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75-499: A CNC machine is a motorized maneuverable tool and often a motorized maneuverable platform, which are both controlled by a computer, according to specific input instructions. Instructions are delivered to a CNC machine in the form of a sequential program of machine control instructions such as G-code and M-code, and then executed. The program can be written by a person or, far more often, generated by graphical computer-aided design (CAD) or computer-aided manufacturing (CAM) software. In

150-505: A personal computer system. Most applications support solid modeling with boundary representation (B-Rep) and NURBS geometry, and enable the same to be published in a variety of formats. Based on market statistics, commercial software from Autodesk, Dassault Systems , Siemens PLM Software , and PTC dominate the CAD industry. The following is a list of major CAD applications, grouped by usage statistics. Machining Machining

225-698: A technical drawing with the use of computer software . CAD software for mechanical design uses either vector-based graphics to depict the objects of traditional drafting, or may also produce raster graphics showing the overall appearance of designed objects. However, it involves more than just shapes. As in the manual drafting of technical and engineering drawings , the output of CAD must convey information, such as materials , processes , dimensions , and tolerances , according to application-specific conventions. CAD may be used to design curves and figures in two-dimensional (2D) space; or curves, surfaces , and solids in three-dimensional (3D) space. CAD

300-434: A "crash" occurs when the machine moves in such a way that is harmful to the machine, tools, or parts being machined, sometimes resulting in bending or breakage of cutting tools, accessory clamps, vises, and fixtures, or causing damage to the machine itself by bending guide rails, breaking drive screws, or causing structural components to crack or deform under strain. A mild crash may not damage the machine or tools but may damage

375-438: A common component of most hobby CNC tools. Instead, most hobby CNC tools simply rely on the assumed accuracy of stepper motors that rotate a specific number of degrees in response to magnetic field changes. It is often assumed the stepper is perfectly accurate and never missteps, so tool position monitoring simply involves counting the number of pulses sent to the stepper over time. An alternate means of stepper position monitoring

450-463: A cycle will involve a crash. Although such simulation is not new, its accuracy and market penetration are changing considerably because of computing advancements. Within the numerical systems of CNC programming, the code generator can assume that the controlled mechanism is always perfectly accurate, or that precision tolerances are identical for all cutting or movement directions. While the common use of ball screws on most modern NC machines eliminates

525-457: A finished product. A finished product would be a workpiece that meets the specifications set out for that workpiece by engineering drawings or blueprints . For example, a workpiece may require a specific outside diameter. A lathe is a machine tool that can create that diameter by rotating a metal workpiece so that a cutting tool can cut metal away, creating a smooth, round surface matching the required diameter and surface finish. A drill can remove

600-426: A good machine operator can have parts finished to a high standard whilst a CNC workflow is still in setup. In modern CNC systems, the design of a mechanical part and its manufacturing program are highly automated. The part's mechanical dimensions are defined using CAD software and then translated into manufacturing directives by CAM software. The resulting directives are transformed (by " post processor " software) into

675-407: A heat-affected zone, as opposed to laser and plasma cutting . With the recent proliferation of additive manufacturing technologies, conventional machining has been retronymously classified, in thought and language, as a subtractive manufacturing method. In narrow contexts, additive and subtractive methods may compete with each other. In the broad context of entire industries, their relationship

750-707: A large box as a safety measure (with safety glass in the doors to permit the operator to monitor the machine's function), often with additional safety interlocks to ensure the operator is far enough from the working piece for safe operation. Most new CNC systems built today are 100% electronically controlled. CNC-like systems are used for any process that can be described as movements and operations. These include laser cutting , welding , friction stir welding , ultrasonic welding , flame and plasma cutting , bending , spinning, hole-punching, pinning, gluing, fabric cutting, sewing, tape and fiber placement, routing, picking and placing, and sawing. The first CNC machines were built in

825-442: A new form of prototyping called digital prototyping . In contrast to physical prototypes, which entail manufacturing time in the design. That said, CAD models can be generated by a computer after the physical prototype has been scanned using an industrial CT scanning machine. Depending on the nature of the business, digital or physical prototypes can be initially chosen according to specific needs. Today, CAD systems exist for all

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900-495: A number of key C modules with their own APIs . A CAD system can be seen as built up from the interaction of a graphical user interface (GUI) with NURBS geometry or boundary representation (B-rep) data via a geometric modeling kernel . A geometry constraint engine may also be employed to manage the associative relationships between geometry, such as wireframe geometry in a sketch or components in an assembly. Unexpected capabilities of these associative relationships have led to

