Engraving Materials
Last updated
Last updated
In 3D mode, we can adjust the laser power (wattage) for each dot individually.
In basic raster engraving mode, every dot gets the same laser output.
n 3D mode, the laser fires continuously between most dots, ensuring a gradual change in engraving depth when transitioning between shades of gray.
This excludes transitions from 100% black to 100% white (or vice versa).
Because of this laser behavior, adjustments to the artwork are necessary, making 3D engraving more challenging.
In this sample, the black background would be engraved away. Using this technique, the leaf stands up away from the background, with the edges of the leaf being the highest points and the stems being engraved the deepest.
This image would engrave deepest around the edges of the leaf and less deep in the body.
Acrylic -in all its different forms - has been shown to be especially flammable when cut with the laser.
There are two types of acrylics and each is suitable for different applications.
Cast acrylic sheets and objects are made from a liquid acrylic that is poured into molds that can be set into various shapes and sizes. This is the type of acrylic used for the awards you see on the market. Cast acrylic is ideal for engraving because it turns a frosty white color when engraved. While it can be cut with a laser, it will not give you flame-polished edges.
Fire Warning: Your laser system's high-intensity beam can generate extremely high temperatures, potentially igniting flammable materials and causing dangerous open flames. This poses a risk to both the machine and the building.
Extruded acrylic: Will form into sheets once used with laser. It is formed through a higher-volume manufacturing technique, so it is typically less expensive than cast, and it reacts very differently with the laser. Extruded acrylic will cut cleanly and smoothly and will have a flame-polished edge when laser cut. But when it is engraved, instead of a frosted look you will have a clear engraving.
Most acrylic is engraved on the backside to produce a look-through effect from the front surface.
Remove the protective adhesive paper from the back of the acrylic before engraving. Since you are engraving the backside of the acrylic, you will need to reverse or mirror your artwork before sending the job to the laser.
Engrave the acrylic at a high speed and low power. A small amount of power is all it takes to mark acrylic and high-power levels tend to distort the acrylic when engraving.
Anodized aluminum is a coated aluminum that comes in a variety of colors and can usually be easily engraved with a CO2 laser.
Black anodized aluminum is great to work with because it turns white when engraved and provides the best contrast of all of the colors of anodized aluminum.
Some colors of anodized – red for instance – will not turn completely white when laser engraved.
Red anodized will produce a light pink color.
Performing a second pass can result in some improvement, but usually a slight shadow of color will remain.
Engrave anodized aluminum at high speeds and low powers for crisp, clean results.
Too much power applied to the anodized coating will distort the engraving and tends to over-burn the image.
Since the frequency of the CO2 laser is not compatible with bare metals, uncoated brass cannot be laser engraved.
In order to engrave brass with a CO2 laser you need to use brass that has some sort of coating – typically paint.
The laser removes the paint and exposes the brass substrate.
Painted Brass Engraving Techniques
Engrave painted brass with a high speed and low power setting.
It takes very little power to remove the paint coating and too much power will melt the paint and distort the image.
Caution: When engraving brass-coated pens, avoid those with hard epoxy paint unsuitable for CO2 lasers. Use only pens tested or designed for CO2 laser engraving. Many pens fit for fiber lasers don't work with CO2 lasers.
When a laser strikes glass it fractures the surface, but it will not engrave deeply or remove material.
The fracturing of the glass surface will produce a frosted appearance but can cause roughness and chipping depending on the type of glass being engraved.
While the frosted appearance is desired, the roughness and chipping are not.
Glass Engraving Techniques
To produce a smooth frosted finish, here are some tips:
300 DPI: Using a lower resolution, around 300 DPI, produces a better result on glass as you separate the dots you are engraving.
Masking: Some people find that applying a thin, wet sheet of newspaper or paper towel a little larger than the engraving area also helps with heat dissipation and improves the engraving. Just be sure that there are no wrinkles in the paper after it is applied.
Dish Soap: Using your finger or a paper towel, apply a thin coat of liquid dish soap – any kind will do – over the area to be engraved. This will dissipate the heat when engraving.
Polish: If there are small shards of glass, you can polish the area with a ScotchBrite pad or something similar.
Note: Be cautious when laser engraving leaded crystal. The differing expansion rates of lead and crystal can cause cracks. Using a lower power setting may help, but always have a spare in case of breakage.
Notary seals can be easily manufactured using 1/16-inch (1.5 mm) thick delrin plastic.
A seal consists of two pieces - a male die and a female die, both shown below.
The male die consists of white lettering on a black background and the female die is an inverted and mirrored image of the male.
Inverting and mirroring are easily accomplished in most graphics software packages. Simply duplicate the male die, invert the black and white colors, and then mirror the image.
The male image should be produced without the use of outlines around the text or graphics. Add a .007 to .010 inch (0.178 mm to 0.254 mm) outline to the text and graphics of the female die. This outline creates a large enough void between the male and female dies to emboss paper without tearing.
Apply a .001 outline around the seal to define the outside edge of the seal. Use the Combined Mode to first raster engrave the seal and then vector cut out the seal.
There are two types of available engraving plastics:
Rotary plastics:
Rotary plastics are designed for rotary engraving systems that use a mechanical spinning bit to remove material.
Therefore, the depth of the top layer or “cap sheet” was designed to make it easy to rotary engrave.
Cap sheet thickness was approximately .010 inches (0.254 mm) thick and laser engraving was nearly impossible because by the time you applied enough power to get through the cap sheet the laser melted and deformed the plastic.
