A computer numerical control (CNC) router is a computer-controlled cutting machine which typically mounts a hand-held router as a spindle which is used for cutting various materials, such as wood, composites, metals, plastics, glass, and foams. CNC routers can perform the tasks of many carpentry shop machines such as the panel saw, the spindle moulder, and the boring machine. They can also cut joinery such as mortises and tenons.
A CNC router is very similar in concept to a CNC milling machine. Instead of routing by hand, tool paths are controlled via computer numerical control. The CNC router is one of many kinds of tools that have CNC variants.
Applications
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A CNC router can be used to produce items such as door carvings, interior and exterior decorations, wood panels, sign boards, wooden frames, moldings, musical instruments, furniture. In addition, they see use in industry in the thermoforming of plastics by automating the trimming process. CNC routers can help ensure part repeatability and sufficiently efficient output for production, or allow one-off designs to be made.
Use
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Control panel for a large DMS 5-axis CNC routerCNC routers are controlled by a computer. Coordinates are uploaded into the machine controller from a separate program. CNC router are often used with two software applications—one to make designs (CAD) and another to translate those designs into a G-code or M-code program of instructions for the machine (CAM) in vertical, horizontal and perpendicular coordinates. As with CNC milling machines, CNC routers can be controlled directly by manual programming, but CAD/CAM allows wider possibilities for contouring, speeding up the programming process and in some cases creating programs whose manual programming would be impractical. On some controllers the G-code can be loaded as a vector file on the router control panel. A vector file can be created from a picture file by using a drawing (CAD) software.
The human operator selects the machine tool (such as a 1⁄4-inch (6-MM) v-bit or a 3⁄4-inch core box bit), speed, cut depth and tool path. For cut path, most machines give the options of tracing the vectors, cutting outside the vectors, or cutting inside the vectors. The operator determines the center point of the part, clamps the part onto the table, moves the bit directly above the marked center and down to the face of the part, and marks this as the starting point. The operator moves the bit up a few inches and selects the run G-code function. The machine begins to cut the design.
Computer-aided manufacturing
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CAM software makes the CAD drawing/design into a code called G-code. The illustration shows what a bare-bones CNC machine might look like without its computer controller.
Sizes and configurations
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CNC routers come in many configurations, from small home-style D.I.Y. "desktop", to large industrial routers manufactured for commercial use. CNC routers are used in sign shops, cabinet making, aerospace and boat-making.
Although there are many configurations, most CNC routers have a few specific parts: a dedicated CNC controller, one or more spindle motors, servo motors or stepper motors, servo amplifiers, AC inverter frequency drives, linear guides, ball screws and a workspace bed or table.
In addition, CNC routers may have accessories such as vacuum pumps, with grid table tops or t-slot hold down fixtures to hold the parts in place for cutting. CNC routers are typically available in 3-axis and 5-axis CNC formats. Many manufacturers offer A and B axis for full 5-axis capabilities and rotary 4th axis. Common industrial CNC router sizes include 4 × 8 feet and 5 × 10 feet.
Many CNC routers today are made of aluminum extrusion which provide great flexibility as this can be shipped from almost anywhere unassembled but also provides size options. Some popular extrusion used are MakerSlide, V-Slot linear rail, and 8020 T-Slotted profile.
Materials
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Wood
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A typical CNC wood routerA CNC wood router is a computer-controlled router tool that carves/etches objects or images into the face of a piece of wood.[1] The CNC Router is ideal for hobbies, engineering prototyping, product development, art, and production works. The CNC works on the Cartesian coordinate system (X, Y, Z) for 3D motion control; however, typical CNC operated systems can only make carvings on flat planes. The machine sits on a track and is not capable of making round or spherical cuts. Parts of a project can be designed in the computer with a CAD/CAM program, and then cut automatically using a router or other cutters to produce a finished part. In some instances, the table will not come with a router included. This allows the user to change out routers for different applications. For lighter strained cuts, they could use a lower grade router but for more intensive applications.
Metal
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Milling is the machining process of using rotary cutters to remove material from a workpiece advancing (or feeding) in a direction at an angle with the axis of the tool. It covers a wide variety of operations and machines, on scales from small individual parts to large, heavy-duty gang milling operations. It is one of the most commonly used processes in industry and machine shops today for machining parts to precise sizes and shapes.
Stone
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A stone CNC router is a type of CNC router machine designed for marble, granite, artificial stone, tombstone, ceramic tiles, glass machining, polishing for arts and crafts, etc. Wood, metal and stone require different "bits" or "inserts". There is bit call as diamond tools with different diameter 4mm, 6mm, 8mm mainly used. For wood CNC-ing, bits with sharp cutting edges are used, while for Stone CNC-ing, the bits are made of a metal bar with a sintered layer of extremely hard but roughly shaped particles. Routing CNC is more like grinding than cutting.
Because stone dust is very abrasive, these routers also have much better protection for the guide rails (below cover). With "wood" routers the guide rails are often visible from the outside & unprotected, while stone routers are fully covered.
Stone routers also have a water recirculation system. A small jet of water is pointed at the router bit and this captures almost all fine stone dust in the water, which then flows to a collection reservoir where the stone particles settle on the bottom.
