DDIN Library

Flexible Magnetic Die Cutting in Europe and North America

Details: Written by Robert Larson

A phrase that I have used many times in articles and speeches is “The only constant thing in life is change”. This is especially true when it comes to the diecutting process cutting, perforating and trimming all types of materials and products. In the past 50 years, the techniques and types of tooling to cut, perforate or trim different materials has changed considerably. I would like to explore with one segment of the total diecutting process, the use of flexible magnetic rotary and flat dies especially in Europe and North America.

Diecutting of paper products has been traditionally split between flat bed die cutting and rotary die cutting. Both systems have their place in the total process of cutting paper and paperboard products. I am noticing a definite trend where many applications that were once favored in the flat bed arena are now being transferring over to the narrow and wide web rotary world of diecutting. This is especially true in the cutting of labels, tags, envelopes and other paper products such as folding cartons and corrugated boxes.

In the rotary system of diecutting, different types of tooling have evolved such as soft anvil steel rule rotary dies, solid hard anvil rotary dies, segmented solid rotary dies and the flexible magnetic rotary die. Each rotary die system has evolved, been improved upon and can often be replaced with other systems when converters of die cuttable materials seek out lower cost tooling, faster delivery of tooling along with higher rates of production at lower costs per cut piece. This is particularly true today in the case of the development of and the increasing use of flexible magnetic rotary dies.

The use of narrow web rotary dies in the flexographic printing industry goes back to the 50’s and the basic concept of rotary diecutting has changed little over the years. The advent of the computer and CNC rotary machining techniques enhanced the process of producing long lasting solid anvil rotary dies. Their biggest drawback was their heavy initial cost and length of time to deliver the tooling that justified this type of tooling only for long run jobs.

The advent of the flexible magnetic rotary die provided an economical solution to provide tooling that was far less expensive than traditional solid rotary dies with faster turn-a-round in the delivery process and required minimal set-up times between shorter and shorter production runs. Flexible magnetic dies were practical for narrow web operations up to 24 inches wide. Over that width, the cost of a magnetic cylinder has been prohibitive but, the costs are now becoming more affordable. Normal line speeds using flexible dies are from 300 to 500 feet per minute. These speeds are equal to those found with solid engraved rotary dies.

The technique of producing a chemically etched flexible die became possible in 1936 with the development of spark erosion or EDM (electrical discharge machining). European and North American cutting diemakers first developed the chemically etched flexible magnetic die in the 70’s and have improved the process ever since. The technology of producing flexible dies was developed first in the United States in the early 1970’s by Pierson Kang at ChemPar who produced electronic parts and circuit boards. Today Mr. Kang and James Redd, are co-owners of Xynatech, Inc., of Rio Rancho, New Mexico, who is a major manufacturer of flexible magnetic dies.

In 1974, Atlas Die, Inc. in Elkhart, Indian licensed the technique of producing flexible dies from a German diemaker and in 1979 established their own chemically etched facility producing magnetic flexible dies from spring steel and held in place with a magnetic cylinder. Today there are probably 5 or 6 major producers of chemically etched dies in Europe and North America. Environmental concerns with the disposal of chemical waste materials and the cost of entering the marketplace have limited further competition in the international arena.

In 1986, Ron Spring, a leading British authority in the label industry, estimated that total sales of flexible magnetic dies worldwide in producing only labels was estimated at £60,000,000. He estimated that the regional figures would be around:

United States £14,000,000

Europe £11,000,000

Japan £5,000,000

United Kingdom £3,000,000

Australia £1,000,000

Ten years later in 1996, it was estimated that the over all value of world wide sales of flexible magnetic dies both rotary as well as flat could have expanded possibly 25% to possibly 50%. This is due to the fact that flexible magnetic dies are today being used to cut an even wider array of materials and products.

In recent years, it seems that European diemakers have taken a leading position in the development of flexible dies. Zimmer Industries, Inc. in the USA, has pioneered producing unique micro perforating teeth on the edges of flexible dies. This innovation, using as many as 120 teeth per inch makes possible the effective micro perforating of virtually any desired shape on materials as common as paper and as exotic as plastic film, vinyl’s, foils and a wide range of tear resistant materials, such as Tyvek and tear resistant (plasticized) papers. Zimmer also sells a complete range of micro perforated steel rule blades.

Generally speaking, the use of flexible dies in the European market has been more focused in the conversion of prime labels (i.e., packaging labels) than in the USA. This includes many plastic labels for such things as household products and cosmetics. Those applications have been almost non existent in the USA up until recent times. The US label market has been heavily waited towards EDP (Electronic Data Processing) or computer labels. Today. flexible dies are capturing more of a market share in items such as bingo cards, business forms, direct mail coupons, pressure sensitive postage stamps, tags (standard and tear resistant), membership or wallet cards, Rolodex cards and licenses using foils, Mylars, paper, plastic films, PE and PP plastics, composite materials and tear resistant materials like Tyvek™ and vinyl’s.

