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Introduction
Here is the most complete and thorough explanation of CNC machining on the internet.
You will learn:
What is CNC Machining?
How CNC Machining is Used –
Parts and Components Made by CNC Machining –
Industrial Uses for CNC Machining –
And much more …
Scroll down to chapter one to begin.
Chapter One: What is CNC Machining?
CNC machining is an electromechanical process that precisely controls tools across three to five axes, removing excess material to create parts and components. Initial designs are generated in CAD and then converted into CNC codes, which provide programmed instructions to the tools in a CNC machine.
CNC machining delivers cutting-edge quality on turned components through a wide range of applications that involve both vertical and horizontal machining.
CNC machines' multitasking capabilities enable the completion of a component or part in a single operation with both ease and efficiency. These machines handle a variety of applications, including bushings, collars, fasteners, fittings, inserts, machined components, washers, pins, nuts, spacers, spindles, standoffs, drive shafts, and splined shafts, among others.
Chapter Two: What Is The CNC Machining Process
CNC (Computer Numerical Control) machining is a systematic and efficient process designed for the precise production of parts. Computer-controlled machines execute various programmed tasks, starting with the creation of two- or three-dimensional renderings on a computer.
After the design file is loaded and coded, the machine executes each operation according to the specified design parameters.
The CNC Machining Process
The key distinction between CNC machining and other manufacturing processes is that CNC machining is a subtractive method, which involves removing layers of material to achieve a specific shape.
Computer Programming
The success of CNC manufacturing hinges on precise initial programming. The software must be accurately coded with instructions that keep the machine within its operational limits. The effectiveness of CNC equipment relies on the quality of these instructions, which are crafted with care to minimize errors and avoid production delays.
Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM)
CAD-CAM refers to the software used for designing and machining parts and components with a CNC machine. CAD (Computer-Aided Design) software is used to design, draw, and shape parts using geometric shapes and constructs. CAM (Computer-Aided Manufacturing) software, in turn, takes the information from CAD and converts it into machine language, known as G-Code.
Before converting the CAD-designed model into machine language, CAM software determines the cutting paths for the tools to remove excess material from the workpiece. CAD and CAM work together to provide the CNC machine with precise and accurate instructions for executing the required cutting operations.
CNC Machine Setup
Before downloading the CAD-CAM program into the machine, it must be equipped with the appropriate cutting tools. Tool changing can be done in two ways: the first method involves selecting tools from a tool cart and manually placing them into the machine.
TThe second method involves an Automatic Tool Changer (ATC), which stores tools on a drum or chain. When programmed with the necessary tools, the ATC automatically removes the old tool and inserts the new one. The ATC is designed to save time and enhance efficiency.
A crucial aspect of CNC machine setup is establishing the gauge point, which measures the distance from the tool tip to a reference point. Properly setting this gauge point ensures that the tool cuts to the correct depth.
One of the final steps in CNC machine setup is testing the coolant or lubricant. Coolant can be delivered through air, mist, flood, or high pressure. It's crucial to check the pressure at which the coolant is delivered, as incorrect pressure can damage the tool, while an incorrect amount can harm the machine and equipment.
A common mistake during CNC machine setup is neglecting to check the coolant, which might have an unpleasant odor, be insufficient in quantity, have a low concentration, or be improperly filtered.
Work Holding
Work holding is a device used to secure, support, and mount the workpiece. Also known as a CNC fixture, it ensures conformity, interchangeability, and smooth operation. Unlike a jig, which primarily guides tools, the work holding device stabilizes and supports the workpiece.
Similar to the tools used on a CNC machine, work holding fixtures come in various types, including those for turning, milling, drilling, boring, and grinding.
Loading the G-Codes
G-codes have been accepted as the universal language for CNC machining. Though there are standard G-codes for all CNC machines, manufacturers will change G-codes to make them specific to their machines. There is a G-code for every movement of the cutting tools in a CNC machine.
