Metalworking is the process of shaping and reshapingmetals in order to create useful objects, parts, assemblies, and large scale structures. As a term, it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale: from hugeships, buildings, andbridges, down to preciseengine parts and delicatejewellery.
The historical roots of metalworking predate recorded history; its use spans cultures, civilizations and millennia. It has evolved from shaping soft,native metals likegold with simple hand tools, through thesmelting of ores and hotforging of harder metals likeiron, up to and including highly technical modern processes such asmachining andwelding. It has been used as an industry, a driver of trade, individual hobbies, and in the creation of art;[1] it can be regarded as both a science and a craft.
Modern metalworking processes, though diverse and specialized, can be categorized into one of three broad areas known as forming, cutting, or joining processes. Modern metalworking workshops, typically known asmachine shops, hold a wide variety of specialized or general-usemachine tools capable of creating highly precise, useful products. Many simpler metalworking techniques, such asblacksmithing, are no longer economically competitive on a large scale in developed countries; some of them are still in use in less developed countries, for artisanal or hobby work, or for historical reenactment.
The oldest archaeological evidence ofcoppermining and working was the discovery of a copperpendant in northernIraq from 8,700 BCE.[2] The earliest substantiated and dated evidence of metalworking in theAmericas was the processing of copper inWisconsin, nearLake Michigan. Copper was hammered until it became brittle, then heated so it could be worked further. In America, this technology is dated to about 4000–5000 BCE.[3] The oldestgold artifacts in the world come from the BulgarianVarna Necropolis and date from 4450 BCE.
Not all metal required fire to obtain it or work it.Isaac Asimov speculated that gold was the "first metal".[4] His reasoning being, that, by itschemistry, it is found in nature as nuggets of pure gold. In other words, gold, as rare as it is, is sometimes found in nature as anative metal. Some metals can also be found inmeteors. Almost all other metals are found inores, a mineral-bearingrock, that require heat or some other process to liberate the metal. Another feature of gold is that it is workable as it is found, meaning that no technology beyond a stonehammer andanvil is needed to work the metal. This is a result of gold's properties ofmalleability andductility. The earliesttools were stone,bone,wood, andsinew, all of which sufficed to work gold.
At some unknown time, the process of liberating metals from rock by heat became known, and rocks rich in copper,tin, andlead came into demand. These ores were mined wherever they were recognized. Remnants of such ancient mines have been found all overSouthwestern Asia.[5] Metalworking was being carried out by theSouth Asian inhabitants ofMehrgarh between 7000 and 3300 BCE.[6] The end of the beginning of metalworking occurs sometime around 6000 BCE when coppersmelting became common in Southwestern Asia.
Ancient civilisations knew of seven metals. Here they are arranged in order of theiroxidation potential (involts):
The oxidation potential is important because it is one indicator of how tightly bound to the ore the metal is likely to be. As can be seen, iron is significantly higher than the other six metals while gold is dramatically lower than the six above it. Gold's low oxidation is one of the main reasons that gold is found in nuggets. These nuggets are relatively pure gold and are workable as they are found.
Copper ore, being relatively abundant, and tin ore became the next important substances in the story of metalworking. Using heat to smelt copper from ore, a great deal of copper was produced. It was used for bothjewelry and simple tools. However, copper by itself was too soft for tools requiring edges and stiffness. At some point tin was added into the molten copper andbronze was developed thereby. Bronze is analloy of copper and tin. Bronze was an important advance because it had the edge-durability and stiffness that pure copper lacked. Until the advent of iron, bronze was the most advanced metal for tools andweapons in common use (seeBronze Age for more detail).
Outside Southwestern Asia, these same advances and materials were being discovered and used around the world. People inChina andGreat Britain began using bronze with little time being devoted to copper.Japanese began the use of bronze andiron almost simultaneously. In the Americas it was different. Although the peoples of the Americas knew of metals, it was not until theEuropean colonisation that metalworking for tools and weapons became common. Jewelry andart were the principal uses of metals in the Americas prior to European influence.
