Guidance for Tooth Profile Selection of Welded Refiner Plates Based on Long/Short Fibers

I. How the tooth profile of refiner plates controls fiber length (core principle)

1. retains long fiber tooth shape (low shear, minimal cutting)

Representative tooth types: Soft fin, curved teeth, wide-groove relief teeth, and large-angle inclined teeth

Relief/long-lasting fiber grinding disc

design feature

1. The tooth surface is curved with dulled edges, exhibiting weak shear force that only rubs along the fibers without causing transverse cutting.
2. The tooth and groove widths are substantial, resulting in gentle slurry retention and a lower specific edge load (SEL).
3. 90° vertical arc-shaped tooth grooves to reduce fiber impact-induced fracture;
4. The partitioning and densification design involves first breaking up the slurry masses before gently agitating them with a broom.

Fiber properties: Fully retains the length of coniferous long fibers, enhances tear resistance and tensile strength, with minimal loss of wet weight.

1. Short fiber tooth type (high shear capacity, strong cutting ability)

Representative tooth types: Cut fin, straight radiating teeth, narrow dense fine teeth, acute serrations

Special grinding disc for cutting short fibers

design feature

1. The straight edge features sharp teeth with small tooth tips, exhibiting extremely strong shear force;
2. The teeth are narrow with fine grooves, and the fibers are repeatedly cut.
3. Parallel straight teeth collide to rapidly sever long fibers;
4. Small-angle teeth enable high-speed frictional cutting of the slurry.

Fiber effect: Significant shortening of long fibers results in shorter fibers, improving paper uniformity and smoothness, but reducing tear strength.

3. Balanced broom-shaped tooth pattern (balancing length and filaments, suitable for cultural paper)

Representative tooth type: Broom fin

Balanced broaching grinding disc

The tooth edges are moderately sharp, primarily designed for crushing and fibrillation, with slight cutting capability, making them suitable for blending long and short fibers.

II. Paper types requiring long fibers (to be used with long-lasting curved/soft-fin grinding pads)

·Long-fiber raw materials: coniferous wood (pine, spruce, 2–5 mm), cotton pulp, hemp pulp, and cowhide pulp

1. High-strength paper for packaging

• Wavy core paper, kraft board, paper bag paper, and heavy packaging paper require: high ring compression strength, tear resistance, anti-tearing properties, long-fiber framework structure, tensile strength, and load-bearing capacity.

2. Industrial Special High-Strength Paper

• Requirements for filter paper, cable paper, insulation paper, cement bag paper, and sandpaper base paper: fold resistance, tensile strength, and low susceptibility to breakage, with toughness provided by intact long fibers.

3. Special Durability Papers

• Banknote paper, archival Xuan paper, oil canvas base paper, non-woven fabric pulp. Requirements: ultra-high tear resistance, aging resistance, and high wet strength.

4. High-end noodle packaging paper and liquid packaging cardboard

The surface layer contains short fibers for smoothness enhancement, while the core layer/basis layer is rich in long fibers to ensure stiffness and structural strength.

III. Paper types requiring short fibers (to be used with Cut Fin straight-tooth cutting blades)

Short fiber raw materials: broad-leaved wood (eucalyptus, poplar, 0.5–2 mm), bamboo pulp, deinking waste paper pulp

1. Print on writing paper

Copy paper, double-coated copper paper, light-coated paper, book and periodical paper, notebook paper. Advantages: tightly interwoven short fibers, smooth surface with excellent uniformity, even ink adhesion, and absence of pinholes.

2. Household Papera

Toilet paper, facial tissue, napkins and pocket tissue Advantages of short fibers: soft and fluffy texture, delicate hand feel, excellent absorbency; a small proportion of long fibers blended in improves wet strength.

3. Thin-sheet specialty paper

Cigarette paper, carbonless copy paper, cellophane, and thin food packaging paper require the following properties: thinness, uniformity, even light transmittance, and absence of paper fibers or cloud spots caused by excessive long fibers.

4. Newsprint and low-grade printed waste pulp paper

The long fibers of waste paper are shortened through cutting to improve uniformity and reduce fiber shedding.

IV. Comparison Summary Table

Table

V. Practical Recommendations for Production Equipment Selection

1. High-strength paper with pure long fibers: Use Soft Fin curved length-preserving grinding discs throughout the process; ensure adequate disc spacing to avoid unnecessary cutting.
2. Pure short-fiber lifestyle paper/Print paper: First-stage coarse grinding disperses pulp lumps; second-stage fine grinding uses a cut-fin mechanism to precisely control fiber length.
3. High-end cardstock produced by blending long and short fibers: the bottom layer uses long fibers with soft fins, while the surface layer employs short fibers with cut fins; the pulp is then graded and pulped accordingly.
4. Advantages of welded stainless steel arc-shaped fiber retention grinding discs: free from casting pores, featuring high precision in vertical arc-shaped teeth, preventing pulp blockage and tooth loss, and maintaining stable fiber length over long periods.