Milling plywood and wood is a relatively inexpensive method of processing, as it is possible to perform many diverse operations with one CNC machine. Modern equipment provides ample opportunities for working with plywood sheets and wooden blanks. Among the available operations: cutting along a straight and curved contour, making chamfers, recesses, holes of different profiles, engraving the surface at different depths.
The principle of milling plywood and wood
CNC plywood milling is fast and extremely accurate. Processing is carried out in accordance with a predefined algorithm. To draw up the control program, it is necessary to have a graphic layout of the future part, on the basis of which the tool path is built. When choosing processing parameters, it should be remembered that different scenarios should be used for different types of wood. Therefore, before manufacturing the part, especially before starting the run, it is recommended to check the correctness of the selected mode on the test sample.
Next, a plywood or wooden billet is fixed on the working surface using clamping devices, the tool necessary for the operation is inserted into the collet, and the execution of the control program is started. A rotating cutter, in contact with the surface, layer by layer removes material. The speed, direction of movement of the tool relative to the workpiece, the depth of its impact, the material is controlled by a computer. The operator has the opportunity to monitor the processing process and, if necessary, stop work to adjust data, make changes to the algorithm. Each technological operation uses its own tool, which changes automatically (in the presence of a car shift system) or manually. It should be remembered that with a mill it is impossible to make sharp corners, small elements commensurate with the diameter of the mill – most often they remain undercut. In other cases, the CNC milling result is of excellent quality and accuracy, and in the case of serial production, it also has a high level of repeatability of parts.
How to design a milling layout
The drawing must be done in vector format. To do this, you can use any graphics program, for example, Adobe Illustrator, AutoCAD, Corel DRAW … Ready-made models can be found in:
- software package that comes with the hardware;
- libraries of programs for 3D modeling on the websites of companies that provide cutting services;
- online stores, websites;
- social networks, in specialized forums.
Standard equipment on the CNC machine contains licensed software. One of the tasks of the software is to translate a graphic layout created in vector format into program codes understandable to the machine.
Types of plywood and wood and its features
Different types of wood differ in structure and resistance to cutting, which should be taken into account when milling wood. Softwoods include conifers, aspen, poplar, linden, and chestnut. Oak, beech, apple, pear, cherry, birch have more rigid wood. Among hard varieties, walnut, acacia, maple, and mountain ash can be distinguished.
Plywood is a multilayer material made of sheets of thin wooden veneer glued together. Plywood can be classified by:
- The wood of which it is made.
- Deciduous (birch, beech, maple …) The leading positions are occupied by birch plywood, which has a light, even shade and good texture. It is used in the manufacture of furniture, interior decoration, for the manufacture of gift and souvenir products.
- Coniferous plywood is most often used in construction. This is due to its cheapness. The material has a richer color and contrasting texture.
- Combined plywood is made from different types of wood and combines its properties.
- Impregnation and water resistance.
- FC. urea resin with low water resistance is used as an adhesive component. FC is environmentally friendly and is used in the manufacture of furniture, packaging, structural elements and decoration used indoors.
- FSF. The binder component is phenolic resin, which provides high strength and water resistance of the adhesive joint. use the material only for external work. The use of FSF indoors is not allowed, since phenol-formaldehyde adhesive has a carcinogenic effect on the human body.
- fb. Plywood, impregnated with bakelite varnish, has a high tensile strength and increased moisture resistance, so it can be used in aggressive environments.
- Type of surface treatment – unpolished (NS), polished on both sides (Ш2), polished on the front side (Ш1).
- Quality (1-4 grades). The first grade has a minimum number of defects; as the grade increases, the quality of plywood deteriorates.
Subtleties of setting up equipment for working with plywood and wood
In terms of price /quality /terms, milling occupies a leading position. The maximum thickness of a wooden workpiece is limited by the length of the cutting part of the tool. The cutting speed when working with different materials and tools can reach 5 or more meters per minute. The only inconvenience: due to the presence of a mill of a certain diameter, milling is rarely used for the manufacture of miniature products.
