In order to achieve a certain engraving effect on a specific material, it is required to absorb a certain amount of laser energy. This energy should be regarded as the laser energy absorbed by the material = laser power / engraving speed. Simply speaking, to increase the laser energy absorbed by the material, the laser power should be increased or the engraving speed should be reduced. As for the final method, it depends on the material and the final engraving effect.
In general users will avoid high and low speeds because that reduces productivity. In fact, it is not only the engraving speed that affects the engraving efficiency, but also the engraving accuracy. From our practical experience, the objects engraved with 500dpi and 600dpi precision are very different from the inside, and the time spent is about 20~30%. Under normal circumstances, users will use 500dpi to complete most of the work, and only use 600dpi or higher settings when cutting or when high-density energy is required, so the final engraving effect may be determined by the engraving material. New users generally do not have a very good understanding of the characteristics of materials, nor do they have a deep understanding of the engraving forms of different materials, which will inevitably cause certain losses to customers.
The following is an introduction to some commonly used engraving materials and their engraving performance methods, for reference:
First, the performance of grayscale
Ordinary mechanical engraving cannot engrave dots of different thicknesses in an economical way, so it does not have a grayscale representation.
Laser engraving realizes engraving in the way of dots, which has a natural advantage in grayscale performance. For this reason, the grayscale representation can be used as much as possible in the engraving design. The advantage of this is that on the one hand, the coloring process is reduced and the cost is saved; When the user is using it, first fill the graphics with different grayscales (the text must be converted into graphics first), select the black and white mode for the engraving output, and try the effects of different dots. The accuracy is generally not more than 500dpi.
2. Carving materials
A. Logs (unprocessed wood)
Wood is by far the most commonly used material for laser processing and is easy to carve and cut. Light-colored woods like birch, cherry, or maple are well-gassed by the laser, making them more suitable for engraving. Each wood has its own characteristics, and some are denser, such as hardwoods, which require higher laser power when engraving or cutting. We recommend that you first study the engraving properties of unfamiliar woods before engraving.
Sometimes customers may ask you to engrave on plywood, in fact, it is not much different from engraving on wood, just a little attention, the engraving depth should not be too deep. The glued back edges after cutting will also turn black like wood, the key is to see what kind of wood the plywood is made of.
The depth of the laser engraver cutting wood is generally not deep, within 5mm, this is because the power of the laser is small, if the cutting speed is slowed down, the wood will burn. For specific operations, you can try to use large-sized lenses and use the method of repeated cutting.
After wood carving, there will generally be a feeling of being burned, and it has a primitive artistic beauty that matches the wood background color. The depth of the color mainly depends on the laser power and carving speed. However, some woods are usually softer. , you can't change its color no matter what (eg: birch). Sometimes customers may ask you to color the finished product, you can use acrylic paint.
2. Density veneer
A. Ordinary density veneer
This type of MDF is the kind of wood pallet we often use for sign linings. The material is high density board with thin wood grain on the surface. The laser can engrave on this cutting-edge material factory, but the color of the engraved pattern is uneven and black, and generally needs to be colored. Usually you can use a 0.5mm two-color plate for inlays to get better results by learning the proper design.
B. Laser-specific density veneer
Some MDF is specially designed for laser engraving, and the engraved pattern is uniform in color, and it has a good effect without coloring.
C. to clean
The MDF surface can be cleaned with a damp cloth after engraving.
Acrylic or alkyd paint can be used. When engraving, the color of the graphics can be set to 60% grayscale, so that the bottom surface of the engraving is somewhat pitted to improve the adhesion of the color.
3. Acrylic (a faceted glass)
Acrylic is the most commonly used engraving material after wood, it is easily cut and engraved by laser engraving techniques, comes in a variety of shapes and sizes, and is relatively inexpensive. There are two production processes for plexiglass: casting and calendering. Laser engraving mainly uses plexiglass produced by casting, because its frosting effect after laser engraving is very white, which is in sharp contrast with the original transparent texture. Laser engraving technology, calendering The plexiglass produced in this way is still transparent after laser engraving, without a sufficient contrast effect. When you buy a face off work, you should emphasize to the dealer that it is of high purity, otherwise the purchased material may melt when engraving or cutting.
In general, plexiglass is engraved on the back, that is to say, it is engraved from the front and viewed from the back, which makes the finished product more three-dimensional. When engraving on the back, please mirror the graphics first, and the engraving speed should be fast and the power should be low. If the power is too high during engraving, uneven stripes will appear on the bottom surface. If you want to carve deeper, you can try to carve several times. In the case of back carving, the local coloring should be carved deeper first, and then polished with a flame polishing machine before coloring can be added. Without polishing, the color seen from the front will not be uniform.
Plexiglass is relatively easy to cut. If the customer's requirements are not high, it can be delivered after cutting without the need for flame polishing. Otherwise, the blowing device should be used when cutting to improve the quality of the cut. When cutting plexiglass over 8mm, the larger lens should be replaced.