There are now new forces in the marketplace which change the needs for different types of flat and rotary tooling. For example, in a recent conversation with a leading US producer of flat bed label steel rule dies, Ashwell Label Dies in Largo, Florida, the diemaker stated that they noticed a dramatic shift of customer preference away from their traditional flat bed steel rule dies to rotary dies in label making and the shift was towards the flexible magnetic dies primarily because of cost considerations in the cost of tooling, delivery time and the minimum set-up times between short run jobs. Also, they mentioned that a wider range of materials are being used in the label industry that can used the flexible magnetic rotary die.

Price markers in supermarkets and stores, once a prime item for diecutting have declined in importance as bar codes and “shelf talkers” or display discount coupons have increased. Thermal transfer dies, which were unheard of a few years ago which now account for a significant share of the market. The laser printer has had a dramatic impact on pressure sensitive label usage. Laser printer stationary, laser printer generated business cards, greeting cards and other micro perforated items have expanded in the marketplace. Sheeted products using a range of liners from thin to thick liners account for a large new area of business for flexible dies.

In the USA, a new phenomena is just beginning with the use of micro perforated flexible dies to cut postage stamps. The United States Postal Service has just issued it’s first micro perforated postage stamp utilizing a chemically etched magnetic rotary die. Flexible magnetic dies will capturing a greater share of the existing market for perforated stamps where traditionally gummed postage stamps were traditionally produced on class A male & female tooling die sets. Another development has been the bi-level or two level flexible magnetic die whereby both the pressure sensitive label and it’s liner stock can be cut in one operation.

Zimmer Industries Inc., has recently introduced their patented method for using micro perforated chemically etched dies for cutting linerless labels. The impact of labels without liners or carriers will be dramatic, both in significant label cost reductions and in the removal of the ecological problem caused by the non-recyclability of most liners. New areas of possibilities are opening up flexible dies in electronic circuitry, medical products, thin metallics as well as small packaging cartons.

The techniques or methods of producing flexible dies is also improving and ever changing. Up until two or three years ago, flexible dies were produced using high carbon spring steel. Today, we see magnetic (400 series) stainless steel in use. Stainless steel has as an advantage of not rusting plus longer cutting life due to it’s high chrome content. There are now several different coating techniques that can be used to lengthen the cutting life of the cutting edge of a flexible die. New ideas that are currently being tested are the use of laser as well as cryogenic heat treating to prolong the cutting edge life of the dies.

The ultimate goal of producing any type of cutting die is obtaining the sharpest possible edge that lasts a long time in diecutting. Advances in flexible dies are also being made in this area. CNC sharpening of chemically etched dies, especially in Europe, is on the rise. While there may not be an appreciable advantage in cutting paper with a CNC sharpened edge vs. the chemically etched blade, there does seem to be an advantage in cutting plastics with a CNC sharpened flexible die. The use of CNC sharpening techniques are particularly advantageous for diemakers who could not produce a fine sharp edge by etching techniques and required costly manual labor to put a razor sharp edge on a die. This technique is becoming more popular in the production of flexible dies.

The magnetic cylinder is a vital part of the whole process. Today the ceramic surfaced magnetic cylinder is the state of the art in holding the flexible die in registration to the rotary cylinder or a flat surface. An alternative method of mounting the die is the adhesively mounted die. This is a new patented process that has pockets in the back of the die which hold the adhesive.

Changes in the construction of and use of flexible dies has not been rapid, but have been steady over the years. The economy of using flexible magnetic rotary or flat dies over traditional steel rule flat bed dies and solid or segmented rotary dies will mean a shift in the types of dies used in the label industry.

A definite enhancement in the life of chemically etched/machined magnetic dies has been the I-Best ion beam treatment developed by QM Technologies in Albuquerque, New Mexico. This process today has proven to be extremely well adapted to magnetic chemically/machined flat and rotary dies. What the I-Best system does is to bombard the surface, edge and blades of the die with a powerful ion beam charge. This almost instantly melts the surface structure of the die and instantly cools the surface. Without going into the technical why’s and how’s of why it works, the important thing is that it does. The die becomes tougher and in many cases the edge hardness is much harder. The bottom line is that in the case of flexible magnetic dies, end users are seeing dramatic increases in cutting life with dies treated in this process. It is a clear example of a space age technology that has been adapted to improving the functionality and life of cutting dies.

The flexible magnetic die is going to become more common place in the converting process. In many cases, I think that the flexible magnetic die will displace traditional steel rule tooling. We will see flexible magnetic dies with greater blade depths to accommodate thicker materials. We will see larger dies enter the marketplace as diemakers bring on-line processing equipment that can accommodate larger sheet sizes. The day of this type of tooling is still in the definite uphill climb. It will be interesting to watch what changes take place in the next few years in the diecutting process, especially in the area of magnetic flexible dies.