While various software can generate G-codes from a CAD design, they can also be handwritten or conversational, bypassing the need for a CAD design. G-codes can be loaded into the CNC machine via USB, directly from the CAM computer, or programmed directly into the machine.
Program Proofing
Program proofing is the final step before making the actual cuts. The purpose of proofing is to verify the accuracy of the program and ensure the CNC machine setup is correct, thereby preventing issues with the G-code.
This process is used to check for any errors in the G-code. Proofing can be done by "cutting air," where the machine runs through the cutting process without actually cutting the workpiece. While effective, this method is time-consuming and ties up the machine. Another approach is using a G-code simulator, a computer program that simulates the CNC process.
Machining the Part
Once all preparations are complete, it's time to insert the workpiece and begin cutting. The first workpiece should be monitored closely as it goes through the CNC process. This initial piece acts as a prototype for all subsequent parts and provides valuable data on the success of the programming.
Execution
After completing the setup and testing processes, the CNC machine is ready for production. CNC machining enables manufacturers to produce parts faster, more efficiently, and safely, ensuring each part is an exact duplicate of the original design.
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Chapter Three: What Are The Types of CNC Machining
A significant advantage of CNC machining is its ability to perform a wide array of cuts. CNC machines can create an unlimited number of shapes, designs, configurations, and images. This capability enhances the quality of the final part and eliminates errors and flaws.
Types of CNC Machining
Though CNC machines can be programmed to perform a single function, one of their benefits is the ability to execute multiple operations in a single cycle. This feature allows producers to insert a single workpiece and perform several cuts during one machine cycle.
Two types of cuts in CNC machining are male and female. Male cuts are made around the outside edges of the workpiece to ensure it has the proper dimensions. Female cuts are made on the inside of the workpiece. Whether the cuts are male or female, the corners of the cuts are typically rounded.
Cleanout cuts are similar to female cuts but do not penetrate all the way through the workpiece. Center or online cutting, on the other hand, follows the center of the vector shape.
Lathe CNC Machining
Lathe CNC machining rotates the workpiece during the cutting operation. Unlike milling machines, lathe-type CNC machines typically have fewer axes, making them shorter and more compact.
Milling is the most common CNC machining process and encompasses various operations, including pocketing, facing, slotting, chamfering, and boring. This process employs multiple-point cutting tools and involves feeding the workpiece into the tool in the same direction as its rotation.
Face Milling: Face milling involves cutting surfaces that are perpendicular to the cutter axis of a part. Shell mills or fly cutters are used for this purpose depending on the type of surface that is required.
Pocket Milling: Pocket milling machines away large amounts of material, which saves time and increases the amount of material that is removed.
Slot Milling: Face milling cutters perform slot milling, which is cutting grooves into the workpiece. There are various types of slots, which include closed or open, long or short, straight, deep or shallow, and wide or narrow.
Chamfering Milling: Chamfer milling eliminates sharp edges and leaves a smooth sloped surface.
Boring Milling: Much like the name implies, boring milling enlarges the size of holes using a single cutting point.
In CNC machining, drilling is typically performed with the workpiece positioned perpendicular to the drill bit. Various types of drill bits are used to create different sizes of cylindrical holes. Drilling along non-perpendicular axes can be accomplished using specially designed machines.
CNC Grinding
CNC grinding employs a precision tool with a rotating wheel to remove material from the workpiece. Typically performed at the end of the CNC machining cycle, this process utilizes an abrasive wheel to eliminate burrs at high speeds. The grains on the grinding wheel chip away at the workpiece to achieve the desired shape.
CNC Turning
Turning CNC processes involve cutting the workpiece while it rotates. Performed on a lathe CNC machine, this operation feeds the cutting tool along the surface of the spinning workpiece, removing excess material from the circumference to achieve a precise diameter.
