Slitter Blade Selection Guide: Materials, Wear and Replacement Intervals

The choice of slitter blade directly affects cutting quality, production efficiency and cost control. Here's a detailed guide on material selection, wear judgment and replacement intervals:

First, the blade material selection

1. Common materials and applicable scenarios

◦ High Speed Steel (HSS)

▪ Features: Good wear resistance, high toughness, moderate price.

▪ Application: Paper, film, soft metal (such as aluminum foil), nonwovens and other medium-hardness materials.

◦ Tungsten carbide (tungsten steel)

▪ Features: high hardness (HRC90+), strong wear resistance, but brittleness.

▪ Application: high-precision slitting (such as lithium battery pole piece, copper foil), carbon fiber, high-density plastic and other hard materials.

◦ Ceramic blades

▪ Features: Super hard and wear-resistant, high temperature resistant, but easy to chip.

▪ Application: Scenarios with high abrasion resistance requirements (such as glass fiber, silicone tape), but impact cutting needs to be avoided.

◦ Coated inserts (e.g. TiN, DLC coatings)

▪ Features: The surface hardness is improved, the friction coefficient is reduced, and the life is extended by 30%-50%.

▪ Application: Materials with high cleanliness requirements (such as optical films, medical composite materials).

2. Key points of material selection

◦ Hardness of the matching material: The hardness of the blade should be higher than that of the material being cut (usually HRC difference ≥ 20).

◦ Consider toughness requirements: Choose high-speed steel with good toughness for cutting materials that are easily deformable (such as elastic film).

◦ Corrosion resistance: Stainless steel substrates or coated blades are recommended for wet cutting or corrosive environments (e.g., seafood package slitting).

Second, wear judgment and monitoring

1. Common types of wear

◦ Edge passivation: The cutting resistance increases, and the burrs at the edge of the material increase.

◦ Chipping/Cracking: Localized chipping of the blade, resulting in periodic scratches on the slitting surface.

◦ Adhesion wear: Material debris adheres to the cutting edge (commonly found in plastics, tapes), affecting the cut finish.

◦ Corrosion and wear: Rust or chemical spots appear on the blade's surface.

2. Detection method

◦ Visual inspection: Use a magnifying glass to observe whether the cutting edge is smooth and free of defects.

◦ Touch test: Touch the edge of the edge with your finger (pay attention to safety) and feel whether there is a significant unevenness.

◦ Cutting quality analysis: Regularly check the edge burr rate, width tolerance and other indicators of the slitted product.

◦ Equipment monitoring: Early warning by slitting machine power fluctuations (power rise after wear) or acoustic emission sensors.

Third, replacement cycle reference

1. General Advice

◦ Ordinary materials (such as paper, PP film): Inspect every 8-12 hours, replace every 3-60,000 meters.

◦ High wear materials (such as fiberglass, metal foil): Inspect every 2-4 hours, replace every 0.5-20,000 meters.

◦ High-precision scenes (e.g., optical film): mandatory replacement every 1-20,000 meters, even if there is no obvious wear.

2. Tips for prolonging life

◦ Regular flipping use: The double-edged blade can be turned over 1-2 times to equalize the wear.

◦ Proper Installation: Ensure the blade is parallel to the bottom roller to avoid biased grinding.

◦ Cleaning and maintenance: Alcohol is used to remove blade adhesions after each shutdown to prevent corrosion.

◦ Phased use: The new insert is prioritized for high-precision products, and after wear, it is downgraded to handle rough cutting tasks.

Fourth, blade management suggestions

1. Establish a file: Record the material, usage time, cutting mileage and reason for replacement of each knife.

2. Spare parts inventory: Reserve 10%-15% of redundant blades based on historical data to avoid emergency downtime.

3. Supplier Collaboration: Collaborate with manufacturers to repair blades (such as regrinding, recoating) to reduce costs by 30%-60%.

Example scenario:

• Lithium battery separator slitting: select carbide coated blades, check the cutting edge every 4 hours, and replace every 50,000 meters.

• Corrugated cardboard slitting: high-speed steel blades, inspected every shift, re-ground 2-3 times after wear and then scrapped.

Through scientific material selection and refined management, the slitting efficiency can be significantly improved and the average cost per ton can be reduced.