Optimize Packaging Strength with the Right Edge Crush Test Formula & Methods

In today's dynamic logistics and e-commerce environment, ensuring the safety and integrity of the flow of product is extremely important.

So, what is an Edge Crush Test?

This is the standard test that measures a corrugated cardboard's performance under pressure. In simplified terms, it's the amount of force that a piece can withstand along its edge (along the flutes) before it buckles or crushes. This value, conventionally expressed in pounds per lineal inch (PLI) or kilonewtons per meter (kN/m), is directly related to the stacking strength of a corrugated box. The higher value of ECT signifies stronger material and thus can bear more weight without collapse. This is an important measurement, especially for companies shipping their products stacked.

Who benefits from a robust edge crush test?

In fact, any industry that uses corrugated packaging will benefit from a comprehensive understanding and application of ECT. From manufacturers to distributors and e-commerce companies, the integrity of their boxes is paramount. That same packaging engineer for a large electronics company may holistically use the edge crush test unit to specify exactly what board grab to use with new product launches and protect delicate components. If it's a food and beverage company shipping around heavy canned goods, they would have a much greater focus on the ECT value to avoid crushing during transportation and storage. The bottom line is: if you are concerned about product protection, reductions in the costs of damaged products, and sustainability factors in packaging, you will likely be very tuned into the ECT value.

How is the Edge Crush Test performed?

ECT does require special equipment, primarily an edge crush tester machine. The general method for testing involves accurately cutting a sample of corrugated board, usually to a 2-inch x 1.1-inch size, and then placing the sample vertically between the platens of the tester. The machine applies a continuously increasing compressive force in a direction that results in buckling of the sample. The peak force recorded at the time of buckling is the ECT value.

There are a few main ways in which ECT is performed, and each has slightly different preparation:

Wax Edge Test: Wax is applied to the edges of the specimen to prevent "edge effects." That is to say, raw edges from a board can, and will, absorb moisture and weaken, thus yielding an artificially low ECT reading. This method is used for a more accurate representation of internal compressive strength of the board.
Unwaxed Edge Test: This test is easier since the edges are not waxed. It is quicker but sometimes gives values which are slightly lower because of possible edge damage during the preparation of the sample or absorption of moisture.
Also of significance is the orientation of the flutes in relation to the compression force. A long-standing edge crush tester manufacturer will design machines capable of handling different flute types accurately.

Importance of the Edge Crush Test Standard

It is important, especially for international supply chains, that businesses can specify packaging requirements for products that will be universally understood and met.

Calculating Box Compression Strength with the Edge Crush Test Formula

While the ECT value does tell you the strength of the board itself in many instances, it becomes necessary to predict the stacking strength of a finished box. This is where the edge crush test calculator fits in, often using the McKee formula:

BCT = K * ECT * √ (t * Px * Py)

Where:

BCT = Box Compression Test: predicted stacking strength of the box
K = Empirical constant (varies with flute type, board type and test conditions)
ECT = Edge Crush Test value of the corrugated board
t = Board thickness
Px = Perimeter of the box (2 * Length + 2 * Width)
Py = Circumference of the box (2 * Depth + 2 * Width) 

Using this equation, the online edge crush test calculator will help the packaging designer to correctly estimate how much weight a box can bear in case of stacking in warehouses or during shipment. This foresight is invaluable to avoid product damage and optimize space.

How to Get the Right Edge Crush Tester Manufacturer

First things first, investing in an edge crush tester machine requires choosing the right reputed edge crush tester manufacturer. These are some of the things that you should look for in a manufacturer.

Accuracy and precision: The high-quality machines will give you consistent and repeatable results.
Compliance to Standards: The machine will be manufactured to meet all the applicable ASTM, TAPPI, or ISO standards.
Ease of Use: An intuitive interface will facilitate the operation and thus efficiency in testing.
Durability and Longevity: The machine should be manufactured in such a way that it can sustain the working conditions of an industrial setting.
Technical Support and Calibration Services: Access to continuing technical information and calibration services is very important in assuring the accuracy of the equipment. In conclusion, the Edge Crush Test is much more than a simple technical measure; it is meant to be a valuable resource that aspires to enhance strength in packaging, minimizes the amount of packaging wasted, and protects your products.
Knowing the formula for an Edge Crush Test, getting samples from respected established laboratory-based practices, and using good quality equipment, stands to equip each business with better and more informed decisions toward improved packaging that is stronger, more efficient, and cost-effective.
Optimize packaging strength with the right Edge Crush Test formula and methods for reliable, durable corrugated boxes. If you’re looking to improve load-bearing performance, accurate ECT evaluation is essential. For expert testing instruments and support, contact +91 9210 903 903 or email info@prestogroup.com.