Microscopical analysis to facilitate problem solving in the paper industry

Walter J. Rantanen

Technical Leader, Fiber Science

Appleton, WI

I. Fiber Defect

II. Sheet Defect

III. Machine Damage

• SWBK 66 47 • HWBK 254 151

• SWM 1 -Control Area

• SWBK 73 108

• HWBK 144 162Translucent

• SWBK 164 135

• HWBK 247 193

Clumped Area

• SWBK 45-47%

• HWBK 53-55%Control

• SWBK 58-60%

• HWBK 40-42%Defect

Damage to corrugation roll (severe)

Fiber clinging to corrugation roll flutes

Much of this fiber is in area of flute damage

Except for very slight improvement in Caliper & Basis Weight, no correlation for problem

Basis Weight, Caliper, Absorbency

Peel test (Did not easily release particles)

Sticky spots in Paper?

High Density spots in Paper?

Paper Medium flute fracture?

Paper Medium

U

W

Y

P

Problem

Yes

Yes

No

No

Observations

Large block-like Shives Present

Shive & particulate debris

Uniform Looking numerous Shives

Uniform Looking numerous Shives

Examination of Shive

Foil application with H2O

Some protrusion creation but not a clear cause

Rapid wetting did not release fiber

Chunks of fiber or resin clumps causing the

damage by getting lodged in the flute roof and

problem compounds with each revolution

Not accepted that fiber or hard shives could cause problem

Believe a harder particle is doing damage

Large size of shives, larger hard particles are a possibility

Running over a million feet of medium before the problem noticed

Proposal to attempt quantification of shive and/or large

particles

Use pulp lab equipment for

processing large sheets

Y 4x objective

Y 4x objective

P 4x objective

W 4x objective

W 4x objective

U 4x objective

U Stone-like 4x objective

U 4x objective Quartz Cross Polars

U 10x objective Glass

U 10x objective Glass Cross Polars

U 4x objective Resin Clump

Quartz

Glass

Big Polymer Pieces

Small Pebbles