The Machining Encyclopedia

Many common terms have a different meaning when they are mentioned in the machining space. For example, if you look up in the dictionary the word “Turning,” you will get the definition “the act of a person or thing that turns”. In machining, it means an operation performed on a lathe. Other terms have the same meaning, but the focus is very different when strictly within the machining jargon. A good example is the word “Speed”, which maintains its origin but has a particular angle (Cutting Speed) when spoken by a machinist. The Machining Doctor’s Glossary gives you the definitions of each term in the machining industry.

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  • Advanced Cutting Materials
    Advanced Cutting Materials
    Advanced Cutting Materials in machining refers to CBN, PCD, and Ceramic-based inserts. The common property between them is that they are harder than carbide grades, and therefore provide unique solutions to machine exotic materials and hardened steel. Read More
  • Alloying Elements for Machining
    Alloying elements for machining
    Alloying element is a chemical element added to the primary substance of the material (in most cases ferrous) to tweak and enhance mechanical, metallurgical, and physical properties to suit different engineering needs. Read More
  • Aluminium Wheel
    Aluminum Alloys
    Aluminum in machining is referring to Aluminum alloys made from Aluminum (Al), with additional alloys that are usually silicon (Si), copper (Cu), magnesium (Mg), and manganese (Mn). Aluminum is a popular engineering material due to its low density (2.5 times lower than steel) and high(...) Read More
  • PMK ISO material groups
    Application Range
    A common format to describe the Application Range of a given Grade. Letter - Raw material: P - Steel M - Stainless Steel K - Cast Iron N- Non-ferous S - Superalloys H - Hardened Steel. Numbers:5 to 45 represnts how "difficult" is the application. 05 - Most Favorable 45- Least favorable Read More
  • Hardness measurment device
    Brinell scale
    One of the most common units used for listing the hardness of steel materials. the test is done with a 10 mm steel ball pressed with 3000 Kgf (6,614 Lbf). Common values for machined materials range from 100 HB for very soft materials up to 650 HB for heat-treated steels. Read More
  • Tungsten Carbide
    Carbide Grade
    In the machining jargon, the term “Carbide Grade”, or simply “Grade” refers to the combination of sintered tungsten carbide, coating, and other treatments that the cutting indexable insert or solid carbide tool are made off. Each grade is suitable for different materials, cutting conditions(...) Read More
  • Cast Iron ISO K
    Cast Iron
    Cast Iron (ISO K), is a group of Iron- Carbon-Silicone materials with 1.8-4% of Carbon (C) and 1-3% of Silicon (Si) content. The silicon pushes part of the carbon out of the solution, forming graphite flakes. The material is brittle at room temperature but has a low melting point and thus has(...) Read More
  • CBN Insert
    CBN Inserts
    PCBN (Nicknamed CBN) stands for “Polycrystalline Cubic Boron Nitride”, the second hardest material, second only to diamond. In addition to its high hardness (4,500 HV), it also has excellent hot hardness and chemical stability. Therefore, it can successfully machine Steel up to 70 HRC and(...) Read More
  • Ceramic Insert
    Ceramic Inserts
    Ceramic Inserts are indexable inserts made from Aluminium Oxide Al2O3 or Silicon Nitride Si3N4. They have a hardness of 2,100-2,500 HV (About 40% above carbide), which enables them to machine Hard Steel up to 55 HRC. It can also machine cast iron and nickel-based alloys six times faster(...) Read More
  • Cermet Insert
    Cermet Inserts
    Cermet is a cutting material combining ceramics and metals (usualט Nickel). The result is a harder substrate than carbide, therefore more wear-resistant, and enables machining at higher cutting speeds. The downside is very low toughness, and therefore, it is used only for finishing(...) Read More
  • Chip Load (Maximum CHip Thickness)
    Chip Load
    Chip load has two meanings: (1) The maximum load that the cutting edge of a specific milling cutter (or indexable insert) can withstand without yielding or having a very short tool-life. (2) The maximum width of the chip that the tooth (or indexable inerts) of a milling cutter cuts out of the(...) Read More
