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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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Products based on high-density polyethylene (HDPE) are commonplace in everyday life. Its purity means that HDPE products are approved by the FDA and USDA for direct contact food-grade use. Blow-molded HDPE jugs are used to package milk, water, and fruit juices as well as detergents and motor oils. Injection molding processes produce HDPE yogurt and margarine containers. Because HDPE also resists solvents and acids, sheets of HDPE are used as containment liners to prevent soil and groundwater contamination in sanitary landfills. In this laser-drilling application, the task was to drill 0.71 mm (0.028”) diameter holes through the rim of blow-molded HDPE containers. Our drilling setup consisted of a Firestar f201 (200W) laser and a fixed beam delivery system containing a 127 mm (5.0”) positive meniscus lens.
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This optic provides a 203 micron (0.008”) focused spot with a 6.35 mm (0.25”) depth of focus. In addition, we used an air assist at a pressure of 3.4 bar (50 PSI) to eliminate any melting or heat effect in the drilled area. To produce the desired hole diameter of 0.71 mm (0.028”) with our 127 mm lens, we fixtured the part approximately 5.1 mm (0.20”) out of focus. Using a PWM frequency of 5 kHz, we set a power level of 200 watts and fired the laser for 0.22 seconds. The resulting hole diameter in the 1.8 mm (0.07”) thick HDPE material meets the customer’s specification precisely with no charring or melting of the surrounding material.
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As electronic circuit boards become smaller and more densely packed, it becomes difficult to find room to place part numbers and manufacturing data. The solution to this loss of board space is to create and mark barcodes that are more compact. When choosing a barcode type, the best solution is often a 2D code—either Data Matrix or QR Code—because of their compact size and large data capacity. Most linear barcodes require a considerable amount of horizontal space even when encoding only a few characters. This customer application demonstrates the types of small-scale marks you can create using Synrad CO2 lasers and marking heads. The goal was to create very small 2D codes, with individual cell sizes around five mils (0.005” or 0.13 mm), on FR4 circuit boards. Our marking setup consists of a 48 Series, 10-watt laser coupled to an FH Flyer marking head. The Flyer head was equipped with an 80 mm lens that produces a 116-micron (0.005”) focused spot across the mark field. The 2D Data Matrix code contains 32 characters and measures 2.54 mm by 2.54 (0.10”) square with individual cells measuring 127 microns (5 mils or 0.005”). On the Format tab, the 2D Barcode Bitmap property was changed to No, so WinMark Pro marks unfilled vector circles instead of filled squares, and the 2D Barcode Circle Radius property was set to 10%. On the Marking tab, we set a Power, duty cycle percentage, corresponding to 5 watts and a mark Velocity of 1397 millimeters per second (55 inches/second). Below the 2D code, we added a 42-character human-readable text object. We created the text using WinMark Pro’s Simple stroke font with a Text Height of 0.74 mm (0.029”) and added 0.13 mm (0.005”) of Extra Character Spacing for readability. The text string was marked using 5 watts of power at a speed of 381 mm/second (15 inches/second). We marked the 2D code and text object in a total cycle time of 0.41 seconds. By itself, the 2D code required only 0.25 seconds to lase. Our very small 2D code with five-mil cells is vision system readable and achieved “A” grades for percent contrast, axial uniformity, and error correction. |
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Yes, type 33-expansion borosilicate glass can be engraved! This type of glass has two primary components—boric oxide (13%) and silica (80%)—giving it a linear coefficient of thermal expansion (CTE) of 3.3 PPM/°C at 20 °C, which is the source of the term “33 expansion”. As a reference, diamond has a CTE of 1.0 while the CTE of 304 stainless steel is 17.3. Compared to common soda-lime glass, borosilicate glass has higher thermal capacity, higher chemical resistance, and provides superior light transmission. Because of these properties, there are widespread uses for borosilicate glass in home appliances (in ovens, fireplaces, and furnaces), in industry (for items like sight glasses and chemical vessel linings); and in the fields of biotechnology, optics, and photovoltaics. For this particular application trial, we were asked to create grooves along the length of a borosilicate tube as shown in the first photo. Our engraving setup consisted of a Firestar f201 laser coupled to an FH Series marking head that was equipped with a 200 mm optic to obtain a 290-micron (0.011”) focused spot with a 5 mm (0.196”) depth of field. After creating a single rectangular polyline measuring 1.4 mm (0.055”) wide by 91.4 mm (3.6”) long in WinMark Pro, we set the Array Columns property to 8 to create eight engraved bands and set Polyline Fill Type to Fill. We set Power, duty cycle percentage, to obtain 140 watts; Velocity to 3810 millimeters per second (150 inches/sec); Resolution to 300; and finally, the Mark Passes property was set to 150. This last step enabled us to repeat 150 high-speed passes in order to control both heat input and engraved depth into the glass.
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At these settings, we were able to engrave eight bands in the borosilicate glass tube, each to a depth of 0.38 millimeters (0.015”), in a cycle time of 90 seconds per tube. As seen under the microscope in the second photo, the grooves are clean and smooth with no fracturing. Microscopic air bubbles entrained in the grooves are evidence the glass was liquefied to a molten state during laser processing.
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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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