) testing program gives operations a way to evaluate seal quality on their actual cartons, with their actual tape, before packages leave the facility.
WHY IT MATTERS
Why Packaging Performance Is Evolving—and What’s Driving the Change
Packaging performance is evolving across distribution and fulfillment environments. Today’s corrugated boxes contain significantly more recycled fiber than they did a decade ago—an important sustainability win that is reshaping the surfaces tape must bond to. This introduces more variation in texture, increased surface roughness, and less uniform adhesion conditions.
At the same time, packaging operations are moving faster, handling greater carton diversity, and operating under increased visibility when issues occur. Seal integrity plays a more critical role than ever, directly impacting product protection, customer experience, and operational efficiency. Understanding the factors influencing seal performance today is the first step toward building more consistent, reliable packaging processes in a rapidly changing environment.
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ROOT CAUSE |
WHAT IT MEANS FOR YOUR LINE |
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Higher recycled content in corrugate |
Rougher, uneven carton surfaces make it harder for tape adhesive to form a strong initial bond, increasing the risk of lifting and peeling. |
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Inconsistent carton surface quality |
Texture variation, coatings, dust, and debris create weak adhesion points even when the right tape is applied correctly. |
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Tape stretching and lifting |
Improper tension or application pressure causes tape to stretch on application, reducing contact area and creating weak points along the seal. |
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Shipping and handling stress |
Bumps, drops, vibration, compression, and shifting during transit expose weak seals that looked fine on the line but fail in the field. |
THE SOLUTION
What Is AF2K Testing and Why Does It Matter?
AF2K stands for Adhesion Force to Kraft. It is a standardized test that measures the force required to break a tape seal on an actual corrugated carton — not a lab sample, not a controlled surface, but the real box your line is sealing right now.
A specialized gauge applies downward force to the sealed flap and records the point of failure. The result is a direct, quantified measurement of how well your tape is bonding to your cartons under your operating conditions. It checks:
- Adhesion strength: How much force the seal can withstand before failing.
- Seal uniformity: Whether adhesion is consistent across the length of the seal or shows weak points.
- Tape stretch: Whether tape is being over-tensioned during application.
- Tape head pressure: Whether the applicator is delivering consistent, adequate contact pressure.
- Surface contact: Whether the tape is fully bonding across the carton surface or leaving gaps.
- Seal durability: How the seal is likely to perform under real shipping conditions.
The critical advantage is timing. AF2K testing happens before packages ship, giving your team the data to identify weak seals and correct the root cause, not just react to failures after the fact.
HOW IT WORKS
AF2K Testing on Your Line: What to Expect
AF2K testing is designed to run directly on your packaging operation, not in a remote lab. IPG's team brings the testing equipment to your facility and evaluates seals on your actual cartons, running through your actual equipment, under normal operating conditions.
The process gives your team the ability to:
- Identify weak adhesion: Pinpoint which carton types, tape applications, or machine settings are producing below-threshold seals.
- Compare closure methods: Run side-by-side comparisons of different tape types, widths, or application settings to see which combination delivers the strongest result on your specific cartons.
- Confirm seal reliability: Validate that your current setup is producing seals strong enough to survive the transit conditions your packages actually face.
- Validate application consistency: Identify whether variability in seal quality is coming from the tape, the machine, the carton surface, or operator technique.
- Reduce in-transit issues: Fix weak seals before packages leave, not after customers report them.
Results are actionable and immediate. Changes to tape selection, machine tension, head pressure, or application technique can be tested and validated in the same session.
WHEN TO USE AF2K
Signs Your Operation Should Run an AF2K Assessment
AF2K testing is most valuable at predictable trigger points. Consider scheduling an assessment when you notice:
- Rising tape failures or customer complaints: If your return or damage rate is climbing, testing identifies whether the problem is the tape, the machine, or the carton.
- A change in box supplier or corrugated spec: A new corrugated source (even with the same dimension and weight spec) may have a different surface that requires tape or tension adjustment.
- New shipping lanes or carrier requirements: Different transit conditions put different stress on seals. What holds for ground shipping may not hold for air freight or long-haul routes.
- Equipment changes or maintenance: After a tape head replacement, machine service, or speed adjustment, AF2K testing confirms the line is still producing compliant seals.
- Seasonal volume increases: Before peak season, testing confirms your setup can maintain seal quality at higher throughput.
- Sustainability initiatives: If you're switching to higher-recycled-content corrugate to meet sustainability targets, AF2K testing ensures your tape specification keeps pace with the change in carton surface.
OPTIMIZING APPLICATION
The ET Xtreme Tape Head: Consistent Application Is Half the Battle
AF2K testing frequently reveals that seal failures aren't caused by the wrong tape, they're caused by inconsistent application. Tape that stretches during application, lifts at the edges, or doesn't fully contact the carton surface will fail regardless of its adhesive rating.
IPG's ET Xtreme tape head is engineered to address the application side of the equation. It applies tape with controlled, consistent pressure, ensuring the adhesive bonds deeply into the corrugated surface on every carton, not just most of them. The ETX reduces tape stretching, prevents lifting and popping, improves seal uniformity, minimizes tape wrinkles, and enhances overall package integrity.
For high-volume operations, the ETX also delivers repeatable, measurable results across the entire production run so quality doesn't drift as the shift progresses or line speed increases. AF2K testing and the ET Xtreme tape head work as a system: test to find the problem, apply to solve it, test again to confirm.
IPG PROGRAMS & PRODUCTS
Tools to Measure, Optimize, and Seal Right
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AF2K Testing, Adhesion Force to Kraft IPG's AF2K testing program evaluates seal quality directly on your cartons, on your line, under real operating conditions. It measures adhesion strength, seal uniformity, tape stretch, head pressure, surface contact, and seal durability — and delivers actionable recommendations to close performance gaps before packages ship. Schedule an assessment with IPG's Packaging Diagnostics team. |
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ET Xtreme Tape Head The ET Xtreme tape head applies tape with consistent, controlled pressure, ensuring deep adhesive contact with the corrugated surface on every carton. It reduces stretching, prevents lifting, improves seal uniformity, and minimizes wrinkles, delivering repeatable, measurable seal quality across high-volume lines. Frequently identified through AF2K testing as the solution to application-driven seal failures. |
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Packaging Diagnostics, Full End-of-Line Assessment AF2K testing is one component of IPG's broader Packaging Diagnostics program, which evaluates your entire end-of-line operation - tape adhesion, case seal integrity, machine efficiency, and more. If tape failures are a symptom, Packaging Diagnostics finds the cause. Schedule a checkup with IPG's machinery support team. |
BOTTOM LINE
Tape Performance Is Measurable. Make It Measured.
Tape failure is not random. It has causes. In the carton surface, the application equipment, the tape specification, or the transit conditions and those causes are findable with the right testing. AF2K testing gives quality control engineers, packaging engineers, and operations directors the data they need to make informed decisions about tape selection and application, not reactive ones after the damage is done.
If your operation is seeing more failures than it used to, or if you have changed your carton supplier, line speed, or box mix, an AF2K assessment is the right starting point. IPG's team can run the test on your line and deliver the recommendations your operation needs to get sealing quality back where it belongs.
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Ready to Find Out How Your Seal Is Really Performing? Download IPG's AF2K eBook or schedule an on-site assessment with IPG's Packaging Diagnostics team. |