  • Chromium Alloying element
    Chromium
    Chromium added to carbon steel in percentages greater than 11% creates Stainless Steel. At this percentage and greater (When combined with Nickel), the corrosion resistance of steel vastly increases, and oxidation of the iron is prevented. Chromium also helps to improve mechanical properties,(...) Read More
  • CNC Lathe Machine
    CNC Machine
    A CNC machine is a computer-controlled manufacturing cell that has several moving axes (Usually 2-5). The most common are milling and turning machines, But CNC can also refer to grinders, laser cutting machines, and 3D printing machines. Read More
  • CVD coating layers of a carbide insert
    Coating
    A thin layer of 3 to 20 microns (0.0001-0.0007") that is added on top of the sustrate of the cutting tool. The coating is typically composed of a series of sub-layers composed of mostly titanium nitride, aluminum oxide, and titanium carbon nitride. This thin layer directly enhances the(...) Read More
  • Chromium Alloying element
    Cr
    Chromium added to carbon steel in percentages greater than 11% creates Stainless Steel. At this percentage and greater (When combined with Nickel), the corrosion resistance of steel vastly increases, and oxidation of the iron is prevented. Chromium also helps to improve mechanical properties,(...) Read More
  • CNC Machine Crash
    Crash
    In machining, a crash refers to the unfortunate event where the cutting tool hits the workpiece during rapid traverse. It is caused by an operator's error or a fault in the CNC program. The result of a crash can be a broken tool, but severe cases could also damage the machine. Read More
  • Carbide Insert Cutting Edge geometry
    Cutting Edge
    Cutting edge refers to the "Micro-Geometry" of the cross-section at the tip of the inserts that engages with the workpiece material. Although the length of the cross-section could be less than 1 mm it has an enormous effect on the performance. Read More
  • Cutting Speed
    Cutting Speed
    In machining, the words "Speed", "Cutting Speed", "SFM" and "Surface Speed" all refer to the relative velocity between the tip of the cutting edge and the workpiece. The definition is the same for all machining operations turning, milling, etc. Opposed to feedrate which has a different(...) Read More
  • CVD coating layers of a carbide insert
    CVD (Chemical Vapor Deposition)
    As its name suggests, in this process the coating forms a chemical bond with the substrate. Therefore, the adhesion to the substrate is very strong. With CVD it is possible to create a thick coating of 5 to 25 microns. Due to its thicker layer, CVD provides excellent heat insulation and(...) Read More
  • Machining Cycle Time
    Cycle Time
    Cycle time is the duration that takes a machine to complete the manufacturing of a part. An average of a manufacturing series should be used for a reliable calculation, so tools and workpiece changes are also taken into account. Read More
  • Drilling
    Drilling is a machining process that cuts a circular bore in the materials (usually metal). Drilling can be performed on a milling machine with the cutting tool rotates against a static workpiece, or on a lathe machine, where the material rotates against a static drill. (The exact same drill(...) Read More
  • Milling Feed per tooth and table feed
    Feed Per Revolution (Milling)
    Feed per Revolution is the linear distance that a milling cutter travels during a single spindle rotation. It is calculated by (1) Dividing the Table Feed by the Spindle Speed. (2) Multiplying the Feed per Tooth by the Number of teeth. Read More
  • Milling Feed per tooth and table feed
    Feed Per Tooth
    Feed per Tooth can be defined in two ways: (1) The linear distance traveled by a milling cutter during one full spindle rotation (Feed per Revolution) divided by the number of teeth of the cutter. (2) The maximum chip thickness (Chip load) when the radial depth of cut is greater or equal to(...) Read More
  • Milling Feed per tooth and table feed
    Feed Speed
    Milling Feed Rate (Also called Table Feed and Feed Speed), is the linear velocity of a milling cutter relative to the workpiece, measured in [mm/min] or [inch/min]. Read More
  • FeedRate
    Feedrate (Turning)
