This Article takes an In-depth look at Machining Types, Tools and Uses
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In manufacturing, machining is a process employed to create products, parts, and designs by removing material from a workpiece. This method incorporates various types of processes that utilize power-driven tools for chipping, cutting, and grinding to modify a workpiece to meet precise specifications. The machining process is instrumental in producing items such as metal fasteners, costume jewelry, toys, and hand tools. Occasionally, a completed part might require refinements to satisfy quality benchmarks or specific manufacturing criteria. In such situations, machining is used to achieve the desired finish and appearance.
Machining extends beyond metals, offering versatility across numerous materials. For example, molding is conventionally used to shape plastic and rubber items. Often, post-molding enhancements are necessary, implemented through machining techniques such as drilling holes, material removal, or shape refinement. Even pliable materials like paper can be machined to reach distinct patterns or forms.
A variety of machining tools are used to shape, deform, and mold metal to produce a specific geometric shape. Part of the machining process is to secure the workpiece using a gripping device to hold it in place while the tool runs across it. Prior to the industrial revolution, machining functions were performed by hand. Modern technology has taken those handcrafting skills, using computerized numerical control (CNC), and programmed them in machining equipment to be repeated multiple times accurately and precisely.
To carry out the various operations needed to shape a workpiece, a range of tools is necessary. The selection of these tools is done with precision to guarantee the high quality of the finished product.
Below, you'll find a list of some common machining tools, along with their descriptions:
Machining drill bits come in various types, such as center, twist, and ejector, each serving a distinct purpose. Center drill bits are ideal for making precise small holes, which can then be further enlarged using a twist drill bit. Ejector drill bits are designed to increase the diameter and depth of existing holes, with single or multiple cutting heads available; the single head type creates larger holes, while multiple head versions handle even bigger sizes.
Insert drill bits are cost-effective and simple to use, featuring a ground point to aid in alignment. However, they often leave burrs that necessitate additional finishing work due to the secondary processing required.
Twist drill bits are equipped with corkscrew flutes that offer sharp and accurate drilling but need frequent sharpening. Unlike insert drill bits, twist drill bits do not produce burrs, eliminating the need for deburring. These versatile bits can drill into most materials except masonry and concrete, making them well-suited for machining metal.
Drilling is a fundamental machining process that involves using a drill bit to create a circular hole in a workpiece. It is the most frequently used machining technique, accounting for about 75% of machining operations. A drill jig is held in a chuck connected to a spindle, driven by a drill head operated by a pulley system and electric motor. The drilling tool, whether controlled electronically or manually, is then brought down onto the workpiece surface.
Milling produces three dimensional shapes using a rotating multi-edge cutting tool. In CNC manufacturing, the milling tool can be programmed to move in several directions on a fixed workpiece. The process can create parts in a wide range of shapes with features such as slots, pockets, and grooves. There are several kinds of milling tools depending on the type of cuts required.
End mills, unlike drill bits, offer a wider range of applications. They feature eight flutes positioned on their ends and sides, allowing them to efficiently remove significant amounts of material in one pass. A key advantage of end mills is their ability to cut directly into the material without requiring a pilot hole. Among various types of end mills, roughing end mills are particularly popular.
Face mills are primarily used to smooth and polish the surface of a workpiece, making them a common choice for milling operations. The face milling process involves cutting surfaces that are perpendicular to the cutter’s axis or the face of the workpiece. Shell mills and fly cutters are frequently utilized for face milling, with selection based on the required surface finish.
Additional milling tools include slab mills, thread mills, and hollow mills, each designed for specific tasks. Slab mills have cutting teeth along the edge of the cutter, thread mills are used for creating threads in a workpiece, and hollow mills, shaped like a pipe, have teeth located at one end for specialized cutting.
A boring tool is a cylindrical cutting instrument that can rotate on multiple axes, allowing it to create various shapes, slots, and holes. These tools are classified based on the number of axes they can operate on. Most boring tools use between 3 to 5 axes to achieve intricate shapes that other methods cannot produce.
Boring techniques vary depending on the desired hole shape and size, as well as the support provided to the workpiece. The geometry of the holes made through boring is highly precise and controlled. While similar to drilling, boring is a more accurate process that refines a pilot hole created during casting or by other drilling methods.
