There are two types of images that your laser engraver will work with – raster images or vector images and the question is raster or vector better. The two are just different types of computer graphics. So, what is the difference between the two? And which one is better?
Is raster or vector better for laser engraving? Vector images are typically more versatile and flexible than raster images. Working with vector images is a lot easier e.g. you can easily resize it to any size you so wish without pixelating it – there is no upper or lower limit. Vector images are therefore a more popular option.
Using raster images for laser engraving
A raster image, also commonly known as a bitmap image, is comprised of millions of tiny squares which are called pixels. If you zoom into the image, you will be able to see each pixel’s square outline. You can especially see the pixels around the edges of the image because of the significant color contrasts.
- The computer-generated bitmap image made of pixels is interpreted by the laser engraving machine’s CNC controller.
- The laser keeps swiping back and forth across the area where it is working.
- The laser engraver uses the laser in an on-off pattern to individually engrave each pixel into the base material of the workpiece. It is a bi-directional process in which engraving is done in an alternating manner in both directions.
During the line by line engraving process, both axles run with different speed. The speed of the X axle (the axle where the laser-head is attached) is always higher than the Y-axle. The PPI (Pulses Per Inch) also plays a crucial role as it controls the density of the laser points.
Since it engraves one pixel at a time, raster engraving is somewhat slow.
Using vector images in laser engraving
Vector images are made of thin lines and curves which are known as paths. Each path is rooted with a mathematical formula that determines the shape, as well as the fill and border colors.
Vector image engraving is also known as “Scoring.” The CNC controller uses the series of linear X-axis and Y-axis locations and directions for the laser to point based on the image generated by the computer. The laser keeps following the instructions given by the computer and engraves the piece smoothly.
Once the file is imported from a graphics software, the outline is marked for vector engraving. The laser traces the image vector by vector and engraves it on the material. The axles move slowly but simultaneously to achieve a smooth engraving.
Vector engraving works the same as laser cutting except for the power settings. If you use a low power setting, you will get an engraved image but if you use a high-power setting, you will get a laser cut.
Vector engraving is perfect for flat materials and since it engraves in a continuous manner, the vector engraving is less time consuming than raster engraving.
Vector engraving Vs. raster engraving (appearance)
When it comes to appearance, vector engraving looks much finer than raster engraving because raster engraving is just one line thick. Vector engraving is used where finer details are required which is not possible with raster engraving. Vector engraving is therefore perfect for small items like jewelry and other decorative items.
Raster engraving, on the other hand, works perfectly for art-works that come with bolder appearance. The raster engraved artworks look more like 3D objects as the engraved areas are crafted on materials like wood.
Is Raster or vector better – which one should you use?
When to use vector engraving:
If you want to cut or engrave a 2D image on a flat surface, vector images would be the most ideal. Also, think of your desired end product – if you want to achieve an image that only has lines, vector engraving will be perfect.
In the below YouTube Video you will see how the laser beam follows the contour of the design or pattern; it scores the surface rather than cutting through the material.
Typically, this procedure is applied in two ways:
- To designate components where it is necessary to create a serial number or part number for a product in the most economical manner.
- To draw attention to engraved portions of a design or layout on wood, paper, or card, especially if there is a lot of detail and those portions need more contrast from the engraving.
Examples of items to make with vector engraving
- Different types of business signages
- Bookmarks and many other small 2D decors and mementos
- Jewelry, pendent and ear-rings engravings
The most commonly used materials for vector engraving are metal, wood, cork, paper and plastic.
When to use raster engraving?
If you are looking to achieve a 3D image, then you should go with raster images. Raster engraving works well with designs that require different depths of engraving. With raster engraving, you can engrave precise and intricate details onto your material. This is in fact the main reason why raster engraving is more time.
The removal of raster engraved portions is accomplished by the laser beam moving horizontally across the material’s surface from left to right. This warms the surface, causing it to either detach or fragment from the remainder of the surface, vaporizing the material away. Greyscale areas will be engraved with less depth than higher contrast parts, while white is left intact. Sections of the pattern that are filled are completely engraved.
Any material, including wood, leather, MDF, cork, paper, and card, responds nicely to this method.
In the below YouTube Video you can see how raster compares to vector engraving.
Examples of raster engraving projects
- Corporate photo plaques
- Engraved photo plaques which are used for gifting purposes
- Artsy home décor items
Raster engraving is mainly used on softer materials like wood and leather.
As we have seen, vector and raster images both serve distinct purposes so the choice of the best one to use will depend on what you are trying to achieve. But as a rule of thumb, use vector images for 2D image engravings and raster images for 3D engraving projects.