CNC Laser Cutting
CNC laser cutting machines employ a laser cutting tool, which can be a gas, crystal, or fiber laser, depending on the working principle of the tool. Unlike other CNC machining methods, laser cutters do not require tool changes, offering greater flexibility in the cutting process.
Laser cutting is highly precise and faster than traditional methods. Laser CNC machines are well-suited for CNC processes, as they are fully automated and programmable.
Plasma CNC Machining
Plasma CNC machines cut materials using an electrically conductive plasma stream. This high-powered torch can cut through various materials, and like other CNC machines, its movement is controlled by G-codes.
Plasma cutting machines come in two main types: table and gantry. Table models typically have working areas ranging from 1300 mm by 2500 mm to 2000 mm by 6000 mm. Gantry machines offer larger working areas, varying from 2 by 6 meters to 4 by 20 meters.
CNC Router Machine
A CNC router operates similarly to a lathe or milling machine but on a smaller scale. It performs all the functions of a handheld router, making it ideal for shaping and forming wood products. The advantage of using a CNC router over manual methods is its precision and accuracy. Standard router bits can be utilized, and the machine can cut materials along the X, Y, and Z axes.
Five Axis CNC Machining
Typically, CNC machines operate along the three axes: X, Y, and Z. A five-axis machine adds two additional axes, A and B, allowing for more intricate and complex cuts. The increased capability of five-axis machines contributes to shorter production times, making them increasingly popular in various manufacturing processes.
Using a rotating cutting fixture allows the CNC machine to efficiently achieve the required part geometries. The rotating table and positioning capabilities of the five axes reduce stress on the cutting tools, thereby extending the lifespan of both the tools and the CNC machine.
The diagram below is a representation of a five axes CNC machine.
Water Jet CNC Machining
The water jet CNC machining process uses high-pressure water mixed with abrasives to remove excess material from a workpiece. While high-pressure water alone can cut through various materials, adding abrasives like aluminum oxide or garnet enhances the cutting ability, particularly for tougher materials.
The water pressure for a water jet cutter is between 20,000 PSI to 55,000 PSI and is delivered through a narrow nozzle.
Chapter Four: What Is CNC Machining Software
CNC machining originated with the development of numerical control (NC) for automating machine tools through programmable logic. What began as NC in the late 1940s and early 1950s has evolved into today’s advanced computer numerically controlled (CNC) automation.
The key driver behind the advancement of CNC machining has been the development of sophisticated software used to design parts and generate G-code commands for programming CNC machines.
CNC Machining Software
CNC software generates programs that control machine tools, with each aspect of the CNC machine operating through its own specific program. CAD and CAM are fundamental programs used across the industry, with software developers customizing these tools to meet customer requirements and enhance efficiency.
Design Software
Autodesk Fusion 360
Autodesk Fusion 360 is a comprehensive design platform that offers tools for both designing and fabricating. It enables the creation of intricate geometric designs and can simulate their performance to assess the forces or stresses they can endure. The software provides detailed 3D representations, offering a clear preview of the final part or product.
Solidworks
SolidWorks, developed by Dassault Systèmes, employs a parametric approach for modeling and assembling designs. Parameters can be numeric or geometric, tailored to the specific needs of the design. Certain aspects of a design can be set as fixed, ensuring they remain unchanged even if other parts of the model are adjusted.
AutoCAD
AutoCAD is a design software used in manufacturing that enables users to create, modify, and document designs. It features a vast library of symbols for different components, which helps streamline the design process. Its programming facilitates seamless integration with CNC machines, making it a valuable tool for manufacturing workflows.
Solid Edge
Solid Edge offers both drafting and 3D modeling capabilities for product engineering and development. It combines fast performance with user-friendly design features, allowing for precise parametric modeling. The software supports mechanical and electrical design, providing tools for creating complex and detailed renderings for manufacturing.
Rhinoceros
Rhinoceros utilizes geometric profiles based on mathematical models to produce precise representations of curves and surfaces. Its programming allows users to customize the software by adding personal commands and menus. This flexibility makes Rhinoceros a popular choice across various industries.