Boring tools are renowned for their high precision and are preferred for their exceptional accuracy. They can handle very large workpieces with minimal tool deflection and offer outstanding durability. While other tools can also perform boring, dedicated boring tools provide superior power and stability for the task.
Boring operations can be conducted in three primary ways: rotating a stationary bit, rotating the workpiece, or using a stationary tool while spinning the workpiece. This process can be performed horizontally, vertically, or at various angles, often at slower speeds and feed rates to minimize noise and vibrations.
Grinding or abrasive machining tools are a method for material removal that use a rotating wheel cutting across a metal surface to achieve high quality finish. The quality of the finish is created using light cuts and multiple passes to perform precision removal of material. The categories of grinding tools are surface, cylinder, centerless, internal, and specialty.
Surface grinding, also known as hiraken or heiken, involves a vertical or horizontal axis with either a circular or square table. This finishing technique is suitable for both metallic and non-metallic materials. It uses an abrasive wheel along with a chuck and table to remove surface imperfections and oxide layers from a workpiece.
Cylinder grinders are designed for grinding cylinders, rods, and similar shapes. The workpiece is mounted between two centers and rotates in one direction, while the grinding wheel turns in the opposite direction. This method, which resembles lathe operations, is used to create various surface contours, including tapered and straight finishes.
Through-feed centerless grinding tools place the workpiece on a blade positioned between a regulating wheel and a grinding wheel. The regulating wheel moves the workpiece forward while the grinding wheel removes material. Infeed centerless grinding involves the grinding wheel moving radially against the workpiece, ideal for producing complex surface shapes.
Internal grinding tools, also known as ID or bore grinding tools, are used to remove material from the inner diameter of cylindrical or conical workpieces. Similar to cylinder grinders, internal grinders operate like a lathe to precisely form holes within the cylinder. The tool moves in and out of the workpiece to achieve the desired depth of cut.
Turning tools are single-point tools employed on a lathe to cut away material from a rotating workpiece. They are classified into rough and fine categories, each suited to different cutting tasks. Rough turning tools are designed to remove substantial material quickly and feature minimal clearance. In contrast, fine turning tools, used for finishing work, have a larger clearance angle to delicately remove small amounts of material for a smooth finish.
The turning process is used to shape workpieces into axial symmetric forms. In this process, the cutting tool remains stationary while the workpiece rotates. The cutting tool itself is typically a replaceable insert, which can vary in shape, cutting material, coating, and geometry. Common shapes for these inserts include round for durability, diamond for precision, and square or octagonal for additional cutting edges.
Cutting blades must endure significant stress during operation and are usually made from carbide with a protective coating to enhance cutting efficiency and tool life. Historically, steel was used for turning tools, requiring frequent sharpening. However, carbide has largely replaced steel due to its superior wear resistance and hardness.
Turning involves both linear and rotational movements of the workpiece. The cutting speed, measured in surface feet per minute (SFM) or square meters per minute (SMM), refers to the speed at which a specific point on the workpiece’s surface travels. The feed rate denotes the linear distance the tool moves during cutting. Feed rates differ between rough cutting and finishing operations.
There are five types of machining cutting tools that are used according to the type of machine, the project, and the required precision. The list cutting tools includes lathes, several forms of milling tools, routers, plasma cutters, and electrical discharge cutters (EDM). Of the five listed, milling tools are the most common.
The choice of cutting tool significantly impacts the final product’s quality. Factors such as accuracy, production costs, finish quality, material waste, and machine efficiency all depend on the tool holder and the selected cutting tool. Using subpar tools and holders can increase manufacturing costs and potentially damage the cutting machine.
To properly evaluate the cost of cutting tools, consider the various options available, including solid carbide spiral tools, insert tools, custom tools, and polycrystalline diamond (PCD) tooling. While multiple solid carbide bits may be needed, a single PCD tool can handle an entire production run, offer greater longevity, and reduce overall costs. Investing time in selecting the right tool can result in significant cost savings over time.
Most cutting tools feature flutes—helical grooves running along their length. The cutting edges, or teeth, are situated above these flutes. As the tool removes material, chips are directed down the flutes and expelled from the machine. Tools with more flutes are more aggressive and suited for harder materials but may experience chip clogging. Fewer flutes are better for softer materials, allowing larger chips to be cleared more easily.
