Industry News

Ceramic anilox rollers and laser engraving rollers are widely used in flexographic printing of products such as coffee paper cups, salad paper bowls, pet food paper bags, and PVC/PET bottle labels. Although their names are similar, they are actually quite different. Choosing the wrong roller can lead to serious consequences such as scrap rolls and production line stoppages on products like drinking water bottle labels, disposable isolation gowns, and disposable cotton face tissues. This article will analyze the working principles of ceramic anilox rollers and laser engraving rollers, as well as common flexographic printing problems.

Flexo Printing Machine for Cupcake Paper Cups

Working Principle

To most people, ceramics is a material, and laser technology is a process. But in reality, they represent two different generations of technology and application logics.

Ceramic Anilox Roller

Early anilox rollers were indeed mostly coated with metals such as chromium carbide, but later evolved to ceramic oxide. The surface of a ceramic anilox roller is a ceramic layer, which is hard and wear-resistant. However, many years ago, due to limitations in engraving techniques, the cell shapes were mostly simple square or hexagonal pyramids.

Ceramic anilox rollers can be used in flexo printers. They have large cell volumes, but ink release is generally average. The ink tends to clog at the bottom of the cells, resulting in an actual transfer volume lower than the theoretical value. Furthermore, because the cell walls are relatively wide, the fineness of flexographic printing or coating is limited.

It is suitable for primer or protective coating applications where high coating uniformity is not required, and where high coating volume and high viscosity are desired.

Laser Engraving Ceramic Roller

The laser engraving rollers currently on the market typically refer to rollers that use high-power lasers to engrave complex mesh structures on ceramic layers. Their surface is also ceramic. Laser engraving rollers utilize the precise ablation of the laser beam to create honeycomb-like, spiral channels, and even uniquely shaped meshes. They have extremely narrow mesh walls and a very high mesh opening rate. Their special mesh angles make it easier for the slurry to be scraped out by the doctor blade, easily achieving a transfer rate exceeding 90% and ensuring thorough material release. The depth and volume of each mesh cell are almost perfectly uniform.

Flexo Press for Candy Paper Bags

Frequently Asked Questions

Common problems include regular horizontal streaks in the coating, insufficient and fluctuating coating amount, and splattering during high-speed operation. These will be analyzed one by one and solutions will be proposed below.

Regular Horizontal Lines

Horizontal stripes refer to periodic stripes of varying thickness along the tape feed direction, with a fixed spacing. We can determine this by measuring the stripe spacing and calculating whether it equals the roller circumference or is a multiple of the cell pitch.

If it's a traditional low-line-count ceramic roller, the mesh walls may be too wide, causing slurry to accumulate at the mesh walls, creating a "rib effect" on products like non-woven wipes, pill bottle labels, and chocolate bar paper boxes.

If it's a laser-engraved roller, the problem might be due to micro-cracks generated during laser engraving or chipping at the cell edges during use.

We can try reducing the slurry viscosity, increasing the leveling time, or immediately switching to a high-line-count laser-engraved honeycomb cell roller to improve the situation.

Flexographic Printer for Diaper Outer Wrap Films

Small and Fluctuating Coating Amount

Insufficient and fluctuating coating weight manifests as a set gap but the actual dry weight failing to reach the desired level; or a significant weight difference between the beginning and end of the same roll. In this case, we can check for cell blockage. If severe blockage is confirmed and cleaning is ineffective, it indicates that the cell structure of the roller is unsuitable for the current slurry system. In this situation, it should be promptly replaced with a laser-engraved roller optimized for high-solids slurries to prevent coating problems in products such as rice paper bowls, medical packaging sterilization bags, and foil fried noodles food packaging film rolls.

Flexographic Printing Machine for Animal Food Packaging Bags

High-Speed Splattering

High-speed splattering refers to the uneven edges of coatings on products like rice packaging bags, perfume cosmetics bottle labels, and breathable soft-surface baby nappies, often surrounded by a spray of paste, when the speed of machines such as coating machines and label printing machines increases. Manufacturers of adult diaper back sheets and ice cream paper cups attribute this to centrifugal force.

If the cells of a traditional roller are too deep, the paste inside is thrown out before even contacting the substrate due to centrifugal force during high-speed rotation.

Laser engraving technology can precisely control shallow cells, greatly reducing the amount of paste retained in the cells while ensuring sufficient coating coverage, thus suppressing splattering.

Flexo Printing Machinery for Ice Cream Paper Bowls

Ceramic anilox rollers and laser engraving rollers may look very similar on a flexographic machine, but their working principles, common problems, and solutions differ significantly. A thorough understanding and proper application of these rollers can help manufacturers of hamburger paper boxes, paper toothpaste boxes, adult baby diapers, and other similar products improve product quality and enhance brand benefits.