Where fiber settles—and performance takes shape
The wire section of the paper machine is where the slurry becomes a sheet. This moment—mere seconds after the headbox—defines uniformity, strength, and runnability across every ton of product. We walked the wet end with operators at a high-speed SBS board mill to better understand how fiber settles, drains, and forms the base of everything that follows.
What Happens at the Wire?
The wire section uses:
Headbox pressure and slice opening to control jet speed
Forming fabric to support fiber drainage
Vacuum boxes to remove water
Shake and table rolls to help orient fibers
Why It’s Critical
Poor formation at the wire = flaws downstream:
Cloudy coatings
Weak MD/CD tensile ratios
Print mottle and uneven caliper
Warp or curl on drying
Real-time sensors track fiber distribution, drainage rate, and basis weight variation across the web.
What We Saw
One operator used a formation sensor linked to a cross-direction scanner. A spike in uneven fiber density led to a headbox flow adjustment within 60 seconds—preventing a run of uneven rolls.
What to Ask Your Mill
Do you use real-time formation scanners?
How is formation consistency monitored?
Are MD/CD tensile ratios validated by grade?
Can formation data be linked to reel numbers?
Formation Is Foundation
Sheet formation is invisible on a spec sheet—but visible on a press. And for high-spec grades, it’s the difference between premium and problematic.