    In machining, Feedrate is the velocity at which the cutter advances against the workpiece. In Turning it is expressed in units of distance per revolution (Inch Per Revolution [IPR] or [mm/Rev]). In Milling, it is expressed in distance per tooth (...) Read More
  • Milling Feed per tooth and table feed
    Fn
    Feed per Revolution is the linear distance that a milling cutter travels during a single spindle rotation. It is calculated by (1) Dividing the Table Feed by the Spindle Speed. (2) Multiplying the Feed per Tooth by the Number of teeth. Read More
  • Milling Feed per tooth and table feed
    Fz
    Feed per Tooth can be defined in two ways: (1) The linear distance traveled by a milling cutter during one full spindle rotation (Feed per Revolution) divided by the number of teeth of the cutter. (2) The maximum chip thickness (Chip load) when the radial depth of cut is greater or equal to(...) Read More
  • Tungsten Carbide
    Grade
    In the machining jargon, the term “Carbide Grade”, or simply “Grade” refers to the combination of sintered tungsten carbide, coating, and other treatments that the cutting indexable insert or solid carbide tool are made off. Each grade is suitable for different materials, cutting conditions(...) Read More
  • Grooving on a lath
    Grooving
    Grooving is an operation performed on a lathe machine in order to create radial grooves. Machining grooves is one of the more challenging turning operations performed on a lathe machine. Grooving tools are often thin and less stable. Three sides of the insert are in contact with the workpiece,(...) Read More
  • Hardness measurment device
    Hardness
    Hardness is a measurement of the resistance to localized plastic deformation caused by force or abrasion. Materials with high hardness would generally be stronger and more wear-resistant, but on the other hand, more brittle and sensitive to fracture. Read More
  • Hardness measurment device
    HB
    One of the most common units used for listing the hardness of steel materials. the test is done with a 10 mm steel ball pressed with 3000 Kgf (6,614 Lbf). Common values for machined materials range from 100 HB for very soft materials up to 650 HB for heat-treated steels. Read More
  • Honing
    Honing is a process that rounds the tip of the cutting edge, typically to a radius size is between 0.001-0.003" (0.03-0.08 mm) . It is usually done with sandblasting. Read More
  • Hardness measurment device
    HRC
    Rockwell [HRC/HRB/HRA] is one of the most common units used for listing the hardness of machined materials. the test is done by measuring the depth of penetration of a sphere under a large load compared to the penetration made by a reference preload. Read More
  • HSRA Heat resistance super Alloys
    HRSA
    Heat-resistance super-alloys (ISO S) are a group of materials engineered to have very high strength and superb corrosion resistance. These alloys must also preserve these properties at very high temperatures and chemically hostile environments. They are mainly used in jet engines, turbines,(...) Read More
  • Hardness measurment device
    HV
    Vickers [HV] is a common unit used for listing the hardness of carbide grades and other hard cutting materials such as Ceramics, CBN, and PCD. The test is done by measuring the surface area of the indentation created by a diamond in the shape of a square-based pyramid. Read More
  • FeedRate
    IPR
    IPR stands for "Inch Per Revolution". It is the Americal common unit for Feedrates on CNC lathe machines. In the rest of the word, feedrate is displayed in mm/rev. Read More
  • Cast Iron ISO K
    ISO K
    Cast Iron (ISO K), is a group of Iron- Carbon-Silicone materials with 1.8-4% of Carbon (C) and 1-3% of Silicon (Si) content. The silicon pushes part of the carbon out of the solution, forming graphite flakes. The material is brittle at room temperature but has a low melting point and thus has(...) Read More
  • Stainless Steel SO M
    ISO M
    Stainless steels (ISO M), as their name suggests are a group of steel alloys with a shiny appearance and good corrosion resistance. The base element (70-80%) is Iron (Fe) with a minimum of 10.5% Chromium; most grades will have additional alloying elements such as nickel (Ni) and molybdenum (Mo). Read More
  • Non Ferrous ISO N
    ISO N
    In the machining world, Nonferrous (ISO N) refers to metals that do not contain any Iron (Fe). Non-ferrous have inferior mechanical properties when compared to steel and usually cost more per Kg. They are used when one of their specific properties are needed. Read More
