Contact Dryers & Die Cutting (Laser & Traditional): “Cutting Costs And Time”, Specialist Printing

Businesses are continually looking for ways to identify cost savings and implement energy efficient solutions. Screen printing companies specializing in flexible membrane switches (flex circuits) are no different in their approach to screen printing and die cutting their stable of products. As capital expenditures begin to loosen, equipment manufacturers are hard at work to design and build equipment that directly addresses the bottom line. It is back to the basics for many equipment manufacturers who are busy looking for technology advancements and innovation. Now is the time to develop a new way to produce the same product that will save any company significant money.

Contact Dryers vs. Traditional Air Dryers

There are many applications where traditional air drying systems continue to make for a good investment. They are typically 15% cheaper than contact dryers, which is a deciding factor for many businesses. However, when you peel back the benefits of the contact dryer over traditional air drying equipment the initial investment savings quickly go away.

Conventional air drying ovens blow heat over the surface of a web or sheet of material. In general, inks harden by drying, or evaporating the solvent out of the ink. There are three factors that contribute to how fast they will dry using an air dryer; temperature, amount of air flow and air humidity. A contact dryer uses a heated platen along with surface air assistance to dry the ink from the bottom to the top therefore capturing heat energy below the surface of the printed substrate. Since many inks require different temperatures and drying time the more consistent and concentrated the heat the better and more efficient the drying process.

For example, if an electro-conductive ink requires a drying temperature of 100 C to fully dry the ink on a given substrate. As the air travels across the surface of the ink the heat dissipates quickly. This can be very inefficient since most of your heating elements need to be constantly brought back up to the required temperature. Since a contact dryer uses a heated platen that dries the ink from the bottom to the top this eliminates “skin effect” on the ink because the drying begins below the surface of the ink and finishes at the top. Once the heated plate reaches the desired heating temperature it can be up to 70% more efficient because the heat is captured and does not require constant energy to the heating elements. The heated platen usually contains three heating elements within the system. Generally, the third heating element at the end of the dryer requires much less energy because the heat remains constant from beginning to end. A hot air dryer consistently requires the same amount of energy throughout the dryer because of the loss of heat when blowing air across the surface.

Another benefit of a contact dryer is the time required to dry the ink. Since it can dry inks more efficiently and faster than a traditional air dryer the floor space required is reduced. With square footage within a facility at a premium the ability to shorten the overall footprint of a screen printing line can save businesses a significant amount of money.

The traditional air dryer will continue to work for many screen printing applications. It is important to recognize that there are alternative technologies in the field that are offering energy efficient alternatives.

Traditional Die Cutting vs. Laser Die Cutting

When looking at the finishing end of your printing business it is important to take into consideration run lengths, registration requirements and cut quality. Traditional die cutting equipment like flat bed die cutting has been the standard. As the trend for shorter run jobs continues to creep into the printing industry the need for a flexible, accurate die cutting solution is evident. Gantry laser cutting systems have been working on flexible membrane switch applications because of the accuracy (+/- 0.1mm or better) and flexibility. The bigger issue has been the speed. A gantry laser system mechanically moves the material OR the laser head into position while it is cutting. A galvanometer (galvo) laser system offers flexibility, speed and relative accuracy by remaining stationary above the roll or sheet of material and allowing micro movements of mirrors to redirect the laser light around the die cut line.

The debate between either a gantry or galvo laser die cutting system is a sub-plot of the overall die cutting discussion. Cut quality remains a question mark for many first time technology gazers, however, companies are constantly testing different substrates to assure for quality products. Polyesters, polycarbonates, paper and many other materials are candidates for laser cutting while research laboratories have been set up by many equipment manufacturers to evaluate any quality concerns.

In the past, accuracy was a question mark for galvo laser die cutting systems but with the integration of XY plotter tables into galvo sheet fed laser designs this argument has subsided . For example, the lead on a flexible circuit may be identified as the most critical part of the circuit. If this lead (or plug) does not meet a minimum requirement of +/- 0.1mm or better then the part may be considered defective. Since the gantry system moves to the desired cut point it maintains the necessary accuracy. The galvo system is mounted a fixed distance above the sheet so cutting a part on the edge of a sheet can create accuracy issues. By moving the table (or the head in certain applications) to a predetermined position the accuracy of the galvo laser die cutting system reaches +/- 0.1mm.

Removal of weekly, monthly, yearly expenses of tooling offers the biggest cost savings for any finishing department. Include in the discussion the lost time in waiting for new tools to arrive or the set up/make ready required for installing a new tool and laser die cutting begins to make sense. The initial hurdle for this technology can be price as is the case in the above section about drying systems, however, following the initial investment the laser die cutting systems eliminates the need to purchase tooling for new product designs or replacing damaged dies. In order to evaluate the viability of laser die cuttingtechnology a screen printers must first look at the inventory of tools on their shelves and determine if the pain is such that removing these tooling costs is enough to justify an investigation. Cut quality, return on investment and speed requirements will all take care of themselves upon consultation with a laser die cutting equipment provider.

In summary, each new technology requires greater initial investment, however, once you look past the price tag there are many benefits to consider. The most important thing is always to identify pains and have good information to solve any given issue.

Mike Bacon is vice president of sales and marketing for Spartanics, which manufactures laser die cutting systems, steel rule die cutting systems, screen printing lines, automated counters and other equipment. Spartanics is available for technology demonstrations and contract manufacturing services. Inquiries should go to sales@spartanics.com.

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