To get started with laser engraving, you need at least an entry-level laser engraver and some basic know-how of operating the machine.
To learn laser engraving, you need to understand how various factors such as the type of laser, workpiece material, design, optimal parameters, etc., affect the engraving process. While different lasers have different material capabilities, setting the optimal laser parameters will ensure uniform and high-contrast engraving on the workpiece.
This article will tell you everything you need to get started with laser engraving.
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Learn Laser Engraving: Absolute Basics
Laser engraving is the process of using a high-energy laser beam to remove the material from the surface of the workpiece, at the desired depth and in the desired shape.
However, the ability of the laser to engrave the material depends upon the type of laser being used.
On the other hand, a fiber laser is ideal for laser engraving metal workpieces.
Furthermore, a MOPA fiber laser provides the ability to produce color laser engravings on certain metals.
Apart from the type of laser, there are various other factors that affect the ability of the laser to produce quality engravings.
Sign-up for our Free 7-day Course on Lasers to learn more about laser cutting and engraving.
Selecting the Right Material
The selection of the right workpiece material is determined by the intended application and the type of laser you own.
Although diode lasers can be used for engraving almost every laserable material, they are less effective when engraving materials with bright colors.
Apart from that, a diode laser can even pass through transparent materials, without having any significant engraving effect on the workpiece.
Whereas a CO2 laser provides comparatively better flexibility as it can engrave almost every non-metal workpiece.
Furthermore, the thickness of the workpiece also plays an important role because engraving a soft and thin material can result in the loss of structural strength of the material, collapsing it under its own weight.
However, you can perform different types of laser engravings based on the thickness of the workpiece.
Preparing the Design
The design plays an important role in laser engraving as it directly affects the final engraving output.
Any deviation in the design will also result in the deviation of engraving from its required dimensions.
Generally, laser engraving involves raster design files that contain tiny pixels and each pixel is engraved by the laser individually.
As a result, raster engraving provides better control over the contrast and detailing of the engraving, making them ideal for applications such as laser engraving a photo on the workpiece.
On the other hand, vector designs are best suited for laser cutting but are also used for engraving lines and curves with small widths.
Raster engraving over a large area can often reduce the strength of the material and is therefore recommended to ensure that the depth of such engravings is not greater than half the thickness of the workpiece.
Apart from that, when preparing a raster engraving design, it is advised to remove any unwanted background from the image to highlight the subject of the engraving.
After removing the background, the image is turned into a grayscale model and you can alter its contrast and brightness to enhance the blacks and grays of the image.
You can use any photo editing software to prepare an image for raster laser engraving, and export it in formats such as .JPEG, .PNG, .BMP, .TIFF, etc.
Whereas, for preparing a vector design, you will need CAD software capable of generating vector files such as .SVG, .AI, .EPS, .PDF, etc.
You can get a detailed explanation of raster and vector designs in our Free 7-day Course on Lasers.
Adjusting Laser Focus
Laser focus is another factor that plays an important role in determining the quality of an engraving.
Setting the right focus ensures the smallest spot size with the highest laser intensity. As a result, a small spot size ensures clean engraving with tight dimensional tolerance.
However, an out-of-focus laser results in a larger spot size, which is often used to produce darker engravings on flammable materials like paper, that can catch fire under a high-intensity laser.
Furthermore, adjusting the laser focus also provides the ability to produce sub-surface laser engravings in glass and acrylic workpieces.
You can also use a rotary axis kit, coupled with a good laser for engraving cups, tumblers, and other cylindrical objects.
Setting Optimal Parameters
After ensuring the perfect laser focus, it is time to set the optimal laser parameters for your applications.
Laser cutting/engraving software such as LaserGRBL or LightBurn can be used to set the parameters for laser cutting.
Although you can refer to laser cutting thickness and speed charts to get the estimated optimal parameters for your process, these values are more of a reference rather than accurate parameters.
This is because each setup varies from the other and therefore requires a bit of trial and error to get the best-suited parameters for your application.
Therefore, it is strongly advised to perform test runs and find the optimal parameters before engraving the actual workpiece.
These test runs help you calibrate your laser focus and set the optimal values for various parameters like laser power, engraving speed, engraving resolution, etc.
Laser power determines the intensity of the laser being projected on the workpiece to perform the engraving.
High laser power can remove material at a faster rate and can produce darker engravings.
However, using an extremely high laser power can lead to fire hazards or melt the workpiece, making it important to regulate the laser power during the engraving process.
A 20W diode laser can be used to engrave a variety of materials such as paper, wood, glass, metal, etc.
Engraving speed is the speed at which the laser head moves along the workpiece to produce the desired engraving pattern.
A slow engraving speed results in longer dwell time, increasing the depth and contrast of engraving, whereas a fast engraving speed results in light engravings and can also lead to vibrations that affect the engraving quality.
However, the engraving speed is also dependent upon the laser power, making it important to set the perfect balance between power and speed to get the desired engraving output.
Generally, when using a 20W diode laser to engrave aluminum, an engraving speed of 8,500 mm/min at a laser power setting of around 65% power is recommended.
Engraving resolution is the number of dots per inch (DPI).
The higher the DPI setting, the better the detailing of the engraving.
However, the engraving resolution is limited by the spot size of the laser, as it cannot produce dots smaller than its spot size.
Therefore, increasing the DPI beyond a certain limit will result in overlapping of the laser engraving, thereby reducing the clarity of the engraved image.
Generally, 800 - 1200 DPI is recommended for good-quality engraving outputs.
Executing the Engraving Process
After performing the test runs and setting the optimal parameters for your application, you can execute the process to get the desired engraving output.
The design file is imported into control software, which then converts the design into G-codes and sends the command to execute the engraving process.
Although laser engraving is an automatic process, certain materials can cause fire hazards or produce harmful fumes, making it important to constantly monitor the process to avoid any accidents.
Furthermore, lasers can be extremely dangerous if comes in contact with the skin or eyes of the operator.
To get started with your laser engraving projects, all you need is a good laser engraver, prerequisite knowledge about laser cutting and engraving software, and optimal parameters for your application.
Different materials require different laser parameters, making it important to perform test runs.
Moreover, some materials, such as vinyl and PVC can produce toxic fumes and can damage the laser engraver. Therefore, it is important to ensure that the material is safe to be processed under a laser.
Although laser engravers are available in desktop designs suitable for indoor use, it is strongly advised to include a safety enclosure to limit laser exposure, preventing accidents.
Frequently Asked Questions (FAQ)
What are the basic requirements to get started with laser engraving?
The basic requirements to get started with laser engraving include a laser engraver, CAD software or photo editing software, the design, control software, and the material to be laser engraved.
Can I use a raster image for laser cutting?
Yes, you can use a raster image for laser cutting. However, it is more convenient and economical to use a vector design to make the cut in the material and remove the workpiece. For example, when performing a circular cut in the workpiece, the vector design will carve the circumference of the circle, resulting in the removal of the material, whereas, the raster design involves vaporizing the entire area of the circle to produce the desired cut.
Why does laser engraving produce smoke?
Laser engraving produces smoke because it involves vaporizing the material to produce the desired cut, which results in the burning of the material, generating smoke.