  • Steel ISO P
    ISO P
    Steel (ISO P) is Iron (Fe), with the addition of 0.1 – 2.5 wt. % of Carbon (C). Besides carbon, steel may also contain many other alloying elements up to a total content of around 20%. Pure Iron is very soft. By “playing” with the mix and amount of the different alloying elements, Iron gains a(...) Read More
  • K Land
    A "Land" is a small flat area, typically 0.002-0.02" (0.05-0.5 mm) long that connects between the tip of the cutting edge to the rake angle. Read More
  • Land
    A "Land" is a small flat area, typically 0.002-0.02" (0.05-0.5 mm) long that connects between the tip of the cutting edge to the rake angle. Read More
  • Machinability Rating
    Machinability
    Machinability is the ease with which a metal can be machined. It is represented in percentage relative to a reference metal. A smaller value means the metal is harder to machine. Very difficult to machine materials can rate 10-20%, while very easy to machine material can reach 200-400% Read More
  • Manganese
    Manganese is one of the most common alloying elements. It is added to almost all Steel, stainless steel, and aluminum alloys. In each one of them, it has a different role. In steel, it helps with heat treatment. In stainless steel, it is a nickel substituted and in Aluminum to enhance strength. Read More
  • PMK Material Groups
    Material Groups in Machining
    In the machining industry, workpiece materials are divided into groups. Classifying correctly the material group gives a good starting point to choose the correct grade and initial cutting speed. Read More
  • Chip Load (Maximum CHip Thickness)
    Maximum Chip Thickness
    Chip load has two meanings: (1) The maximum load that the cutting edge of a specific milling cutter (or indexable insert) can withstand without yielding or having a very short tool-life. (2) The maximum width of the chip that the tooth (or indexable inerts) of a milling cutter cuts out of the(...) Read More
  • Milling Cutter
    Milling
    Milling is a machining process that cuts materials (usually metal) by rotating a round cutter as it moves along a workpiece. The cutter is either solid carbide or a steel body with indexable inserts. It can have one cutting edge or several (Up to dozens). More cutting edges yield higher(...) Read More
  • Milling Feed per tooth and table feed
    Milling Feed Rate (Table Feed)
    Milling Feed Rate (Also called Table Feed and Feed Speed), is the linear velocity of a milling cutter relative to the workpiece, measured in [mm/min] or [inch/min]. Read More
  • Mn
    Manganese is one of the most common alloying elements. It is added to almost all Steel, stainless steel, and aluminum alloys. In each one of them, it has a different role. In steel, it helps with heat treatment. In stainless steel, it is a nickel substituted and in Aluminum to enhance strength. Read More
  • Molibdenum - Alloying Element
    Mo
    Molybdenum, like chromium, effects the corrosion resistance of steel. Molybdenum also increases the hardenability, toughness, and tensile strength of steel. The hardenability is increased by lowering the required quench rate during heat-treatment. Molybdenum also decreased the risk of pitting(...) Read More
  • Molibdenum - Alloying Element
    Molybdenum
    Molybdenum, like chromium, effects the corrosion resistance of steel. Molybdenum also increases the hardenability, toughness, and tensile strength of steel. The hardenability is increased by lowering the required quench rate during heat-treatment. Molybdenum also decreased the risk of pitting(...) Read More
  • Nickel Alloying Element
    Ni
    Nickel is one of the most important alloying element in the machining world. It is added in various quantities to many materials having a major effect on their properties. Its presence in high quantity creates materials that are very hard to machine. Read More
  • Nickel Alloying Element
    Nickel
    Nickel is one of the most important alloying element in the machining world. It is added in various quantities to many materials having a major effect on their properties. Its presence in high quantity creates materials that are very hard to machine. Read More
  • Non Ferrous ISO N
    Nonferrous Materials