975-404: A series of step-down gears. Open-loop control works as long as the forces are kept small enough and speeds are not too great. On commercial metalworking machines, closed-loop controls are standard and required to provide the accuracy, speed, and repeatability demanded. As the controller hardware evolved, the mills themselves also evolved. One change has been to enclose the entire mechanism in

1050-473: A sharp cutting tool to remove material to achieve a desired geometry. Since the advent of new technologies in the post–World War II era, such as electrical discharge machining , electrochemical machining , electron beam machining , photochemical machining , and ultrasonic machining , the retronym "conventional machining" can be used to differentiate those classic technologies from the newer ones. Currently, "machining" without qualification usually implies

1125-599: A significant Material Removal Rate (MRR), to produce a shape close to the desired form but leaving some material on the piece for a subsequent finishing operation. Finishing cuts complete the part and achieve the final dimension, tolerances , and surface finish. In production machining jobs, one or more roughing cuts are usually performed on the work, followed by one or two finishing cuts. Roughing operations are done at high feeds and depths – feeds of 0.4–1.25  mm/rev (0.015–0.050 in/rev) and depths of 2.5–20 mm (0.100–0.750 in) are typical, but actual values depend on

1200-399: A three-dimensional Cartesian coordinate system . This system is a typical plane often seen in mathematics when graphing. This system is required to map out the machine tool paths and any other kind of actions that need to happen in a specific coordinate. Absolute coordinates are what are generally used more commonly for machines and represent the (0,0,0) point on the plane. This point is set on

1275-755: A wide group of users. These include the CAVE or HMDs and interactive devices like motion-sensing technology Starting with the IBM Drafting System in the mid-1960s, computer-aided design systems began to provide more capabilitties than just an ability to reproduce manual drafting with electronic drafting, and the cost-benefit for companies to switch to CAD became apparent. The software automated many tasks that are taken for granted from computer systems today, such as automated generation of bills of materials , auto layout in integrated circuits , interference checking, and many others. Eventually, CAD provided

1350-402: Is a manufacturing process where a desired shape or part is created using the controlled removal of material, most often metal, from a larger piece of raw material by cutting. Machining is a form of subtractive manufacturing , which utilizes machine tools , in contrast to additive manufacturing (e.g. 3D printing ), which uses controlled addition of material. Machining is a major process of

1425-469: Is a type of virtual construction engineering simulation incorporating time or schedule-related information for project management. CAD has become an especially important technology within the scope of computer-aided technologies , with benefits such as lower product development costs and a greatly shortened design cycle . CAD enables designers to layout and develop work on screen, print it out and save it for future editing, saving time on their drawings. In

1500-568: Is an important industrial art extensively used in many applications, including automotive , shipbuilding , and aerospace industries, industrial and architectural design ( building information modeling ), prosthetics , and many more. CAD is also widely used to produce computer animation for special effects in movies, advertising and technical manuals, often called DCC digital content creation . The modern ubiquity and power of computers means that even perfume bottles and shampoo dispensers are designed using techniques unheard of by engineers of

1575-527: Is any process in which a cutting tool removes material from the workpiece (the workpiece is often called the "work"). Relative motion is required in traditional machining between the device and the work to remove material; non-traditional machining processes use other methods of material removal, such as electric current in EDM (electro-discharge machining). This relative motion is achieved in most machining operations by moving (by lateral rotary or lateral motion) either

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1650-406: Is generally via a computer mouse but can also be via a pen and digitizing graphics tablet . Manipulation of the view of the model on the screen is also sometimes done with the use of a Spacemouse/SpaceBall . Some systems also support stereoscopic glasses for viewing the 3D model . Technologies that in the past were limited to larger installations or specialist applications have become available to

1725-452: Is made of a harder material than the work material. The cutting edge serves to separate the chip from the parent work material. Connected to the cutting edge are the two surfaces of the tool: The rake face, which directs the flow of the newly formed chip, is oriented at a certain angle and is called the rake angle "α." It is measured relative to the plane perpendicular to the work surface. The rake angle can be positive or negative. The flank of

1800-422: Is often in the form of electronic files for print, machining , or other manufacturing operations. The terms computer-aided drafting ( CAD ) and computer-aided design and drafting ( CADD ) are also used. Its use in designing electronic systems is known as electronic design automation ( EDA ). In mechanical design it is known as mechanical design automation ( MDA ), which includes the process of creating

