SYNRAD, INC. - http://www.synrad.com  
Thursday, February 5, 2009
Issue 205

Cutting Thermoplastic Elastomer Polyolefin
(TPO)

Marking Vinyl
(PVC) Fabric

Marking Ceramic
SMT Components

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.


Cutting Thermoplastic Elastomer Polyolefin (TPO)

Thermoplastic Elastomer Polyolefin (or TPO) is unique among thermoplastics because it does not contain plasticizers. This means that TPO-based products retain the same degree of flexibility regardless of ambient temperature. In addition, TPO is easily thermoformed (which lowers unit cost) and is easily recycled at the end of its product life. Because of these traits, TPO is the material of choice for manufacturing ski boot shells, ATV parts, imitation-slate roofing tiles, and many automotive pieces like fenders, bumpers, running boards, splashguards, and instrument panel skins.

For this application test, we were asked to determine edge quality, cut speeds, and power requirements when cutting 3.56-millimeter (0.14”) thick TPO sheets. Our cutting setup consisted of an XY table and cutting head fitted with a 127 mm (5.0”) focusing lens that provides a 203-micron (0.008”) spot with a 6.35 mm (0.25”) depth of focus. For this particular material, we used clean, dry air at 1.7 bar (25 PSI) as the assist gas.





This 0.14” thick TPO sample maintained the
same edge quality (clean edges with minimal
melting) when cut at power levels of 100, 200,
and 400 watts.

 


 

Our tests determined that TPO exhibits a very linear relationship between laser power and cut speed. Using 100 watts of power, we achieved cut speeds of 1.27 meters per minute (50 inches per minute) and reached 2.54 meters/minute (100 IPM) with 200 watts. During our final tests at the 400-watt power level, we obtained cut speeds of 5.08 meters/minute (200 IPM). In all test cases throughout the power range of 100 to 400 watts, TPO cut quality remained the same. As shown in the photograph, this material exhibits a cleanly cut edge with minimal melting.


Marking Vinyl (PVC) Fabric

Vinyl (also known as polyvinyl chloride or PVC) is one of those ubiquitous materials seen everywhere in modern life, in part because it is both water- and flame-resistant. At one end of the spectrum are vinyl products such as wire insulation, vinyl siding, and PVC pipe and at the other end of the spectrum are fabrics such as vinyl shoes, raincoats, and upholstery. Vinyl fabric is used in many outdoor applications, especially when exposed to the elements where UV and mildew/water resistance is important. This category includes seats and cushions for outdoor furniture, boats, automobiles, and ATVs.

All of these vinyl products exhibit one similarity—they provide a nicely contrasting image when marked with a CO2 laser. Vinyl fabrics exhibit the same high-visibility, high-contrast mark as seen on other PVC and PVC-coated products including tubing and wire insulation.

Our marking setup for this application consisted of a 25-watt laser, an FH Series marking head (equipped with an FLA125 lens), and a copy of our WinMark Pro laser marking software. The 125 mm lens provides a focused spot size of 180 microns (0.007”) with a 3 mm (0.118”) depth of focus over the extents of the mark field.







Both vinyl fabrics were marked using 25 watts
of power and exhibit sharp, high-contrast images.
The black vinyl was marked at a speed of 50
inches per second and the gray fabric was
marked at 75 inches per second.

We created the SYNRAD graphic in WinMark Pro’s Drawing Editor using an Arial TrueType outline font at a Text Height of 11.1 mm (0.4375”). We used 25 watts of power for both samples—the black vinyl sample was marked at a Velocity of 1270 millimeters per second (50 in/sec) in a cycle time of 0.47 seconds while the gray vinyl was marked in 0.38 seconds at a Velocity of 1905 mm/second (75 in/sec).

 

 


Marking Ceramic SMT Components

Surface mount technology (SMT) components are used extensively in manufacturing electronic circuit boards due to their small size and compatibility with automated assembly processes. Because of their small size, component identification becomes an issue as labels are impractical and ink-jet marks are difficult to read when character sizes are very small.

The best solution for marking very small characters or codes is laser marking due to the laser’s small focused spot (116 microns or 0.005” for an 80 mm lens). Generally, minimum character size should be seven to ten times the focused spot size for best readability and character quality. Actual character size can vary depending on the material composition—how it reacts to the CO2 wavelength—and mark velocity—where, in some cases, tip writing can produce marks that are smaller than the focused spot diameter.


 





The 0.032” tall characters on this 2.5 mm x 3 mm ceramic SMT capacitor were marked using 9 watts
of power at a speed of 9 inches per second in a
cycle time of 0.35 seconds per part.

In this application, we were asked to mark an eight-digit identification code on ceramic surface mount capacitors that measure only 2.5 mm by 3 mm (0.098” x 0.118”). To perform this task, we set up a Synrad CO2 laser with an FH Series marking head and installed an 80 mm focusing lens that provides a 116-micron (0.005”) diameter spot with a 0.8 mm (0.032”) depth of focus.

Using our WinMark Pro laser marking software, we created an eight-digit code using “Simple”, one of WinMark’s twelve built-in stroke fonts. For Power, we set a duty cycle percentage corresponding to nine watts and then set a marking Velocity of 229 millimeters per second (9 in/sec). With these parameters, we marked eight highly-legible characters measuring only 0.82 mm (0.032”) high in a cycle time of 0.35 seconds per part.


Browse Synrad's Applications Database

Search our online library for more applications of Synrad's sealed CO2 laser technology. Search by keyword, material, or process.
http://www.synrad.com/search_apps/Default.htm

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