Concora Crush Tester

The Concora Crush Tester performs a series of tests to determine the rigidity and crush resistance of corrugated material. It is used in conjunction with the Concora Liner Tester.

The first test measures the flat crushing resistance of a laboratory-fluted corrugated material. The second test determines the edgewise strength, parallel to the flutes, of a short column of single-, double-, or triple-wall corrugated fiberboard. The third test evaluates the ability of corrugated material to contribute to the compression strength of a corrugated box by measuring the edgewise compression strength of a laboratory-fluted strip of corrugated material in a direction parallel to the fluted tips.

Test 1: Flat crush of corrugated medium

Equipment for Testing

Procedure

Cut a .5" x 6.0" test sample. The 6.0" dimension shall be in the machine direction of the medium. The sample should be conditioned according to TAPPI T 402. Samples should be used immediately after fluting and applying tape.

Run the test sample through the fluting operation. Place the comb over the fluted specimen so that it is held firmly in the flutes of the rack. Carefully turn the rack over, so as not to damage the specimen and apply double-sided tape to the exposed flute tips and stroke down carefully. Remove the prepared specimen from the comb and place it, flutes up, onto the lower platen of the Concora Crush Tester and test it for flat crush, applying force at the prescribed rate.

Test 2: Edgewise compression strength (short column test)
(TAPPI Test Method T 811-om-88)
Equipment for Testing
Concora Crush Tester

Procedure

Cut 10 representative samples from material selected in accordance with TAPPI T 400. Use a circular saw or other cutting device to cut clean and parallel edges. Cut all samples 2.0" in width with a height of 1.25" for B-flute samples, 1.5" in height for C-flute samples and 2.0" in height for A-flute samples.

Dip the loading edge (long edge) into molten paraffin to a depth of ¼" and hold in the paraffin until it begins to migrate (determined visually) above the ¼" mark. Normally a 3-second dip in 156°-165°F is satisfactory. Immediately after dipping blot the edges on heated paper toweling which has been warmed to 171°-180°F. Condition the sample prior to use according to TAPPI T 402 standards.

Place the sample, paraffin edge down, on the Concora Crush Tester platen, using metal guide blocks on each side of the sample to hold it perpendicular to the platen. Apply compression force to the sample until 5-15 lbs. of pressure is applied to the sample. Remove the guide blocks, and continue the same rate of pressure until the sample fails.

Test 3: Fluted edge crush
(TAPPI Useful Method 801)
Equipment for Testing

Procedure

Cut 10 representative .5" x 6.0" test samples. The 6.0" dimension shall be in the machine direction of the medium. The sample should be conditioned according to TAPPI 402.

Run the test sample through the fluting operation. As soon as possible (6-8 seconds) insert the fluted sample into the Concora Liner Tester.

Place the Liner Tester with sample into the Concora Crush Tester and apply the load to the specimen until a maximum pressure is reached.