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SYNRAD, INC. - http://www.synrad.com
Thursday, March 30, 2006
Issue 134
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Marking PVC-Coated Coaxial Cable
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Marking Invar
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Welding Pyrex Glass
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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.
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Marking PVC-Coated Coaxial Cable
Polyvinyl chloride (PVC) is currently the most common material for electrical wire insulation and jacketing. PVC is mechanically tough and features good flame and moisture resistance at low cost. PVC reacts well with the 10.6 micron CO2 wavelength by exhibiting nicely contrasting marks on both light and dark materials. The accompanying photo shows contrasting laser marks on both black-jacketed and yellow-jacketed RG-type video cable.
To setup this six-character mark, we created a text object in WinMark Pro, selected the ‘Simple’ stroke font, set a Text Height of 3.7 mm (0.15”), and added 0.16 mm (0.007”) of Extra Character Spacing. On the Marking tab, we set a Velocity of 50 inches per second (IPS) and a Power – duty cycle percentage – corresponding to 25 watts. The mechanical setup consists of an FH Series marking head equipped with a 125 mm lens that provides a 180-micron (0.007”) spot and a 3 mm (0.118”) depth of focus.
Using these parameters, we marked the six-character mark in a cycle time of 0.09 seconds per mark. At this cycle time with a 125 mm lens, we can achieve tracking marks “on-the-fly” at continuous line speeds of 67.8 meters per minute (223 feet/min).
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Contrasting marks were achieved on the black
and yellow PVC-coated cables using 25W of power.
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Marking Invar
Invar is a low-expansion nickel-iron alloy that exhibits the lowest thermal expansion of any metal in the range of 20–230 °C. In fact, many years ago Synrad manufactured Invar-stabilized lasers for scientific applications where the laser’s optical support structure was fabricated from Invar in order to minimize changes in the output wavelength caused by temperature variations in the laser chassis. Today, Invar is primarily used to produce thermostats for household appliances as well as internal components found in computer monitors and televisions where design requirements call for maintaining precise dimensions over wide temperature ranges.
As a demonstration of marking 12.7 mm (0.5") thick Invar blanks, we mounted an FH Series Index marking head to a Firestar t80 laser and installed a 125 mm HP (high power) lens to accommodate the t80’s power density.
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We achieved a high-contrast mark on this piece of Invar nickel-iron alloy using 80 watts of power at a galvanometer velocity of one inch per second.
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In WinMark Pro, we created a six-character text object using the ‘Simple’ font, one of WinMark’s twelve built-in stroke fonts and set a Text Height of 6.35 mm (0.25”) with 0.25 mm (0.01”) Extra Character Spacing added to enhance readability. Mark Velocity is 25.4 mm per second (1”/second) and the Power (duty cycle percentage) corresponds to 80 watts. This combination of power and 180-micron (0.007”) spot size produces a power density exceeding 1.5 million watts per square centimeter at the work surface. Using these settings, we achieved a highly contrasting six-character mark on the Invar blank in a cycle time of 1.98 seconds per mark.
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Welding Pyrex Glass
Pyrex®, a low-expansion borosilicate glass widely used in many consumer and scientific applications, has consistently proven its strength and durability since 1915. In the kitchen, your glass measuring cups, baking dishes, and serving plates are likely made from Pyrex; in laboratories worldwide there are benches filled with pipettes, flasks, and other Pyrex glassware.
This unique request calls for sealing glass pipettes by welding one end closed. This is an ideal CO2 laser application (and one that we frequently see) since the laser provides an excellent pin-point heat source capable of generating several hundred thousand on up to millions of watts per square centimeter depending on laser output power and focused spot size.
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This before (right) and after (left) photo shows a sealed spherical end after “welding” the glass
pipette with 50 watts of power.
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Our glass welding setup consists of a rotary stage suspended beneath a gas jet manifold. The manifold holds a 63.5 mm (2.5”) positive meniscus focusing lens that provides a 100-micron (0.004”) spot with a 1.8 mm (0.07”) depth of field. A gas jet fitting below the optic provides a connection for the assist gas, which in this case is 0.07 bar (1 PSI) of clean, dry air.
Each pipette has an outside diameter of 2.1 mm (0.0825”) with a wall thickness of 0.25 mm (0.01”) and is spun at 330 revolutions per minute by the rotary stage. By firing 50 watts of power for approximately 10 revolutions, it took 1.8 seconds per part to achieve a perfectly welded spherical end.
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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
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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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Copyright © 2006 SYNRAD, Inc. All rights reserved.
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.
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