The core of machining involves removing material from a workpiece using a cutting tool. The choice of tool depends on the workpiece’s hardness and the desired shaping or forming. Additionally, other factors must be considered to ensure the cutting tool is well-suited for the specific machining process.
Sawing is one of the oldest and most widely used machining processes. It has evolved over time to accommodate new materials and techniques. This process is primarily used to cut sections from a workpiece without strict tolerance considerations. CNC sawing is employed for various tasks, including both finishing and shaping.
There are two main types of sawing: continuous cutting and reciprocating cutting. Both methods serve similar purposes but utilize different techniques. Reciprocating sawing involves moving the saw blade back and forth to cut material, operating with each stroke or a single stroke as part of CNC machining.
Continuous cutting involves a saw that moves in one continuous direction to remove material. This technique includes various forms, such as friction cutting and abrasive cutting. Friction cutting, for instance, uses a high-speed saw to heat and melt specific areas of the workpiece, eliminating the need for teeth on the saw blade.
Sawing tools are categorized based on their intended outcomes. Cutoff sawing is used for removing large portions of material where precision is less critical and is suited for thin kerf applications. Contour sawing is designed to create specific shapes and is akin to milling. While CNC machining or milling can achieve similar results, sawing tools may require specialized tooling to match the precision and effects of sawing.
A broach, used in broaching, is a cutting tool resembling a saw but with varying tooth widths and configurations. Each tooth on a broach is slightly higher than the one before it. Unlike a saw, where teeth cut simultaneously, a broach removes material progressively as its teeth increase in height from the first to the last. The gradual increase in tooth height determines the depth of material that can be removed by the broach.
Broaches are intricate tools designed for specific tasks and come in various shapes and sizes tailored to meet application requirements. They are categorized based on the type of cutting job and the force applied by the machine. Basic broaches typically cut a single surface and feature a rectangular cross-section with a single set of teeth.
Simple broaching operations often use an arbor press, but more complex tasks require specialized or dedicated broaches. The choice of broach depends on the machine’s characteristics used to operate it. Some machines pull the broach through the workpiece, while others push it. Traditional broaching machines operate vertically, moving the broach up and down, whereas horizontal broaching machines are used for longer workpieces and support the broach with braces.
Broaching is an efficient method that simplifies the process for operators, as the tool’s design inherently manages adjustments during production. The cutting action is quick, precise, and repeatable, exerting significant force on the workpiece. Therefore, the workpiece must be strong enough to endure the forces involved in the broaching process.
Planing is an essential machining process used to shape and smooth a workpiece. It involves adjusting the size and form of materials to meet design specifications by pressing and rotating the workpiece against a fixed, stationary cutting tool. As the workpiece rotates, material is removed by the cutting tool, sculpting the surface. The process of planing is defined by the surface characteristics it produces.
Although planning and shaping are sometimes mistakenly considered the same, they are distinct processes. The main difference lies in their interaction with the workpiece: shaping involves a stationary workpiece with a moving tool, while planing features a rotating workpiece with a stationary tool. Shaping is typically used for smaller projects, whereas planing is suited for larger workpieces requiring more extensive material removal.
Planing tools use a single-point cutting tool to make substantial cuts, flatten surfaces, or cut keyways. Planer machines can execute various planning tasks within a machine cycle. Critical factors for successful planing include cutting speed, feed rate, and cut depth, all of which must be precisely adjusted before starting the process.
Chemical machining, or etching, utilizes acidic or alkaline chemicals to remove material from a workpiece without relying on mechanical force, pressure, or friction. The workpiece is submerged in a chemical solution within a tank for a specified duration, allowing the chemicals to dissolve the material.
The process involves several components: a tank, a heating coil, and a stirrer. The tank, lined with a non-reactive coating, holds the chemical solution and resists etchant corrosion. The heating coil, positioned near the tank’s bottom, regulates the temperature, while the stirrer ensures even mixing of the etchant to maintain consistent concentration and heat distribution.
An etchant, a potent chemical agent, reacts with the workpiece material to dissolve it. To shield specific areas from etching, the workpiece is covered with a non-reactive coating called a maskant. This maskant protects regions that should not be affected by the chemical solution, allowing precise machining of the exposed parts.