CAM Software
After a design is created in CAD, its parameters and features must be converted into g-code for the CNC machine. This conversion process is facilitated by CAM software, which streamlines and enhances the efficiency of the machining workflow.
Things that CAM software does:
Error checking: checks for geometrical errors
Tool path generation: programmed coordinates a tool must follow
Configuration: sets voltage, cutting speed, and depth of cuts
Efficiency: selects the proper orientation for the greatest efficiency
Inventor CAM
Inventor CAM, a component of Autodesk, simplifies CNC design and programming. It offers features such as reducing roughing time, minimizing tool paths, and programming for 4 and 5 axes cuts. Additionally, it includes analysis tools to measure distances and monitor speed, feed, and machining time.
Fusion 360
Fusion 360 offers seamless integration between CAD and CAM by storing tool paths during the design process. The software covers the entire workflow, including planning, implementation, and simulation.
Aspire
The standout feature of Aspire software is its tool path optimization, which enables the programming of cuts that mimic a hand-carved appearance. Its tools calculate the cutting profile to create gaps that ensure parts fit together seamlessly.
HSMWorks
HSMWorks integrates with Fusion 360, SolidWorks, and Inventor, offering a comprehensive set of tools compatible with various cutting devices, including water jets, plasma cutters, and lasers. It supports 5-axis cutting simulations and handles complex designs with multi-axis contours. Additionally, HSMWorks features a roughing strategy for efficient material removal.
SprutCAM
SprutCAM is versatile CAM software that can function both as a standalone application or integrate with various CAD programs. It supports features similar to other CAM software, including multi-axis designs and multitasking capabilities, allowing for simultaneous operation of multiple tools.
STEP
STEP is a widely used file exchange format known for its clear and readable text coding. It is commonly utilized with CAD programs to facilitate data transfer between different systems.
The CAM programs mentioned here represent just a fraction of the available options. Other notable CAM software includes EdgeCAM, BodCAD-CAM, CAMWorks, Esprit, GibbsCAM, and HyperMill.
Chapter Five: What Materials that CNC Machining is Used to Shape
CNC machining can shape a vast array of materials, with the primary constraints being the manufacturing process, the desired shape, and design specifications. The key consideration is whether the material can endure the stress and manipulation involved in the CNC process.
The type of material determines the cutting tools, cutting speed, feed rate, and how deep the cut will be.
Materials that CNC Machining is Used to Shape
Aluminum
Aluminum has an exceptional strength to weight ratio as well as thermal and electrical conductivity and protection against corrosion. It can easily be machined at low cost and is ideal for creating prototypes.
The variety of aluminum alloys used for CNC machining include:
6061 – is the most commonly used.
6082 – is mostly used in Europe.
7075 – is used in the aerospace industry where there are concerns regarding weight. 7075 can be heat treated to increase its strength and hardness.
5083 – has exceptional strength and resistance to salt water and can be welded.
Stainless Steel
Stainless steel is a popular choice in CNC machining due to its strength, ductility, and resistance to wear and corrosion. It can be welded, machined, and polished, and is available in both magnetic and non-magnetic varieties.
Varieties of stainless steel that is used for CNC machining:
304 – is the most common stainless steel used.
316 – is another commonly used stainless steel. Unlike 304, it is resistant to the effects of saltwater.
2205 – has higher strength than other stainless steels and is used in harsh and severe conditions.
303 – has excellent toughness but low corrosion resistance.
630 or 17-4 – is capable of being hardened to 44Rc when heat treated and can withstand extremely high temperatures.
Alloy Steel
Alloy steel is manufactured by adding various elements to carbon steel, enhancing its hardness, toughness, and resistance to fatigue and wear.
The types of alloy steels used for CNC machining are:
4140 – has excellent mechanical properties but is not suitable for welding.
