Universal Laser Systems ULS-25PS, Operation Manual

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ADDITIONAL COMMENTS
There are two types of acrylic available, cast and extruded. Cast turns white or frosted
and extruded remains clear when engraved. Use extruded acrylic for paint filled
engraving and cast for regular engraving. Cast engraves better without masking.
Lightly engrave the surface to frost it with a low power setting such as the first setting
listed above. If deep engraving is desired, it is necessary to mask the acrylic with
transfer tape to prevent the smoke from damaging the clear surface of the acrylic.
However, another problem with deep acrylic engraving is that the intense heat creates
a white, crusty, deposit that accumulates along the edges of the area that was just
engraved and is impossible to remove without causing damage. Engraving lightly and
without masking seems to be the better all around alternative.
If only cutting acrylic, extruded works better and is less expensive than cast. The cut
edges of extruded acrylic will appear to be more highly polished and clearer than cast
acrylic when laser cut. When cutting acrylic, it might be necessary to remove both
sides of the original masking and re-mask with transfer tape if cutting through the
original masking produces flaming. The original masking is coated with wax and will not
absorb water. If cutting through very thick acrylic, re-mask both sides with transfer tape
and dampen the masking on both sides of the acrylic with water from a spray bottle.
Elevate the acrylic off the table at least 1/8 inch, re-focus, then proceed to cut.
Elevating the acrylic will allow the beam to completely pass through the material which
allows the smoke and heat to escape from underneath. If cutting directly on the
engraving table, the trapped heat might cause the bottom edge of the cut to pit and
distort. Re-masking and dampening with water will act as a heat sink to pull the laser
heat away from the cutting area resulting in less distortion or heat effected zones (HAZ).
When dampening, be sure not to leave puddles of water. Puddles of water will reduce
cutting depth significantly. For the best results when combining engraving and cutting
on the same piece, first engrave lightly and unmasked. Then mask with transfer tape,
dampen, elevate, re-focus, and cut as a second step.
Paint filling the engraved area is possible by first masking the acrylic or leave on the
original masking then engraving through the masking. Before removing the masking,
brush or spray on some acrylic based or water based paint right on to the masking.
When the paint is dry, remove the masking and the paint will remain in the recessed
area of the engraving. Remember to use extruded acrylic when paint filling and cast
acrylic when simply engraving.
WARNING:
Acrylic is extremely flammable. Do not leave the laser system unattended
when cutting or engraving.
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