Before immersion in the etchant, the workpiece undergoes thorough cleaning to remove contaminants, rust, and foreign materials. Effective cleaning is crucial as any residue can prevent the maskant from adhering properly. After cleaning, the workpiece is coated with the maskant.
Post-machining, the workpiece undergoes a demasking process where the maskant is removed, followed by a cleaning stage to eliminate any residual etchant and maskant. The part is rinsed with pressurized cold water to ensure complete removal of any remaining substances.
Chemical machining offers several benefits over more aggressive methods. It provides uniform material removal without chips or flakes, achieving a smooth finish with precise tolerances. This method avoids mechanical stress on the workpiece and can easily create complex and intricate contours.
Electrochemical machining (ECM) uses a negatively charged cathode and a positive anode workpiece immersed in an electrolyte fluid. The DC current drives the reaction between the cathode and the workpiece, where the cathode, shaped inversely to the desired feature, removes material from the anode without direct contact, thus avoiding thermal wear and allowing for multiple uses.
The anode or workpiece must be made of conductive metals, often including hard-to-machine materials like iron, nickel, nitinol, titanium aluminide, and chrome-based alloys, usually in plate or bar forms. The electrolyte acts both as a conductive medium facilitating the electrochemical reaction and as a flushing agent to clear away dissolved metal. It is continuously circulated between the cathode and anode to ensure process stability.
A power supply is essential for providing the necessary current to drive the electrochemical reaction, influencing the process speed. ECM operates on low voltage but high current DC power, with advanced versions employing pulsed currents to deliver intermittent power bursts.
As a non-contact method, ECM eliminates tool wear and produces smooth, burr-free finishes on the workpiece. This process is effective on the hardest conductive metals, as the hardness of the metal does not affect its cutting capability.
Abrasive jet machining (AJM) involves propelling small, hard abrasive particles at high speeds to erode material from a workpiece. An air compressor powers the AJM tool, using inert gases or air to propel particles as small as 0.001 inches (0.0254 mm) in diameter. The high-speed impact of these particles wears away material to shape the part or product.
The abrasive particles continuously strike the workpiece, concentrating their impact to cut and erode material. These particles travel at speeds between 150 m/s and 300 m/s, carried by a gas stream. A filter cleans the gas to prevent contaminants from affecting the cutting process, and the gas pressure is carefully regulated to achieve the desired cutting depth and force.
An adjustable nozzle attached to the gas stream further controls the abrasive flow. The nozzle, typically made of tungsten carbide to resist wear, can be adjusted for precise angular cuts and comes in various shapes, including circular or rectangular and straight or angled designs.
Various abrasives are used in AJM, such as silicon carbide, aluminum oxide, glass beads, and sodium bicarbonate, suitable for different materials and shapes. The choice of abrasive depends on factors like material removal rate (MRR), the type of workpiece material, and the required precision.
Ultrasonic machining employs high-frequency vibrations combined with abrasive particles to precisely remove small amounts of material from a workpiece. This technique is effective for removing surface material without affecting the underlying crystalline structure, allowing for the creation of highly durable, strong components with exceptional accuracy and tight tolerances.
The ultrasonic machining setup includes precision-calibrated equipment made from steel or nickel, which vibrates at specific frequencies. Initially, a slurry composed of abrasives like boron carbide, silicon carbide, diamond, cubic boron nitride, or aluminum oxide mixed with water is applied to the workpiece’s surface.
In the ultrasonic machining process, vibrations target the slurry, causing the abrasive particles to grind away the material. The frequency of these vibrations is controlled by software, enabling precise adjustments. The slow, controlled removal of material minimizes stress on the workpiece, ensuring strong, durable parts with high precision.
Despite its precision, ultrasonic machining requires thorough cleaning to remove residual particulate matter. This step is crucial, particularly for producing optics and microelectronic components where cleanliness is essential.
Ultrasonic machining is well-suited for a wide range of materials, including hard and brittle substances. It is particularly effective for machining glass, ceramics, and quartz, and is advantageous for materials sensitive to heat, as it does not involve thermal effects.
Electronic beam machining utilizes a high-speed stream of electrons directed at a workpiece to remove metal material. Electrons in this process travel at speeds up to half the speed of light, making it ideal for precision microcutting. Upon impact, the high-velocity electrons generate enough heat to melt and vaporize the metal, thanks to the kinetic energy from the electron collisions.
