A hydraulic headbox installed on a modern tissue machine is designed to deliver a uniform, low consistency stock stream to the nip between the two forming fabrics. Several geometries of the stock jet, including jet length, jet angle, and jet impingement, have a large effect on sheet formation and sheet quality. This module covers some common headbox adjustments and other equipment settings that can affect the stock jet geometry.
Learning Objectives
- Describe the purpose of the headbox in the tissue making process
- Define the terms "jet length," "jet angle," and "jet impingement"
- Identify the jet length, jet angle, and jet impingement in a stock jet diagram
- Describe the impact of stock jet geometry and sheet formation on the appearance and strength properties of the sheet
- Describe the effects of the slice opening and fan pump speed on stock jet geometry