Using mechanical and laser methods for plywood processing
Plywood has become widespread in everyday life, construction, advertising and souvenir production and many other industries. Plywood products are widely represented in the decoration of premises, in landscape design, as packaging, elements of external and internal structures … The use of a certain cutting and engraving technology depends on the material properties, its thickness, specified quality requirements imposed on the final product. Modern CNC equipment provides high accuracy of positioning and cutting performed, which is one hundredths of a millimeter, which allows high-quality cutting of plywood.
From the history of the appearance of plywood
Before considering the various ways of processing plywood, let’s get acquainted with the features of the material itself. The history of plywood begins in the late 17th century, when British engineer Samuel Bentham created the prototype of a shelling machine for veneer. Much later, Estonian furniture maker A. Luther began to use material that was glued together from several layers of veneer for the seats of chairs. And the Russian inventor Kostovich, who independently developed equipment for the manufacture of veneer sheets and glue for gluing them, arranged sheets of veneer with alternating fibers. Thanks to this design and composition of the adhesive, the material turned out to be very durable, resistant to moisture and not subject to rotting.
Laser cutting and engraving capabilities of plywood
The layered structure of the material, the differences in wood veneer and adhesive component affect the quality of cutting. For laser cutting the most suitable plywood brand FC, which is used as the glue carbamide resin. The performance of cutting such plywood is much higher than when working with moisture-resistant materials: PSF, glued with phenolic resin and FB, impregnated with bakelite varnish. It should be remembered that cutting laser plywood with a thickness of more than 10 mm is not desirable. To cut a thick sheet would have to increase power and reduce the cutting speed, and this can cause overheating of the treatment area and the charring of the edges.
Cutting technology is a highly concentrated thermal effect of the laser on the material. A laser beam focused on a narrow beam, falling on the surface, causes a sharp heating of the impact zone and burns the plywood to the required depth. At the same time, the cutting line turns out to be very thin – fractions of a millimeter, and the edges are even and neat even when small items are made, for example, with openwork cutting. However, when the beam hits areas with excess glue or non-uniform areas in the inner layers (knots, seals), the radiation power may not be enough to cut through the material. In this case, you have to go through the trajectory again. Another processing nuance is a change in the hue of the cut line towards a darker tone. This can be both an undesirable factor and a positive quality, for example, engraving due to this property is more expressive.
Features of the processing of plywood on a milling machine with CNC
An alternative to laser technology, which has some limitations, is milling cutting. CNC machines allow milling plywood of various brands, regardless of the thickness of the workpiece, accurately reproducing the specified electronic layout. The use of computer control almost completely eliminates processing errors and the probability of rejection. The abundance of various cutting tools makes it possible to perform many complex operations with both flat blanks and with volumetric details.
Influence of material properties on tool selection and milling mode
Features of plywood impose increased requirements used for processing mills. The presence of glue between layers, irregularities quickly wears out the tool, so for working with this material it is recommended to use carbide mills. Milling takes place in two stages – roughing and finishing, and at a considerable cutting depth, roughing can be done in several passes. The use of counter milling and increased spindle rotation speed helps to avoid chipping and other edge defects; a slight roughness of the cut zone is removed by additional grinding. The correct choice of tool and speed mode guarantees a quality result, while an increase in excess of the required number of spindle turns or feed speed can lead to overheating of the cutter and the burner of the material.
Pros and cons of mechanical and laser processing of plywood
In general, both methods provide high performance, excellent quality of cutting and engraving, allow you to perform complex threads, apply images and inscriptions to the surface. Among the advantages of modern equipment, both laser and milling, one can name the possibility of creating exact copies in any quantity up to large-scale production.
Laser cutting and engraving are indispensable when performing small parts and highly artistic works. Among the advantages of this technology:
- A narrow cut zone. So there is no need for technological indents.
- Contactless. The tool does not wear out.
- No additional edge processing required.
- Ability to perform complex and exclusive projects.
The disadvantages include restrictions on the thickness of the material, darkening of the edges, as well as the complexity of processing moisture-resistant brands of plywood.
These problems are solved by milling. However, the processing of plywood billets with a mill also has its own nuances: fast tool blunting, the need for polishing cuts. For the manufacture of miniature products, milling is practically not used, since even the smallest mill has its own diameter, which means that it is impossible to obtain geometrically distinct internal corners using this method. The composition of the material also has an influence on the quality characteristics. For example, birch plywood lends itself well to processing, and consisting of coniferous wood is prone to fiber stratification, scoring, and therefore it is practically not used for engraving.