About 2700 BCE, production of bronze was common in locales where the necessary materials could be assembled for smelting, heating, and working the metal.[7] Iron was beginning to be smelted and began its emergence as an important metal for tools and weapons. The period that followed became known as theIron Age.[8]
By the historical periods of thePharaohs inEgypt, theVedic kings inIndia, theTribes of Israel, and theMaya civilization inNorth America, among other ancient populations, humans had begun to attach value toprecious metals over and above any available functional metal tools and weapons.[9][10] Gold or silver trinkets becameluxury goods inantiquity.[11] In some cases rules for ownership, distribution, andtrade were created, enforced, and agreed upon by various peoples.[12] By the above periods metalworkers were very skilled at creating objects of adornment, religious artifacts, andtrade instruments ofprecious metals (non-ferrous), as well as weaponry (usually offerrousmetals and/oralloys).[13] Sophisticated techniques were practiced by artisans,blacksmiths,atharvavedic practitioners,alchemists, and other categories of metalworkers around the globe. For example, thegranulation technique occurs in numerous ancient cultures before the historic record shows people traveled to far regions to share this process.[14]Metalsmiths today still use this and many other ancient techniques.
Over time, metal objects became more common and ever more complex. The need to further acquire and work metals grew in importance. Skills related toextracting metal ores from the earth began to evolve, and metalsmiths became more knowledgeable. Metalsmiths became important members of society.[15] Fates and economies of entire civilizations were greatly affected by the availability of metals and metalsmiths.[16] The metalworker depends on the extraction of precious metals to makejewelry, build more efficientelectronics, and forindustrial and technological applications fromconstruction toshipping containers torail, andair transport. Without metals, goods and services would cease to move around the globe on the scale we know today.
Metalworking generally is divided into three categories:forming,cutting, andjoining. Most metal cutting is done by high speed steel tools or carbide tools.[17] Each of these categories contains various processes.
Prior to most operations, the metal must be marked out and/or measured, depending on the desired finished product.
Marking out (also known as layout) is the process of transferring adesign orpattern to aworkpiece and is the first step in the handcraft of metalworking. It is performed in many industries or hobbies, although in industry, the repetition eliminates the need to mark out every individual piece. In the metal trades area, marking out consists of transferring the engineer'splan to the workpiece in preparation for the next step, machining or manufacture.
Calipers are hand tools designed to precisely measure the distance between two points. Most calipers have two sets of flat, parallel edges used for inner or outer diameter measurements. These calipers can be accurate to within one-thousandth of an inch (25.4 μm). Different types of calipers have different mechanisms for displaying the distance measured. Where larger objects need to be measured with less precision, atape measure is often used.
| Material | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Process | Iron | Steel | Aluminium | Copper | Magnesium | Nickel | Refractory metals | Titanium | Zinc | Brass | Bronze |
| Sand casting | X | X | X | X | X | X | 0 | 0 | X | ||
| Permanent mold casting | X | 0 | X | 0 | X | 0 | 0 | 0 | X | ||
| Die casting | X | 0 | X | X | |||||||
| Investment casting | X | X | X | 0 | 0 | 0 | X | ||||
| Ablation casting | X | X | X | 0 | 0 | ||||||
| Open-die forging | 0 | X | X | X | 0 | 0 | 0 | ||||
| Closed-die forging | X | 0 | 0 | 0 | 0 | 0 | 0 | ||||
| Extrusion | 0 | X | X | X | 0 | 0 | 0 | ||||
| Cold heading | X | X | X | 0 | |||||||
| Stamping &deep drawing | X | X | X | 0 | X | 0 | 0 | ||||
| Screw machine | 0 | X | X | X | 0 | X | 0 | 0 | 0 | X | X |
| Powder metallurgy | X | X | 0 | X | 0 | X | 0 | ||||
| Key:X = Routinely performed,0 = Performed with difficulty, caution, or some sacrifice,blank = Not recommended | |||||||||||
Casting achieves a specific form by pouring molten metal into a mold and allowing it to cool, with no mechanical force. Forms of casting include:
Theseforming processes modify metal or workpiece by deforming the object, that is, without removing any material.[19] Forming is done with a system of mechanical forces and, especially for bulk metal forming, with heat.