4340 – unlike 4140, 4340 can be heat treated to increase its hardness and can be welded.
Brass
Brass is an alloy known for its machinability, electrical conductivity, and suitability for low-friction applications. Its attractive appearance makes it popular for decorative architectural elements. Brass C36000, the most commonly used type in CNC machining, is favored for its tensile strength and corrosion resistance, making it ideal for high-volume production.
Polycarbonate
Polycarbonate is a durable thermoplastic known for its machinability and exceptional impact resistance. Its transparency makes it well-suited for applications like fluidic instruments and automotive glazing. Additionally, polycarbonate is easily shaped and worked, adding to its versatility.
Inconel
Inconel alloys, a trademarked brand by Special Metals Corporation, are nickel-chromium-based alloys known for maintaining structural integrity at high temperatures and resisting oxidation. These alloys are designed for harsh and extreme environments. Notable Inconel alloys include Inconel 625, Chronin 625, Altemp 625, Haynes 625, Nickelvac 625, and Nicrofer 6020.
Thermoplastics
Several thermoplastics offer the strength and hardness needed for CNC machining. These include POM (commercially known as Delrin), Teflon (PTFE), and high-density polyethylene (HDPE).
POM – has very high machinability and is used for CNC parts that require high precision, stiffness, low friction, and dimensional stability.
Teflon – has chemical and thermal resistance with a low friction coefficient. It is able to withstand temperatures of 200o C and is an excellent insulator flor electrical components .
HDPE – has excellent impact resistance, a high strength to weight ratio, and weathering resistance.
Chapter Six: Swiss Turning and CNC Machining
Swiss CNC machining is an efficient and cost-effective technique for high-volume production of small parts. Its key advantages are short cycle times and flexibility, making it ideal for large-scale manufacturing.
Originally considered a specialized tool for watchmaking, Swiss machining has evolved into a crucial method for producing small parts. A distinctive feature of Swiss machining is its headstock's movement, which enables simultaneous rotational and longitudinal motion with radial tool holders, facilitating rapid forward and backward operations.
What is Swiss CNC Machining?
Swiss CNC machining originated during the first industrial revolution in the Bienne region of Switzerland, driven by watchmakers' need to produce increasingly smaller watch components. The process emerged to meet this demand, thanks to its precision in manufacturing tiny diameters.
The key distinction between Swiss CNC machining and traditional lathes lies in the movement of the headstock. While traditional lathes have a stationary headstock, Swiss machining features a headstock that moves the workpiece, which is supported by a guiding bushing.
In Swiss CNC machining, the workpiece is secured to the headstock and advances through a guide bushing. As it moves in the Z direction, it is simultaneously shaped and cut by the tooling, allowing for precise machining during its movement.
Swiss CNC machining eliminates overhang, reducing the risk of tool deflection and ensuring that the tool remains aligned with its programmed path.
Advantages of Swiss Machining
Accuracy in Machining Small Parts
In traditional machines, the tool is introduced to the workpiece and moves around it. In Swiss machines, however, the workpiece moves to the tool, enabling the production of more intricate and complex configurations with greater speed and precision.
Simultaneous Turning and Milling
Simultaneous operations are possible because the workpiece moves rather than the tool. This allows multiple cuts to be completed within a single cycle.
Cycle Time
A major concern in modern manufacturing is time, as customers demand quick production of parts. Swiss machining significantly reduces cycle time by performing multiple cuts in one cycle, thanks to the workpiece moving rather than the tool.
Bar Stock
The main advantage of Swiss machining is its capability to work with smaller bar stock, which is more affordable and lowers the overall cost of the part.
Length to Diameter Ratios
The higher the length-to-diameter ratio, the less setup time is needed. Unlike traditional methods, Swiss machines can accommodate a greater length-to-diameter ratio due to the way the bar stock is fed into the machine.
