A hydraulic headbox is designed to deliver a uniform, low consistency stock stream to the Fourdrinier wire. It is important to monitor the geometry of the stock jet because it greatly impacts the appearance and performance of the sheet. Only by understanding the variables that affect the stock jet, and how the jet geometry affects sheet properties, can one begin to make adjustments to the headbox to optimize sheet quality.
•Describe the purpose of the headbox in the papermaking process
•Define the terms "hydraulic," "jet impingement angle," "jet landing point," "sheet formation," "jet-to-wire ratio," and "rush/drag"
•Describe the impact of stock jet geometry and sheet formation on the appearance and strength properties of the sheet
•Identify and describe common headbox adjustments and settings that affect the stock jet geometry
•Describe the effects of the slice opening and fan pump speed on stock jet geometry
