It's no secret. Acrylic, due to its strength, clarity, beauty and versatility, has earned a place of esteem in the awards industry. Add laser engraving to the mix and you can create a host of memorable and practical products.
Acrylic, by definition, is a thermoplastic, resin-based, plastic engraving substrate. Developed in the 1930's, acrylic has achieved great success due to its strength and beauty. In the awards and related industries, the applications are almost endless. Favorite product ideas include pyramids, paperweights, obelisks, POP displays, signage, stand-up plaques and a host of ad-specialty items.
Basically, acrylic is developed one of two ways-cast or extruded. Both methods produce quality acrylic. However, there are differences in how each type of acrylic reacts to a laser. Cast acrylic will frost when engraved by laser, a look that is desirable for many applications. Extruded acrylic tends to engrave clear and works well for deep engraving and color filling. It is available in clear through opaque, and in a wide range of colors and finishes. There are even a number of bright colors that can be used for a light-piping effect. For laser cutting, extruded acrylic works better, leaving a flame-polished finished edge, and it is also less expensive than cast acrylic.
Acrylic can be purchased in sheets that are ready to fabricate. This is an economical way to buy it. However, if you're going to fabricate it yourself, you will need the proper tools and expertise to do it. The other option is to buy pre-fabricated products that are ready to engrave. A variety of products, shapes and colors are available, and they can be purchased through industry suppliers or their distributors.
To laser engrave acrylic, one can engrave directly onto the piece, to produce an attractive surface etch, or reverse engrave the art for more of a three-dimensional look. Pieces with multiple sides (pyramids, obelisks, towers, etc.) can be engraved on more than one side for some interesting effects. Laser engraved acrylic can also be used in conjunction with other materials for a variety of unique looks. One example of this is to laser-engrave a flat piece of acrylic and attach it to a wooden board. Certificates, photos, diplomas, newspaper clippings, etc., can be "sandwiched" between the acrylic and the board for a truly unique gift or award. Also, acrylic does lend itself well to a variety of other imprinting methods, including pad printing, screenprinting, and mechanical engraving. By combining materials and imprint methods, you can create a host of creative products for your customers.
When engraving on acrylic, try low power and high speed. This will give you an attractive surface-etch. Actual settings will vary, depending on the machine, the material and the desired effect. Your machine manual and the supplier of your material may give you settings with which to start.
Acrylic does have a tendency to scorch or burn when exposed to the heat of a laser. Higher speeds will help, but for deeper engraving and certain applications, you might find that masking the piece with a low-tack, sticky-back paper will protect the acrylic from overexposure to the heat of the laser. If you are going to be adding paint, leave the mask on until the paint is applied and has dried.
Acrylic does tend to scratch easily. Avoid over-handling and leave the manufacturer's protective mask on all but the areas to be engraved. Use only soft and non-abrasive materials for cleanup.
Present-day laser-engraving machines were designed to also cut through thin materials. Acrylic is a good example of a material that cuts well with a laser. The manufacturers recommend 25 watts of power to cut through 1/4" acrylic; 50 watts of power will effectively cut 1/2" acrylic. The thicker the material, the slower your cutting will be, so it is always advantageous to use the thinnest material possible for the job you are doing. Multiple passes may also be required when you do not have enough laser power, or a slow enough speed setting to cut through the acrylic.
When cutting, you will want to elevate the acrylic off of the tabletop of the machine you are working with at least 1/8". This will allow for a freer airflow in removing heat, smoke and debris from the work area. This results in a cleaner cut with less "flash-back" on the bottom side of your cut piece.
When laser-cutting acrylic, most people like to remove the paper/poly or poly cover sheet supplied on the sheet of acrylic from the manufacturer. After removing the factory-supplied masking, try to use a paper mask with a self-adhesive backing on it. Another technique used when laser engraving and cutting acrylic is to use a newspaper-type paper-unprinted is the best. Dampen the paper, then apply it to the surface of the acrylic. Go ahead and do your engraving and cutting while the paper is still wet. This should give you a cleaner edge on your finished product. Any one of these mask or cover-sheet techniques should help the finish of your laser-cut acrylic, and protect the surface of the acrylic from unwanted scratches.
Another tip to use when cutting acrylic with a laser is to lower your focus down on your laser system. Rather than focusing your laser beam onto the surface of the material, move the focus one-third of the way down into the material. This should concentrate the energy of the beam for better cutting results. With a little experimenting, you might even be able to break the "hard edge" of the cut on either the top or bottom of the finished piece.
If you are going to be cutting a lot of acrylic, there are a variety of options, including cutting tables and air assist, that will help you cut cleaner and more efficiently. All of these accessories should make your job easier and your finished products much nicer.
If your job requires the addition of color, there are a variety of methods used to accomplish this. The first step, of course, is to make sure that your artwork is suitable for adding color. Detailed art or fine lines will not accept paint very well. You will also want to engrave at a deeper depth for color filling. Make sure the area is clean and dry prior to adding any paint.
Paint pens or magic markers can be used to apply the paint or mask the piece prior to laser engraving. After engraving, paint the engraved area. Water-based latex paints or enamels will work. (Be careful of solvent-based products when finishing acrylic. It might look great today, but tomorrow or the next day, micro-crazing on the edges of the laser-processed areas might appear.) When the paint is dry, remove the mask. Excess paint can be removed with products like WD40.
Again, acrylic does tend to scratch easily. Remember that any cleanup needs to be done with a clean, soft cloth.
Color can also be added through screenprinting, either prior to laser engraving or after. This does require special equipment and expertise. If you do not have the capabilities in-house, consider teaming up with a local screenprinter.
To attach acrylic to other surfaces, use what works. Some flat pieces will come with drill holes already in place. If you are cutting your own pieces out, laser cut your screw holes when you are cutting out your parts. Remember to use decorative or attractive screws that will add, not detract, from the visual appeal of the product. Make sure anything that you do attach is attached securely. Having a product fall apart later will reflect badly on you and your company.
Acrylic is a tried-and-tested product used for a variety of products in our industry. By combining acrylic with the versatility of a laser-engraving system, you are well on your way to creating many attractive and useful products for your customers.
By DIANE C. BOSWORTH