The process starts with a negatively charged cathode that generates the electrons. These electrons are accelerated by a positively charged anode placed behind an annulus bias grid, reaching speeds up to half the speed of light. An electromagnetic lens focuses the electron beam, while a deflector coil ensures the beam is directed accurately to the desired location on the workpiece.
DC current is used to power the electron beam, heating a tungsten filament to approximately 2500°C (4532°F). This high temperature causes the tungsten filament to emit electrons, which are then directed by the anode grid cup toward the workpiece. The focused electron beam, with its high power density, rapidly melts and vaporizes the material on the workpiece's surface within microseconds.
Electronic beam machining is widely favored for its precision and ability to create extremely small holes without direct mechanical contact with the workpiece. It is a fast and efficient method that can machine even the hardest materials while preserving their physical and metallurgical properties, making it suitable for delicate and brittle materials as well.
The types of machining listed here are a few of the methods used in modern production. Specialty and custom tools are continually being perfected to meet the needs of innovative designs.
Mechanical methods of machining have been used for many years. Through innovation and technological advances, other processes have developed to remove layers without the need for grinding, boring, or mechanical tools. Some of these techniques are referred to as burning where the workpiece is heated and melted to achieve a shape or design. The most common types are laser, oxy-fuel, and plasma.
A laser beam, of high energy, contacts the workpiece creating thermal energy. The heat created melts, burns, and vaporizes the surface of the workpiece to shape it into a design. There are two types of lasers – gas and solid state. With a gas laser, gases are used to generate heat, which are He-Ne, argon, and Co2. Solid state lasers have different forms, which include YAG (yttrium aluminum garnet), Nd:YAG ( neodymium-doped yttrium aluminum garnet), and ruby. The laser cutting process can shape steel or etch patterns. Its benefits include high-quality surface finishes and cutting precision. Laser machining produces accurately placed cuts of high precision and has the ability to cut or shape any type of material.
Oxy-fuel cutting, also known as gas cutting, is mostly used to cut thick steel plates. The heat source for oxy-fuel cutting is produced by combining oxygen with some type of fuel such as acetylene, gasoline, hydrogen, or propane. The oxy-fuel torch heats the workpiece to kindling temperature, around 960° C. Once the proper temperature is achieved, pure oxygen is directed through a nozzle onto the heated cut. The oxygen changes the heated and unprotected steel into an oxidized liquid by an exothermic reaction. The created slag is blown out of the heated cavity. The process can cut deeper angles up to 70o and is more economical than the other burning methods.
Plasma cutting is an efficient and cost-effective technique used to cut steel. This process utilizes a plasma torch to create a plasma arc for the cutting operation.
The torch fires an electrical arc that transforms an inert, ionized gas, or plasma, which reaches an extremely elevated temperature. The heat from the torch is applied to the workpiece at high speed to melt away unwanted material. Metals machined in this way are electrically charged since an electrical current flows between the electrode of the torch and the workpiece. Plasma cutting can cut thin or thick materials. Handheld torches can cut materials of up to 38 mm thick while CNC devices can cut steel sheets of up to 150 mm thick.
Unlike traditional cutting methods that use heat to melt away excess material, non-traditional techniques rely on erosion to achieve the desired results. Methods such as waterjet cutting and electric discharge machining do not require physical tools to remove material. Instead, they utilize the power of abrasive-laden water jets and electrical discharges to cut through the workpiece.
Waterjet cutting is a versatile fabrication process that uses water under high pressure, mixed with an abrasive, to cut materials into custom shapes and designs. Water is pressurized using an intensifier or direct drive pump, which is capable of producing significant fluid pressure. As the water enters the cutting head, the water goes into an opening containing a hard jewel such as a diamond, sapphire, or ruby. The velocity of the water increases at the opening, which can reach 2500 mph. Abrasive powder is added to the water stream to cause erosion. Waterjet cutting is typically used on materials that can suffer damage or deformation from heat processes.
The EDM process is known as spark machining, spark eroding, die sinking, wire burning or wire erosion. Material is removed from a workpiece through the use of thermal energy without the use of grinding, drilling, cutting, pressure or force. Conductive materials are shaped and cut using an electrode that creates an electrical discharge between the workpiece and an electrode that melts and vaporizes material.