For high-quality milling of plywood (wooden) billets , it is important to find the right balance between the productivity of the equipment and the requirements for the surface finish of the finished product. The main parameters affecting the quality of processing are the spindle speed and feed rate. The optimal mode is chosen using calculations or empirically. To work with wood, the spindle is most often used at a speed of 15,000 – 18,000 rpm. The remaining parameters have approximately the following ratio: the value of the working feed, measured in m /min, and the depth of material removal in one pass are equal to the mill diameter in mm. But not everything is so simple – the depth of cut greatly depends on the hardness of the material. Therefore, this formula can be applied only to medium-density wood. When processing hard rocks, a layer should be removed in one pass, not exceeding half a diameter of the cutter. When processing soft rocks, it is permissible to go as deep as possible into the material (per pass) by 1.5 mill diameters.
unobvious moments at work /how to avoid marriage
Wood, plywood are relatively easy to machine. However, it should be borne in mind that the cutter undergoes dynamic loads during processing, the value of which depends, inter alia, on the properties of the material being processed. When curving cutting a plywood sheet or a workpiece with a rotating cutter, there is a high risk of veneer tearing and chips. To reduce the likelihood of such deficiencies, the use of low-grade or defective plywood should be avoided.
Milling plywood may be accompanied by the appearance of a hairiness along the cutting line, which is eliminated with sandpaper. To make the edge smooth and smooth, you should use a specialized tool and not work with a blunt cutter.
Processing defects can also occur as a result of incorrectly selected tools and processing parameters. A deterioration in the quality of the workpiece (and damage to the tool itself) can be caused by an insufficiently sharp mill or the choice of a too thin mill in combination with a large depth of material removal.
Increased spindle revolutions at a low feedrate, as well as the reverse situation (low revolutions + fast feed) lead to damage to the tool and poor cutting quality.
CNC milling machine is a complex mechanism consisting of mechanical, electrical, electronic components and systems. Sources of danger can be either parts of the equipment or improperly fixed workpieces, as well as production waste. There is a great opportunity to get injured in case of careless actions in contact with rotating elements (spindle, milling cutter). Lack of grounding can cause electric shock. Heated machine parts and parts can cause burns. Also, flying chips, fine sawdust, and dust can cause harm to health.
It is possible to ensure safe operation on the machine if simple rules are followed:
- Before starting, always check the health of the machine. Pay attention to lubrication, cooling system, grounding.
- At idle, check the condition of the controls, the work of moving parts.
- Securely secure the workpiece and milling cutter.
- Do not use the defective tool.
- Keep hands out of the danger area. Remove finished products from the table only after the machine stops.
- Monitor the status of operating equipment. If the equipment does not work properly, stop processing until troubleshooting.
A wide range of milling applications
The concept of milling includes many different works: straight-line cutting, figured cutting, drilling, creating relief, the design of profile edges … If you add to this list the ability to work with any thickness of materials, such popularity of this processing method becomes clear. Milling of wooden and plywood blanks is used in the manufacture of souvenirs, decor items, household items, containers, furniture and other goods.
Production of souvenirs
CNC milling is great for serial souvenir production. Traditionally made of plywood and wood:
- decorative decorations for home and office;
- carved caskets;
- thematic magnets, calendars;
- children’s toys, creative blanks;
- dishes for bars, cafes, restaurants – serving boards, bonfires, trays, coasters;
- high-quality, durable packaging;
- gift wrap, bottle boxes.
A new direction is gaining popularity – the manufacture of plywood toppers, hashtags, thematic labels that are used to decorate festive events.
Cutting plywood in advertising
Lightweight and durable plywood is widely used for the manufacture of advertising structures. It can be small plates, signs, POS-products or dimensional signs, volume letters and inscriptions. Milling can achieve any shape of the product. Workmanship does not depend on the size of the products, it is guaranteed high, thanks to the use of CNC equipment.
using milling techniques in furniture production
Plywood furniture is environmentally friendly, strong and durable. Milling cutting is used to cutting plywood sheets , to obtain structural details of different configurations and sizes. In addition to the manufacture of objects that are simple in shape (shelves, walls, cabinet doors), complex elements of decor and relief decoration of the facade are cut with a mill. CNC milling allows you to obtain individual parts for the manufacture of furniture for individual orders or to establish serial production, for example, cabinet furniture.