Marking auto glass
In this competitive industry, lasers have the potential to offer glass fabricators significant advantages
Glass as an industry covers a broad range of very familiar applications ranging from wine bottles to automobile windows to architectural doors, building exteriors, and solar panels. The material itself is perceived as a commodity, and one of the few products in the age of high technology that is still manufactured with a couple of the basic elements (earth and fire). As basic as this may seem, there have been significant strides in innovation within the industry to provide complex shapes, improved reliability, and security in a post 9/11 environment and coatings that draw from semiconductor processes for performance that belies the humble nature of the base material.
Innovation attracts innovation. Lasers are being used for a number of glass-related processes. One of the most common applications is marking text and graphics for identification on each piece of glass for internal tracking in production, performance verification at a construction site, and traceability for regulatory compliance. Lasers also are used to remove coatings for automotive applications and for processing some of the complex materials used for solar panel fabrication.
Figure 1. Laser marking tempering logos at Spec-Temp.
The choice of a laser must address a number of technological and commercial requirements. The transparent nature of the base material limits the use of visible lasers, which is why we find CO2 lasers with a wavelength of ~10 µm in wide use for most of the common marking requirements. The emergence of industrialized UV lasers may target more sophisticated applications, but they are generally lacking the power levels needed for a high-volume, high-throughput industry.
For lasers to replace the traditional marking processes of sandblasting or the chemical etch of a stencil, they must demonstrate a clear cost benefit. Advances in the manufacturing of solid-state CO2 lasers has dropped price points to a level where it is quite easy to consider the use of these rugged and reliable products on a production floor. The traditional benefits of permanent marks and the flexible management of the part information are a good fit for most of the glass fabricators.
Providing a tool that can be used in production does not start and end with just a lower price. It takes a good sense of the industrial requirements and a form factor that fits into the current manufacturing process to provide the impetus needed to replace the existing marking processes. Virtek Laser Systems (Waterloo, Ontario) has found that by working closely with a few innovators in the field of glass fabrication a design can be articulated to satisfy this requirement. It has taken the form of integration with existing part handling or is embodied as a standalone unit for flexible positioning on a plant floor.
Spec-Temp (Antwerp, OH), a glass fabricating and tempering company serves the automotive and marine industries, as well as commercial and home fixturing manufacturers. Their capabilities include glass bending, screen-printing, edgework, custom holes, tempering, and heat strengthening.
With its existing sand etching systems the company was required to mark before the washer, which meant that it did not have the flexibility to respond to varying production demands. The sand etching process was also labor-intensive, prone to operator error and poor mark quality. Plus, the need for cost-effective date coding was another factor that spurred the company to seek alternate marking technology.
They installed three Virtek GlasMark Mobile systems that are easily moved around the shop floor to mark tempering logos and date codes on the different glass products. Production demands are now easily met with the mobile units providing maximum efficiency and flexibility. GlasMark software allows the work to be programmed from Spec-Temp's internal main computer network so customized marking is fast and easy.
According to Ray DeLong, product manager, "The three systems paid for themselves in less than six months based on reduced scrap and labor savings from reduced re-work alone."
The GlasMark systems provide a higher quality mark and more consistent results than sand-etching, which is subject to wear and tear of masks and reliant on operator efficiency. Spec-Temp has successfully converted this into increased sales by offering custom marking of logos. Customers readily appreciate this value-added service as it increases their visibility in the marketplace.
Barber Glass (Guelph, Ontario) supplies premium quality products to the architectural glazing, automotive after-market, and furniture industries. The company wanted to reduce scrap caused by scratches during the production process. The major culprits of these scratches were material handling and sand used in the marking operation.
An automated seaming production line was implemented to eliminate glass handling along with a Virtek GlasMark Inline laser marking system to remove sand from the line.
The laser unit is mounted inline with the high-speed seaming system, eliminating the need for material handling to mark the glass. According to John Barber, president, "The GlasMark system was integrated seamlessly with the line and the added benefit of being able to mark serialization and date codes is a definite plus. It allows us much greater control."
System software maintains all of the logos, stencils, and text in an interactive database, eliminating masks and the set-up times associated with the old process. Marking requirements—location, orientation, and view—are predetermined in the order entry process. The operator pushes a button to select the work order required.
The company reports that GlasMark consistently delivers marking times of 300 to 900 milliseconds for standard markings. Drew Macklin, operations manager, adds, "The quality and consistency of the laser marking is far superior to any of the sand marking we had previously been able to achieve. Customer returns due to defective marking have been virtually eliminated and likely the most impressive benefit of the laser marking system has been a zero down time record."
Barber Glass has since expanded the use of laser marking systems in its plant. The company has installed two GlasMark Mobile units in its laminating production area.
Lasers have the potential to provide significant benefits for glass fabricators in a competitive industry. The value of their contribution goes beyond off-the-shelf components and is more readily accepted when their needs have been met with a complete system-level solution. As acceptance of laser technology grows, the industry-specific solutions will continue to multiply and match the current level of innovation in the glass industry.
José Downes is director, global marketing and engineering products, for Virtek Laser Systems, Waterloo, Ontario, www.virtek.ca.