Laser Diecutting: A New Approach

Technically speaking laser diecutting is the cutting of a substrate by the vaporization of material using concentrated, high wattage laser beams in a small spatial area. Essentially laser diecutting technology burns away material to provide shapes that are pre-determined by a prepress operator. An unlimited number of shapes and sizes can be programmed into the system.

This new cutting technology is rapidly changing the way products are manufactured throughout the world. Within the past seven years, laser diecutting has a growing number of supporters due to cut quality improvements; increased throughput speeds; and savings in tooling costs, waste material, and job changeover. The companies that have invested in laser cutting technology are reaping the benefits of their early adaptation behaviors.

Times have changed

Production managers and engineers within printing companies are looking for alternatives to traditional diecutting methods because job runs are getting shorter due to an increase in private labeling and a push for lower inventory counts. With digital printing paving the way in short-run printing, laser diecutting is filling the void in the finishing department. Traditional diecutting machines are making room for complementary forms of digital diecutting. Since many printers have transitioned to prepress operations required for digital printers the stage has been set for a new, digital form of diecutting.

High-speed lasers in the label and packaging markets use a set of mirrors called galvanometer heads (galvo) that redirect the laser beam around the cutting path of a given job. The laser diecutting machines of today can not only cut ovals, squares, circles, and rectangles similar to traditional diecutting equipment, they can also achieve high-quality, intricate cuts for custom applications at high speeds. Aside from the obvious advantages of savings in tooling costs and "uptime" on the press, there are many unseen advantages to laser cutting technology. Printing companies are finding new business opportunities outside of their traditional markets by differentiating their label portfolio from the competition. Also, customers are transferring job set-up responsibilities to existing prepress operators, therefore reducing the number of machine operators on the shop floor. Finally, customers are increasing their profit margin on short-run jobs by using the automatic changeover capabilities available on several laser diecutting systems.

The truth about laser cutting

Most laser cutting systems will cut between 315 and 472 inches per second. The cutting speed range is a direct result of the type of material and the cut configuration that are required for the job. This variation in speed is similar to the number of colors that a digital printer runs on any given job.

Materials such as paper absorb laser energy to a greater degree than polyesters (PET). Polypropylene (PP) materials absorb more energy and have different laser cutting characteristics than PET and paper materials. So when a new material is specified for a laser diecutting system a 15-20 minute testing period is required. These testing periods allow the operator to adjust the laser energy and depth-of-cut settings for the laser. When a specific material has been qualified, the settings can be saved and recalled when this substrate is required for another job.

In general, materials such as paper, PET, PP, abrasives, and certain types of vinyl cut well on a galvo laser. Clear materials also cut well on lasers if the top substrate to liner material is configured correctly. In terms of the label and packaging markets, most top-coat materials range from 1.8 to 2.5 mil thick. The cutting speed in relation to the thickness of the substrate will vary, although this is usually more relevant where the material is thicker than 10.0 mil.

The cut configuration and part layout also have an effect on the speed of the laser. The laser scan head—a set of mirrors designed to reflect the laser beam—is essentially tracing around the part layout on a roll or sheet of material. The smaller the part and larger the quantity laid out across the cutting area, the faster, or slower, the machine runs.

Most laser diecutting systems on the market will run between 65 and 328 fpm. Given that most digital printers run comfortably between 65 and 131 fpm, the laser will keep up with these speeds. Laser systems can be equipped with 200 W, 400 W, and 1,000 W laser sources and this directly affects the throughput for any laser system. Any qualified laser system supplier is equipped to recommend the proper laser source along with any traditional converting options required for a customer's application.

Another key misnomer about a laser cutting system is that it costs a lot to maintain the system. The most expensive parts of a laser system are the laser source and scan head; however, the maintenance for these components is quite low. Most laser cutting system suppliers use a sealed CO2 laser. The advantage of a sealed CO2 laser is that after 12,000 production hours the laser can be recharged for a nominal fee of $12,000 to $15,000. Depending on the number of shifts a company runs, the laser will run between four and six years on a single charge.

Some challenges

One of the challenges of laser diecutting is defining laser friendly materials. Certain types of vinyl will yellow around the edges and PVC is not recommended due to the gases emitted following laser cutting. Cutting quality depends on both the type of control software a manufacturer uses and on the material construction. The laser beam wavelength for systems in the label market is 10.6 micron, which provides the fastest, best quality, and most versatile laser source for cutting label and packaging stock materials. However, a clear PP on a clear PP liner does not cut well because of the sealed CO2 laser's wavelength of 10.6 micron. The laser actually passes through the top PP material and cuts the carrier liner first. Manufacturers of laser diecutting systems are working hard to come up with laser friendly material configurations to use in the marketplace.

A market that is only scratching the surface of accepting laser cutting technology is the carton market. The demand is increasing dramatically for laser cutting given the expensive tooling and short runs; however, the production quality of laser cutting a 14 pt. carton stock is under debate. Sophisticated belt scrubbing techniques to remove debris and fume extraction systems are being developed to remove the smell and charring (or browning) around the edge of a laser cut carton. Throughput speed is also an issue, so companies are developing dual-head 1,000 W laser systems to increase throughput speeds.

Prepress operation

The laser cutting systems that are sold on the market today put a great deal of emphasis on workflow. Customers are trained on how to take a vector-based file and upload it to the laser operating software. This can be done from a PC anywhere within the plant or from a separate location. Some laser operating software will take the vector die line and optimize performance on the laser cutting system. This ultimately guarantees that the laser will cut at the fastest possible speed.

Laser cutting systems are equipped with "pen settings" that determine the energy and depth of cut for a material type. Traditional kiss cutting has a specific energy setting for a specific material that is optimized during the material testing process. If a job requires a kiss cut and a more intricate through-cut, then the job file may establish two or three pen settings for the given job file. This advanced technology gives the customer unlimited potential for custom products or limited setup for standard products.

Where do you fit in?

Laser diecutting technology has moved beyond the approval stage of the innovating consumers and believers. Innovators are the companies that make or break technology as we know it. They are visionaries. Equipment manufacturing companies with new technology thrive on innovation and the customers that are willing to shake up the status quo.

The early adopters that value their competitive edge in the manufacturing business have already invested in laser diecutting technology. These are companies that are willing to invest during the beginning stages of acceptance. They recognize early on, that if they want to maintain their leading positions within the industry, they need to stay ahead of the pack and start meeting their customers' needs before they take their business elsewhere.

The early and late majority buyers are doing their research and are beginning to recognize the benefits that come along with laser diecutting. Laser diecutting is no longer a mystery technology that is still being developed for the future; laser diecutting technology is here. These companies are streamlining their operations and creating digital cells within their plants.

Lastly, there are the laggards. These are the buyers that have a hard time moving away from their conventional ways of doing things. These are the individuals and businesses that will not accept or adapt to new technology until they are absolutely forced to do so. By the time they accept the changing landscape, their client base may have already decreased and they are trying to catch up.

About the author—Mike Bacon is the VP of sales and marketing for Spartanics, a supplier of laser cutting systems and plastic card manufacturing equipment. A graduate of Indiana University, he has more than 16 years of experience in the label, packaging, and converting markets. pP