The EDM process excels at creating intricate shapes in hard materials. In this technique, both the workpiece and electrode are immersed in a dielectric fluid. Electrical current flows through the electrode, forming plasma zones that melt away material from the workpiece, resulting in a cavity that mirrors the electrode's shape.
Electrodes for EDM are crafted from various conductive materials, which influence the precision and form of the cutting. Commonly used metals for electrodes include copper, brass, graphite, molybdenum, silver tungsten, and tellurium copper, chosen for their conductivity and resistance to erosion.
There are three main types of EDM: die sinking, wire, and hole drilling. Die sinking, also known as ram or cavity EDM, is used to create parts with detailed cavities and sharp edges. Wire EDM, or wire erosion, produces precise extrusion dies and follows a similar method to die sinking. Hole drilling EDM is specialized for creating deep, fine holes and achieves this without leaving burrs.
Computer numerical control (CNC) machining emerged as a technological advancement in the 1950s, originally developed for manufacturing helicopter rotors. In the late 1950s, a project aimed at creating computer-aided design (CAD) software led to the development of AutoCAD. The integration of AutoCAD with CNC technology has significantly enhanced machining processes, enabling the production of parts at reduced costs with increased precision.
CNC has been applied to a broad range of manufacturing, production, and processing equipment. Software and programming, using the G-code computer language, develop commands and instructions to guide a machine through the shaping of a workpiece. The implementation of CNC has led to a decrease in losses due to human error and a significant drop in the amount of waste. Once a CNC machine is coded, it needs minimal maintenance or downtime and completes production at a faster rate.
Speed and lowered labor costs have made CNC a highly cost efficient method for producing high volume production runs. Down times for mishandled materials, insufficient supplies, or other production errors are eliminated. Every product and part is precision produced in accordance with exacting design specifications. Producers using CNC have the added benefit of more control of the total production process.
Precision machining is employed to produce components with minimal errors and tight tolerances, ensuring a high-quality finish. Techniques such as milling, turning, and electrical discharge are commonly used in this process, which requires meticulous attention to the design specifications.
This method is selected for its capability to meet exact dimensions specified in the design. Parts with stringent requirements for precision machining are subject to very tight tolerances, typically ranging from 0.0005 to 0.2, depending on the material and initial dimensions. Deviations beyond these tolerances can render the parts unusable.
The advent of CNC machining has greatly enhanced precision machining by improving tolerance levels and surface finishes. CNC technology allows designs to be transferred directly from computer models to the machine, which is programmed to execute every detail. The quality of the finished product can vary based on the CNC machine's capabilities.
Surface finish is a crucial aspect of precision machining, characterized by factors such as texture, roughness, and waviness. Each of these is quantified using mathematical formulas to assess the finish quality. Equipment manufacturers provide specifications detailing the achievable finish quality of their machines.
Precision machining is essential in industries like aerospace and medical manufacturing, where components must meet exacting standards for performance and safety, such as those used in spacecraft and specialized medical devices.
The 5-axis machining process extends the capabilities of traditional X, Y, and Z axes by adding two additional axes, A and B. This enhancement allows for shaping a workpiece on five sides in a single setup, eliminating the need for extra turning or additional setups. With a 5-axis machine, cycle times are faster, waste is reduced, spindle uptime increases, and operation becomes easier without requiring highly specialized training.
While a 3-axis CNC machine moves the part sideways on the X axis, vertically on the Y axis, and back and forth on the Z axis, the 5-axis machine introduces the A and B axes. The A axis tilts the worktable, and the B axis rotates it. The swivel-rotate style of 5-axis machines rotates the spindle, which is ideal for handling heavier parts, whereas the trunnion style features a moving table, making it suitable for high-volume production.
The advantages of 5-axis CNC machining include:
5-axis CNC machining often makes the seemingly impossible achievable by allowing a machine to complete all necessary cuts for a part in a single cycle. This capability streamlines operations such as milling, boring, tapping, threading, and grinding into a one-step process, enabling the creation of complex and intricate parts. Whether for single parts or high-volume orders, a 5-axis CNC machining system can handle both efficiently.
Machined parts are created through machining, a process that was once labor-intensive but has been revolutionized by CNC technology. Modern CNC machines are programmed to perform a variety of functions, delivering exceptionally accurate and precise cuts to produce high-quality parts. Unlike cast or forged parts, machined components are made with superior precision and accuracy.
