Depending on the grade and end use, different tests are performed to assess the quality of the paper or board being produced on a machine. Physical tests assess physical properties of the sheet, such as density, thickness, and different kinds of strength. Common physical tests include basis weight or grammage, moisture content, caliper, density, bulk, smoothness, porosity, stiffness, tensile strength, burst strength, tear strength, and folding endurance. This module will introduce some common physical tests, followed by a discussion on the importance of sample collection and conditioning, sheet formation, and moisture content.
Learning Objectives
At the end of this module, you will be able to:
- List common criteria used to differentiate between paper and board grades
- List some common paper and board grades
- Describe basis weight testing, including principles and units
- Describe moisture testing, including principles and units
- Describe caliper, density and bulk testing, including principles and units
- Describe smoothness testing, including principles and units
- Describe porosity testing, including principles and units
- Identify the organizations which have established standard testing, sampling, and conditioning procedures
- Explain how sheet formation and moisture content can affect test results
- Describe the importance of standardized sampling techniques and sample conditioning