Polyurethane foam
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Polyurethane foam can also be cut using a CNC router in order to produce complex shapes which would otherwise be difficult or impossible to replicate by hand. Depending on the type of foam being converted, a CNC router would be able to cut through up to an 8lb density. By converting a CAD design file into a CAM file, the CNC Router is able to read relevant information and produce a highly accurate finished product.
References
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For a fully comprehensive guide on CNC machining, check out of CNC Machining Guide.
Choosing the suitable metal for CNC Machining involves analysing various factors. Depending on the part or product being CNC machined, the metal you choose and its properties will play a vital role in the success of the final part. For example, the metal may need to be resistant to extreme temperatures or be resistant to bending or breaking under pressure. Corrosion resistance, workability, price, weight and cosmetic appearance all factor in when it comes to choosing the right metal.
CNC machines can indeed cut metal and are widely used due to their high precision and accuracy. Depending on the material in question and its strength and hardness, CNC machining will yield different results and finishes.
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There are various CNC machines, and depending on cost, material, finish quality and design, a suitable CNC machine will be used. Popular methods of CNC Machining include:
CNC milling and machining are extremely common manufacturing processes, and it’s easy to see why. CNC (Computer Numerical Control) machining offers rapid production while requiring minimal human input compared to traditional methods. Benefits of this include a more cost-efficient workforce but, more importantly, less room for human error.
Not only are parts made swiftly, but CNC machining allows for extremely high levels of quality, repeatability and precision. There is also a wide range of materials that CNC machining can be used for, ranging from plastics, metals and ceramics.
There is a multitude of metals available for CNC machining. In this blog post, we will look at a selection of commonly used metals used within CNC machining. These recommendations also apply to CNC turning and multi-axis machining.
Titanium is a particularly strong and resilient metal whilst maintaining an excellent strength-to-weight ratio. It is highly workable and can be welded with ease. Although it conducts heat well, it possesses poor electrical conductivity. Whilst titanium responds well to anodising for a clean finish and protection, it reacts unfavourably to polishing. Titanium is lightweight and offers high strength, and has brilliant corrosion resistance and high-temperature resistance. For this reason, it is a popular choice for aircraft industry parts, biomedical and military. A popular titanium grade is Ti6Al4V (also known as TC4 and Grade 5).
There are many different grades of stainless steel, which are categorised into four main types: Ferritic, Austenitic, Martensitic, Duplex.
The most common Stainless Steel is Austenitic, which is our focus today. Their chemical structure includes Manganese, Nitrogen and Nickel, which provides good machinability and weldability. The three most common grades used in CNC machining processes are:
Aluminium is the most commonly used material in CNC milling processes due to its machinability, workability and versatility. It also provides a modest strength-to-weight ratio.
Aluminium 7075 is a high-grade metal with excellent strength. However, its strength can make it more challenging to produce designs with more complexity. Al7075 is ideal for CNC machined parts which require sustained durabilities, such as frames within the automobile and aerospace industries. Al7075 has great properties such as ductility, toughness, high strength with good fatigue resistance. This means it is a common material choice for high-stress structural components in aerospace.
Aluminium 6061, however, has far better workability and is generally considered to be an economical grade. It has good atmospheric corrosion resistance but low resistance to corrosion from chemicals. Al6061 is the most commonly used aluminium grade and is ideal for automobile parts, frames and much more. Aluminium 6061 is generally seen as a general-purpose aluminium, with good strength to weight ratio and good machinability. However, when exposed to saltwater, it has poor corrosion resistance and is not as strong as other aluminium alloys required for more demanding applications.
Magnesium AZ31: Although aluminium has an excellent strength-to-weight ratio, AZ31 can be up to 35% lighter whilst maintaining the same strength. As you can imagine, this means it is also higher on the price scale. Lightweight and durable, AZ31 is great for aircraft components, power tools and laptops. However, despite good workability, it does have some flammable properties.
Brass is highly versatile and is commonly used in plumbing systems. It also tends to be used in musical instruments and cosmetic applications, and home decor. This is because it is highly workable and can achieve an extremely high polish, making it aesthetically pleasing. In addition to this, it is naturally resistant to saltwater corrosion and is devoid of flammable properties. Brass is also used for electronic hardware, commercial fittings and aerospace parts. As it is a copper-zinc alloy, brass does not become brittle at low temperatures. It is a great choice for pipe fittings, with excellent thermal conductivity, and its attractive colour options make it a popular option for products that require a high-quality finish. Brass is also one of the easiest metals to CNC Machine.
EN 1045 steel is highly workable and particularly suitable for welding. This steel grade shows high strength levels and tends to be more economical than stainless steel. Like stainless steel 303, it is often used for gears, nuts and other resilient mechanical parts. It is a good steel for applications requiring greater strength or hardness, such as shafts, axles, bolts and studs.
D2 Steel is another member of the steel family and is significantly strong and durable. D2 Steel is also highly resistant to abrasion and wear. The strength and hardness of D2 steel make it suitable for parts that need high structural integrity and resistance to bending.
Get It Made offers a wide range of materials for CNC Machining, including materials not listed above. Explore more of our CNC machining services on our website or check our CNC Machining Guide. Why not get in touch to discuss your material requirements and kick-start your project today? Arrange a CNC machining quote today, and our team will respond within 24 hours.