What jobs does the headbox perform in a Fourdrinier paper machine?

In a Fourdrinier machine, the headbox serves as a critical component responsible for the uniform distribution of wet paper stock onto the moving wire screen. Its primary functions include:1

• Flow Regulation: It maintains a continuous flow of stock at constant velocities, ensuring that equal quantities of properly dispersed fibers are supplied across the entire width and length of the sheet-forming surface.1
• Dispersion and Metering: By utilizing internal baffles and a knife slice, the headbox improves fiber dispersion and meters the flow to ensure the resulting paper sheet has a uniform weight.1
• Jet Formation: In modern, enclosed, and pressurized headboxes, the design is optimized to develop a precise jet of liquid stock onto the moving wire to accommodate high-speed production.1

Essentially, the headbox acts as the initial control point that determines the consistency and quality of the paper sheet before the drainage and formation processes begin on the Fourdrinier table.1