Plasticdeformation involves using heat orpressure to make a workpiece more conductive to mechanical force. Historically, this and casting were done by blacksmiths, though today the process has been industrialized. In bulk metal forming, the workpiece is generally heated up.
These types of forming process involve the application of mechanical force at room temperature. However, some recent developments involve the heating of dies and/or parts. Advancements in automated metalworking technology have made progressive die stamping possible which is a method that can encompass punching, coining, bending and several other ways below that modify metal at less cost while resulting in less scrap.[20]
Cutting is a collection of processes wherein material is brought to a specified geometry by removing excess material using various kinds of tooling to leave a finished part that meets specifications. The net result of cutting is two products, the waste or excess material, and the finished part. In woodworking, the waste would be sawdust and excess wood. In cutting metals the waste is chips orswarf and excess metal.
Cutting processes fall into one of three major categories:
Drilling a hole in a metal part is the most common example of a chip producing process. Using anoxy-fuel cutting torch to separate a plate of steel into smaller pieces is an example of burning. Chemical milling is an example of a specialty process that removes excess material by the use of etching chemicals and masking chemicals.
There are many technologies available to cut metal, including:
Cutting fluid orcoolant is used where there is significant friction and heat at the cutting interface between a cutter such as a drill or an end mill and the workpiece. Coolant is generally introduced by a spray across the face of the tool and workpiece to decrease friction and temperature at the cutting tool/workpiece interface to prevent excessive tool wear. In practice there are many methods of delivering coolant.
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The use of an angle grinder in cutting is not preferred as large amounts of harmful sparks and fumes (andparticulates) are generated when compared with usingreciprocating saw orband saw.[23] Angle grinders producesparks when cutting ferrous metals. They also produceshards cutting other materials.
Milling is the complex shaping of metal or other materials by removing material to form the final shape.[24] It is generally done on amilling machine, a power-driven machine that in its basic form consists of amilling cutter that rotates about the spindle axis (like adrill), and aworktable that can move in multiple directions (usually two dimensions [x and y axis] relative to the workpiece). The spindle usually moves in the z axis.[25] It is possible to raise the table (where the workpiece rests). Milling machines may be operated manually or undercomputer numerical control (CNC), and can perform a vast number of complex operations, such as slot cutting,planing,drilling and threading,rabbeting,routing, etc.[26][27] Two common types of mills are the horizontal mill and vertical mill.[28][29]
The pieces produced are usually complex 3D objects that are converted into x, y, and z coordinates that are then fed into theCNC machine and allow it to complete the tasks required.[30] The milling machine can produce most parts in 3D, but some require the objects to be rotated around the x, y, or z coordinate axis (depending on the need).[31] Tolerances come in a variety of standards, depending on the locale. In countries still using the imperial system, this is usually in the thousandths of an inch (unit known as thou), depending on the specific machine.[32] In many other European countries, standards following the ISO are used instead.[33]
In order to keep both the bit and material cool, a high temperature coolant is used.[34] In most cases the coolant is sprayed from a hose directly onto the bit and material.[35] This coolant can either be machine or user controlled, depending on the machine.[36]
Materials that can be milled range fromaluminum to stainless steel and almost everything in between.[37] Each material requires a different speed on the milling tool and varies in the amount of material that can be removed in one pass of the tool.[38] Harder materials are usually milled at slower speeds with small amounts of material removed. Softer materials vary, but usually are milled with a high bit speed.[39]
The use of a milling machine adds costs that are factored into the manufacturing process. Each time the machine is used coolant is also used, which must be periodically added in order to prevent breaking bits.[40] A milling bit must also be changed as needed in order to prevent damage to the material.[41] Time is the biggest factor for costs. Complex parts can require hours to complete, while very simple parts take only minutes.[42] This in turn varies the production time as well, as each part will require different amounts of time.[43]
Safety is key with these machines. The bits are traveling at high speeds and removing pieces of usually scalding hot metal.[44][45] The advantage of having a CNC milling machine is that it protects the machine operator.[46]
Turning is a metal cutting process for producing a cylindrical surface with a single point tool. The workpiece is rotated on a spindle and the cutting tool is fed into it radially, axially or both. Producing surfaces perpendicular to the workpiece axis is called facing. Producing surfaces using both radial and axial feeds is called profiling.[47]
Alathe is a machine tool which spins a block or cylinder of material so that whenabrasive, cutting, ordeformation tools are applied to the workpiece, it can be shaped to produce an object which hasrotational symmetry about anaxis of rotation. Examples of objects that can be produced on a lathe includecandlestick holders,crankshafts,camshafts, andbearing mounts.
