Newsletter 141: Cutting Polyethylene Foam, Marking PVC, Cutting Glass

SYNRAD, INC. - http://www.synrad.com
Thursday, July 13, 2006
Issue 141


Cutting Polyethylene Foam	Marking PVC Tubing	Cutting Thin Glass Substrates

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 Polyethylene Foam

Closed cell polyethylene foam is a moisture-resistant material tough enough to cushion equipment for shipment, resilient enough to cushion knees while gardening, buoyant enough to use in life vests, and durable enough to serve as a joint filler in building construction.

This application tested the feasibility of cutting 9.5-mm (0.375”) thick cross-linked polyethylene foam on a large-area XY table. Our cutting setup is powered by a Firestar f-Series f201 laser with the beam directed through a set of turning mirrors into the cutting head. The head holds a 63.5 mm (2.5”) positive meniscus optic with a 100-micron (0.004”) focused spot and a 1.8 mm (0.07”) depth of focus. Because the foam acts as a waveguide, the short depth of field does not affect edge quality significantly and we gain the higher power density of the 100-micron diameter beam.

Using 200 watts of power, we were able to cut polyethylene foam at a speed of 325 inches/minute.

Using 1.4 bars (20 PSI) of clean, dry air and 200 watts of power, we were able to cut the sheet of closed cell cross-linked polyethylene foam at a speed of 8.25 meters per minute (325 inches/min). The cut edge is exceptionally clean with no discoloration or melt back and exhibits the same resiliency as the rest of the foam sheet.

Marking PVC Tubing

Polyvinyl Chloride (PVC) is one of the few plastics that exhibits high-contrast marks when exposed to the 10.6 micron CO₂ wavelength. Whether extruded as tubing or molded as a component, PVC products are easily laser marked using low powers at high scan speeds.

For this PVC tubing project, the customer’s requirement was to mark a 19-character identification number. To begin, we setup a text object in WinMark Pro using the Simple stroke font. Text Height was set to 4.1 mm (0.163”) and we added 0.28 mm (0.011”) of Extra Character Spacing to increase readability. On the Marking tab, we set a Velocity of 1905 mm/second (75 “/s), a Power (duty cycle percentage) corresponding to 10 watts and a Resolution of 300. Using these parameters, we created lightly engraved, high-contrast marks in a cycle time of 0.14 seconds per mark.

Nicely contrasting marks were created using
10 watts in a cycle time of 0.14 seconds per mark.

Cutting Thin Glass Substrates

Many medical and consumer products are designed and manufactured using thin glass substrates including TFT and LCD displays for flat-screen monitors and cellphones. Thin glass, measuring only 30 microns to 600 microns (0.0012” - 0.0236”) thick, is easily cut with CO₂ lasers and exhibits the same fine edge quality seen in many other laser cutting applications.

Thin glass cutting is an easy one-step cutting process where the laser is typically gated, or pulsed, to control heat input into the glass. The section of glass shown in the photo, measuring 150 microns (0.006”) thick, was cut on an XY table equipped with a 2.5” positive meniscus focusing optic that provides a 100 micron (0.004”) spot size and a 1.8 mm (0.07”) depth of focus. For gas assist, we used 10 PSI of compressed breathing grade air.

Thin glass substrates measuring only
30-600 microns (0.0012-0.0236”) in thickness,
are easily cut with CO2 lasers.

Using 100 watts of power, we cut through the 150-micron thick glass sheet at a speed of 550 inches per minute (IPM) while an external frequency source connected to the UC-2000 Universal Laser Controller gated the laser on and off with 1.2 millisecond pulses at a frequency of 750 Hz.

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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