SYNRAD, INC. - http://www.synrad.com  
Thursday, March 31, 2005
Issue 109

 

Laser Cutting Stained Glass

Unique Idenitfication (UID) Marking

Cutting EVA Foam Gaskets

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.


Laser Cutting Stained Glass

When cutting glass with a CO2 laser, the best “laser only” applications are typically thin glass substrates in the range of 30 to 600 microns (0.0012” – 0.0236”) thick. Without using specialized, and in some cases, proprietary processes, thicker types of soda-lime (float) glass are difficult to laser cut in one step.

Fortunately, the exceptions to the rule are these stained glass samples that cut very well using a Synrad sealed-CO2 laser. As with standard float glass, straight-line cutting of stained glass is easily done by scoring and snapping. The difficulty, as any stained glass artist will tell you, is in creating irregular shapes. Traditionally, curved shapes are made by nibbling away at the contour, by grinding on a diamond wheel, or by cutting using a diamond-bladed bandsaw – all being time- and labor-intensive processes.

Our cutting setup for these opaque and translucent stained glass samples consisted of a Firestar f400 laser with beam delivery provided by an XY “flying optics” system. Beam focus was through a 2.5” positive meniscus lens that provides a 100-micron (0.004”) spot with a 1.8 mm (0.07”) depth of focus.

In addition to creating the brilliant hues and colors seen in stained glass, the addition of metallic oxides or metallic salts to the glass formulation appears to alter the glass structure so that the laser’s intense, localized heating does not lead to unintended thermal fracturing of the glass substrate. Cut edges exhibit the same type of striation patterns seen in metal cutting where vaporized and molten material is blown through the cut area by a high-pressure assist gas.


The cut edge of this red glass shows a brittle, underside dross that removes easily to expose a cleanly cut edge.

 
These small 1.375” (35 mm) diameter circles were cut out of a translucent yellow glass using 400W at a speed of 50 IPM.

The straight line and circular cuts shown (from sample thicknesses of 0.130”) were obtained using 400 watts of power at a cut speed of 50 to 60 inches per minute (IPM). We used 60 PSI of air as a gas assist during cutting. The photos show discolored dross present on the bottom edge of all cut faces, however the dross is brittle and easily removed – leaving a clean laser-cut edge!


UID Marking

UID (Unique Identification) is a globally unique "part identifier" containing data elements used to track the history of Department of Defense products throughout their service life cycle. The use of UID is a mandatory U.S. Department of Defense (DoD) requirement for all solicitations issued on or after Jan. 1, 2005.

The UID part identifier is formed by combining the manufacturer’s identification and part identification numbers with predefined formatting and transmission characters. This UID data is then encoded into a Data MatrixTM ECC200 symbol for marking by Direct Part Marking (DPM) processes. Because one of the primary UID goals is to achieve an identification mark that remains readable during the service life of the part or equipment being tracked, UID data must be permanently applied to products using direct means such as laser marking.


The 2D Data Matrix code shown in the photo was scanned by a Microscan Quadrus EZ reader and achieved AIM grades of "A" for percent contrast, axial uniformity, print growth, and error correction.

The 15-mil code (each cell measures 0.015" square) was marked on an anodized aluminum tag using a Synrad laser, an FH Series marking head, and WinMark Pro laser marking software. The FH head used a 125 mm focusing lens to provide a 180-micron (0.007") diameter spot with a 3 mm (0.118") depth of focus. To mark the 29-character 2D code and text object we specified a Power value of 10 watts, a Velocity of 10 inches per second (IPS), and a Resolution setting of 200. Overall marking time was 2.35 seconds.

For further information on Department of Defense UID requirements as well as other applicable marking standards and specifications (MIL, NASA, ISO/IEC) for UID and Machine Readable Information (MRI), see SYNRAD's UID information page at: http://www.synrad.com/UID/dod_uid.htm.


Cutting EVA Foam Gaskets

Ethylene-vinyl acetate (EVA) foam is used in a variety of industrial and consumer applications ranging from floatation vests to shoe insoles to gasketing applications. This flexible, closed-cell copolymer has excellent chemical resistance, good thermal insulation, and retains its flexibility even at subzero temperatures.

EVA foam cuts extremely well using a CO2 laser, which is perfect for low-volume or custom applications where tooling for die cutting is too expensive. Non-contact laser cutting is also appropriate in high-volume manufacturing as it eliminates maintenance downtime resulting from cutter adjustment or replacement and product changeovers are simply a matter of loading a new cut file into the motion system.


Using a Synrad 100W laser customized gaskets were easily created from a 6.5mm thick sheet of Ethylene-vinyl acetate (EVA) foam.

This application involved cutting gaskets from a sheet of 0.256” (6.5 mm) thick EVA foam. A CAD file containing a full-scale drawing of the gasket drives the XY motion system, which in turn, controls a cutting head containing a 2.5-inch positive meniscus lens. Focused spot size is 0.004” with a 0.07” depth of focus. Using 100 watts of power and 10 PSI of air assist, each gasket is cut at a velocity of 275 inches per minute for an overall cycle time of 4.84 seconds per part.


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


Contact Us:

 

Synrad, Inc.

4600 Campus Place

Mukilteo, WA  98275

Tel:  1-425-349-3500

Fax: 1-425-349-3667

E-mail: synrad@synrad.com

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SYNRAD and Synrad product names are trademarks or registered trademarks of SYNRAD, Inc. All other trademarks or registered trademarks are the property of their respective owners.