Gray scale representation
Ordinary mechanical carving cannot carve points of different thickness in an economical way, so it does not have the form of gray scale. Laser engraving is to achieve engraving by means of dots, which has natural advantages in grayscale performance. For this reason, the grayscale representation is used as far as possible in the carving design, which has the advantage of reducing the coloring process and saving the cost on the one hand; On the other hand, it enriches the means of expression of sculpture and increases the level of graphics. When using, users should fill the graphics with different gray levels (text should be converted into graphics first), and choose black and white mode for engraving output. You can try the effect of different dots, and the accuracy is generally not more than 500dpi.
1. Log (unprocessed wood)
Wood is by far the most commonly used laser processing material, which is easy to carve and cut. Light colored wood, such as birch, cherry or maple, can be well gasified by laser, so it is more suitable for carving. Every kind of wood has its own characteristics. Some are dense, such as hardwood, which requires more laser power when carving or cutting. We suggest to study the carving characteristics of unfamiliar wood before carving.
Sometimes customers may ask you to carve on plywood. In fact, this is not very different from carving on wood, but it is a little important to note that the carving depth should not be too deep. The edge of the plywood after cutting will also be blackened like the wood. The key is to see which kind of wood is used to make the plywood.
3. Wood cutting
The depth of wood cutting by laser engraving machine is generally not deep, within 5mm, because the laser power is small. If the cutting speed is slowed down, the wood will burn. For specific operation, try to use large-sized lenses and use the method of repeated cutting.
Methods of laser cutting and carving various materials
After wood carving, there will be a feeling of being burned. It has a primitive artistic beauty when matched with the wood background color. The color depth mainly depends on the laser power and carving speed. However, some wood is usually soft, and you can't change its color no matter what (such as birch). Sometimes customers may ask you to color the finished product with acrylic paint.
1. Ordinary density veneer
This type of density board is the kind of wooden pallet that we often use to make sign lining board. The material is high-density board, and the surface is pasted with thin wood grain. Laser can be used to carve on such materials, but the carved patterns are uneven in color and blackened, so they are generally colored. Generally, you can learn appropriate design and use 0.5mm double color plate for inlay to obtain better effect.
2. Special density veneer for laser
This kind of density board is specially designed for laser engraving. The carved patterns are uniform in color and have good effect without coloring
After carving, use a damp cloth to clean the surface of the density board.
Acrylic pigment or alkyd paint can be used. When carving, the color of the figure can be set to 60% gray scale to make the bottom of the carving have some pits, so as to improve the color adhesion.
Acrylic is the most commonly used carving material, second only to wood. It is easy to cut and carve. It has a variety of shapes and sizes, and its cost is relatively low. There are two production processes of plexiglass: casting and calendering. The laser engraving machine is mainly used to produce the plexiglass by casting. Because the frost effect produced by laser engraving is very white, which is in sharp contrast with the original transparent texture. The plexiglass produced by calendering is still transparent after laser engraving, which does not have a sufficient contrast effect. Therefore, you should emphasize the high-purity one to the dealer when purchasing, Otherwise, the purchased materials may melt when they are carved or cut.
Generally, the plexiglass is carved on the back, that is, from the front to the back, which makes the finished product more three-dimensional. When back carving, please mirror the figure (i.e. reverse), and the carving speed should be fast and the power should be low. If the power is too high when carving, uneven stripes will appear on the bottom. If you want to carve deeper, you can try to carve more. In the case of back carving, the local coloring should be carved deeper first, and then polished with a flame polishing machine before filling. If not polished, the color seen from the front will not be uniform.
Organic glass is relatively easy to cut. If the customer's requirements are not high, it can be delivered after cutting without flame polishing. Air blowing device shall be used during cutting to improve the cutting quality. When cutting plexiglass exceeding 8mm, replace the large-sized lens. (Note: The operator shall not leave when cutting plexiglass, because there may be flame during cutting.)
Acrylic pigments can be used. Other pigments may damage the finish of PMMA.
1. Bicolor plate
The double color plate is a kind of engineering plastic specially used for carving, which is composed of two or more layers of color composite. In the double color plate, it can be divided into two categories: mechanical and laser. Some mechanical plates can also be used for laser carving. The characteristic of laser engraving board is that the surface color layer is thin, and the whole board is thinner than the mechanical board. When purchasing a two-color plate, if you are not sure whether it can be used for the laser machine, you can consult the seller first or take a small piece to try first. Our experience is that if the surface color of the plate is very thin, you can generally laser carve, if the surface color is thick, you can try to carve twice.
If the laser plate is used for carving, the effect will be very good, with obvious contrast and clear edges. When using a mechanical plate with a thin surface, the carving effect is not much different from that of the laser plate. If you look carefully, the edges may not be as clear as the laser plate. Generally, users should not use the mechanical plate with thick surface, otherwise, the laser power should be reduced, and the bottom can be removed by repeated carving. The final effect may not be good. On the double color plate with large contrast (such as black and white plate), the gray scale image can be carved. After a large number of carvings, the double color plate itself may be deformed, which can be leveled by hand after being heated with hot water.
Generally, users will ask you to cut the dual color plate. If you use a laser plate, you can cut it after carving. Pay attention that the speed should not be too slow. Do not cut through at one time. It should be carried out in three or four times, so that the edges of the material cut out are flat and there is no melting trace. When carving, the power should be just right, and should not be too large to avoid melting traces. If a mechanical plate is used, it can only be cut to 50% of the depth, and then broken by hand and then sanded to smooth the edges. If the user has a mechanical machine, he can cut it off on the mechanical machine first, and then move it to the laser machine for carving.
After carving, use a damp cloth or alcohol to clean the surface. However, it should be noted that if the laser power is set too high during engraving, a layer of dust that is difficult to wipe off may be attached to the surface of the bicolor panel.
If the user's requirements are not high, the dot can be used to represent those different colors in the logo. If it is necessary to paint, the painted area should be carved deeper. Acrylic paint or alkyd enamel can be used. Other paints may damage the surface finish of the two-color panel.
Painted copper plate
1. Painted copper plate
Generally, copper cannot be laser engraved. But now there is a material whose surface is attached with a special paint film. The laser can completely vaporize the paint film on the surface, and then expose the bottom copper plate. Generally, the manufacturer will polish the copper plate or make special treatment before painting, so that the exposed area after carving can have enough finish and can be kept for a long time. If the copper surface is not treated, a protective film shall be made again after carving to avoid oxidation and surface contamination after a long time.
Generally, small power can be used for high speed and accuracy setting above 500dpi.
After carving, use a damp cloth or alcohol to clean the surface.
If the user's requirements are not high, the dot can be used to represent those different colors in the logo. Acrylic paint can be used for those that need to be painted. Other paints may damage the surface finish of the copper plate.