Fiber Furnish Calculator

Design a paper fiber blend from softwood kraft, hardwood kraft, mechanical, and recycled pulp. Predict strength, formation, opacity, freeness, and fiber cost.

Inputs

Softwood kraft (%)

Hardwood kraft (%)

Mechanical pulp (%)

Recycled fiber (%)

Target paper GSM

Tab to move between fields

Results

Tensile index (0-100)

Tear index (0-100)64

Burst index (0-100)67.6

Formation (0-100)69

Opacity index (0-100)53.5

Freeness (CSF ml)500

Fiber cost ($/ton)$610.00

Total input (%)100

Dry Fiber Per (sq m)0.08

How to Use This Calculator

Enter the percentage of each fiber type — softwood kraft, hardwood kraft, mechanical, and recycled (values are auto-normalized to 100%).
Input your target paper weight in GSM.
Review predicted strength indices: Tensile Index, Tear Index, Burst Index.
Check Formation Index and Opacity Index to assess printability.
Use Freeness (CSF ml) and Fiber Cost per Ton to optimize drainage and economics.

How the result changes with Softwood kraft (%)

Softwood kraft (%)	Tensile index (0-100)
10	61.3
35	69.3
65	75
90	78.1

What each input means

Softwood kraft (%): Long-fiber softwood kraft pulp percentage. High strength, good tear resistance.
Hardwood kraft (%): Short-fiber hardwood kraft pulp. Better formation, smoothness, and printability.
Mechanical pulp (%): TMP or groundwood mechanical pulp. High opacity, low cost, lower strength.
Recycled fiber (%): Deinked recycled fiber. Cost-effective but variable quality.
Target paper GSM: Target paper weight in grams per square meter.

What each result means

Tensile index (0-100): Predicted tensile strength index (higher = stronger).
Tear index (0-100): Predicted tear resistance index.
Burst index (0-100): Predicted burst strength index.
Formation (0-100): Sheet formation quality (higher = more uniform).
Opacity index (0-100): Predicted opacity (higher = more opaque).
Freeness (CSF ml): Estimated Canadian Standard Freeness affecting machine drainage.
Fiber cost ($/ton): Estimated fiber raw material cost per ton of paper.
Total input (%): Sum of all fiber percentages (auto-normalized to 100% for calculations).

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Softwood kraft (%) = 30, Hardwood kraft (%) = 40, Mechanical pulp (%) = 0, Recycled fiber (%) = 30 = 5 input(s) provided
Calculate Tensile index
Tensile index = sw * 95 + hw * 65 + mech * 40 + rec * 45
68 = 68
Calculate Tear index
Tear index = sw * 100 + hw * 55 + mech * 45 + rec * 40
64 = 64
Calculate Burst index
Burst index = sw * 90 + hw * 70 + mech * 35 + rec * 42
67.6 = 67.6

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