Lathes have four main components: the bed, the headstock, the carriage, and the tailstock. The bed is a precise & very strong base which all of the other components rest upon for alignment. The headstock'sspindle secures the workpiece with achuck, whose jaws (usually three or four) are tightened around the piece. The spindle rotates at high speed, providing the energy to cut the material. While historically lathes were powered bybelts from aline shaft, modern examples uses electric motors. The workpiece extends out of the spindle along the axis of rotation above the flat bed. The carriage is a platform that can be moved, precisely and independently parallel and perpendicular to the axis of rotation. A hardenedcutting tool is held at the desired height (usually the middle of the workpiece) by the toolpost. The carriage is then moved around the rotating workpiece, and the cutting tool gradually removes material from the workpiece. The tailstock can be slid along the axis of rotation and then locked in place as necessary. It may hold centers to further secure the workpiece, or cutting tools driven into the end of the workpiece.
Other operations that can be performed with a single point tool on a lathe are:[47]
Chamfering: Cutting an angle on the corner of a cylinder.
Parting: The tool is fed radially into the workpiece to cut off the end of a part.
Threading: A tool is fed along and across the outside or inside surface of rotating parts to produce external or internalthreads.
Boring: A single-point tool is fed linearly and parallel to the axis of rotation to create a round hole.
Drilling: Feeding the drill into the workpiece axially.
Knurling: Uses a tool to produce a rough surface texture on the work piece. Frequently used to allow grip by hand on a metal part.
Modern computer numerical control (CNC) lathes and (CNC) machining centres can do secondary operations like milling by using driven tools. When driven tools are used the work piece stops rotating and the driven tool executes the machining operation with a rotating cutting tool. The CNC machines use x, y, and z coordinates in order to control the turning tools and produce the product. Most modern day CNC lathes are able to produce most turned objects in 3D.
Nearly all types of metal can be turned, although more time & specialist cutting tools are needed forharder workpieces.
There are many threading processes including: cutting threads with atap or die, thread milling, single-point thread cutting, thread rolling, cold root rolling and forming, and thread grinding.[48][49] A tap is used to cut a female thread on the inside surface of a pre-drilled hole,[50][51] while a die cuts a male thread on a preformed cylindrical rod.[48]
Grinding uses an abrasive process to remove material from the workpiece.[52] Agrinding machine is a machine tool used for producing very fine finishes, making very light cuts, or high precision forms using anabrasive wheel as the cutting device.[53] This wheel can be made up of various sizes and types of stones,diamonds orinorganic materials.[54]
The simplest grinder is a bench grinder or a hand-held angle grinder, for deburring parts or cutting metal with a zip-disc.
