When you design and build a CNC machine, the first thing that needs to be designed is the base of the machine (bed). The base connects all other parts together, bears the lion's share of the resulting loads and determines the mutual arrangement of motors and axle transmissions, etc. Perhaps the design of the bed will depend on what materials and processing tools you have, the drives that fit into the budget, and so on. This often happens when designing a one-off product for your own use. For this reason, in homemade CNC It is difficult to find two exactly the same parts in routers. However, it is necessary to imagine possible types frame structure in order to be able to choose the best option and to purchase missing components.
X-AXIS STRUCTURE
The X-axis is the basis for the entire machine, since the X-axis is the axis closest to the ground. The X-axis frame has 3 main tasks:
- Serves as the basis for the rest of the machine
- Supports the X-axis linear system
- Carries a desktop
Full support frame
The full support frame is one of the best options and is used in most professional machine tools. "Fully supported" means that the structure rests on the floor or other supporting surface along its entire length and width. Such a construct means that it will not be possible to make a portal covering the desktop with a "ring". Such a design is very rigid, and most importantly, it does not bend under vertical loads, its own weight and the weight of the spindle. This is a significant point, since a deflection over a long length can negate all efforts - a deflection of 0.1 mm is only permissible if you expect to get an accuracy of 0.5 mm from the machine. This option also has disadvantages, first of all, it is the need to install two gears on one axle - two screws, two nuts, two motors and two drivers. Synchronization of the axes can be done programmatically, or you can use a belt drive from the transfer pulley to two axles. In this case, you must make sure that the motor power is sufficient to rotate the two axes. With a full support structure, you do not have to think about the weight of the material from which the frame will be and its effect on deflection - it will be transferred entirely to the reference plane.
Full support bed and full support rails
Full support is when an object abuts the support along its entire length. Moreover, not only the bed, but also the guide axes can act as an object. The role of the type of fastening of the guides is discussed in separate articles: Linear guides in CNC machines and Selecting guides for a CNC machine, but this will be later, here we will only pay attention to the support of the bed, and what it is possible to make the machine with full support of the guides, but point support of the bed: this design does not prevent the machine from deflecting under vertical loads.
Rig with full Y-axis support and partial X-support
The most common design option, you can see it in the picture. The X-axis frame is placed on a plane with its legs, leaving free space at the bottom, beams carrying the working table are placed across. As a result, the table gets high stiffness when bending along Y, and low - when acting along X. The portal in this case has a closed contour and two beams connecting the portal posts from above and below. The lower beam is connected to the transmission nut, moving in the free space under the frame. This construct implies the installation of guides both with fixation along the entire length (profile rails) and at the ends (shafts). In any case, deflection cannot be avoided, but the first case will allow you to somewhat reduce the error, since the portal will follow the curves of the X axis. The partially supported X design is suitable when the length of the X axis is not too long and does not fit high demands Z-axis precision. If not, consider other options.
Rig with full X-axis support and partial Y-support
If we only have one motor and one drive screw for the X axis, but we want to get high precision positioning, you can use this view. In it, the X-axis frame is located entirely on the reference plane, and there are no beams along the Y-axis. The freed space is used for the portal's movement - the portal frame is located inside the X-axis frame. Now, no matter how the portal is loaded, the X-axis will not bend (elastic deformations of the material beds are not taken into account due to their small size). But the Y axis can bend and - the desktop. The desktop in this case is the most problem place - it must be constructed in such a way that it does not interfere with the movements of the lower beam: this means that it will be possible to fix it only at the edges, and the table will be subject to deflection. Before using such a construct, make a decision that the most important thing is the absence of deformations in the machine itself, or so that the machine and the table can still bend as a whole.
Other options
There are other layouts, as well as various variations of those already outlined. For example, to get the advantages of a fully supported bed, you can abandon the lower gantry beam and set the U-shaped portal in motion with a screw located on top - by attaching the ball screw nut to the upper beam (although this is rather cumbersome and makes it difficult to access work area). You can turn to the classic solution - to place 2 drives on the sides of the X axis.
Movable work table
In it, the movement of the portal along the X axis is replaced by the movement of the desktop. This allows you to solve several problems at once, including getting the bed and guides with fixation along the entire length (the figure shows the option without fixing), but reduces the working area. It also has the advantage that only one X-axis drive is required.
During the development of the bed, the material has a significant influence on the choice of the construct - different materials are deformed in different ways. The following materials are most popular:
- Aluminum machine profiles
- Rolled steel
- Milled parts from aluminum alloys type D16T
- Cast iron
- Polymer materials -polymer concrete, polymer granite
- Others budget materials - plywood, MDF, plexiglass
Be sure to consider material properties when creating your machine.
Numerical control is the main element that automates the processing of materials on CNC machines. In order to process (manufacture) a certain part, the operator creates a program that the machine executes. Previously, when there were no automated machines, it was used to process complex contours hand tool... Also for pattern milling could be used hand cutter... CNC milling machines provide the most accurate material processing.
Originally milling machines were designed for milling metal products from ferrous and non-ferrous metals. Later, milling machines began to be widely used for processing wooden products – solid wood, plywood, fiberboard, chipboard. For woodworking, in contrast to metalworking, simpler machines with weak spindles can be used.
The material that has received mass distribution is plywood. Plywood is quite versatile and inexpensive material, which allows you to use it in different areas production. The main ones are furniture production, construction and interior design, packaging, insulating products, as well as various parts that are not subject to high loads and friction.
Plywood processing is not as simple as it might seem at first glance. Having a layered structure, it is prone to chipping at the cutting sites. In addition, the adhesive used to bond the layers contributes to rapid wear. cutting tool... Laminated, veneered, sanded and not sanded plywood lends itself to milling.
