Originally Published January/February 2001
Simplicity, Reliability, and Functionality Drive R&D in Marking Technologies
Suppliers of pad, transfer, ink-jet, and laser printing equipment offer insights on recent innovations.
The suitability of one printing or marking method over another is often dictated by the application, the material that is being marked, and the size of the production run. Printing technologies that require plates, for example, are cost-effective for print runs in which parts are marked identically, but they would not be feasible for serialized or individual marking operations. In addition, the use of ink may be undesirable for certain applications.
Pad, transfer, ink-jet, and laser printing technologies do share one trait, however: R&D that has resulted in advances with the potential to benefit device manufacturers. In this section, key equipment suppliers share recent developments within their companies as well as in their industries as a whole. For an exhaustive list of equipment manufacturers and complete contact information, see the accompanying Buyers Guide on page 92.
Smart labels support read-and-write operations
One recent development in transfer printing is the introduction of radio-frequency identification (RFID) labels, or so-called "smart labels." Manufacturers can encode data in RFID labels, which appear and function like standard labels, explains Matt Ream, senior product manager for RFID systems at Zebra (Vernon Hills, IL). The encoded data can be read with a handheld or fixed-position RFID reader and writer.
Radio-frequency identification (RFID) labels do not require direct contact or line-of-sight visibility to be read. Zebra has developed a transfer printer for the production of RFID labels.
"One of the advantages of the smart label is that radio frequency is used to read the data on the label," says Ream. "This means it does not require direct contact or line of sight. Unlike a bar code, you don't have to see it to read it, which makes it very suitable for harsh environments. If you scratch the label or get dirt on it, you can still read the tag. One of the other advantages is that it's a read-and-write technology. After you print and program the label, you can actually update the information as needed." For example, label data can be changed when it is necessary to reship an item to a different location, or quantity numbers can be modified to maintain up-to-the-minute inventory tracking.
Zebra has just released the R-140 transfer printer for the production of smart labels. The R-140 has been designed to work like Zebra's direct thermal and thermal-transfer printers: "Operators can print and encode in one step without having to learn anything new," he says.
Ream contends that RFID represents a major innovation for medical labeling not only for its usefulness in tracking and traceability, but also because it has the potential to introduce substantial clinical improvements. For example, Zebra has been working with a company called En-Vision America (Normal, IL), which has developed a product called ScriptTalk that reads RFID drug labels aloud to patients who are unable to read the labels themselves. Ream also notes that critical applications such as blood storage can benefit from this technology. In France, for example, a major effort is under way to standardize the labeling of blood bags using RFID labels to ensure traceability. As blood tests are performed, the label can be updated to reflect the most recent results, thus reinforcing quality assurance.
Cold-marking laser process lessens material degradation
Medical device manufacturers are benefiting from improvements in the precision and control afforded by laser marking equipment. Coherent Laser Division (Santa Clara, CA) offers a laser marking process that it calls "cold marking," in which a UV laser creates a color change on the surface of plastic components to produce high-resolution marks without degrading the component material.
"Typically when you use laser marking, you melt the surface of a part by creating pits or decomposition materials," says Paul Crosby, vice president of Coherent. "With cold marking, the reaction takes place underneath the surface or right at the surface, so the component is not degraded. This can be very useful from a regulatory standpoint and can be done in a sterile environment." Crosby notes that this technology, which has actually been available for five or six years, is still just starting to be deployed for the medical manufacturing industry.
Laser technology is suited for marking very small components and fitting a large amount of information in a small area, and suppliers such as Coherent are constantly seeking ways to increase this precision. Subjected to increasing regulatory and quality control pressures, device manufacturers need to code more information at higher resolutions in small spaces so that the information can be readily retrieved later, says Crosby. As laser marking continues to make gains in precision, device manufacturers can also improve their product-tracking efforts.
Pad printers draw from a better inkwell
Device manufacturers who use pad printing can benefit from several recent advances in inks, plates, and prepress operations.
"Inks have improved so much," says Doug Parker, vice president of sales at Imtran Inc., a Foilmark Corp. company (Newburyport, MA). "The use of faster drying inks, improved control over inks, and greater opacity" are among the advances he cites.
One innovation of acute interest to the device industry, Parker says, is the introduction of radiopaque inks for catheter markings that block x-rays, enabling doctors to see the position of catheters. Unlike the previous generation of radiopaque inks that were not suited for invasive procedures, these new inks meet medical requirements for use in the body.
Parker also points out that printing plates have undergone significant changes. Improvements have been introduced in the types of polymers that are used to fabricate plates, says Parker, and the availability of very thin steel plates have made medium-sized production runs more economical than ever before.
Improving prepress operations continues to be a focus for the pad printing industry as a whole, adds Parker. "Prepress is going to be the future of pad printing," he says. "The simpler we can make the process, the more usable pad printing will be." To improve prepress operations, Imtran has developed a pinning system for aligning printing plates. Imtran produces plates that are designed to fit subplate pins to ensure precise and easy alignment. "When the customer buys the plates, they are already punched and they fit right onto the subplates," says Parker.
Ink-jet printers focus on ease of use
"We strive to make ink-jet printers that are ever more simple and reliable," says Andy Millar, product support manager at Willett America (Ft. Worth, TX). "We are continually working to develop systems that you could basically take off the shelf, put on your line, and be ready to use without any special training."
One of the major improvements developed by Willett is the incorporation of a self-cleaning feature on its printers. When an operator stops a self-cleaning Willett printer, the machine automatically flushes out any excess ink from its printheads, so that it is ready to print when it is restarted. Not only does self-cleaning make printer operation easier, says Millar, but it also reduces mess and the possibility of contamination, a major concern for medical manufacturers. Millar notes that Willett printers with this self-cleaning function can remain on the production line for several weeks without requiring attention. Leslie Laine
Photo Courtesy of Wilden Engineering- Und Vertriebsgesellschaft mbH
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