Unlike forging and casting, machining allows for the easy production of prototypes, which can be examined and modified to meet specific application requirements. The CNC process begins with creating a CAD rendering, which is then downloaded into a CNC machine to quickly produce a prototype. This feature helps prevent losses during mass production.
Machined parts can be manufactured from a diverse range of materials, including steel, aluminum, brass, copper, titanium, stainless steel, and various plastics. The choice of material depends on the part’s intended use and the material’s mechanical properties, durability, strength, and versatility. Metals are commonly used for parts in industries such as automotive, aerospace, and construction, while plastics are often used in electronic devices, medical equipment, household products, and automotive applications.
While metals and plastics are the most commonly used materials for producing machined parts, machining is also effective for forming and shaping composite materials and ceramics. These materials offer unique characteristics that can meet specific application demands. Composite materials, such as epoxy resin, fiberglass, and Kevlar, are valued for their high strength-to-weight ratio, stiffness, and corrosion resistance. Ceramics, on the other hand, are known for their hardness, brittleness, thermal stability, and chemical resistance. Like composites, ceramics are recognized for their high strength, wear resistance, and non-conductivity.
The widespread adoption of machined parts is largely due to the numerous benefits they offer that are unmatched by other manufacturing methods. Machining eliminates the need for molds, dies, or other processing tools, reducing costs compared to casting and molding. It allows for production runs ranging from single, complex parts to large quantities, and also accommodates adjustments for special orders without affecting the original production requirements.
Unlike molding and die processes that require a minimum order quantity due to the creation of molds or dies, machining does not impose such requirements. Machining utilizes a blank placed into a CNC machine, which performs all necessary operations to shape the part. This capability enables small businesses to undertake extensive production runs without needing to alter tooling or develop specialized equipment.
Prototyping is a notable advantage of machining, allowing multiple iterations at low cost. Clients provide a CAD rendering to a machining engineer who then creates a prototype. If needed, adjustments can be made to the CAD design, leading to the production of additional prototypes. This iterative process is significantly less costly compared to altering molds or casting new dies.
Machining enables the creation of parts with any shape, size, or dimension, regardless of wall thickness or tapering. It allows for the production of parts that are either robust and durable or intricate and detailed. While there are some limitations regarding internal sections and channel depth, machining offers significant design flexibility for engineers.
This aspect of machining contributes significantly to its popularity. CNC machining allows for achieving extremely tight tolerances, as the part's parameters are fed into the machine, which executes each operation with high precision. Typical CNC machining tolerances are ±0.005 inch (0.127 mm), though it is possible to achieve even tighter tolerances of ±0.001 inch (0.0254 mm), comparable to the width of a human hair.
Such precision in adhering to design parameters ensures the production of parts with exceptional accuracy, making them a perfect fit for their intended applications.
The efficiency of CNC machining allows for rapid production without additional preparation or tool development. The process is driven by technology and computer inputs, allowing quick adjustments to accommodate urgent requests. Production can be shifted between large and small jobs without compromising quality, making it possible to fulfill a part request within a single day if needed.
In die and molding processes, tools must be shaped and formed before production begins. The part’s dynamics are carefully reviewed to ensure the die meets all requirements. Once a die or mold is created, making changes or corrections is not feasible. Conversely, machining allows for flexibility. A prototype is typically created and tested before full production to confirm it meets design specifications.
Once the prototype is approved, CAD data is transferred to the CNC machine to start production. During production, adjustments can be made or the design can be completely revised with minimal cost. This flexibility in machining enables modifications and updates at any production stage, leading to cost and waste savings.
Machined parts are made from a solid blank, preserving the material's original grain structure and strength. This inherent strength is crucial, as many machined components play critical roles in various applications and processes, ensuring reliability and durability in their final form.
Unlike molding and casting, machining does not involve the creation of flash, sprues, or flow lines, which require labor-intensive removal. Instead, machining processes such as bending, crimping, cutting, and drilling are directly performed on the blank, leaving the part ready for use or shipping once machining is complete.
Custom machined parts are created for various reasons, including the unavailability of parts, specific requirements, unique designs, or urgent needs. Previously, these parts were made using manual methods like lathes, mills, or stamping machines. However, with CNC machining, producing custom parts has become much more efficient and straightforward.