Grinders have increased in size and complexity with advances in time and technology. From the old days of a manual toolroom grinder sharpening endmills for a production shop, to today's 30000 RPM CNC auto-loading manufacturing cell producing jet turbines, grinding processes vary greatly.[55]
Grinders need to be very rigid machines to produce the required finish. Some grinders are even used to produce glass scales for positioning CNC machine axis. The common rule is the machines used to produce scales be 10 times more accurate than the machines the parts are produced for.[56]
In the past grinders were used for finishing operations only because of limitations of tooling. Modern grinding wheel materials and the use of industrial diamonds or other man-made coatings (cubic boron nitride) on wheel forms have allowed grinders to achieve excellent results in production environments instead of being relegated to the back of the shop.[57]
Modern technology has advanced grinding operations to include CNC controls, high material removal rates with high precision, lending itself well to aerospace applications and high volume production runs of precision components.[58][59]
Filing is combination of grinding and saw tooth cutting using afile. Prior to the development of modern machining equipment it provided a relatively accurate means for the production of small parts, especially those with flat surfaces.[60] The skilled use of a file allowed amachinist to work to fine tolerances and was the hallmark of the craft. Today filing is rarely used as a production technique in industry, though it remains as a common method ofdeburring.[61]
Broaching is a machining operation used to cutkeyways into shafts.[62]Electron beam machining (EBM) is a machining process where high-velocity electrons are directed toward a work piece, creating heat and vaporizing the material.[63]Ultrasonic machining usesultrasonic vibrations to machine very hard or brittle materials.[64]
Welding is afabrication process that joins materials, usually metals orthermoplastics, by causingcoalescence. This is often done bymelting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, but sometimes pressure is used in conjunction withheat, or by itself, to produce the weld.[65]
Many different energy sources can be used for welding, including a gasflame, anelectric arc, a laser, anelectron beam,friction, andultrasound. While often an industrial process, welding can be done in many different environments, including open air,underwater and inspace. Regardless of location, however, welding remains dangerous, and precautions must be taken to avoid burns,electric shock, poisonous fumes, and overexposure toultraviolet light.
Brazing is a joining process in which a filler metal is melted and drawn into acapillary formed by the assembly of two or more work pieces. The filler metal reacts metallurgically with the workpieces and solidifies in the capillary, forming a strong joint. Unlike welding, the work piece is not melted. Brazing is similar to soldering, but occurs at temperatures in excess of 450 °C (842 °F). Brazing has the advantage of producing less thermal stresses than welding, and brazed assemblies tend to be more ductile than weldments because alloying elements can not segregate and precipitate.
Brazing techniques include, flame brazing, resistance brazing, furnace brazing, diffusion brazing, inductive brazing and vacuum brazing.
Soldering is a joining process that occurs at temperatures below 450 °C (842 °F). It is similar to brazing in the way that a filler is melted and drawn into a capillary to form a joint, although at a lower temperature. Because of this lower temperature and different alloys used as fillers, the metallurgical reaction between filler and work piece is minimal, resulting in a weaker joint.
Riveting is one of the most ancient metalwork joining processes.[66] Its use declined markedly during the second half of the 20th century,[67] but it still retains important uses in industry and construction, and in artisan crafts such asjewellery,medieval armouring andmetal couture in the early 21st century. The earlier use of rivets is being superseded by improvements inwelding and componentfabrication techniques.
Arivet is essentially a two-headed and unthreadedbolt which holds two other pieces of metal together. Holes aredrilled orpunched through the two pieces of metal to be joined. The holes being aligned, a rivet is passed through the holes and permanent heads are formed onto the ends of the rivet utilizing hammers and forming dies (by eithercold working orhot working).Rivets are commonly purchased with one head already formed.
When it is necessary to remove rivets, one of the rivet's heads is sheared off with acold chisel. The rivet is then driven out with ahammer andpunch.
This includesscrews, as well asbolts. This is often used as it requires relatively little specialist equipment, and are therefore often used inflat-pack furniture. It can also be used when a metal is joined to another material (such aswood) or a particular metal does not weld well (such asaluminum). This can be done to directly join metals, or with an intermediate material such asnylon. While often weaker than other methods such as welding or brazing, the metal can easily be removed and therefore reused or recycled. It can also be done in conjunction with an epoxy or glue, reverting its ecological benefits.