1875-409: Is required between the tool and work to perform a machining operation. The primary action is at a specific cutting speed . In addition, the device must be moved laterally across the work. This is a much slower motion called the feed. The remaining dimension of the cut is the penetration of the cutting tool below the original work surface, reaching the cut's depth. Speed, feed, and depth of cut are called

1950-461: Is the combination of AI , using a large number of sensors , with the goal of achieving flexible manufacturing . EDM can be broadly divided into "sinker" type processes, where the electrode is the positive shape of the resulting feature in the part, and the electric discharge erodes this feature into the part, resulting in the negative shape, and "wire" type processes. Sinker processes are rather slow as compared to conventional machining, averaging on

2025-416: Is the problem of achieving the right finish or surface smoothness on the workpiece. The inferior finish found on the machined surface of a workpiece may be caused by incorrect clamping , a dull tool, or inappropriate presentation of a device. Frequently, this poor surface finish, known as chatter, is evident by an undulating or regular finish of waves on the machined surfaces of the workpiece. Relative motion

2100-439: Is the use of computers (or workstations ) to aid in the creation, modification, analysis, or optimization of a design . This software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing. Designs made through CAD software help protect products and inventions when used in patent applications. CAD output

2175-441: Is used in many ways depending on the profession of the user and the type of software in question. CAD is one part of the whole digital product development (DPD) activity within the product lifecycle management (PLM) processes, and as such is used together with other tools, which are either integrated modules or stand-alone products, such as: CAD is also used for the accurate creation of photo simulations that are often required in

2250-760: Is used in the design of tools and machinery and in the drafting and design of all types of buildings, from small residential types (houses) to the largest commercial and industrial structures (hospitals and factories). CAD is mainly used for detailed design of 3D models or 2D drawings of physical components, but it is also used throughout the engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies to definition of manufacturing methods of components. It can also be used to design objects such as jewelry, furniture, appliances, etc. Furthermore, many CAD applications now offer advanced rendering and animation capabilities so engineers can better visualize their product designs. 4D BIM

2325-418: Is usually not available, so crash or slip detection is not possible. Commercial CNC metalworking machines use closed-loop feedback controls for axis movement. In a closed-loop system, the controller monitors the actual position of each axis with an absolute or incremental encoder . Proper control programming will reduce the possibility of a crash, but it is still up to the operator and programmer to ensure that

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2400-608: The manufacture of many metal products, but it can also be used on other materials such as wood , plastic , ceramic , and composites . A person who specializes in machining is called a machinist . As a commercial venture, machining is generally performed in a machine shop , which consists of one or more workrooms containing primary machine tools. Although a machine shop can be a standalone operation, many businesses maintain internal machine shops or tool rooms that support their specialized needs. Much modern-day machining uses computer numerical control (CNC), in which computers control

2475-620: The part program . Positioning control is handled using either an open-loop or a closed-loop system. In an open-loop system, communication takes place in one direction only: from the controller to the motor. In a closed-loop system, feedback is provided to the controller so that it can correct for errors in position, velocity, and acceleration, which can arise due to variations in load or temperature. Open-loop systems are generally cheaper but less accurate. Stepper motors can be used in both types of systems, while servo motors can only be used in closed systems. The G & M code positions are all based on

2550-466: The 1940s and 1950s, based on existing tools that were modified with motors that moved the tool or part to follow points fed into the system on punched tape . These early servomechanisms were rapidly augmented with analog and digital computers, creating the modern CNC machine tools that have revolutionized machining processes. Now the CNC in the processing manufacturing field has been very extensive, not only

2625-443: The 1960s. Because of its enormous economic importance, CAD has been a major driving force for research in computational geometry , computer graphics (both hardware and software), and discrete differential geometry . The design of geometric models for object shapes, in particular, is occasionally called computer-aided geometric design ( CAGD ). Computer-aided design is one of the many tools used by engineers and designers and

2700-519: The 2000s, some CAD system software vendors shipped their distributions with a dedicated license manager software that controlled how often or how many users can utilize the CAD system. It could run either on a local machine (by loading from a local storage device) or a local network fileserver and was usually tied to a specific IP address in latter case. CAD software enables engineers and architects to design, inspect and manage engineering projects within an integrated graphical user interface (GUI) on