    In the machining world, Nonferrous (ISO N) refers to metals that do not contain any Iron (Fe). Non-ferrous have inferior mechanical properties when compared to steel and usually cost more per Kg. They are used when one of their specific properties are needed. Read More
  • Parting off
    Parting Off
    Parting off is the operation of separating the part from the raw material on a lathe machine. Most smaller parts machined on a lathe include a paring process, thus making it one of the most popular operations. The operation can be performed on a "full rod" and called "Parting to Center", and(...) Read More
  • PCD Insert
    PCD Inserts
    PCD stands for "Poly Crystalline Diamond", the hardest available cutting material. PCD is a synthetic diamond produced by sintering together selected diamond particles with a metal matrix at high temperature and high pressure. The result is 90-95% diamond content material that reaches a(...) Read More
  • Droplets on the face of a carbide insert before post treatment
    Post Treatment
    All coatings have flaws in their surface uniformity caused by coating droplets and non-uniform grain size. Most modern grades add a post-treatment after the coating process. This treatment is usually sandblasting or tumbling, aiming to smoothen the finial coating layer, thus reducing the(...) Read More
  • PVD coating layers of a carbide insert
    PVD (Physical Vapor Deposition)
    In PVD, the coating layer is spattered on the substrate and does not form a chemical bond with it. Therefore, the adhesion is lower, but the process induces compressive residual stress that improves the overall toughness of the carbide insert. PVD is good for creating thin coatings between 1(...) Read More
  • Surface finish measurment
    Ra
    Ra is the most commonly used unit to measure and report surface roughness. According to ASME B46.1, Ra is the arithmetic average of the absolute values of the profile height deviations from the center-line, recorded within the evaluation length. The profile to analyze is obtained by either an(...) Read More
  • Hardness measurment device
    Rockwell scale
    Rockwell [HRC/HRB/HRA] is one of the most common units used for listing the hardness of machined materials. the test is done by measuring the depth of penetration of a sphere under a large load compared to the penetration made by a reference preload. Read More
  • CNC Spindle
    RPM
    RPM stands for “Revolutions Per Minute”. In machining, it refers to the spindle speed of a CNC machine. On a lathe, it would the speed at which the workpiece is rotating and on a milling machine the speed at which the cutting tool is rotating. In Gcode it is represented with S for example G00(...) Read More
  • Surface finish measurment
    Rz
    Rz is the second most commonly used unit. Rz is calculated by measuring the vertical distance from the highest peak to the lowest valley within the scanned profile. The highest five peaks and the five deepest valleys are taken, then averaging these distances. Rz will always yield a higher(...) Read More
  • Cutting Speed
    SFM
    In machining, the words "Speed", "Cutting Speed", "SFM" and "Surface Speed" all refer to the relative velocity between the tip of the cutting edge and the workpiece. The definition is the same for all machining operations turning, milling, etc. Opposed to feedrate which has a different(...) Read More
  • CNC Spindle
    Spindle
    In machining, a spindle is the rotary unit of the machine. In a Lathe, the spindle is rotating the workpiece. In milling and grinding machines, the spindle is rotating the cutting tool. Some machine tools have several (Or even many) spindles, some of which rotate workpieces and other rotate(...) Read More
  • Stainless Steel SO M
    Stainless Steel
    Stainless steels (ISO M), as their name suggests are a group of steel alloys with a shiny appearance and good corrosion resistance. The base element (70-80%) is Iron (Fe) with a minimum of 10.5% Chromium; most grades will have additional alloying elements such as nickel (Ni) and molybdenum (Mo). Read More
  • Steel ISO P
    Steel
    Steel (ISO P) is Iron (Fe), with the addition of 0.1 – 2.5 wt. % of Carbon (C). Besides carbon, steel may also contain many other alloying elements up to a total content of around 20%. Pure Iron is very soft. By “playing” with the mix and amount of the different alloying elements, Iron gains a(...) Read More
  • Substrate of a carbide insert under a microscope
    Substrate