Quantities
A key advantage of Swiss machining is its capacity for rapid production of large quantities. The process involves loading bar stock and allowing the machine to run autonomously. During this cycle, the machine performs milling, drilling, reaming, and sawing, resulting in completed parts that are ready for shipment.
Cost Savings
A key advantage of Swiss machining is its capacity for rapid production of large quantities. The process involves loading bar stock and allowing the machine to run autonomously. During this cycle, the machine performs milling, drilling, reaming, and sawing, resulting in completed parts that are ready for shipment.
Precision
Swiss machining was initially developed for its capability to produce precision diameter parts with high accuracy and efficiency. This remains true for modern Swiss CNC machining, which can achieve dimensional tolerances of ± 0.0001 inches, a critical requirement in today’s market.
Chapter Seven: What Industries that Use CNC Machining
The complexity, accuracy, and precision of CNC machining have made it indispensable across numerous industries. The ongoing demand for precisely engineered parts is crucial for developing modern products. Advances in CNC technology have made it vital for producing many contemporary items, spanning fields such as medical, aerospace, automotive, and technology.
Precision is crucial in industries where components must perform reliably in life-or-death situations, such as in the medical field, defense, petrochemical, and aerospace sectors. A failure of a critical part in these areas can jeopardize lives, making it essential to use CNC machining for producing and engineering parts and assemblies that must function flawlessly in critical applications.
Industries that Use CNC Machining
Medical Industry
Parts for the medical industry are often customized to meet individual patient needs. Since many medical components are disposable to prevent infections, they must be manufactured with high precision and in large quantities. CNC machining is well-suited to fulfill these requirements, providing the accuracy and scalability needed to meet the demand.
Aerospace
Aerospace components must withstand high speeds, intense air currents, and significant pressure. Each part of an aircraft needs to be meticulously engineered to handle these demanding conditions. The aerospace industry requires tolerances as tight as 0.0004 inches. CNC machines are capable of meeting these stringent requirements by machining highly durable materials with exceptional precision.
Materials used in the aerospace industry include titanium, aluminum, nickel, and various plastics. The choice of material depends on the specific application and the required material properties.
Parts produced for the aerospace industry using CNC machining include:
Manifolds
Bushings
Airfoils
Landing gear parts
Electrical connectors
Antennae
Oil and Gas
The oil and gas industry requires parts that, despite their large size, must still maintain the precision and dimensional stability typical of smaller components. Ensuring precise fit is crucial to avoid any potential failures. CNC machining is used to produce essential parts such as pins, rods, valves, pistons, and drill bits.
In the oil and gas industry, durability is crucial to ensure parts last without frequent replacements. Given the industry's need for quick turnaround times, CNC machining is heavily relied upon for its efficiency and precision.
Military and Defense
In the military and defense industries, parts must meet stringent government standards and regulations. Similar to the oil and gas sector, these components need to be exceptionally durable, sturdy, and long-lasting. Frequent repairs or replacements could result in delays and pose significant risks to safety and mission success.
Machining parts for the military involves additional challenges, such as maintaining secrecy. CNC machining is crucial in this context due to its ability to provide quick and precise turnaround times. This capability is essential for meeting the military's urgent and confidential needs.
Electronics
In the electronics industry, the requirements for parts contrast sharply with those of the oil and gas sector, making CNC machining essential for electronic component production. While precision remains crucial, the primary focus is on the small size of components, which need to be extremely accurate and well-dimensioned. This emphasis on size and accuracy mirrors the challenges that led to the development of Swiss CNC machining.
The tight tolerances, small dimensions, and high precision required for electronic components leave minimal room for error. Many parts must be micromachined to meet stringent design specifications.
Marine
As the name implies, the marine industry has the unique requirement of its components being water resistant. Parts may be exposed directly to water or be subjected to high humidity environments. To meet the needs of the marine industry, parts must be produced under special conditions out of materials that meet the exacting requirements.
Another key factor for the marine industry is total portability and the ability to withstand the harsh conditions found on sea-going vessels. Just like materials in other industries, marine components must be highly durable, as a ship at sea may not have the means to easily replace a failed part.
