Combating Wire Marking in Paper Production

Wire marking—those unwanted impressions left by the forming fabric (or "wire")—can sabotage sheet quality, increase rejects, and inflate costs. While the core issue often stems from the fabric itself, here we’re zeroing in on how Paper Makers, can take charge and keep production top-notch and also what Fabric Manufacturers do to reduce wire marking.

How to Combat Wire Marking from Paper Makers End:

1. Uneven Wire Surface or Wear: Worn or uneven wire weaves transfer patterns to the paper. Inspect your wire regularly using wear profile analysis and replace it promptly when wear is detected to ensure a smooth, consistent surface.

2. Residue Buildup on Wire: Sticky pulp or contaminants cause localized marks. Upgrade to high-pressure micro-travel showers or cutting-edge cleaning systems to keep your wire sparkling clean.

3. Inconsistent Pulp Properties: Abrasive or uneven pulp worsens marking. Monitor and fine-tune pulp quality to ensure consistency and minimize abrasive effects.

4. Localised Wear from Misalignment: Any localised wear band due to misalignment or uneven surfaces of moving or stationary elements (e.g., rolls or suction boxes) may cause impressions that reflect on the paper. Conduct routine machine audits to ensure proper alignment and surface condition of all components.

5. Very High Vacuum Levels: Excessive vacuum can intensify wire marking by increasing pressure on the sheet. Optimize vacuum settings to balance dewatering efficiency with minimal marking risk.

6. Worn or Poorly Designed Wire Seams: Degraded seams mark the sheet. Team up with wire suppliers to select tough, low-profile seams tailored to your machine.

Strategy for Forming Fabric Manufacturers:

Wire marking, where unwanted patterns transfer to the paper sheet, is primarily a fabric-related issue that originates at the manufacturing level.

 Why Fabric Marking Happens ? Some reasons and solutions-

1. Weave Pattern: While the top surface of Forming Fabrics, especially SSB (sheet support binder) designs, is smooth, the bottom side’s longer float weave pattern—used to enhance fabric life—often causes marking on the paper. Generally people check only the top surface for wire marking, but the bottom side impression of longer float twill mark is the main reason for wire marking. It was observed that instead of straight twill, broken twill reduces the wire marking considerably.

2. High Bottom Weft Diameter: To increase fabric life, manufacturers often use larger-diameter bottom weft yarns, which can imprint patterns on the paper surface, for same reason as explained above.

3. Weaving and Heat Setting: Uneven tension during warping, weaving, or heat setting—particularly insufficient width-wise (CD) tension during heat setting—can exacerbate marking tendencies. Apply higher, controlled CD tension during heat setting to enhance fabric stability and reduce marking potential.

4. Top Monoplanity: Higher top surface monoplanity (plane difference between top warp and weft knuckles) contributes to marking. Monitor and minimize top monoplanity by controlled weaving and heat setting tension, as explained in point no 3.

5. Top Surface grinding: After applying all the above procedures, if still some customers face wire marking, implement top surface grinding during finishing to enhance smoothness, particularly for sensitive applications.

By addressing these manufacturing factors, you can produce fabrics that minimise marking and boost customer satisfaction.

Have tips or strategies for tackling wire marking? Share them in the comments!

For more insights, visit www.pmccentre.com for tailored solutions.