Welcome to The Laser Shop, a column dedicated to real life production for the professional laser engraver. Designed as a “refresher” for experienced laser operators, The Laser Shop will also update you on the latest techniques and materials. The Laser Shop is a great resource for new laser system users too and will help you create professional results in a short amount of time. In each issue we’ll tackle projects from the simple to the extreme. Stay tuned for this exciting series as practical, day-to-day laser projects are presented in detail. This issue’s project will include reverse engraving, assembling and readying for presentation a two-piece acrylic award. This is an existing ready-to-engrave award consisting of the main part of the award and the base. Our first step will be engraving the main part of the award and then we’ll attach it to the base. This particular award poses a small challenge in that its rounded edges make it difficult to abut against the ruler on the corner of the laser’s table, which makes positioning difficult, particularly if you’ll be engraving more than one trophy. Therefore, we’ll start by making a temporary positioning guide. Engraving on the main part of the award starts by first measuring the outside dimensions of the piece (Fig. 1). We’ll use these dimensions to create a position guide or temporary fixture on the engraving table of the laser. High tolerances are maintained in the manufacture of the award, however, as it’s cut and polished, the award size often varies slightly from one award to another. By creating and using a positioning guide for placing the acrylic blank in the laser, these size variations no longer become an issue. Continuing on to create the position guide, draw a rectangle in your layout software using the dimensions of the main acrylic piece (Fig. 2A). When drawing the rectangle, remove the fill color and apply an outline with a fine line thickness so that your laser will vector cut the outline. When using CorelDRAW, I set my line thickness to “hairline” for this purpose. Position the rectangle about an inch or more away from the top and left ruler. This will come in handy later when you’re positioning the acrylic part on the engraving table. Use the rectangle as your guide when entering the text and placing the logo. Use the rectangle to help center the graphics (when using CorelDRAW) by selecting all of the items to be centered and the rectangle, then use the hot keys Shift the letters “c” and “e” on the keyboard to center your artwork (c = top to bottom centering, e = side to side centering). |
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| Keep in mind, when creating a layout where the acrylic award has a beveled (or radius) edge on it, you’ll probably want to reduce the engraving area, since the bevel or radius visually encroaches into the space. The best engraving designs usually have enough room on all sides (margins) so the engraving doesn’t look too crowded. The final step in your graphic preparation is to mirror the graphic. You mirror the graphic because you’ll be engraving on the back side of the acrylic. With the mirroring done correctly the laser engraving will be right reading when viewed through the acrylic. To mirror the graphic (using CorelDRAW) start by selecting all of the items (Fig. 2B), then type Alt + F9, this will bring up the Scale and Mirror docker. Click on the button for “Horizontal Mirror” then click “Apply.” Your graphic is now ready to be laser engraved (Fig. 2C). Engraving your acrylic award is a two-step process. The first part is the printing of just the outer rectangle that you’ll use for the positioning template. The second part of the process is the printing of the actual engraving part of your graphic design. Start the printing process by placing a piece of medium tack paper mask (Fig. 3A) on your laser engraving table. I like to cover a much larger area than is actually needed with the paper mask and rub it onto the table by hand. Next, select just the outer rectangle portion of the graphic design. Print the rectangle by typing Ctrl + P. This is the hot key for the print function. When the Print dialog box appears, click the button for “Selected Object.” If you have the preview feature enabled, you’ll see just the rectangle in your preview window. Next, click on the “Properties” button to access the print driver for your laser system. Select a vector power and speed setting for cutting the paper mask material. These should be a moderate speed setting with a low power setting. With my 40 watt system I use a 20% speed setting and a 5% power setting for this operation. Click “OK” and print the job to the laser. Start the laser and cut the paper mask to create the positioning box on the engraving table (Fig. 3B). Upon completion of the cutting job on the paper mask, position your acrylic award top in the box that you just laser cut (Fig. 4). Take your time and carefully position the acrylic piece. Also, be sure the back side of the award is facing up. If the award has protective paper on it, remove it before you begin engraving. |
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Now you’re ready to engrave the award and the process is started by printing the engraving portion of the graphic to the laser system. In your layout program, select the mirrored graphic that you created and enter Ctrl + P. Again, the print dialog box appears; make sure the selected item button is clicked on. Click on the “Preferences” button to bring up the print driver for your laser system. Select a speed and power setting for the raster function. These settings for my 40 watt laser system are 100% speed and 50% power. I’m using an award that’s decorated with a colored marble finish. The power setting I recommend for this marble finish is 5% higher than is typical for a plain acrylic award without the marble finish. Start the laser and engrave on your acrylic award (Fig. 5). After the engraving is complete, do a visual inspection of the engraving before removing the award from your laser. You should see white colored engraving without a hint of the marble colored finish. This tells you that your laser has successfully engraved completely through the colored coating and into the acrylic. The engraving shouldn’t be too deep into the acrylic. You want it to engrave just slightly into the surface for the highest quality results. Now it’s time to fasten the award to the base (Fig. 6). For joining two pieces of clear acrylic, I prefer to have a strong but perfectly transparent joint. The easiest way to achieve this is to use a methylene chloride-type acrylic glue and a technique known as “solvent welding.” To do this, remove any of the protective paper masking on the base as well as the award top. Open your can of acrylic glue and draw some of the glue into the hypodermic-like applicator. Point the applicator tip vertically and push on the applicator to remove any air. |
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Position the base on a flat and level table or surface. Center the award top on the base. Carefully tilt the award top towards the back and guide the tip of the applicator to the back edge, where the award top is still touching the base. Gently squeeze the applicator and move it along the length of the award top. The thin glue will automatically draw into the joint where the top and base are touching. Gently tip the award top vertically keeping a visual as you work the air bubbles towards the front of the award. The result should be a perfectly clear, bubble-free glue joint. Allow at least two hours for the glue to dry completely. Two important and final steps not to be missed. One, apply a small sticker with your company and phone number for reordering and as general advertising. And two, polish the award with an acrylic polish (Fig. 7) before delivering it to your customer. A polished award sparkles with brilliance and this will make it the ultimate in professional products. Stay away from paper towels and window cleaner when polishing acrylic. Use only a super soft acrylic cloth and a polish like Novus 2 for scratch free results. Like any other engraving process, practice makes perfect. Plan ahead to make sure you have the correct materials and practice on a test piece to get the hang of how to create a professional project. Perfect presentation will pave the way to repeat purchases. |
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