Parts produced using CNC machining for seagoing vessels include:
Insulating cases
Propellers
Engine components
Electronic parts
Prototype molds
Boat parts
Firearms
The primary focus for the firearms industry is accuracy and precision. CNC machining is preferred for producing firearm components because it offers in-process quality control and monitoring to meet strict tolerances. A notable advantage of CNC machines in this industry is their ability to record and log serial numbers, which are engraved directly on each component. This capability facilitates easy tracking and cataloging of the parts.
Optics
The optics industry faces the challenge of machining complex geometries. CNC machining offers a significant advantage due to its flexibility and capability to perform 5-axis cuts, which is particularly beneficial for lightweight materials. Optic components often feature high aspect ratios, specialty bevels, precise cut holes and inserts, and accurately positioned mounting surfaces.
In many cases, for the optics industry, ultrasonic CNC machines are used for their accuracy and precision.
Telecommunications
In the telecommunications industry, the accuracy, reliability, and high tolerances of CNC machining are essential due to the potentially severe consequences of failure. Durability and robustness are crucial for telecommunications parts, as any breakdown or error can lead to significant and critical issues.
CNC machining is well-suited for telecommunications applications because of its ability to achieve high tolerances and exceptional reliability. Similar to the optics industry, telecommunications components often involve complex and intricate geometries, which pose engineering and design challenges. Common materials used include aluminum, stainless steel, and brass.
Automotive
Among the many industries that utilize CNC machining, the automotive sector has the greatest need and benefits the most from its efficiency and rapid turnaround times. The automotive industry is continually searching for improved and more efficient methods for producing components and parts. As a pioneer in adopting advanced technological methods, it was among the first industries to extensively use CNC machining.
The key features of CNC machining that have become defining for the automotive industry include rapid production speed, automation, precise repeatability, accuracy, and ease of customization. Components such as interior panels, starter motors, cylinder heads, gearboxes, and drive axles are produced quickly and efficiently to meet production requirements and specifications.
Chapter 8: CNC Terminology
Like any computer programming, CNC machining uses its own programming language to control actions and movements. While various coding formats exist, G-codes are the primary language used to direct CNC machine tools on the required movements and processes. The CNC machine translates computer-aided design (CAD) instructions into these G-codes.
While there are countless CNC terms, including proprietary ones used by different manufacturers, some terms are universally recognized and understood across all industries, much like G-codes.
The term "5-axis" refers to the number of axes a CNC machine has for movement. The primary axes are the X-axis, Y-axis, and Z-axis, which run along the bed of the machine. In addition to these basic axes, two of them feature additional motion modes that enable the machine to perform complex and intricate movements, including rotations.
Address
The command block of a CNC machine is governed by letter address commands, which vary in meaning depending on the G-code present in the command block. Each letter in these commands represents a specific function; for example, "T" indicates tool selection, while "L" denotes the fixed cycle loop count.
Automatic Tool Changer (ATC)
The primary advantage of CNC machines is their capacity to execute complex and intricate cutting operations autonomously. The Automatic Tool Changer (ATC) swaps tools on a CNC machine according to the task at hand, and this process is managed through G-code commands.
Axis
The term "axis" refers to the plane of motion for a CNC cutting tool. The main axes are the X, Y, and Z axes, with additional B and C axes introduced to enable further motions..
Bed
The bed of a CNC machine supports the machine and holds the workpiece during machining. Like spindles, beds can be either fixed or mobile. In a fixed bed setup, the bed stays in place while the spindle moves, whereas in a mobile bed setup, the bed moves while the spindle remains stationary. The design of the bed varies depending on the machine manufacturer and the specific requirements of the part being produced.
CAD (Computer Aided Design)
CAD (Computer-Aided Design) software helps engineers create detailed renderings of their designs. These CAD designs can be downloaded into a CNC machine, where they are converted into G-codes for production.
