Newsletter 155: Marking Plastic, Engraving Hardwood, Marking Glass

SYNRAD, INC. - http://www.synrad.com
Thursday, February 8, 2007
Issue 155


Marking Laser-Engravable Plastic	Engraving Hardwood	Marking Glass Bottles

SYNRAD's sealed CO₂ lasers are used in a variety of industrial processes including cutting, welding, drilling, and marking. This news brief showcases some of the interesting materials and products that are processed daily by Synrad's line of CO2 lasers and marking heads.

This issue highlights a few of the many decorative marking and engraving applications that are accomplished using our lasers. Visit the upcoming ARA International Awards Market in Las Vegas, Feb 21-24, 2007 for more laser engraving resources and information.

Marking Laser-Engravable Plastic

Many opportunities exist today for marking contrasting text and graphics on plastic materials with CO₂ lasers. Common industrial and commercial uses include equipment identification or process description tags as well as award and trophy engraving applications. In response to this demand, several plastic manufacturers offer laser-engravable plastics - typically a thin cap sheet bonded to a thicker white or black substrate. The CO₂ beam ablates, or removes, the cap sheet producing a nice, clean contrasting image.

For this demonstration, we marked on a 0.05"- thick white substrate covered by a black 0.002" thick cap sheet. This combination provides a nice white mark against a black background. Our marking setup includes a Synrad sealed CO₂ laser, FH Series marking head (equipped with a 125 mm focusing lens), and WinMark Pro laser marking software.

We began the drawing by first importing a vector image of a mariner's sextant, which was created in an .HGL (HP Graphics Language) format.

With Synrad's FH marking head, this entire image (2.5"x3") was marked in just over 7 seconds.

See this application in action!

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Next, we drew a circle, added TrueType text, and then radiused the text to blend with the circle. Text and circle objects were set to mark using 10 watts of Power with a Velocity of 25 inches per second (IPS) at a Resolution of 300. The sextant image was also marked using 10 watts, however Velocity was increased to 32 IPS and Resolution was set to 600.

Overall cycle time for marking the 2.5" by 3.0" image was 7.03 seconds - made more impressive by the fact that the sextant image alone contains over 650 individual polylines!

Laserbits, a supplier of laserable materials, offers laser tips and a free online newsletter for the engraving industry. Visit them at www.laserbits.com.

Engraving Hardwood

Marking or engraving wood is another great CO₂ laser application. Because cutting occurs through a chemical degradation process where the wood is burned away, marking provides a nicely contrasting mark while engraved depth is controlled by power, velocity, and the number of mark passes. Depending on the application, images and/or text can be burned into a variety of wood-based objects ranging from wine barrels to award plaques. Marking vector or grayscale bitmap images is accomplished by using a Synrad laser, FH Series marking head, and WinMark Pro laser marking software or by purchasing a purpose-built system incorporating a Synrad CO₂ laser from a laser engraver manufacturer.

Engraving wood is an excellent application for CO₂ lasers, resulting in clean, contrasting marks. This image was marked using 30W of laser power.

The image shown in the photo was engraved into a piece of walnut hardwood using an FH Series marking head driven by WinMark Pro. The marking setup consisted of an FH Head equipped with a 125 mm lens, providing a 0.007” (180 micron) spot size with a 0.118” (3 mm) depth of focus. The encapsulated PostScript (EPS) image was imported into WinMark’s Drawing Editor where text and a border were added.

The bridge image was marked using 30 watts of power and a Velocity of 25 inches per second (IPS). Resolution was set to 600 and Mark Passes (to provide engraved depth) was set to 2. For the border, we also used 30 watts, but changed Mark Passes to 3 and reduced Velocity to 15 IPS. The descriptive text was created using WinMark Pro’s built-in European stroke font. Text Height was set to 0.1” and we added 0.015” of Extra Character Spacing. Marking parameters for the text object were set to 30 watts of power at a Velocity of 30 IPS using 3 Mark Passes and 300 Resolution. Using the settings described above, this 3.5-inch by 1.6-inch image was marked in a cycle time of 14.6 seconds.

Marking Decorative
Glass Bottles

As manufacturers of glass products continue to learn about the ease of use and cost savings that result when replacing labeling, etching, or blasting operations with CO₂ laser marking, they are finding more and more products to mark, label and even decorate. Today, it is common to find window panes, automotive glass, CRT displays, and glass bottles being laser marked with serial numbers, part numbers, 1D and 2D codes, corporate logos, and decorative artwork.

The photo shows an example of a decorative glass bottle marked using an FH Series marking head. We used a 125 mm focusing optic that produced a 180-micron (0.007”) spot with a 3 mm (0.118”) depth of focus. At a galvanometer velocity of 18 inches per second (IPS) and a power of 19 watts, we marked the 20 mm by 13 mm (0.80” x 0.52”) image in an overall cycle time of 0.94 seconds.

Using an FH Series marking head, we marked a
decorative pattern on the glass bottle shown above.

Laser Engraving System or Galvo Marking Head?

The applications described in this newsletter were accomplished using Synrad's family of FH-Series Marking Heads, but for decorative marking and engraving applications, a laser engraving system is often used. Which is right for your application?

A Marking Head uses two galvanometers (optical scanners) to steer the laser beam, making it an ideal tool for marking small areas (field sizes< 250 x 300mm) at high marking speeds. For this reason, marking heads are often integrated into production lines for industrial coding and marking. A laser marking setup incorporating a galvo-based marking head features a small footprint and the flexibility to change lenses to achieve very small spot sizes and accommodate various working distances.

A laser engraver incorporates a laser and beam focusing assembly supported on a moving gantry, allowing for much larger work areas than galvo-based marking heads. Laser engraving systems range from desktop-sized models to larger floor models that can accommodate large format work (up to ~ 36 x 24"). They are desirable for applications that require a consistent spot size over a larger area. Unlike marking heads, which are frequently sold as components to larger configurations, laser engraving systems are self-contained units, requiring no integration or additional components after purchase. Please visit our system supplier pages to locate systems incorporating Synrad CO₂ lasers.

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