SYNRAD, INC. - http://www.synrad.com  
Thursday, July 27, 2006
Issue 142

Marking Powder-Coated Steel

Cutting Polyester Spacer Tape

 Kiss Cutting Sil-Pad

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 Powder-Coated Steel

Although SYNRAD CO2 lasers successfully mark bare steel and stainless steel using powers around 80–100 watts of power, our lower power lasers work very well when the part surface is painted or coated. An example of low-power metal marking is this 25 W application for marking powder-coated steel parts. As shown in the photograph, ablating the paint creates a very high-contrast mark.

The mark setup consists of an FH Series marking head equipped with a 200 mm lens that creates a 290-micron (0.011”) diameter spot with a 5 mm (0.197”) depth of focus. In our WinMark Pro laser marking software, we created a 20-character alphanumeric part number measuring 98.8 mm (3.89”) long with a Text Height of 8.95 mm (0.35”) followed by a filled ellipse measuring 2.54 mm by 7.62 mm (0.10” × 0.30”).


This high-contrast mark on a powder-coated steel surface was made using 25 W at a speed of 20 inches per second.

For both objects, we set a marking Velocity of 508 mm per second (20 inches/sec) at a Power (duty cycle percentage) equivalent to 25 watts. We then chose a marking Resolution of 300 for the stroke text object and 150 for the filled ellipse. At these settings, we achieved overall cycle times of 0.94 seconds to mark both the 20-character part identifier and the filled ellipse.


Cutting Polyester Spacer Tape

Double-coated spacer tape is used in product applications as a spacer between a membrane keypad and an appliance or equipment housing. For example, cutouts are made in the spacer tape using laser or die cutting to match the position of the membrane pushbuttons. After applying the spacer tape to the membrane panel, the entire keypad panel is aligned and adhered to the faceplate of the appliance.

For this customer application test, we cut both 14-mil and 5-mil double-coated polyester carrier tape (adhesive and liner paper on both sides of the spacer tape). Overall thickness, including adhesive and liner, was 0.63 mm (0.025”) for the 14-mil spacer tape and 0.37 mm (0.016”) for the 5-mil tape.








14-mil polyester spacer tape, coated on both sides with adhesive and liner paper was cut at 700 inches per minute using 200 watts of power.

Our cutting setup consisted of an XY table and cutting head fitted with a 63.5 mm (2.5”) positive meniscus lens that provides a 100-micron (0.004”) focused spot and a 1.8 mm (0.07”) depth of field. Using 200 watts of power and 1.4 Bars (20 PSI) of air assist, we achieved cut speeds of 17.8 meters per minute (700 inches/minute) on the 14-mil tape with an overall thickness of 25 mils. When cutting the 5-mil tape—with a total thickness of 16 mils—we achieved cut speeds of 35.6 meters/minute (1400 IPM). Cut edges are clean with only a slight melt back of the disposable paper liner.

Kiss Cutting Sil-Pad

Sil-Pad® is a thermally-conductive interface material developed for the electronics industry. This flexible silicone material is designed to conduct heat away from discrete components or circuit board assemblies into a heat sink, heat spreader, or equipment chassis.

In this application, specific component shapes are kiss cut away from the paper backing material and bonded to devices that are later installed on circuit boards. This particular thermal material is a fiberglass-reinforced silicone substrate coated with adhesive and covered by a paper liner on one side. The photograph shows a shape that was laser cut to fit a TO220 transistor case.

To cut this shape out of a sheet of Sil-Pad, we setup an FH Series marking head / Firestar t-Series (t100) laser combination and installed a 125 mm HP (high-power) lens. The 125 mm lens provides a 180-micron (0.007”) spot over an 80 mm by 99 mm (3.2” × 3.9”) mark field.





A piece of Sil-Pad cut to fit a TO220 transistor
case is shown next to a transistor with its thermal interface already applied. We cut this part in 0.34 seconds using 100 watts of power at a cut speed
of 8 inches per second.

 


To create the TO220 case outline in WinMark Pro, we simply drew an 11.4 mm by 16 mm (0.45” × 0.63”) rectangle and positioned a 3.2 mm (0.125”) circle for the mounting screw hole. Alternatively, we could have just as easily imported a CAD drawing of the TO220 outline into WinMark. To kiss cut the 10-mil (0.254 mm) thick Sil-Pad from its 7.5 mil (0.045 mm) liner, we set a Power—duty cycle percentage—corresponding to 100 watts and a Velocity of 203 mm per second (8 inches/second). At these parameters, parts are cleanly cut from the sheet at a rate of 1 part every 0.34 seconds.


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


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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