SYNRAD, INC. - http://www.synrad.com  
Thursday, June 24, 2004
Issue 90

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.

Cutting Thin Glass Substrates

These glass sheets, measuring only 30–600 microns (0.0012–0.0236”) in thickness, are easily cut with CO₂ lasers.

Over the past several years, glass marking has developed into one of the premier CO₂ laser applications, especially in the commercial, industrial, and automotive glass industries. Until now however, glass cutting with CO₂ lasers was not feasible since the thickness of typical glass products exhibited substantial fracturing caused by the stress of localized heating effects. For glass between 1 and 10 mm thick, laser cutting becomes a two-step process of scribing and snapping.

Today though, products ranging from microscope slides to covers for flat-panel displays on laptop computers and cell phones are made from thin glass substrates. These glass sheets, measuring only 30–600 microns (0.0012–0.0236”) in thickness, are easily cut with CO₂ lasers and demonstrate the same fine edge quality seen in many other laser cutting applications.

The section of glass shown in the photo is 150 microns (0.006”) thick and was cut on our XY stage using 100 watts of power at a speed of 550 inches per minute (IPM). The laser was gated with 1.2 ms pulses at a frequency of 750 Hz through a UC-2000 Universal Laser Controller. A 2.5” positive meniscus optic (0.004” spot size and 0.07” depth of focus) provided beam focus while 10 PSI air provided the gas assist.

Marking Grayscale Images

Grayscale image using WinMark Pro.







Original .tiff image

Since the inception of WinMark Pro®, SYNRAD’s laser marking software, WinMark Pro has supported the importation and marking of numerous bitmap and vector file formats. Since bitmaps usually contain color information and laser marking is a monochrome marking process – the laser is either On or Off – some type of color reduction must take place. In the past, WinMark Pro offered a choice of three algorithms: Bayer Dithering, Error Diffusion, and Halftone. Each reduction method marks some combination of geometric shapes or dot spacing to fool the eye into seeing shades of gray; essentially converting a color image into a black & white image. The downside is that the image is subtly transformed, sometimes appearing grainy.

The recent release of version 18 firmware for our FH Series Index and Tracker marking heads and Fenix Laser Markers combined with the release of WinMark Pro v4.3.3.4528 now offers true 8-bit Grayscale reproduction. Grayscale marking provides an accurate reproduction of continuous-tone B&W or color images including photographs and other scanned images.

To mark a Grayscale image using WinMark Pro, open a blank drawing, click the File menu, and choose Import… . Locate a continuous-tone color image (usually saved in a BMP, TIF, or JPG format), and then click Open. When the Import Color Raster Bitmap dialog box opens, click the Gray Scale radio button and then click OK. The color image is imported and placed on the Drawing Canvas as an 8-bit, 256 level, Grayscale image. Grayscale images are marked using a continuous scan method where mirror speed across the image is held constant (using the specified marking Velocity) and power is varied according to the intensity of each pixel.

The photo at left compares the cover of our tri-fold laser brochure to the same TIF file marked using Grayscale on a piece of laser-markable tile. The Synrad laser image was marked with a Firestar v40 laser operating at 40W while an FH Index marking head equipped with a 200 mm focusing lens (290-micron spot with a 5 mm depth of focus) provided beam delivery. Mark Velocity was 20 inches per second. As with all bitmap (raster-scanned) images, cycle time is relatively slow since the beam must scan every pixel in the image. This image, comprising 1.88 million pixels at 300 DPI, required a cycle time of 6.75 minutes to mark.

The upgrade firmware file, Update_18.asc, for FH Series Index and Tracker marking heads and Fenix Laser Markers as well as the latest WinMark Pro build, v4.3.3.4528, for Windows® 98, NT4, 2000, and XP operating systems using PCI-bus Fiber Link Controller Cards is available for installation from our ftp site at ftp://apps.synrad.com/01w. Login to our ftp site with the username “winmark” and the password “winmark01”.

Machining Wire

25W pulsed, rounding 0.008" wire tip.

A smooth tip is required of wires that need to be threaded or pushed through narrow and delicate conduits. While mechanical cutting causes sharp edges that may tangle or damage these conduits, the thermal heat of a laser naturally causes the wire to form a rounded tip ( the material tends to the minimum surface energy, represented by the hemispherical shape).  The use of heat to produce a fast and efficient "balling effect" needs to be direct and reliable.  Torches, for example, produce unreliable results. This application is ideal for the laser, highlighting its potential as a delicate small source heating operation. 

Browse Synrad's Applications Database

Search our online library for more applications of Synrad's sealed CO₂ laser technology. Sort by material, process, or industry.

http://www.synrad.com/search_apps/Default.htm

Do you have an interesting application using Synrad Lasers?  Would you like to see it published in the Synrad Newsletter?  We would love to hear from you!  Please send your story ideas to: editor@synrad.com

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Copyright (c) 2004 SYNRAD, Inc. All rights reserved.