Operation before forming fabric installation and subsequent debugging

The forming fabric, also known as the paper machine dewatering fabric, is a key consumable item on the papermaking machine. Proper use can improve paper quality, production efficiency and operating costs. The following will explain how to better use the forming fabric, including usage precautions and maintenance.

What Should You Pay Attention to before Installing the Forming Fabric?

(1) When unpacking and inspecting the forming fabric, be careful not to scratch the net with sharp tools such as knives, check the information (whether the net number and specifications are consistent with the requirements), and check whether there are obvious defects, stains or creases on the net surface.

(2) When installing the forming fabric, ensure that the installation area is clean and tidy, sweep the floor and avoid hard objects on the equipment to prevent wear and tear on the net surface. When hoisting, it is recommended to use a wide and soft lifting belt (do not use wire rope) for balanced lifting to prevent deformation and damage caused by local force on the forming fabric.
(3) When unfolding, be steady. Lay the forming fabric flat on the ground or on a special support to ensure it stretches naturally. Do not pull or twist it forcibly. Confirm the running direction of the mesh (marked with the running arrow) to ensure correct installation. Slowly and steadily put the forming fabric into the paper machine to ensure that the mesh does not get caught or bumped and can pass smoothly through various rollers, water suction boxes and other components. Use a mesh guide to prevent the forming fabric from running off.

How Should the Forming Fabric be Debugged after Installation?

After installing the forming fabric, start it at a low speed. After starting the paper machine, slowly and evenly tighten the fabric. Initial tension should be minimal. Follow the recommended values provided by the equipment manufacturer or fabric supplier. Excessive tension shortens fabric life and increases operating load. Correct deviation promptly. During low-speed operation, closely observe the fabric’s trajectory and use the correction roller to make fine adjustments to ensure the forming fabric remains centered and stable. Adjust the corrector roller in small, gradual steps, avoiding sudden adjustments that could cause wrinkles. Pay attention to the vacuum level in the vacuum box, adjusting it gradually from low to high to ensure uniform dewatering and avoid severe localized wear on the fabric surface. Inspect the dewatering components to ensure the chopping board and vacuum box panels are flat, smooth, and free of wear and grooves.

Maintenance of the Forming Fabric in Normal Operation

(1) The forming fabric must be regularly flushed with high-pressure water, especially the contact surface of the mesh (the pulp contact surface) and the running surface in contact with the dewatering element, to remove fibers, fillers, and rubber materials that are blocked in the mesh holes; when flushing, the angle and pressure of the high-pressure water needle should be adjusted to achieve the best cleaning effect without damaging the forming fabric, and chemical cleaning should be performed regularly to dissolve sticky substances that cannot be washed away by water. In addition, foreign matter in the paper material should be handled in time to prevent it from getting stuck between the mesh and the roller and causing the mesh to push or tear.
(2) Maintain appropriate tension. Under the premise of meeting the process requirements, try to use a lower working tension. Excessive tension is the main cause of premature fatigue damage to the forming fabric; the surface of the parts that the mesh contacts (vacuum box, chopping board, roller) should be checked to see if it is flat, burrs, damage or adhesives.
(3) If the machine needs to be stopped, the tension of the forming fabric should be relaxed and the machine should be kept running at a low speed to prevent deformation caused by prolonged stationary position. If the machine is stopped for a long time, the forming fabric should be removed and properly stored after cleaning. (4) Ensure the quality of pulp screening, reduce impurities, pay attention to the addition of fillers and chemical reagents, and avoid the formation of sticky sediments that block the mesh.

Problems that Cause the Forming Fabric to Come off the Machine

(1) Wrinkles: This phenomenon is mostly caused by uneven tension of the forming fabric, improper calibration, roller non-parallelism and local wear. It is recommended to check one by one according to the above.
(2) Increased mesh wear: Check the surface condition of all contact parts. Ensure that the contact surface is smooth when the forming fabric is running.
(3) Mesh blockage: Flush regularly and improve the pulp and chemical system.
(4) Longitudinal tearing: If this happens, stop the machine immediately, find and remove the hard objects stuck in the mesh, and repair the equipment defects.

Observing and paying attention to these matters will help maximize the performance of the forming fabric, significantly extend the life of the mesh, thereby reducing production costs and stabilizing paper quality.