2775-457: The 2D systems, although many 3D systems allow using the wireframe model to make the final engineering drawing views. 3D "dumb" solids are created in a way analogous to manipulations of real-world objects. Basic three-dimensional geometric forms (e.g., prisms, cylinders, spheres, or rectangles) have solid volumes added or subtracted from them as if assembling or cutting real-world objects. Two-dimensional projected views can easily be generated from

2850-461: The X-axis, and all future motions are now invalid, which may result in further collisions with clamps, vises, or the machine itself. This is common in open-loop stepper systems but is not possible in closed-loop systems unless mechanical slippage between the motor and drive mechanism has occurred. Instead, in a closed-loop system, the machine will continue to attempt to move against the load until either

2925-582: The case of 3D printers, the part to be printed is "sliced" before the instructions (or the program) are generated. 3D printers also use G-Code. CNC offers greatly increased productivity over non-computerized machining for repetitive production, where the machine must be manually controlled (e.g. using devices such as hand wheels or levers) or mechanically controlled by pre-fabricated pattern guides (see pantograph mill ). However, these advantages come at significant cost in terms of both capital expenditure and job setup time. For some prototyping and small batch jobs,

3000-528: The component from machine to machine. In either case, the series of steps needed to produce any part is highly automated and produces a part that meets every specification in the original CAD drawing, where each specification includes a tolerance. Motion is controlling multiple axes, normally at least two (X and Y), and a tool spindle that moves in the Z (depth). The position of the tool is driven by direct-drive stepper motors or servo motors to provide highly accurate movements, or in older designs, motors through

3075-551: The concepts they described evolved into widespread existence. Therefore, during the Machine Age , machining referred to (what we today might call) the "traditional" machining processes, such as turning , boring , drilling , milling , broaching , sawing , shaping , planing , abrasive cutting , reaming , and tapping . In these "traditional" or "conventional" machining processes, machine tools , such as lathes , milling machines , drill presses , or others, are used with

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3150-575: The correct speeds and feeds in the program provides for a more efficient and smoother product run. Incorrect speeds and feeds will cause damage to the tool, machine spindle, and even the product. The quickest and simplest way to find these numbers would be to use a calculator that can be found online. A formula can also be used to calculate the proper speeds and feeds for a material. These values can be found online or in Machinery's Handbook . Computer-aided design Computer-aided design ( CAD )

3225-433: The cutting conditions. They form the three dimensions of the machining process, and for certain operations, their product can be used to obtain the material removal rate for the process: where Machining operations usually divide into two categories, distinguished by purpose and cutting conditions : Roughing cuts are used to remove a large amount of material from the starting work part as rapidly as possible, i.e., with

3300-418: The designer to create products that fit the human form and visual requirements as well as they interface with the machine. Originally software for CAD systems was developed with computer languages such as Fortran , ALGOL but with the advancement of object-oriented programming methods this has radically changed. Typical modern parametric feature-based modeler and freeform surface systems are built around

3375-431: The designer with the ability to perform engineering calculations. During this transition, calculations were still performed either by hand or by those individuals who could run computer programs. CAD was a revolutionary change in the engineering industry, where draftsman, designer, and engineer roles that had previously been separate began to merge. CAD is an example of the pervasive effect computers were beginning to have on

3450-413: The drawing sheet can easily be adjusted in the final draft as required, unlike in hand drafting. 3D wireframe is an extension of 2D drafting into a three-dimensional space . Each line has to be manually inserted into the drawing. The final product has no mass properties associated with it and cannot have features directly added to it, such as holes. The operator approaches these in a similar fashion to

3525-423: The drive motor goes into an overload condition or a servo motor fails to get to the desired position. Collision detection and avoidance are possible, through the use of absolute position sensors (optical encoder strips or disks) to verify that motion occurred, or torque sensors or power-draw sensors on the drive system to detect abnormal strain when the machine should just be moving and not cutting, but these are not

3600-418: The drive system is weaker than the machine's structural integrity, then the drive system simply pushes against the obstruction, and the drive motors "slip in place". The machine tool may not detect the collision or the slipping, so for example the tool should now be at 210mm on the X-axis, but is, in fact, at 32mm where it hit the obstruction and kept slipping. All of the next tool motions will be off by −178mm on

3675-400: The industry. Current computer-aided design software packages range from 2D vector -based drafting systems to 3D solid and surface modelers . Modern CAD packages can also frequently allow rotations in three dimensions, allowing viewing of a designed object from any desired angle, even from the inside looking out. Some CAD software is capable of dynamic mathematical modeling. CAD technology

