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SYNRAD, INC. - http://www.synrad.com |
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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 Glass-Filled PBT As mentioned in previous Newsletters, the primary benefit of blending a glass fiber fill into plastic formulations is to add reinforcement. In the case of PBT—polybutylene terephthalate, a polyester thermoplastic—a 30% glass fill creates dimensionally stable parts that are rigid and tough. When those parts are laser-marked, the addition of a glass-fill allows the CO2 beam to create dark, contrasting marks as opposed to the engraved, slightly contrasting marks seen on “pure” plastics. What you may not know is that WinMark Pro contains a property that allows you to easily control the darkness and depth when marking glass-filled plastic. The first photo shows a glass-filled PBT part that we marked using 25 watts of power at a galvanometer velocity of 381 mm per second (15 inches/sec). The combination of PBT engraving and charring of the glass fiber creates a nicely contrasting, readable mark in a cycle time of 0.9 seconds per component. This works very well for the customer who is operating a high-speed production line where short cycle times are important. The second photo shows a similar mark on identical material. This particular application was less focused on cycle time but instead demonstrates the completion of a very high-contrast mark on 30% glass-filled PBT. We used the same mark properties as before (25 watts at 15 inches per second) however this time we modified the value of the Mark Passes property (located on the Marking tab). For the 2D code, we specified 5 Mark Passes and then specified 7 Mark Passes for the text object. This change forces WinMark Pro to mark the 2D code five times in succession followed by seven consecutive text marks. The result is a dramatic high-contrast mark that is easily read by a barcode scanner or the human eye. In many cases, adjustments to WinMark Pro’s Mark Passes property helps to fine-tune mark quality without overburning or overheating the material.
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Cutting Woven Wire Cloth This metal cutting application involves cutting 0.28 mm-thick (0.011”) woven stainless steel mesh where each individual strand is made of 0.165 mm (0.0065”) diameter stainless steel wire. The combination of wire diameter and the plain Dutch weave provides a 60-mesh material, which is about the same mesh count per inch as the filter installed on your kitchen faucet. To perform our trials, we first setup the cutting head on our XY stage with a 63.5 mm (2.5”) positive meniscus lens that provides a 100-micron (0.004”) focused spot with a 1.8 mm (0.07”) depth of field over the extents of the table. Although the optical setup for cutting 316 stainless steel mesh is similar to the setup for cutting solid stainless plate, the most important variable is the type of assist gas. For the woven mesh, we used 5.5 bar (80 PSI) of high-purity air—breathing grade—instead of oxygen. The air assist contains enough oxygen to enhance cutting without causing run-away combustion of the fine wire mesh. |
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Using a Firestar f-series laser at a power level of 200 watts, we cut lengths of this woven stainless steel mesh at speeds of 5.08 meters per minute (200 inches/minute). The cleanly cut edge exhibits a slight discoloration, which is commonly seen when laser processing stainless steel. For applications that cannot tolerate any discoloration (or applications where the stainless pieces are later welded), the use of high-pressure nitrogen assist provides exceptional results, albeit at much slower cut speeds. |
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Marking 2D Codes on Molded Polyamide Polyamide, also known as Nylon®, is the material of choice when injection molding automotive, electronic, consumer, and industrial products. Formulations containing glass or mineral fill provide additional rigidity, impact resistance, and hardness making polyamide an ideal plastic for products subject to mechanical or thermal stresses. For this application we were asked to mark a 2D Data Matrix code on an automotive component molded from a polyamide formula containing a 35% glass fill. Our marking setup consisted of a SYNRAD sealed CO2 laser, an FH Series marking head, and a copy of our WinMark Pro laser marking software. |
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A 125 mm lens was installed on the marking head in order to obtain a 180-micron (0.007”) focused spot with a 3 mm (0.118”) depth of focus. Using WinMark Pro, we opened a new mark file and created a 2D code object. The 14 × 14 symbol holds a maximum of 16 numeric or 10 alphanumeric characters. We then sized the code to an overall length and width of 6.4 mm (0.252”) square, which equates to an 18-mil cell size. On the Marking tab, we set a Power, duty cycle percentage, corresponding to 10 watts and a Velocity of 1143 mm per second (45 inches/sec). On the Format tab, we set the 2D Barcode Bitmap property to No and set a 2D Barcode Circle Radius of 45%. Those last two steps force WinMark to create a vector circle at 45% of the cell size instead of marking a fully rastered cell. Using these settings, we were able to create 10-character 2D codes on the polyamide material in a cycle time of 0.26 seconds per part. We verified our codes with an RVSI vision system and achieved average barcode read rates of 8 milliseconds per read.
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Search our online library for more applications of Synrad's sealed CO2 laser technology. Sort by material, process, or industry. |
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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. |
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