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Top 5 Mistakes to Avoid During Edge Crush Testing

Top 5 Mistakes to Avoid During Edge Crush Testing

21-Jul-2025

Presto Instruments

Edge Crush Testing (ECT) is an important quality control test conducted to determine the strength and durability of corrugated cardboard, particularly for packaging purposes. Unfortunately, most manufacturers and testers unwittingly commit the same mistake throughout the ECT, resulting in incorrect readings and substandard product quality. 

Such errors can lead to non-performing packaging, higher damage levels during transport, and customer dissatisfaction. The good news is that all these problems are preventable. Through recognizing the main errors and adopting best practices, manufacturers can guarantee more consistent test results and stay within industry standards.   

A basic understanding of edge crush testing  

Edge crush Tester (ECT) is used as the quality control that determines the edgewise compressive strength of the corrugated board. It evaluates how much force a product of corrugated material bears when pressure is applied to its edge, which is crucial for stacking strength. This test is essential in evaluating the stacking strength of boxes, particularly in shipping and storage conditions. 

How to perform edge crush testing

Edge Crush Testing is a standard procedure for evaluating the stacking stability and strength of corrugated cardboard and comparable packaging materials. The test indicates the compressive load to which a material can be subjected along its edges before buckling or collapsing. 

The ECT value, normally measured in pounds per inch or kilonewtons per meter, indicates resistance to edge compression and is one of the most important measures of a box's structural integrity under transport and storage conditions. These are the steps in performing edge crush testing, briefly: 

  • Specimen preparation: A specimen is cut to precise dimensions and conditioned.
  • Placement in the testing machine: The Specimen is vertically placed between the platens of a testing machine.
  • Load application: Compressive load is applied until buckling.
  • Measurement and recording: Maximum force is measured as the ECT value.
  • Analysis and interpretation: The ECT value is utilized to determine material strength.

Mistakes to Avoid During Edge Crush Testing

During edge crush testing, the most common mistakes that need to be avoided are: Incorrect sample preparation, misalignment of the specimen, ignoring environmental conditions, using uncalibrated equipment, and more. Here are the top 5 mistakes described along with the solution:  

Mistake 1 - Incorrect Sample Preparation 

The most common mistake made with edge crush testing is testing specimen preparation. If the corrugated board specimen is not cut to size, has ragged or uneven edges, or is not perpendicular, the results of the test can be severely diminished. 

An improperly cut sample will not transfer the load evenly along its edge, and your crush strength measurements will be lower or inconsistent. This not only impacts test reliability but may also result in non-compliance with applicable standards such as TAPPI or ISO.

How to Avoid -  Always cut with a precision cutter specifically for use in edge crush testing to achieve clean, straight cuts. Make certain the specimen sizes precisely adhere to the standard (usually 25mm x 100mm). Inspect each sample with a square to ensure exact right angles. Handle carefully to prevent edge damage. Training staff and using calibrated equipment will also reduce error at this point. 

Mistake 2 - Misalignment of the Specimen during Testing 

Misalignment upon the placement of the specimen in the test machine is a critical problem. If the board is slightly off in its vertical position or not centered on the platen, the applied force will not be similarly distributed. This will cause bending or tilting, leading to premature buckling of the board and recording a spuriously low edge crush value.

This type of erroneous reading has the potential to impact packaging design and product safety during shipping.

How to Avoid - Utilize alignment guides that hold the specimen vertically and centered over the platen. Many testing machines have positioning fixtures built into them—always utilize them if possible. Educate technicians to thoroughly check alignment for each test, and promote repeat testing to establish accuracy.  

Mistake 3 - Ignoring Environmental Conditions 

Edge crush testing is temperature and humidity-sensitive. Corrugated board can pick up moisture from the air, weakening its structure and its compressive strength. Test results under uncontrolled or changing conditions can be non-comparable or inconsistent. This led to inaccurate quality assessments and unreliable packaging performance during storage and transport.

How to Avoid - Condition all test samples in a controlled environment (usually 23°C and 50% RH) for a minimum of 24 hours before testing, according to ISO or TAPPI requirements. Perform the test in a temperature- and humidity-controlled laboratory to reduce variability. Document environmental parameters with each test result to maintain traceability and consistency.

Mistake 4 - Using Uncalibrated Equipment 

Testing equipment not recently calibrated or worn out can generate misleading results. For instance, if the platens are damaged or uneven, or if the load cell is not calibrated, then the force applied may not be the true edge crush strength. Continued minor deviations can, over time, cause significant inaccuracy.

How to Avoid - Make regular equipment calibration and maintenance according to the manufacturer's schedule. Check the platens for wear, cleanliness, and alignment prior to each batch of tests. Replace or repair damaged components in a timely manner. Have a calibration log and verify the machine's load cell with traceable standards.

Mistake 5 - Not Following a Standardized Test Method 

Failure to use standardized test procedures (such as TAPPI T-839 or ISO 3037) may result in non-consistent approaches and invalid comparisons. Technicians may alter compression speed or skip sample conditioning in certain labs. This results in non-compliant data that cannot be benchmarked or verified in testing. 

How to Avoid - Comply strictly with established standards and have all employees trained in those particular procedures. Utilize standards-compliant settings for compression rate, sample conditioning, and equipment configuration. Record all details of the test process, including deviations, and conduct regular audits to maintain standardization throughout.

How Presto Instrument edge crush tester helps in testing 

Presto Instrument edge crush tester enables manufacturers to certify that their packaging is strong enough to endure vertical pressure while stacking and transportation, minimizing damage risk. With accurate results, easy-to-use features, and testing consistency with international standards, our edge crush tester not only enhances product quality but also customer confidence.

Through the removal of guesswork and inconsistencies in packaging strength, this machine is very important in quality control, maximizing performance, and guaranteeing the strength of packaging material.

Presto Instruments is a leading Edge crush Tester Manufacturer in Indonesia, committed to global quality standards. Our equipment is designed to improve product reliability, reduce defects, and ensure consistent performance. Trusted by industries worldwide, we offer reliable and customized solutions to meet your testing needs. Contact us today.

 

 

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