3750-409: The last line of the program. The format for a G-code is the letter G followed by two to three digits; for example G01. G-codes differ slightly between a mill and lathe application, for example: [Code Miscellaneous Functions (M-Code)]. M-codes are miscellaneous machine commands that do not command axis motion. The format for an M-code is the letter M followed by two to three digits; for example: Having

3825-425: The machine is operated safely. However, during the 2000s and 2010s, the software for machining simulation has been maturing rapidly, and it is no longer uncommon for the entire machine tool envelope (including all axes, spindles, chucks, turrets, tool holders, tailstocks, fixtures, clamps, and stock) to be modeled accurately with 3D solid models , which allows the simulation software to predict fairly accurately whether

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3900-455: The machining code provided and it is up to an operator to detect if a crash is either occurring or about to occur, and for the operator to manually abort the active process. Machines equipped with load sensors can stop axis or spindle movement in response to an overload condition, but this does not prevent a crash from occurring. It may only limit the damage resulting from the crash. Some crashes may not ever overload any axis or spindle drives. If

3975-405: The major platforms ( Windows , Linux , UNIX and Mac OS X ); some packages support multiple platforms. Currently, no special hardware is required for most CAD software. However, some CAD systems can do graphically and computationally intensive tasks, so a modern graphics card , high speed (and possibly multiple) CPUs and large amounts of RAM may be recommended. The human-machine interface

4050-474: The mechanism, by tightly applying pressure against the reference and setting that as the zero references for all following CNC-encoded motions. This is similar to the manual machine tool method of clamping a micrometer onto a reference beam and adjusting the Vernier dial to zero using that object as the reference. In numerical control systems, the position of the tool is defined by a set of instructions called

4125-401: The metal in the shape of a cylindrical hole. Other tools that may be used for metal removal are milling machines, saws, and grinding machines . Many of these same techniques are used in woodworking . Machining requires attention to many details for a workpiece to meet the specifications in the engineering drawings or blueprints. Besides the obvious problems related to correct dimensions, there

4200-422: The models. Basic 3D solids do not usually include tools to easily allow the motion of the components, set their limits to their motion, or identify interference between components. There are several types of 3D solid modeling Top-end CAD systems offer the capability to incorporate more organic, aesthetic and ergonomic features into the designs. Freeform surface modeling is often combined with solids to allow

4275-411: The movement and operation of mills , lathes , and other cutting machines. The precise meaning of the term machining has changed over the past one and a half centuries as technology has advanced in a number of ways. In the 18th century, the word machinist meant a person who built or repaired machines . This person's work was primarily done by hand, using processes such as the carving of wood and

4350-441: The operator to think differently about how to use them and design their virtual components in a different manner. Virtually all of CAD tools rely on constraint concepts that are used to define geometric or non-geometric elements of a model. There are many producers of the lower-end 2D sketching systems, including a number of free and open-source programs. These provide an approach to the drawing process where scale and placement on

4425-477: The order of 100mm/min, as compared to 8x10 mm/min for conventional machining, but it can generate features that conventional machining cannot. Wire EDM operates by using a thin conductive wire, typically brass, as the electrode, and discharging as it runs past the part being machined. This is useful for complex profiles with inside 90 degree corners that would be challenging to machine with conventional methods. Many other tools have CNC variants, including: In CNC,

4500-412: The part being machined so that it must be scrapped. Many CNC tools have no inherent sense of the absolute position of the table or tools when turned on. They must be manually "homed" or "zeroed" to have any reference to work from, and these limits are just for figuring out the location of the part to work with it and are no hard motion limit on the mechanism. It is often possible to drive the machine outside

4575-485: The physical bounds of its drive mechanism, resulting in a collision with itself or damage to the drive mechanism. Many machines implement control parameters limiting axis motion past a certain limit in addition to physical limit switches . However, these parameters can often be changed by the operator. Many CNC tools also do not know anything about their working environment. Machines may have load sensing systems on spindle and axis drives, but some do not. They blindly follow

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4650-461: The precision of some operations involving axis movement reversals during cutting, such as the milling of a circle, where axis motion is sinusoidal. However, this can be compensated for if the amount of backlash is precisely known by linear encoders or manual measurement. The high backlash mechanism itself is not necessarily relied on to be repeatedly precise for the cutting process, but some other reference object or precision surface may be used to zero

