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Question and Answer

Laser Cutting

by Staff

February-March, 2012

How is the laser competitive at low quantities? High quantities?
Laser cutting is not a replacement for diecutting; rather it is an alternative that offers different benefits. Creating dies can be costly and time consuming so when it comes to low-volume jobs, laser cutting often is a more efficient and cost-effective solution. Laser cutting only requires a vectorized digital file, typically Adobe Illustrator, which eliminates the need for creating dies. Working from a digital file not only reduces the cost and storage issues associated with metal dies, but also makes the design production-ready instantly, as there is no need to wait for a die to be created. These circumstances make laser cutting a practical option for low-quantity production.

Laser cutting is especially ideal for applications with feature locations, tolerances, sizes or material characteristics that would be difficult or cost prohibitive to process using a steel rule die. When reviewing higher quantities, laser cutting has an advantage over diecutting in terms of pattern complexity. In most cases, laser cutting would not be a cost-effective alternative to diecutting for high-volume production of basic shapes and patterns. However, if the design involves extensive and complex detail, or tolerances that are unattainable with a steel rule die, then laser cutting can be an option for even high-volume production.

Laser cutting is a process that becomes essential when, for a variety of reasons, the requirements of a job exceed the capability of a blade cut. It is rapidly becoming the tool of choice for many diecutting operations where extremely detailed work is required. When used appropriately, laser cutting can be successfully combined with many other finishing processes with spectacular results. It remains true, however, that if a project can be cut with a conventional die, it is typically the most efficient and cost effective way to go in present times. This may not remain true as technologies advance in the future.

What type of caution should be taken to eliminate any discoloration from the laser cut process?
Because of the nature of a laser cut, there can be some discoloration immediately adjacent to the beam’s path on the target side of the sheet. This effect can be worked around by printing a neutral color on the target side, designing the pieces so the target side is not seen or utilizing the discoloration as a part of the design, such as an “antique” look to a lace pattern. However, the best solution to this potential issue is choosing a stock that cuts cleanly in the early design stages. Discoloration most often is found on stocks having a relatively high percentage of recycled material, perhaps more than 40 percent. This discoloration can become progressively more noticeable with time. Archival and 100-percent cotton papers typically are without any discoloration and remain that way for years. Discoloration also is affected by the thickness of the stock. A thick stock exhibits the effect more than a thin one because more material has been vaporized.

Getting the stock test-cut is the best recommendation. This ordinarily should be offered as a free service by the laser cutter as part of every job where an unfamiliar stock is being used. Also, laser cutters will be able to recommend stocks that have yielded good results in the past.

What are factors to consider when designing for laser cutting as opposed to diecutting?
When using laser cutting as a production method, it is important to keep in mind that the dieline is not limitless; however, when compared to traditional diecutting methods, it allows for considerably higher pattern complexity. Laser cut features are only limited to the size of the narrow laser beam, which is typically .008" to .010". Laser cut features require bridges/connections to maintain a piece’s structural integrity. Laser cut feature to feature distance can be as little as .020"; however, .030" is recommended. High-quality laser cutting systems are equipped with in-line registration techniques that offer cut to print registration tolerations of +/- .010". To hold tolerances at this level, laser cutting does require custom registration marks printed on the sheet layout prior to processing.

What is the latest technology for the laser cutting process?
Presently, the most high-volume laser cutting technology is a unique hybrid system that moves the target stock through the machine in the Y direction, much the same as a conventional offset press, while the laser scans across the sheet continuously with an overlapping pattern in the X direction. The cut image is defined by interrupting the laser’s path with a reflective copper template that has the art etched through it. This is produced using a process similar to that used to etch electronic circuit boards. This style of cutter can cut up to 3,000 sheets an hour and leaves no scrap to vacuum away because the faster-style scan completely covers the area to be removed and vaporizes it. With this system, the laser scan area, not the complexity of the design, determines both speed and cost. Because it is a sheet-fed system and utilizes conventional paper handling methods, it is naturally compatible with other off-line processes such as foil stamping and embossing.

Companies such as LasX and Laser Excel both provide contract production options for laser cutting, and LasX offers laser cutting equipment for purchase for roll to roll, sheet to sheet and roll to sheet automation to tailor a system to varying application requirements.

What applications would merit a laser equipment purchase?
Laser cutting systems can be set up to allow for multiple processes to be performed in the same work area, eliminating the need for alignment during progressive diecuts and the downtime of machine setup encountered during pattern changeovers. These laser processes include through cutting, scoring, perforating, etching and kiss-cutting. Because laser cutting is completely digital, a cut design can be modified on-the-fly, accommodating instant changes from the customer. The ability to process variable data is ideal for personalized production runs as well. Specific applications within the print industry which may merit a laser purchase include greeting cards, promotional materials, signage, labels, direct mail and folding cartons, etc. Laser cutting equipment also is available from companies such as LasX that can be integrated in-line with digital printing technology to provide a more efficient workflow in a one-stop shop.

InsideFinishing would like to thank LasX Industries, Inc., 651.407.0011, www.lasx.com, and Laser Excel, 800.559.7965, www.laserexcel.com, for their assistance with this article.