Laserable plastics
Laserable plastics have been developed with a thinner cap sheet that is .002” to .003” (0.051 mm to 0.076 mm) thick, providing much better engraving and cutting characteristics.
These plastics are commonly referred to as micro laminates; micro-surfaced, or simply laser engraveable plastics.
These plastics are generally very easy to engrave with a laser since they all have similar characteristics.
Choose the Right Plastic
Because there is such a broad range of plastics it is necessary to experiment to determine if a particular type of plastic is laser compatible.
Different color plastics, even if they are from the same manufacturer, will have unique speed and power settings.
If you do not get acceptable initial results with the recommended speed and power settings, start experimenting by first changing only the power setting.
If adjusting the power setting does not work, start over and adjust only the speed setting.
Once you have acceptable results, record those settings for that particular plastic so that you do not have to repeat the experimentation process.
WARNING! Do not engrave PVC (Polyvinyl Chloride). PVC will destroy the optics and mechanics of your Epilog system. Cutting or engraving PVC will void your warranty.
Plastic Engraving Techniques
Always remove the clear protective cover layer before engraving.
Once you have the correct speed and power settings you can improve your engraving results even more by taking the focus lens out of focus (lower the table) by about 1/16 (1.5 mm) of an inch.
This technique enlarges the focus beam a little bit and provides more beam overlap on each pass of the laser.
The greater overlap produces a smoother engraved surface on the plastic and eliminates the grooves that you sometimes see when engraving plastic.
With some plastics it is best to engrave using two passes. The first pass cuts through the cap layer and the second pass cleans away the residue that some plastics leave behind.
Another technique that can be useful is to mask the plastic before engraving with transfer or masking tape.
This will prevent a buildup of residue on the plastic surface. Misting the transfer tape with water will reduce heat buildup and melting on sensitive plastics.
The Dashboard includes settings for producing rubber stamps. Unique stamp attributes – shoulders, widening and more – are controlled in the Advanced tab of the Dashboard after setting the engrave type to “Stamp”.
Creating Your Layout for Stamps
Set up your artwork in Corel so that your computer image looks like the image that you want to stamp.
Areas to be stamped (the raised areas on the stamp) should be black, with the area to be removed white.
The artwork for a stamp file needs to be set up so that the background of the image will be engraved away and the words and letters remain standing.
The two ways of setting up a stamp file are determined by the method you use to define the area that is to be engraved away:
Outside Vector Method:
When a job is sent to the Dashboard, hairlines are separated into a vector process to determine the fence.
This method saves time and material by precisely controlling background engraving.
The outside vector must be 0.003” or less thick and can be any closed shape.
Multiple stamps can fit within one vector.
This method uses a closed outline to define the engraved area.
The laser removes only the background within the Fence, leaving the logo intact.
Bounding Box Method:
Creating Perforated Cuts: Set the vector frequency to 1 or 2 in the print driver.This allows easy removal while keeping the stamp attached for cleaning.
Example 1: Single stamp (will not be cut out)
Example 2: Single circular stamp to be cut out
Example 3: Multiple stamps to be cut
Example 4: The file contains multiple fence lines that will be cut out.
Once you have successfully setup your stamp artwork, you are ready to print your design. In the Dashboard go to the Advanced tab. Under “Engrave Type” select “Stamp”.
Shoulder Settings
The Shoulder setting in the Dashboard adjusts the character shoulder angle. Higher numbers give a wider angle and more support. Users often prefer the default setting of 0.020”.
Widening Settings
The Widening setting in the Dashboard adjusts the character width at its top. A higher value makes the character bolder. The default setting of 0 is often ideal.
Fence
Choose between "Outside Vector" and "Bounding Area." Use Outside Vector with a vector line around the artwork. Use Bounding Area to create a box-shaped fence around the artwork.
Wood is very laser-friendly because it can be easily engraved or cut.
Lighter woods like Cherry or Maple show great contrast when engraved, making them popular for laser work.
Many wood products are designed for laser use, with more to discover.
Epilog recommends that when working with wood other than the ones listed in this section that you investigate the engraving and cutting characteristics before committing to use.
The most common woods used with the laser are Cherry, Walnut, Maple, Alder, & Oak.
These woods are considered hard woods, and have grains that work well with lasers.
Cherry and alder are the most popular woods for engraving. The light, red color of these two woods provides an excellent contrast when engraved.
MDF is an engineered wood product with glued together wood fibers.
Since there are not layers of wood glued together, like in the plywood, the engraving and cutting is much better.
You will produce some charring on the edge of MDF when cut, so you may need to sand the edges after cutting.
Wood Engraving Techniques
To create a quality image on wood, contrast and depth are usually desired. The higher the power levels, the higher the contrast and depth will be.
Speed and Power Settings: The downside is that it takes a lot of power to deeply engrave wood at high speeds.
Most wood can be engraved using full power no matter whether you are using a 30-watt laser or a 120-watt laser.
Depending on the wattage of your laser, the best approach is to set the laser power at 100% and adjust the speed to obtain the desired depth.
Resolution Settings: Wood is a very easy material to work with and you can produce very nice detail with as little as 300 DPI engraving. 600 DPI engraving into wood produces fabulous results, especially on photos
Gray Scales: Gray scales look wonderful when engraved into wood, offering great contrast due to varying reactions at different gray levels. Experiment with clipart by ungrouping it and changing colors from dark red to light yellow before engraving. This creates a shading effect that appears almost 3
Warning: FIRE WARNING: Wood is combustible. Never leave the laser unattended while cutting. Use air assist to minimize flaming caused by excess laser power. See page 1 of the manual for details.
Examples of stamp layouts using Fence Method:
