By selecting the appropriate milling cutter angle, size and feed method, the tool can cut into the workpiece material with minimum vibration and tensile stress. Taking a different approach to drilling can also better utilize milling equipment with less downtime. Coupled with choosing the right tool design and composition, these milling techniques for effective machining can create highly efficient, low-cost processing of workpiece blanks into exquisite parts.

To prolong the life of the tool, in the face milling process, the tool should be programmed to avoid the hole or interrupted part of the workpiece (if possible). When the face milling cutter passes through the middle of a hole in the workpiece, the cutter is milled along one side of the hole and the reverse milling is performed on the other side of the hole, which will cause a great impact on the insert. This can be avoided by bypassing holes and pockets when programming the tool path.

Tool edge preparation is also an important consideration. Mechanical wear in the form of abrasion or adhesive wear causes chips and scratches on the tool. A rounded tool edge prevents the growth of cracks and chips and offers a slower, even abrasion process.

Hollow milling cutters, more often called simply hollow mills, are essentially "inside-out endmills". They are shaped like a piece of pipe (but with thicker walls), with their cutting edges on the inside surface. They were originally used on turret lathes and screw machines as an alternative to turning with a box tool, or on milling machines or drill presses to finish a cylindrical boss (such as a trunnion). Hollow mills can be used on modern CNC lathes and Swiss style machines. An advantage to using an indexable adjustable hollow mill on a Swiss-style machine is replacing multiple tools.  By performing multiple operations in a single pass, the machine does not need as can accommodate other tools in the tool zone and improves productivity.

The machinist needs three values: S, F and Depth when deciding how to cut a new material with a new tool. However, he will probably be given values of Vc and Fz from the tool manufacturer. S and F can be calculated from them:

The history of milling cutters is intimately bound up with that of milling machines. Milling evolved from rotary filing, so there is a continuum of development between the earliest milling cutters known, such as that of Jacques de Vaucanson from about the 1760s or 1770s,[3][4] through the cutters of the milling pioneers of the 1810s through 1850s (Whitney, North, Johnson, Nasmyth, and others),[5] to the cutters developed by Joseph R. Brown of Brown & Sharpe in the 1860s, which were regarded as a break from the past[6][7] for their large step forward in tooth coarseness and for the geometry that could take successive sharpenings without losing the clearance (rake, side rake, and so on). De Vries (1910)[7] reported, "This revolution in the science of milling cutters took place in the States about the year 1870, and became generally known in Europe during the Exhibition in Vienna in 1873. However strange it may seem now that this type of cutter has been universally adopted and its undeniable superiority to the old European type is no longer doubted, it was regarded very distrustfully and European experts were very reserved in expressing their judgment. Even we ourselves can remember that after the coarse pitched cutter had been introduced, certain very clever and otherwise shrewd experts and engineers regarded the new cutting tool with many a shake of the head. When[,] however, the Worlds Exhibition at Philadelphia in 1876, exhibited to European experts a universal and many-sided application of the coarse pitched milling cutter which exceeded even the most sanguine expectations, the most far-seeing engineers were then convinced of the immense advantages which the application of the new type opened up for the metalworking industry, and from that time onwards the American type advanced, slowly at first, but later on with rapid strides".[8]

Heat and vibration, both, can also be managed with the cutting tool material composition. Ranging from carbide steel to ceramic and diamond tips, varying degrees in toughness and hardness are available to best suit the material you are machining. Tool hardness decreases at higher temperatures and is directly proportional to tool wear. Toughness is proportional to impact loads. They are inversely proportional, so each cutting process must be analyzed for the selection of appropriate tool composition.

There are 8 cutters (excluding the rare half sizes) that will cut gears from 12 teeth through to a rack (infinite diameter).

Hollow milling has an advantage over other ways of cutting because it can perform multiple operations. A hollow mill can reduce the diameter of a part and also perform facing, centering, and chamfering in a single pass.

An adjustable hollow mill is a valuable tool for even a small machine shop to have because the blades can be changed out for an almost infinite number of possible geometries.

End mills (middle row in image) are those tools that have cutting teeth at one end, as well as on the sides. The words end mill are generally used to refer to flat bottomed cutters, but also include rounded cutters (referred to as ball nosed) and radiused cutters (referred to as bull nose, or torus). They are usually made from high speed steel or cemented carbide, and have one or more flutes. They are the most common tool used in a vertical mill.

Millingcutter

More and more manufacturers use milling cutters to machine holes in helical or circular interpolation. Although the processing speed of this method is slightly slower than that of drilling, it is more advantageous for many processes. When drilling holes on irregular surfaces, it may be difficult for the drill bit to drill into the workpiece along the centerline, causing the drill bit to drift on the workpiece surface. Drill bits also require about 10 horsepower for each 25mm hole diameter, which means that when drilling on a small power tool, the optimal power value may not be achieved. Using a milling cutter is also optimal for parts requiring many holes, even of different sizes. If the tool magazine’s capacity is limited, the use of milling holes can avoid a frequent shutdown of the machine for tool replacement.

When the tool moves into action, the main declination angle has a great influence on the radial cutting force and cutting depth. The main declination angle is the angle between the cutting edge and the cutting plane. The magnitude of the radial cutting force directly affects the cutting power and the vibration resistance of the tool. The smaller the main declination angle of the milling cutter, the smaller the radial cutting force and the better the vibration resistance, but the cutting depth also decreases. Several standard angles are available providing various milling options for a workpiece.

When selecting a milling techniques cutter suitable for a machining task, various issues such as the geometry, size, and workpiece material to be processed must be considered. With new high-speed milling, the cutting tool design and composition also play an important factor due to both tool life span and efficiencies in tool changes. There are universal tools that may offer milling techniques for effective machining without requiring frequent tool changes, but specific tooling may be best based on the variables of your machine capabilities, workpiece design and material, and budget. Consider these factors to be sure you have the right milling cutters for your machining tasks.

Milling cutters come in several shapes and many sizes. There is also a choice of coatings, as well as rake angle and number of cutting surfaces.

A better way to feed is to use the rolling cutting method. As the name implies, the milling cutter rolls into the workpiece without reducing the feed rate and cutting speed. This means that the milling cutter must rotate clockwise to ensure that it is processed in a milling manner. The chips formed in this way are from thick to thin, which can reduce vibration and tensile stress on the tool, and transfer more cutting heat to the chips. By changing the way, the milling cutter cuts into the workpiece each time, the tool life can be doubled. To achieve this in-feed method, the programming radius of the tool path should be half of the diameter of the milling cutter, and increase the offset distance from the tool to the workpiece.

When face milling large parts, cutters with smaller diameters are used, which leaves much room for improving productivity. In an ideal situation, a milling cutter should have 70% of the cutting edges involved in cutting. When milling holes with a milling cutter, the tool size becomes particularly important. Compared with the hole diameter, the diameter of the milling cutter is too small, then a core may be formed in the center of the hole during processing. When the core falls, it may damage the workpiece or tool. If the diameter of the milling cutter is too large, it will damage the tool itself and the workpiece, because the milling cutter is not cutting in the center and may collide at the bottom of the tool.

A fly cutter is composed of a body into which one or two tool bits are inserted. As the entire unit rotates, the tool bits take broad, shallow facing cuts. Fly cutters are analogous to face mills in that their purpose is face milling and their individual cutters are replaceable. Face mills are more ideal in various respects (e.g., rigidity, indexability of inserts without disturbing effective cutter diameter or tool length offset, depth-of-cut capability), but tend to be expensive, whereas fly cutters are very inexpensive.

The most common type of joint between shell and arbor involves a fairly large cylindrical feature at center (to locate the shell concentric to the arbor) and two driving lugs or tangs that drive the shell with a positive engagement (like a dog clutch). Within the central cylindrical area, one or several socket head cap screws fasten the shell to the arbor.

A face mill is a cutter designed for facing as opposed to e.g., creating a pocket (end mills). The cutting edges of face mills are always located along its sides. As such it must always cut in a horizontal direction at a given depth coming from outside the stock. Multiple teeth distribute the chip load, and since the teeth are normally disposable carbide inserts, this combination allows for very large and efficient face milling.

Milling cutters are cutting tools typically used in milling machines or machining centres to perform milling operations (and occasionally in other machine tools). They remove material by their movement within the machine (e.g., a ball nose mill) or directly from the cutter's shape (e.g., a form tool such as a hobbing cutter).

Selecting a milling cutter is not a simple task. There are many variables, opinions and lore to consider, but essentially the machinist is trying to choose a tool that will cut the material to the required specification for the least cost. The cost of the job is a combination of the price of the tool, the time taken by the milling machine, and the time taken by the machinist. Often, for jobs of a large number of parts, and days of machining time, the cost of the tool is lowest of the three costs.

Another way to improve the milling process is to optimize the milling strategy of the face milling cutter. When programming surface milling, the user must first consider the way the tool cuts into the workpiece. Usually, the milling cutter simply cuts directly into the workpiece. This cutting method is accompanied by a large impact noise because when the insert is withdrawn, the milling cutter produces the thickest chips. Because the blade forms a large impact on the workpiece material, it often causes vibration and produces tensile stress that will shorten the life of the tool.

Regular fly cutters (one tool bit, swept diameter usually less than 100 mm) are widely sold in machinists' tooling catalogs. Fly bars are rarely sold commercially; they are usually made by the user. Fly bars are perhaps a bit more dangerous to use than endmills and regular fly cutters because of their larger swing. As one machinist put it, running a fly bar is like "running a lawn mower without the deck",[2] that is, the exposed swinging cutter is a rather large opportunity to take in nearby hand tools, rags, fingers, and so on. However, given that a machinist can never be careless with impunity around rotating cutters or workpieces, this just means using the same care as always except with slightly higher stakes. Well-made fly bars in conscientious hands give years of trouble-free, cost-effective service for the facing off of large polygonal workpieces such as die/mold blocks.

A bull nose cutter mills a slot with a corner radius, intermediate between an end mill and ball cutter; for example, it may be a 20 mm diameter cutter with a 2 mm radius corner. The silhouette is essentially a rectangle with its corners truncated (by either a chamfer or radius).

Interpolation is also not necessary when using a hollow mill; this can result in a significant reduction of production time.

Most fly cutters simply have a cylindrical center body that holds one tool bit. It is usually a standard left-hand turning tool that is held at an angle of 30 to 60 degrees. Fly cutters with two tool bits have no "official" name but are often called double fly cutters, double-end fly cutters, or fly bars. The latter name reflects that they often take the form of a bar of steel with a tool bit fastened on each end. Often these bits will be mounted at right angles to the bar's main axis, and the cutting geometry is supplied by using a standard right-hand turning tool.

The standard 45° face milling cutter may benefit more in other cutting applications. In face milling, a face milling cutter with an angle of 45° will make the chips thinner. As the cutting angle decreases from 90°, the chip thickness will be less than the feed per tooth, which in turn can increase the feed rate to 1.4 times the original. The radial cutting force of the 45° main declination milling cutter is greatly reduced, which is approximately equal to the axial cutting force. The cutting load is distributed on the longer cutting edge. It has good vibration resistance and is suitable for the overhang of the spindle of the boring and milling machine. When machining flat surfaces with this type of tool, the blade breakage rate is low and the durability is high; when machining cast iron parts, the edges of the workpiece are not prone to chipping. It is well suited to longer processing occasions.

The diameter of a standard face milling cutter can range from Φ16mm to Φ630mm. The diameter of the milling cutter should be selected according to the milling width and depth. Generally, the larger the depth and width before milling, the larger the diameter of the milling cutter. During rough milling, the diameter of the milling cutter of the milling machine is smaller; when finishing milling, the diameter of the milling cutter is larger to accommodate the entire processing width of the workpiece and to reduce the traces of tool connection between two adjacent feeds.

Most shell mills made today use indexable inserts for the cutting edges—thus shank, body, and cutting edges are all modular components.

Slab mills are used either by themselves or in gang milling operations on manual horizontal or universal milling machines to machine large broad surfaces quickly. They have been superseded by the use of cemented carbide-tipped face mills which are then used in vertical mills or machining centres.

Roughing end mills quickly remove large amounts of material. This kind of end mill utilizes a wavy tooth form cut on the periphery. These wavy teeth act as many successive cutting edges producing many small chips. This results in a relatively rough surface finish, but the swarf takes the form of short thin sections and is more manageable than a thicker more ribbon-like section, resulting in smaller chips that are easier to clear. During cutting, multiple teeth are in simultaneous contact with the workpiece, reducing chatter and vibration. Rapid stock removal with heavy milling cuts is sometimes called hogging. Roughing end mills are also sometimes known as "rippa" or "ripper" cutters.

milling中文

Cutters of this form factor were the earliest milling cutters developed. From the 1810s to at least the 1880s they were the most common form of milling cutter, whereas today that distinction probably goes to end mills. Traditionally, HSS side and face cutters are used to mill slots and grooves.

A common use of a hollow mill is preparing for threading.  The hollow mill can create a consistent pre-thread diameter quickly, improving productivity.

Another type of shell fastening is simply a large-diameter fine thread. The shell then screws onto the arbor just as old-style lathe chuck backplates screw onto the lathe's spindle nose. This method is commonly used on the 2" or 3" boring heads used on knee mills. As with the threaded-spindle-nose lathe chucks, this style of mounting requires that the cutter only make cuts in one rotary direction. Usually (i.e., with right-hand helix orientation) this means only M03, never M04, or in pre-CNC terminology, "only forward, never reverse". One could use a left-hand thread if one needed a mode of use involving the opposite directions (i.e., only M04, never M03).

Mechanics are familiar with the cutting noise caused by vibration. It usually occurs when the tool cuts into the workpiece, or when the tool makes a sharp 90° turn while eating. Roll milling of workpiece corners can eliminate this noise and extend tool life. In general, program the corner radius of the workpiece to be 75%-100% of the diameter of the milling cutter. This can shorten the arc length of the milling cutter, allowing higher feed rates and reduced vibration.

A shell mill is any of various milling cutters (typically a face mill or endmill) whose construction takes a modular form, with the shank (arbor) made separately from the body of the cutter, which is called a "shell" and attaches to the shank/arbor via any of several standardized joining methods.

Both convex and concave spherical radii are possible with a hollow mill. The multiple blades of a hollow mill allow this radius to be produced while holding a tight tolerance.

These cutters are a type of form tool and are used in hobbing machines to generate gears. A cross-section of the cutter's tooth will generate the required shape on the workpiece, once set to the appropriate conditions (blank size). A hobbing machine is a specialised milling machine.

Endmilling

Ball nose cutters or ball end mills (lower row in image) are similar to slot drills, but the end of the cutters are hemispherical. They are ideal for machining 3-dimensional contoured shapes in machining centres, for example in moulds and dies. They are sometimes called ball mills in shop-floor slang, despite the fact that that term also has another meaning. They are also used to add a radius between perpendicular faces to reduce stress concentrations.

Hollow mills offer an advantage over single point tooling. Multiple blades allow the feed rate to double and can hold a closer concentricity. The number of blades can be as many as 8 or as few as 3.  For significant diameter removal (roughing), more blades are necessary.

Although there are many different types of milling cutter, understanding chip formation is fundamental to the use of any of them. As the milling cutter rotates, the material to be cut is fed into it, and each tooth of the cutter cuts away a small chip of material. Achieving the correct size of chip is of critical importance. The size of this chip depends on several variables.

High process speeds with large swarf chunks cause both heat and vibration on the workpiece and the tool. This tool wear causes loss of material on the tool and change in the tool shape which will both affect your workpiece quality. Other factors affecting the intensity of tool wear include the workpiece material, the parameters of cutting, and means of cooling. Cooling options, like cutting oil are necessary to help control the heat buildup, but can not prevent it. Heat causes premature wear that can be managed with a range of titanium coatings. Tool coating is as important as the composite the tool is made of concerning oxidization and heat control.

The 90° angle can also be used when machining a flat surface with a square shoulder. A milling cutter with an 88° main angle, however, provides an improved cutting performance. Face milling with 90° square shoulder milling cutters is also very common for certain milling needs, like when the shape of the milled workpiece is irregular, or the surface of the casting will cause the depth of cut to change.

Although the rolling cutting method is mainly used to improve the way the tool cuts into the workpiece, the same machining principle can also be applied to other stages of milling. For large-area plane milling, the commonly used programming method is to let the tool pass through the entire length of the workpiece one after another and complete the next cut in the opposite direction. To maintain a constant radial tool intake and eliminate vibrations, the use of a combination of helical lower knife and rolling milling workpiece corners usually results in better results.

Millingmachine

The side-and-face cutter is designed with cutting teeth on its side as well as its circumference. They are made in varying diameters and widths depending on the application. The teeth on the side allow the cutter to make unbalanced cuts (cutting on one side only) without deflecting the cutter as would happen with a slitting saw or slot cutter (no side teeth).

When milling the plane with square shoulders, select a 90° lead angle. This kind of tool has good versatility and is used in single-piece and small-batch processing. Because the radial cutting force of this type of tool is equal to the cutting force, the feed resistance is large and it is easy to vibrate, so the machine tool is required to have greater power and sufficient rigidity.

Another important quality of the milling cutter to consider is its ability to deal with the swarf generated by the cutting process. If the swarf is not removed as fast as it is produced, the flutes will clog and prevent the tool cutting efficiently, causing vibration, tool wear and overheating. Several factors affect swarf removal, including the depth and angle of the flutes, the size and shape of the chips, the flow of coolant, and the surrounding material. It may be difficult to predict, but a good machinist will watch out for swarf build up, and adjust the milling conditions if it is observed.

More advanced hollow mills use indexable carbide inserts for cutting, although traditional high speed steel and carbide-tipped blades are still used.

Woodbury provides citations[9] of patents for various advances in milling cutter design, including irregular spacing of teeth (1867), forms of inserted teeth (1872), spiral groove for breaking up the cut (1881), and others. He also provides a citation on how the introduction of vertical mills brought about wider use of the endmill and fly cutter types.[10]

This modular style of construction is appropriate for large milling cutters for about the same reason that large diesel engines use separate pieces for each cylinder and head whereas a smaller engine would use one integrated casting. Two reasons are that (1) for the maker it is more practical (and thus less expensive) to make the individual pieces as separate endeavors than to machine all their features in relation to each other while the whole unit is integrated (which would require a larger machine tool work envelope); and (2) the user can change some pieces while keeping other pieces the same (rather than changing the whole unit). One arbor (at a hypothetical price of USD100) can serve for various shells at different times. Thus 5 different milling cutters may require only USD100 worth of arbor cost, rather than USD500, as long as the workflow of the shop does not require them all to be set up simultaneously. It is also possible that a crashed tool scraps only the shell rather than both the shell and arbor. To also avoid damage to the shell, many cutters, especially in larger diameters, also have another replaceable part called the shim, which is mounted to the shell and the inserts are mounted on the shim. That way, in case of light damage, only the insert and maximum the shim needs replacement. The shell is safe. This would be like crashing a "regular" endmill and being able to reuse the shank rather than losing it along with the flutes.

Scientific study by Holz and De Leeuw of the Cincinnati Milling Machine Company[11] made the teeth even coarser and did for milling cutters what F.W. Taylor had done for single-point cutters with his famous scientific cutting studies.

Whereas a hob engages the work much as a mating gear would (and cuts the blank progressively until it reaches final shape), a thread milling cutter operates much like an endmill, traveling around the work in a helical interpolation.

Cutter location is the topic of where to locate the cutter in order to achieve the desired contour (geometry) of the workpiece, given that the cutter's size is non-zero. The most common example is cutter radius compensation (CRC) for endmills, where the centerline of the tool will be offset from the target position by a vector whose distance is equal to the cutter's radius and whose direction is governed by the left/right, climb/conventional, up/down distinction. In most implementations of G-code, it is G40 through G42 that control CRC (G40 cancel, G41 left/climb, G42 right/conventional). The radius values for each tool are entered into the offset register(s) by the CNC operator or machinist, who then tweaks them during production in order to keep the finished sizes within tolerance. Cutter location for 3D contouring in 3-, 4-, or 5-axis milling with a ball-endmill is handled readily by CAM software rather than manual programming. Typically the CAM vector output is postprocessed into G-code by a postprocessor program that is tailored to the particular CNC control model. Some late-model CNC controls accept the vector output directly, and do the translation to servo inputs themselves, internally.

Trepanning is also possible with a hollow mill. Special form blades can be used on a hollow mill for trepanning diameters, forms, and ring grooves.

There are several common standardized methods of mounting shell mills to their arbors. They overlap somewhat (not entirely) with the analogous joining of lathe chucks to the spindle nose.