While these processes are not primary metalworking processes, they are often performed before or after metalworking processes.
Metals can be heat treated to alter the properties of strength, ductility, toughness, hardness or resistance to corrosion. Common heat treatment processes includeannealing,precipitation hardening,quenching, andtempering:
Often, mechanical and thermal treatments are combined in what is known as thermo-mechanical treatments for better properties and more efficient processing of materials. These processes are common to high alloy special steels, super alloys and titanium alloys.
Electroplating is a common surface-treatment technique. It involves bonding a thin layer of another metal such asgold,silver,chromium orzinc to the surface of the product by hydrolysis. It is used to reduce corrosion, create abrasion resistance and improve the product's aesthetic appearance. Plating can even change the properties of the original part including conductivity, heat dissipation or structural integrity. There are four main electroplating methods to ensure proper coating and cost effectiveness per product: mass plating, rack plating, continuous plating and line plating.[68]
Thermal spraying techniques are another popular finishing option, and often have better high temperature properties than electroplated coatings due to the thicker coating. The four main thermal spray processes include electric wire arc spray, flame (oxy acetylene combustion) spray, plasma spray and high velocity oxy fuel (HVOF) spray.[69]
General:
...examines the organisation of metalworking from the Beaker period through the Bronze Age, confirming the common production of bronze when resources were available.
The Iron Age is defined as the last period of Prehistory, bringing enormous economic and technological changes from about 1200 BC.
Highlights the artistic and cultural significance of gold in pre-Columbian Mesoamerican societies like the Maya, far beyond its utilitarian value.
Discusses how gold was highly valued in ancient Egypt and Mesopotamia for its aesthetic, religious, and symbolic properties, associating it with the gods and eternity.
In ancient times, luxury items were characterised first of all by costly materials whose value derived from their rarity. Precious metals such as gold and silver as well as precious and semi-precious stones were luxury materials throughout the world of Antiquity. [...] the value [...] attributed to the raw material quite logically led to sophisticated treatments relying on highly developed techniques, marked in some cases by a purity and simplicity intended to show off the material itself, but in every case aiming at excellence, the perfect technical mastery or indeed transcendent skill that made for an outstanding piece.
Details the development of standardized metal coinage and the legal and trade frameworks that emerged around precious metals in ancient Lydia, Greece, and India.
Describes the sophisticated goldworking techniques of the Moche culture in South America, illustrating the high skill level achieved by ancient metalworkers in creating adornment and religious objects.
Explains the granulation technique and its independent development and use by Etruscan, Greek, and Mesopotamian artisans, indicating widespread sophisticated metalworking knowledge.
In most cases the blacksmith is regarded with awe, if not with esteem. [...] The usual position of the smith in Black Africa [...] is one of high repute, and this is perhaps the logical status in a primitive society so much dependent on his skill and knowledge of metal working, just as it should have been among prehistoric men, to whom the craft would be a high mystery, a gift of the gods, or something akin to sorcery. [...] When the Babylonian conqueror carried away the princes and the mighty men of valour from Jerusalem, he also took all the craftsmen and smiths, and 'none remained save the poorest sort of people of the land'. [2 Kings 24:14]
Discusses how the control of metal resources like bronze and iron was a critical factor in the economic and military dominance of ancient states, shaping their rise and fall.
Milling is a process of using rotating cutting tools to shape a workpiece, achieving high precision and complex geometries.
In a vertical milling machine, the spindle is vertically oriented and the spindles could be normally extended or tables are can be able to be raised or lowered.
CNC machining centers are categorized by the orientation of the spindle... capable of performing a variety of operations.
They can perform various machining operations, including slotting, drilling, and threading.
They are mainly divided into vertical mills and horizontal mills.
The two main styles of machining centers are horizontal and vertical.
G-code is a programming language that tells a CNC machine what actions to perform. It commands tool movement along the X, Y, and Z axes to create complex parts.