Pine. Milling is done on the machine. User Vitaly F. (Orel)
Plywood. Milling is done on the machine. User petr c
Laminate. Milling is done on the machine. User Sergey K. (Gagarin)
But PVC and other types of plastics even easier to process because these materials are less dense and more homogeneous. Plastic is very easy to cut, mill and engrave. The appropriate feed and speed are set depending on the type of material being processed.
Milling is done on the machine. User Sergey K. (Gagarin)
Plexiglass. Milling is done on the machine. User Alexey R. (Krasnodar)
Plastic. Milling is done on the machine. User Nikita T. (Perm)
Among the various materials that are actively processed by the milling method, a large share of the volume of work is occupied by composite materials. Composites (composite materials), as a rule, consist of a plastic base, which is reinforced (reinforced) on one or two sides by more durable materials... Today the standard composite panel is a multilayer sheet material. It contains a polymer filler inside two layers of a thin aluminum sheet... The thickness of the aluminum in this "sandwich" is between 0.1 and 0.5 mm.
Composite plastic. Milling is done on the machine. User Sergey K. (Gagarin)
Textolite. Milling is done on the machine. User Konstantin K. (Krasnodar)
The milling machine carries out not only a straight cut, but also a curved cut. Therefore, on such equipment it is possible to recreate the volumetric relief. The creation of volumetric images on plywood, as well as on any other material is called 3d milling... 3D milling makes it possible to obtain a volumetric image in the form of a relief pattern or an image on any material. The use of structured natural materials, such as wood, allows the volumetric image to interact with the natural patterns of the structure. Here it becomes possible to obtain effects that are unique in their beauty.
3d milling is done on the machine. User Mikhail P. (Smolensk)
The tree has long been considered one of the best materials for the manufacture of household items, and decorative elements... This is not surprising since wood is readily available, relatively inexpensive and durable. In addition, it is safe for health as it is environmentally friendly. clean material... And, with all these advantages, the tree is quite easy to handle. At the same time, the patterns are so beautiful that an ordinary object becomes a real work of art.
And one of the most efficient processing tools of this material is an engraving machine on wood... First, it is fairly easy to use. Secondly, it allows you to perform interesting design on the product. And, thirdly, the finished thing turns out to be so elegant that it looks even more beautiful than with handmade... The machines allow you to save a lot of time and effort for craftsmen, as well as increase the quality of products.
What material works best cNC woodworking machine?
In order for the work to be "clean" and the machine long time worked properly, it is important to choose the right wood. The type of material, its moisture content, surface condition and thickness are all important. Of course, in laser processing, these parameters are not as important as when working with a milling cutter, but it is better to pay attention to them so that the result of the work will please you.
Depending on the type of material, its color and texture, cNC woodworking machine allows you to create unique engraving options. Best results can be obtained with light-colored workpieces that contain a lot of resin. The pattern will be practically "eternal" if done on hard rocks wood such as ash, walnut, oak, mahogany or alder. But it should be borne in mind that oak can be chipped off during processing. It is most convenient to work with a material with less lint. It is better to avoid soft rocks, because only perfectly new cutters can cope with them, and even then with difficulty.
Some more details for wood engraving
It should also be borne in mind that if you need small patterns, then it is best to perform them on walnut blanks. It is important that the humidity is no more than 8 percent.
Ash is suitable for large parts. Maple will be difficult to handle, but the result is very beautiful. Birch is perfect for paintings and panels. The pear is easily processed, and the surface of the product is perfectly smooth. If you choose the right material and calculate your strength, then you will definitely like the resulting pattern.
Automation of the process using CNC milling machines allows you to increase productivity, quality, reduce scrap and provide the most accurate material processing. Modern cnc machines are available to the common user, both in terms of cost and maintenance and management.
Cnc milling machines are used for processing wood (solid wood, chipboard, fiberboard, plywood), plastic, PVC, plexiglass, acrylic, composite materials, textolite, artificial and natural stone, graphite, electronic printed circuit boards, modeling wax (creation of injection molds), etc.
One of the inexpensive and common materials is plywood - multi-layer construction materialmade by gluing veneer. Plywood is used in furniture production, as insulating products in electrical engineering, construction and interior design, etc. Due to its layered structure, it is prone to chipping at the cutting sites. Suitable for milling are sanded and unsanded, laminated and veneered plywood.
It is very easy to process PVC and other types of plastics. Plastic is easy to mill, cut and engrave. It is impossible to imagine modern life without plastic. It is used in many areas of human life. Plastic is cheap, durable, plastic, moisture resistant, low heat and electrical conductivity.
A composite is a continuous heterogeneous material artificially created from several components with different chemical and physical properties... Composite material is widely used in many industrial sectors... The most common example of a composite is textolite, cermet.
The stone has been used by man from time immemorial as a building and finishing material... The main and most valuable property of a stone is its hardness and durability, as well as its aesthetic appeal. However, the hardness of the stone is also a problem in its processing. The milling process is complicated by the fact that when cutting, the material gives off fine chips and dust. Therefore, the machine must be equipped with a powerful spindle and additional basic equipment.
Through milling machine easy to recreate a volumetric relief, image on various materials - 3D milling.
Our company offers high quality materials for CNC burning. On the pages of our catalog you can find any material with which various numerical control machines work, be it plastic, aluminum, rubber, leather, wood, brass-plated steel or anodized aluminum.
All materials for CNC milling can be ordered without leaving the workplace by simply adding the product to the shopping cart. You can also make a purchase over the phone or use the feedback form - in this case, in the most short time our manager will contact you and help you place an order.
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