G and M codes form the core of CNC programming. G-codes are preparatory codes that set up the machine for specific motions, while M-codes are used for controlling auxiliary functions. Each block of code can include only one M-code.
While CNC machines come with pre-programmed M and G codes, they are versatile enough to allow manufacturers to add proprietary codes for specialized functions and operations.
Gantry
The gantry spans the cutting bed, moves along the X-axis, and supports the spindle. There are two types of gantries: fixed and moving. A fixed gantry remains stationary, while a moving gantry travels along the cutting table.
Home Position
The home position is the reference point for the X, Y, and Z-axes and is set by a G-code.
Jig
A jig is a tool designed to hold and position a workpiece accurately, ensuring it remains correctly aligned for cutting operations. For instance, a jig will guide a cutting tool through precise operations during milling.
Kerf
The kerf is the width of the cut into the workpiece.
N Codes
N codes are used to identify specific lines of code, with each code followed by a number that designates a block of code and its line number. When input into a CNC machine, N codes typically progress in increments of five or ten, allowing for space and flexibility in programming.
Nesting
Nesting involves arranging the cutting pattern to minimize waste. The process repositions the original pattern to optimize material usage and reduce excess.
Part Program
The part program includes all instructions for a specific part, serving as the set of commands that trigger cutting, shaping, and other CNC functions.
Post Processor
A post-processor, or "post," converts CAD computer language or images into a format that a CNC machine can understand. In most cases, this language is G-codes.
Resolution
The resolution of a CNC machine refers to its ability to accurately determine its position and precisely follow the letter address command codes for its axes.
Revolutions Per Minute (RPM)
In CNC machining, RPM refers to the rate per minute that the spindle will spin.
Special Characters
Keys from a computer keyboard are also used as code designations. For instance, the percent sign (%) marks the beginning or end of a program, while the backward slash (/) is used for block deletion. Semicolons, parentheses, and dashes serve as codes or commands within blocks of command codes.
Spindle
The spindle is the central component of a CNC machine. It is a rotating assembly designed with a taper for holding tools. Powered by a motor, which can vary depending on the CNC machine's manufacturer, the spindle plays a crucial role in the machining process.
Step Down and Stepover
The step-down refers to the depth that the Z-axis tool cuts into the workpiece, while the stepover is the distance the tool moves laterally from one cutting path to the next.
Vector
Vector files are 2D graphics that include shapes, lines, coordinates, sizes, and colors. They are defined by mathematical equations that establish points on a Cartesian plane, making them easily scalable. The quality and advantages of each vector type can vary depending on the software used.
Conclusion
CNC machining is an electromechanical process that manipulates tools around three to five axes, with high precision and accuracy, cutting away excess material to produce parts and components.
The multitasking ability of CNC machines allows for the completion of a component or part in a single operation, with ease and efficiency.
CNC or Computer Numerical Control machining is a logical and rational process that is planned and designed for the efficient production of parts.
A major advantage of CNC machining is the wide array of cuts CNC machines can make
CNC software creates programs to run a machine tool. Every aspect of a CNC machine has its own program.
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Computer numerical control (CNC) is a fundamental part of modern manufacturing. The majority of machines operate using instructions and guidelines that have been downloaded using a CNC program controller...
Types of Machining
Machining is a manufacturing process used to produce products, parts, and designs by removing layers from a workpiece. There are several types of machining that include the use of a power driven set of machining tools to chip, cut, and grind to alter a workpiece to meet specific requirements...
What is CNC?
The CNC process, computer numerical control, is a method of manufacturing where programmed software directs the operation of factory tools and machinery. It is designed to manage a wide range of complex machines from grinders and lathes to mills and routers...
Contract Manufacturing
Contract manufacturing is a business model in which a company hires a contract manufacturer to produce its products or components of its products. It is a strategic action widely adopted by companies to save extensive resources and...