 |
First die cutter by Stan Avery in
1935 |
By 1940, Avery
had moved beyond his humble beginnings and officially started selling his
products under the brand name Kum Kleen Price Stickers. The company
incorporated in 1946 as Avery Adhesive Label Corporation, and in 1990 merged
with Dennison Manufacturing to form Avery Dennison. Throughout his career, Stan
Avery received 18 patents for his innovations in pressure-sensitive materials
and production technologies. His legacy lives on, not just in the company that
bears his name, but in every self-adhesive label produced today.
Die-cutting
itself predates Stan Avery's innovation by nearly a century. The process was
invented in the mid-1800s to help the shoemaking industry. Cutting leather
soles for shoes by hand was laborious, time-consuming, and expensive. The
invention of the die-cutting machine revolutionized cobbler work, allowing
shoes to be cut to consistent sizes and shapes rather than crafted
individually. This standardization enabled modern shoe sizing as we know it
today.
Flatbed dies are used with hydraulic or mechanical presses and other lifting systems to press a die down on a sheet of material. They are particularly suited for heavier materials and thicker substrates, making them less ideal for pressure-sensitive labels but excellent for applications requiring precision cutting of rigid materials. Steel-rule die cutting uses a formed strip of hardened steel set into a slotted plywood die-board, with rubber ejectors aiding part release after the cut.
While flatbed
die cutting adapted for labels, offers excellent control over each cut and is
ideal for intricate shapes with close tolerances, it operates at a considerably
slower pace compared to rotary systems. Typical speeds range from 1,000 to
5,000 cycles per hour, making it suitable for small or mid-sized batches but
impractical for high-volume label production. The tooling costs for flatbed
dies are significantly lower than rotary alternatives, and the ability to make
quick die changes makes them valuable for short-run or prototype jobs.
The transition from flatbed to rotary die cutting marked a transformative moment in label converting. Rotary die cutting uses a solid cylindrical die that rotates continuously in sync with the web material, paired with an anvil cylinder. The press feeds thin, flexible material, known as web, between these two cylinders. The cutting-edge pinches material against the anvil cylinder, producing clean cuts, perforations, or creases at exceptionally high speeds.
This method
revolutionized label production by dramatically increasing throughput. Modern
rotary die-cutting systems can reach 10,000 cycles per hour or more, with the
fastest machines achieving speeds of 300 meters per minute. The ability to
perform inline with printing and other finishing operations means that labels
can be printed, die-cut, matrix stripped, and rewound in a single pass,
transforming manufacturing efficiency.
A series of
gears or servo motors now, force the die to rotate at the same speed as the
rest of the press, ensuring that cuts line up precisely with the printing on
the material. Rotary presses can incorporate multiple stations that die-cut
specific shapes, perform perforations, create creases, or even cut the sheet or
web into smaller sections. Some machines use automatic eye registration to
ensure cuts and printing align with tolerances measured in fractions of a
millimeter, critical for complex label designs and high-quality output.
The economics
of rotary die cutting favor high-volume production. While the initial tooling
costs are higher than flatbed alternatives, the operational efficiency brings
labor expenses down over time. For standardized, repeat orders running into
millions of labels, rotary systems offer compelling long-term value and
unmatched productivity.
Magnetic
cylinders are precision-engineered metal cylinders embedded with powerful
magnets, either ceramic or neodymium rare earth magnets, on their surface. They
are designed to hold flexible dies—thin, etched steel dies—firmly in place
during rotary die cutting. The magnets ensure that every square inch of the
flexible die remains securely pressed against the precision-ground cylinder
surface, preventing any lifting or shifting during high-speed operation.
 |
| Magnetic Cylinder in production |
In 2005, Bunting Magnetics launched the X-treme Magnetic Die-Cutting Cylinder, the first magnetic die-cutting cylinder in the world with total run-out accuracy below 40 millionths of an inch (1 micron). This level of precision was revolutionary, enabling clean cuts even on extremely thin materials like 1-mil stock with less than 1-mil liners, on "no-look" labels, and on synthetic materials that previously posed challenges.
The advantages of magnetic cylinders transformed the label industry. Mounting and removing flexible dies takes just minutes, dramatically reducing downtime during job changeovers, particularly valuable in short-run label printing or multi-SKU packaging environments. The cylinders weigh significantly less than solid rotary dies, reducing operator fatigue, machine wear, and transportation costs. Most importantly, they enabled the use of flexible dies, which cost a fraction of solid engraved cylinders and could be stored flat, saving valuable warehouse space.
Today, magnetic
cylinders are available for virtually all types of label presses and converting
machinery, from brands like Mark Andy, Gallus, Nilpeter, Omet, Rotoflex, etc.
Custom designs accommodate a variety of special applications, making magnetic
cylinder systems remarkably versatile.
 |
| Flexible die in production |
Production of flexible dies begins with plotting an image directly on the die material. Background material is then removed through chemical etching, and CNC mills create the required cutting or creasing lines with extraordinary precision. The cutting geometry includes profile heights ranging from 0.3mm to 1.5mm and cutting angles that vary based on the material being cut, typically from 30° to 110°.
The
manufacturing process includes several optional treatments. Back grinding
ensures consistent die thickness. Chemical de-burring smooths edges to prevent
damage to the label stock. Most critically, laser hardening and various surface
coatings dramatically extend die life and performance.
Die Materials and Surface Treatments
Standard
flexible dies are CNC-sharpened and feature smooth polished cutting edges
obtained using ultra-fine edge polishing techniques. These universal dies are
suitable for all types of self-adhesive and single-material products including
paper, PP, PE, PVC, PET, Tyvek, thin films on PET liner material, and other
materials that are difficult to cut.
Laser hardening
represented a breakthrough in die technology. Companies like Kocher + Beck were
the first manufacturers in the world to achieve hardness levels of 65 to 68 HRC
through laser hardening technology. This process extends die service life by two
to three times longer than conventional dies. The laser hardening increases
hardness at the tip of the cutting edge based on the carbon content in the
steel, creating exceptional wear resistance while maintaining die flexibility.
For extremely
demanding applications, chrome-coated dies offer even greater durability. A
thin layer of chromium, typically 0.01mm thick with a hardness of 70-80 HRC,
enables extremely high running performance with outstanding wear properties.
These dies are particularly suited for abrasive thermal and thermal transfer
papers used in longer production runs.
Non-stick
coatings represent another important innovation. Special onyx or polymer
coatings have no detrimental effect on the cutting-edge angle or sharpness
while preventing adhesive and ink deposits on the cutting blades. These
coatings are food-safe, FDA-approved, and significantly reduce downtime for die
cleaning. The reduced friction and perfect resistance to wear enable maximum
running performance with a consistently sharp cutting edge.
To
be continued to part-2
Written by Harveer Sahni, Chairman
Weldon Celloplast Limited, New Delhi, January 2026
