Flexography - Basic Introduction

Flexography: An Introduction

The video provides an introductory overview of flexography, commonly known as flexo, focusing on its significance in the packaging industry and its growth trends compared to other printing segments.

Evolution of Flexography

• Flexography emerged in 1951 as a renaming of the process based on industry surveys. It is characterized by flexibility in both the plate material and substrates used.

• Recent technological advancements in flexography have led to improvements in screen rulings, LPI, highlight dots, anilox rolls, and inks. These enhancements have increased competition against lithography.

Applications of Flexography

• Flexography is predominantly used for corrugated packaging (cardboard), flexible packaging (bags, pouches), folding cartons, and labels (roll stock).

• The markets served by flexography include food and beverage industries, household products, cosmetics, pharmaceuticals, and consumer packaged goods.

Resources and Education

• Additional resources for learning about flexography include the Flexographic Technical Association (FTA), FIRST specifications document version six from 2017, and job placement websites like Indeed that feature opportunities from National Printing and Packaging Specialists (NPPS).

• Various colleges across the US offer programs with flexo printing presses such as Clemson University, Fox Valley Technical College, Dunwoody College of Technology, Rochester Institute of Technology (RIT), and Ryerson University.

Mechanics of Flexography

This section delves into the mechanics of flexography detailing the basic process involved in this printing technique.

Printing Process

• The process involves a trough containing liquid ink that is transferred by a pickup roller to anilox roller engraved with patterns. A doctor blade scrapes off excess ink before transferring it to a relief plate.

• The anilox roller fills cavities with ink which are then transferred to raised images on the relief plate. Subsequently, ink is directly transferred to substrates like paper or plastic film.

Comparison with Rotary Letterpress

Identifying Flexography

In this section, the speaker discusses how to identify flexography through specific characteristics and plate-making processes.

Characteristics of Flexography

• The most identifiable characteristic of flexography is the presence of a halo ring around the edges of printed material due to ink being squeezed out towards the outer ends.

• Quarter tone dots in flexography are typically paler in the center, providing another identifiable feature.

• Flexographic plates are relief plates with a physical separation between image and non-image areas, usually made from flexible rubber or polymer materials.

Flexo Plate Making and Mounting

This part delves into the process of making flexographic plates and mounting them onto cylinders for printing.

Flexo Plate Making

• Flexo plates can be analog (made with film) or digital (using CTP technology), with popular manufacturers like DuPont and Kodak.

• Anamorphic compensation is required when mounting flexo plates on cylinders to account for elongation, ensuring proper fit for die-cutting images.

Cylinder Mounting and Impressions

• Cylinders used in flexography have variable diameters for different repeat lengths, mounted using double-faced sticky back tape or sleeves to avoid labor-intensive plate mounting.

• Kiss impressions play a crucial role in transferring images efficiently in flexography, minimizing pressure between plate-substrate interactions.

Inks Used in Flexography

This section explores various types of inks utilized in flexographic printing processes.

Types of Inks

• Inks used in flexography can be water-based (requiring pH considerations), solvent-based (containing VOCs), or UV-cured (popular for narrow web presses).

• Viscosity testing using a zahn cup helps determine ink flow rates, with typical values for flexographic inks falling within 25 to 35 seconds using a number 2 design cup.

Anilox Roll and Substrates

Here, the focus shifts to the anilox roll's role and substrate options suitable for flexographic printing.

Anilox Roll Functionality

• The anilox roll serves as a key component in analog-to-flexo transition, featuring laser-engraved ceramic coating with miniature cells that hold ink volumes measured in billion cubic microns (BCM).

• Stainless steel doctor blades clean excess ink from anilox rolls' surfaces, ensuring precise ink film thickness measurements critical for quality printing results.

Substrate Variety

Plastics Used in Film Production

The speaker discusses the various types of plastics used in film production, including polyesters (PET), polyethylene (PE) in different densities, polyvinyl chloride (PVC), polypropylene (PP), and polystyrene (PS).

Plastics for Film Production

• Polyesters, commonly known as PET

• Polyethylene (PE) available in low-density, medium density, or high density

• Polyvinyl chloride (PVC)

• Polypropylene (PP)

• Polystyrene (PS)

Flexo Printing Press Substrates and Designs

The discussion focuses on the substrates used in flexographic printing presses and the basic design elements of Flexo printing presses.

Substrates and Design Elements

• Flexographic printing presses primarily use web or rotary substrates

• Presses can be stacked vertically or inline

• Common impression cylinder (CIC) for wide webs with faster speeds

• Satellite press configuration on CIC presses

Press Manufacturers and Converters

Various press manufacturers and converters in Buffalo, New York are highlighted along with their acquisitions and name changes.

Press Manufacturers and Converters

• Mark Andy, Gallus, Peter Bapst F&K MPs are prominent press manufacturers

• Flexo printers often referred to as converters due to printing and converting into bags

• Examples of Buffalo-based printers: Resource Label Group, CP Flexible Packaging, CCL Labels Industries

Printing Companies in Buffalo

The speaker lists several printing companies located in Buffalo, New York along with their previous names and acquisition details.

Printing Companies in Buffalo

• Resource Label Group (formerly Kinsler Graphics)

• CP Flexible Packaging (formerly Flexible Transparent)

• CCL Labels Industries Pro-Am Pack (previously Trinity then Sowell Pack)

• Bison Bag

• Cascades/Aim Corrugated/Norampack