    The substrate is the material of the bare cutting insert before coating and post-treatment. The primary property of interest to the machinist is the hardness of the substrate. Very hard substrates have a hardness of 1800 HV and provide excellent wear resistance but are very brittle and can(...) Read More
  • HSRA Heat resistance super Alloys
    Superalloys
    Heat-resistance super-alloys (ISO S) are a group of materials engineered to have very high strength and superb corrosion resistance. These alloys must also preserve these properties at very high temperatures and chemically hostile environments. They are mainly used in jet engines, turbines,(...) Read More
  • Surface Roughness
    Surface Finish
    Surface finish (Also called sometimes surface roughness) is a numeric representation of a surface’s “smoothness”.The number is obtained by scanning the surface with a needle that records the micro “hills” and “valleys” along a linear section. The measurement process produces a chart analyzed(...) Read More
  • Milling Feed per tooth and table feed
    Table Feed
    Milling Feed Rate (Also called Table Feed and Feed Speed), is the linear velocity of a milling cutter relative to the workpiece, measured in [mm/min] or [inch/min]. Read More
  • Titanium Alloys
    Ti
    Titanium is a chemical element with the symbol Ti. Titanium alloy is usually made from about 88% of Ti with alloying elements, mostly vanadium (V) and aluminum (Al). What makes it a unique and useful metal are several properties not found together in other materials. It has an excellent(...) Read More
  • Titanium Alloys
    Titanium
    Titanium is a chemical element with the symbol Ti. Titanium alloy is usually made from about 88% of Ti with alloying elements, mostly vanadium (V) and aluminum (Al). What makes it a unique and useful metal are several properties not found together in other materials. It has an excellent(...) Read More
  • CNC Program
    Tool Path
    In machining, the term "tool path" refers to the line/curve that a cutter travels along the workpiece. The toolpath is defined by a series of straight lines and circular arcs. A collection of tool paths grouped together forms a CNC program. Read More
  • Turning Tool
    Turning
    Turning is a machining process that cuts materials (usually metal) by moving a cutter along a workpiece while the workpiece rotates. The cutter is typically made of steel holder with an indexable insert made from carbide. Due to its fundamentals, turning operation produces only round,(...) Read More
  • CNC lathe Turret
    Turret
    In machining, a turret refers to a tool maganize on a lathe machine that changes tools by rotation. The turret holds numerous tools on its outer diameter. One angle (Position), is the working position. By rotating the desired tool to this angle, it selects the current working tool. Read More
  • V
    Vanadium is used to enhance the control grain size in steel alloys. Adding Vanadium up to 5% reduces the grain size because the vanadium carbides block the formation of larger grains. Finer grain size helps to increase ductility and strength. It is mainly used in Tool Steels, where strength is(...) Read More
  • Vanadium
    Vanadium is used to enhance the control grain size in steel alloys. Adding Vanadium up to 5% reduces the grain size because the vanadium carbides block the formation of larger grains. Finer grain size helps to increase ductility and strength. It is mainly used in Tool Steels, where strength is(...) Read More
  • Cutting Speed
    Vc
    In machining, the words "Speed", "Cutting Speed", "SFM" and "Surface Speed" all refer to the relative velocity between the tip of the cutting edge and the workpiece. The definition is the same for all machining operations turning, milling, etc. Opposed to feedrate which has a different(...) Read More
  • Milling Feed per tooth and table feed
    Vf
    Milling Feed Rate (Also called Table Feed and Feed Speed), is the linear velocity of a milling cutter relative to the workpiece, measured in [mm/min] or [inch/min]. Read More
  • Hardness measurment device
    Vickers scale
    Vickers [HV] is a common unit used for listing the hardness of carbide grades and other hard cutting materials such as Ceramics, CBN, and PCD. The test is done by measuring the surface area of the indentation created by a diamond in the shape of a square-based pyramid. Read More
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