CNC machining can produce unique and non-existent parts with distinctive designs, structures, and functions. Custom parts range from simple gears to complex machine components. A CAD rendering of the part is converted into CNC code, allowing the machine to manufacture the part precisely.
Custom machining encompasses a range of processes, with 5-axis CNC machining being particularly prevalent due to its adaptability and flexibility. The process begins with prototype creation to assess the concept's feasibility. CNC machining simplifies this phase, as any digital format can be used to guide the machine.
Custom machined parts are based on client designs integral to innovative concepts. Often, presenting a custom part marks the culmination of a design process that has undergone rigorous testing and review. Manufacturers chosen for such specialized tasks are experienced CNC machinists with top-notch skills and expertise.
Some machined parts require additional finishing processes to meet design specifications. These treatments alter the part’s surface texture, improve appearance, or add designs. Finishing can be functional, aesthetic, or both, and aims to meet the detailed requirements of the design.
Blasting is an aggressive technique used to achieve specific surface textures by propelling abrasive materials like beads, sand, or gravel at the part. This method must be carefully controlled to avoid damaging the part, making it suitable for larger components that can endure the process.
Anodizing is an electrochemical process that enhances a part’s appearance and durability by adding an oxide layer. This layer provides corrosion resistance and extends the part’s lifespan. Anodizing can be tailored to meet the needs of different parts, with types including chromic acid, sulfuric acid, and hardcoat options.
Powder coating involves applying powdered paint to a part and then baking it to create a durable bond. This process results in a resistant finish that is wear and corrosion-resistant, offering a strong and long-lasting coating.
Several companies across the United States produce programmable CNC machines, each offering innovative solutions and excellent customer service. Their advanced technologies enhance the capabilities of CNC machines, catering to various manufacturing needs.
The Creator Pro features 4-axis capabilities and an electro spindle for rotary machining. Its 6.5-inch gantry clearance and liquid-cooled 3 HP spindle ensure precise and quiet operation. The machine's durable steel frame and interlocking aluminum construction support long-term use, while precision ball screws and prismatic guides enhance performance. The DSP controller simplifies operation.
The Datron M8Cube is designed to efficiently manufacture complex parts. It offers high performance with a large work area and a compact footprint, making it ideal for machining aluminum and other nonferrous metals. With fast cycle times and the ability to handle multiple jobs simultaneously, the M8Cube is easily reprogrammable for urgent tasks. The spindle operates at up to 60,000 rpm with a feed rate of up to 22 m/min (72 ft/min).
The MAG-CX3 500 is a vertical CNC machine known for its precision and adaptability in various applications. Its user-friendly software includes a graphical interface compatible with modern browsers, providing real-time machine condition updates through remote access. Custom features, including graphics and software interfaces, can be tailored to customer needs.
The T Series Super-Precision CNC machines excel in producing parts with extreme accuracy for hard turning applications. Designed for demanding parts, the series is suitable for both two-axis and complex multitask operations. It features varying horsepower (15 HP to 35 HP) and spindle speeds (4000 RPM to 6000 RPM), with chucks available in sizes from 6 inches to 10 inches. The machines use a FANUC 31i control unit for precise programming.
The EC-400 is built for high production with its 4-axis rotary system, offering synchronous motion and efficient chip management. It includes a large work envelope and advanced tool management to extend tool life. Key features include in-process probing for consistency, a 30+1 tool side mount changer, built-in pallet change for 400 mm pallets, and a 6-station pallet pool, enabling unattended machining from start to finish.
The normal functioning of CNC machines is done along the three Z, X, and Y axes. The five axes machines have two more axes accessible, which are namely A and B. The addition of the two extra axes makes it easy to cut complex and intricate parts...
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 initial designs to be machined by CNC machining are created in CAD...
The CNC process was developed in the 1950‘s and took a leap forward in the 1980‘s with the addition of computerization. Unlike other production processes, CNC begins with a rendering by a computer, which creates a two or three dimensional representation of the part to be produced...
G-code is the name of a plain text language that is used to guide and direct CNC machines. For most modern CNC machines, it isn‘t necessary to know the meaning of G-codes since CAD and CAM software is translated into G or M codes to instruct a CNC machine on how to complete a process...
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...
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 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...
