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SYNRAD, INC. - http://www.synrad.com
Thursday, August 24, 2006
Issue 144
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Cutting Automotive Headliners
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Cutting Acrylic
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Marking Silicone Tubing
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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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Cutting Automotive Headliners
CO2 lasers continue to excel in automotive applications as manufacturers strive to improve vehicle quality and cost savings during manufacturing. Integrating a laser with an industrial robot or flatbed cutting table provides a consistent method to accurately cut part after part and the laser’s non-contact cutting method means there is no need to schedule down time for mechanical cutter adjustment or replacement.
The purpose of this application test was to demonstrate the cut speed and quality achieved while using a Firestar f-Series laser to cut automotive headliners. This particular semi-rigid headliner material is comprised of several layers of synthetic fibers with an overall thickness of 1.3 mm (0.050”) bonded to a 1.4 mm (0.056”) thick paperboard base.
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This 1.3 mm thick headliner material was cut using 400W of power at 14 meters per minute (550 in/min).
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The cutting head on our flatbed XY table contains a 63.5 mm (2.5”) positive meniscus lens that provides a 100-micron (0.004”) spot with a 1.8 mm (0.07”) depth of focus. During the cutting process, we delivered 4.1 bars (60 PSI) of clean, dry air coaxially with the beam for gas assist. We obtained cut rates of 14 meters per minute (550 in/min) using 400 watts and 7 meters/minute (275 in/min) using 200 watts of power. In both cases, the synthetic fiber was cleanly cut while the paperboard base exhibits slight charring of the cut edge.
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Cutting Acrylic
Acrylic is an excellent material to cut with a CO2 laser. The cut mechanism is the result of material vaporization and with 100% absorption of the 10.6-micron wavelength even a 25-watt laser can cut 1" thick acrylic! Simple acrylic cutting is straightforward enough—just select a laser power for the required speed. However, when material thickness increases and a flame-polished square edge is required, the set-up becomes more critical. Before continuing, ensure that you are using cast, not extruded, acrylic.
Lens selection
Because acrylic acts as a waveguide to CO2 radiation, a 63.5 mm (2.5”) focal length lens provides reasonable results on 25.4 mm (1.0") thick acrylic. This gives any cutting system a great range on thickness for a single set-up if a perfect cut is not necessary. Generally, for thicker material, a 127 mm (5.0") lens is recommended. When cutting acrylic thicker than 8 mm (0.312”), defocusing into the material helps achieve the best square edge.
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We cut this ¼" thick acrylic puzzle piece
using 100 W at a speed of 50 IPM.
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Gas assist
Gas assist is key to achieving a polished edge. Air must be delivered into the cut area at a pressure that just enables the vaporized acrylic to be ejected through the cut; too much air pressure induces frosting as the edge cools too quickly.
As a rough guide, start with an air pressure of approximately 0.07–0.28 bars (1–4 PSI) although these values are totally related to the nozzle diameter and the stand-off distance from the nozzle to the material. A nozzle diameter around 3.2 mm (0.125”) and positioned about the same distance above the acrylic is recommended. This combination provides a decent tolerance on the gas pressure setting.
When cutting material less than 3.2 mm (0.125”) thick, adjust gas pressure experimentally to find the correct level. Look for an edge that is consistent through the depth of the cut. With thicker acrylic, finding the correct gas pressure is a little easier—initiate the cut with no gas pressure and slowly increase pressure until the topside flaming disappears.
Note that a perfect flame polished edge is not possible. Even the best edges exhibit very slight vertical striations due to the periodic ejection of vapor. Although decreasing cut speed can eliminate these striations, micro cracking then occurs on the cut face.
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Marking Silicone Tubing
Silicone tubing is widely used in the pharmaceutical and biotechnology industries where ultra-pure fluid transfer is essential for health and safety. In addition to its flexibility and puncture-resistance, silicone tubing is free of additives that could leach into, or contaminate, fluids carried by the tubing.
The purpose of this application is to demonstrate the feasibility of marking silicone tubing. Using WinMark Pro, we created a mark file containing 15 sets of two-digit numeric characters laid diagonally across the mark field of an FH Series 200 mm lens. This technique allows us to mark a section of tubing measuring approximately 210 mm (8.3") versus the maximum length of 165 mm (6.5") possible with a vertical orientation. Text objects were created using “Simple”, one of WinMark’s twelve built-in stroke fonts with a Text Height value of 2.7 mm (0.11").
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The silicone tubing provides readable, engraved
marks using 25 W at a mark speed of 20”/s.
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Using 25 watts of Power at a Velocity of 508 mm per second (20 inches/sec), we were able to mark a string of 30 characters total in a cycle time of 0.68 seconds per string.
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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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