5-axis machining involves the rotation of a cutting tool or workpiece along three linear axes (X, Y, Z) and two rotational axes (A, B) to machine complex geometries.
Standard machining tolerances are typically ±0.005" for metal parts, which is a common reference for 'thou' (thousandths of an inch) in imperial measurements.
ISO 2768-1 is intended to simplify drawing indications and specifies general tolerances for linear and angular dimensions.
The heat produced by the cutting action of a tool may cause the workpiece to expand, making accurate machining difficult. To reduce heat, a coolant is generally used.
{{cite book}}:Check|isbn= value: checksum (help)Flood coolant is the most common method of application... A nozzle is aimed at the point of cut, and a pump delivers a high volume of liquid to drench the cutting process.
Some machines have programmable coolant nozzles that can automatically aim the coolant flow at the point of cut, while others rely on manual positioning.
The machinability of materials varies widely, from free-machining aluminum alloys to difficult-to-machine materials like stainless steel and high-temperature alloys.
{{cite book}}:Check|isbn= value: checksum (help)Selecting the correct cutting speed (SFM) and feed rate is critical and depends entirely on the workpiece material.
{{cite book}}:Check|isbn= value: checksum (help)Harder materials require lower surface speeds and lighter depths of cut, while softer materials can be machined at higher speeds and more aggressive feed rates.
Coolants and cutting oils are used to reduce friction, dissipate heat, and improve tool life. Proper maintenance of the coolant system is essential for efficient operation.
{{cite book}}:Check|isbn= value: checksum (help)All tools wear and eventually fail. Managing tool changes based on wear, not failure, is critical to preventing workpiece damage and maintaining quality.
The cost of a machined part depends heavily on the time required to produce it, with complexity being a major driver of machining time.
{{cite book}}:Check|isbn= value: checksum (help)The total machining time, which is unique to each part's geometry and requirements, is one of the most significant variables in determining the final part cost.
Moving machine parts have the potential to cause severe workplace injuries, such as crushed fingers or hands, amputations, and burns.
Hot metal chips produced during machining can cause burns and are a significant fire hazard.
Automated machinery, such as CNC machines, reduces the need for direct operator contact with moving parts, thereby reducing the risk of injury.
Grinding is a process of material removal that uses a rotating abrasive wheel as the cutting tool.
{{cite book}}:Check|isbn= value: checksum (help)Grinding is a machining process that uses bonded abrasive wheels for fine finishing, tight tolerance, and high-precision work on metals and other materials.
Abrasive wheels are composed of abrasive grains (such as aluminum oxide, silicon carbide, cubic boron nitride, or diamond) held together by a bonding agent.
{{cite book}}:Check|isbn= value: checksum (help)Modern CNC grinding machines like the Studer S41 feature automated loading systems and high-speed spindles for complex production tasks.
High-precision glass scales are manufactured using specialized grinding and etching processes to achieve micron-level accuracy.
CBN wheels allow for high-speed grinding of hard ferrous materials, enabling their use in high-production environments rather than just toolroom finishing.
CNC grinding machines are essential for producing high-precision components like turbine blades and landing gear parts in the aerospace sector.
Modern CNC grinding technology combines high material removal rates with micron-level precision for high-volume production of precision components.
Hand filing was a primary method for shaping metals before the advent of power tools, allowing for the precise creation of flat surfaces and small components.
While largely replaced by CNC machining for production, filing remains a vital skill for prototyping, toolmaking, and deburring edges.
Broaching is a machining process that uses a toothed tool to remove material in a single pass, commonly used for cutting keyways in shafts.
Electron beam machining is a thermal process that uses a focused stream of high-velocity electrons to precisely vaporize material.
{{cite book}}:Check|isbn= value: checksum (help)Ultrasonic machining is a mechanical process that uses high-frequency vibrations to drive an abrasive slurry, making it suitable for hard, brittle materials like ceramics and glass.
{{cite book}}:Check|isbn= value: checksum (help)
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