SYNRAD, INC. - http://www.synrad.com  
Thursday, April 29, 2004
Issue 86

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.

Marking Common Plastics

TYGON tubing




Urethane Tubing



Nylon 11 Tubing



Polyethylene Tubing

The four tubing samples shown with this application illustrate typical marks obtained when using CO₂ lasers to mark plastic components. This application was not developed to determine maximum mark speed or optimum mark quality, but rather to demonstrate the different marking mechanisms seen when working with various plastic types.

TYGON^® is a clear laboratory/chemical grade of PVC tubing which produces a lightly engraved, high contrast mark. Other types of PVC tubing and PVC coated wire also exhibit nicely contrasting marks. The contrast, or color change, is induced by heating of the substrate. Mark velocity was 30 inches per second (IPS) using 14 watts of power.

The urethane (green) tubing provides an engraved, non-contrasting mark. At a power setting of 14 watts, urethane tubing marks slightly slower than PVC at a velocity of 25 IPS.

Nylon 11 (red) tubing exhibits a slight contrast caused by a combination of engraving and a light melt-back on each side of the depression. Marking speed was 20 IPS at a power level of 26 watts.

The last example, polyethylene (blue) tubing, provides a slight contrast caused by yet another type of marking mechanism – surface melting. Instead of engraving by material removal, the polyethylene tubing melts at the surface, changing density and volume. This property change on the tubing surface creates a raised mark. Mark speed was 10 IPS using 33 watts of power.

Other dark-colored plastics such as phenolics (including Bakelite) and polycarbonates typically exhibit engraved marks; however, at very low powers (less than 10 watts) these plastics will also mark through the surface melting mechanism, creating a high contrast mark. Careful control of speed and power causes the surface to boil (instead of vaporize) and then quickly cool, which produces a raised mark. The dramatic change in density and volume causes this raised mark to appear much lighter than the surrounding darker surface.

All marks for this application were made using an FH Series marking head fitted with a 125 mm lens. Focused spot size was 180 microns (0.007”) with a 3 mm (0.118”) depth of focus.

Marking FR4 Circuit Boards Directly

Circuit boards, as well as most other components in the manufacturing supply-chain, are bar coded to allow tracking throughout the process from raw board creation to final assembly. Bar coding solutions include affixing pre-printed labels, ink-jet printing, or laser marking. In laser marking applications, marks are typically made on a laser-markable label or ink patch to prevent damage to the FR4 substrate because direct marking frequently results in pinholes through to the underlying copper layer.

The Synrad Applications Lab has developed a set of marking parameters that enable direct 2D coding of FR4 without introducing pinholes into the copper layer. To accomplish this task, we set up an FH Series marking head with a 125 mm lens (180 micron spot size with a 3 mm depth of focus) and then developed a mark file using WinMark Pro laser marking software. In WinMark, we created a 14-character 2D Data Matrix code and set Velocity to 35”/second, Power to 6 watts (duty cycle percentage depends on the laser used), and Resolution to 500.

On the Format tab, we set the 2D Barcode Bitmap property to No (so that we mark unfilled vector circles instead of raster-filled squares) and reduced 2D Barcode Circle Radius to 50%. The resulting code marked in a cycle time of 0.26 seconds and features a cell size of just over six mils (0.00625”) with an overall code size of 0.1” square. We verified code readability using an RVSI CM4000 vision system.

Marking Glass Bottles

Combine SYNRAD’s success in laser marking commercial, automotive, and residential glass products the past several years with the need to add inventory and batch control traceability to consumer products and the result is this bottle marking application.

 A SYNRAD sealed CO₂ laser, FH Series marking head, and WinMark Pro laser marking software provide the ability to mark text and even graphics on glass bottles or containers. WinMark Pro allows the user to mark the same batch or lot number on a specific number of bottles, to serialize individual bottles or batches, or to mark specific information sent from a host computer or server.

This 14-character text object marked in a cycle time of 0.21 seconds. Mark Velocity was set to 19.6 inches per second with 22 watts of Power at a Resolution of 750. We used WinMark Pro’s built-in Simple stroke font with a Text Height of 0.125 inches. Spot size of the 125 mm focusing lens is 180 microns (0.007”) with a 3 mm (0.118”) depth of focus. In a continuous motion application with an FH Tracker marking head, line speeds up to a maximum of 95 ft/min (29.1 m/min) are possible.

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

Do you have an interesting application using Synrad Lasers?  Would you like to see it published in the Synrad Newsletter?  We would love to hear from you!  Please send your story ideas to: editor@synrad.com

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