Different quality of paper has different strength and hardness, for marble， bricks， fruits, and some other heavy-duty products， we have to use strong edge boards and angle boards.
Most people use 18-22bf of paper to produce a corner board edge protector, sometimes, the clients need us to test the strength and hardness before we send samples.
How shall we test the strength and hardness of edge protectors? In China, there is a standard of edge boards, it shows the dimension tolerance, weight, moisture content, and strengths. We have instruments for testing it. Normally we checked the vertical pressing and horizontal pressing strength.
After testing, we can print the graph of different samples， we usually test 5 pieces at least and take the average data. If the testing result couldn’t meet the client’s requirements, then we can change the better quality of glue and paper to improve the strength.