4725-430: The preparation of environmental impact reports, in which computer-aided designs of intended buildings are superimposed into photographs of existing environments to represent what that locale will be like, where the proposed facilities are allowed to be built. Potential blockage of view corridors and shadow studies are also frequently analyzed through the use of CAD. There are several different types of CAD, each requiring

4800-408: The proper cutting fluid is usually included within the scope of the cutting condition. Today other forms of metal cutting are becoming increasingly popular. An example of this is water jet cutting. Water jet cutting involves pressurized water over 620 MPa (90 000 psi) and can cut metal and have a finished product. This process is called cold cutting, which eliminates the damage caused by

4875-444: The specific commands necessary for a particular machine to produce the component and then are loaded into the CNC machine. Since any particular component might require the use of several different tools – drills , saws , touch probes etc. – modern machines often combine multiple tools into a single "cell". In other installations, several different machines are used with an external controller and human or robotic operators that move

4950-427: The stock material to give a starting point or "home position" before starting the actual machining. G-codes are used to command specific movements of the machine, such as machine moves or drilling functions. The majority of G-code programs start with a percent (%) symbol on the first line, then followed by an "O" with a numerical name for the program (i.e. "O0001") on the second line, then another percent (%) symbol on

5025-406: The term machining . The two terms are effectively synonymous , although the long-established usage of the term machining continues. This is comparable to the idea that the verb sense of contact evolved because of the proliferation of ways to contact someone (telephone, email, IM, SMS, and so on) but did not entirely replace the earlier terms such as call , talk to , or write to . Machining

5100-406: The tool provides a clearance between the tool and the newly formed work surface, thus protecting the surface from abrasion, which would degrade the finish. This angle between the work and flank surfaces is called the relief angle. There are two basic types of cutting tools: A single-point tool has one cutting edge for turning, boring, and planing. During machining, the device's point penetrates below

5175-604: The tool, or the workpiece. The shape of the tool, the relative motion, and its penetration into the work, produce the desired shape of the resulting work surface. Machining operations can be broken down into traditional, and non-traditional operations. Within the traditional operations, there are two categories of machining based on the shape they machine; being circular shapes that includes; turning, boring, drilling, reaming, threading and more, and various/straight shapes that includes; milling, broaching, sawing, grinding and shaping. A cutting tool has one or more sharp cutting edges and

5250-453: The traditional milling and turning , other machines and equipment are also installed with the corresponding CNC, which makes the manufacturing industry in its support, greatly improving the quality and efficiency. Of course, the latest trend in CNC is to combine traditional subtractive manufacturing with additive manufacturing (3D printing) to create a new manufacturing method - hybrid additive subtractive manufacturing (HASM). Another trend

5325-415: The traditional machining processes. In the decades of the 2000s and 2010s, as additive manufacturing (AM) evolved beyond its earlier laboratory and rapid prototyping contexts and began to become standard throughout all phases of manufacturing, the term subtractive manufacturing became common retronymously in logical contrast with AM, covering essentially any removal processes also previously covered by

5400-476: The vast majority of backlash, it still must be taken into account. CNC tools with a large amount of mechanical backlash can still be highly precise if the drive or cutting mechanism is only driven to apply cutting force from one direction, and all driving systems are pressed tightly together in that one cutting direction. However, a CNC device with high backlash and a dull cutting tool can lead to cutter chatter and possible workpiece gouging. The backlash also affects

5475-519: The work part's original work surface. The fact is sometimes rounded to a certain radius, called the nose radius. Multiple cutting-edge tools have more than one cutting edge and usually achieve their motion relative to the work part by rotating. Drilling and milling use turning multiple-cutting-edge tools. Although the shapes of these tools are different from a single-point device, many elements of tool geometry are similar. An unfinished workpiece requiring machining must have some material cut away to create

5550-450: The workpiece materials. Finishing operations are carried out at low feeds and depths – dinners of 0.0125–0.04  mm/rev (0.0005–0.0015 in/rev) and depths of 0.75–2.0 mm (0.030–0.075 in) are typical. Cutting speeds are lower in roughing than in finishing. A cutting fluid is often applied to the machining operation to cool and lubricate the cutting tool. Determining whether a cutting fluid should be used and, if so, choosing

5625-399: The writing- forging and hand- filing of metal. At the time, millwrights and builders of new kinds of engines (meaning, more or less, machines of any kind), such as James Watt or John Wilkinson , would fit the definition. The noun machine tool and the verb to machine ( machined, machining ) did not yet exist. Around the middle of the 20th century, the latter words were coined as

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