Several types of endmills

An endmill is a type of milling cutter, a cutting tool used in industrial milling applications. It is distinguished from the drill bit, in its application, geometry, and manufacture. While a drill bit can only cut in the axial direction, a milling bit can generally cut in all directions, though some cannot cut axially.

Endmills are used in milling applications such as profile milling, tracer milling, face milling, and plunging.

Types[link]

Several broad categories of end- and face-milling tools exist, such as center-cutting versus non-center-cutting (whether the mill can take plunging cuts); and categorization by number of flutes; by helix angle; by material; and by coating material. Each category may be further divided by specific application and special geometry.

It is becoming increasingly common for traditional solid endmills to be replaced by more cost-effective inserted cutting tools (which, though more expensive initially, reduce tool-change times and allow for the easy replacement of worn or broken cutting edges rather than the entire tool).

Endmills are sold in both imperial and metric shank and cutting diameters. In the USA, metric is readily available, but it is only used in some machine shops and not others; in Canada, due to the country's proximity to the US, much the same is true. In Asia and Europe, while imperial is readily available, metric diameters are standard.

Geometry and tools[link]

A variety of grooves, slots, and pockets in the workpiece may be produced from a variety of tool bits. Common tool bit types are: square end cutters, ball end cutters, t-slot cutters, and shell mills. Square end cutters can mill square slots, pockets, and edges. Ball end cutters mill radiused slots or fillets. T-slot cutters mill exactly that: t-shaped slots. Shell end cutters are used for large flat surfaces and for angle cuts. There are variations of these tool types as well.

There are four critical angles of each cutting tool: end cutting edge angle, axial relief angle, radial relief angle, and radial rake angle. See graph for common values.

Depending on the material being milled, and what task should be performed, different tool types and geometry may be used. For instance, when milling a material like aluminium, it may be advantageous to use a tool with very deep, polished flutes and a very sharp cutting edge. When machining a tough material such as stainless steel, however, shallow flutes and a squared-off cutting edge will optimize material removal and tool life.

A wide variety of materials are used to produce the cutting tools. Carbide inserts are the most common because they are good for high production milling. High speed steel is commonly used when a special tool shape is needed, not usually used for high production processes. Ceramics inserts are typically used in high speed machining with high production. Diamond inserts are typically used on products that require tight tolerances, typically consisting of high surface qualities (nonferrous or nonmetallic materials). In the early 1990s, use of coatings to reduce wear and friction (among other things) became more common. Most of these coatings are referred to by their chemical composition, such as:

Aluminium Titanium Nitride (AlTiN) coated Endmills, coated using the Cathodic arc deposition technique

• TiN (a basic yellowish coating that has fallen out of wide use)
• TiCN (a popular bluish-grey coating)
• TiAlN and AlTiN (an extremely popular dark purple coating)
• TiAlCrN, AlTiCrN and AlCrTiN (PVD coating).
• PCD veins. Though not a coating some endmills are manufactured with a 'vein' of polycrystaline diamond. The vein is formed in a high temperature-high pressure environment. The vein is formed in a blank and then the material is ground out along the vein to form the cutting edge. The tools can be very costly, however can last many times longer than other tooling.

Advances in endmill coatings are being made, however, with coatings such as Amorphous Diamond and nanocomposite PVD coatings beginning to be seen at high-end shops (as of 2004).

Manufacture[link]

Endmills are typically made on CNC (Computer Numeric Control) controlled Tool and cutter grinder machines under high-pressure lubricants such as water, water-soluble oil, and high-flashpoint oil. Grinding inside the machine is accomplished with abrasive wheels mounted on a spindle (and in some cases, multiple spindles). Depending on what material is being ground, these wheels are made with industrial diamond (when grinding tungsten carbide), cubic boron nitride (when grinding cobalt steel), and other materials (when grinding, for instance, ceramics), set in a bond (sometimes copper).

See also[link]

• Burr (cutter)

References[link]

• Robert H. Todd, Dell K. Allen, Leo Alting, "Manufacturing Processes Reference Guide", Industrial Press Inc., New York, 1994 pg 49-53

Look up end in Wiktionary, the free dictionary.

End or Ending may refer to:

• End (philosophy)
• In mathematics:
  • End (category theory)
  • End (topology)
• End (American football)
• End, a division of play in the sports of curling and target archery
• End key on a modern computer keyboard
• End Records, a record label
• "End", a song by The Cure from Wish
• "End", a Song from Silent Night Fever by Dimension Zero
• End, in weaving, a single thread of the warp

END may refer to:

• European Nuclear Disarmament
• Endoglin, a glycoprotein
• Equivalent narcotic depth, a concept used in underwater diving

Ending may refer to:

• Ending (linguistics)
• Alternate ending
• End of a part of a baseball game
• False ending
• Happy ending
• Multiple endings
• Twist ending
• Endings (film)

See also[link]

• All pages beginning with "End"
• All pages with titles containing "End"
• The End (disambiguation)
• End of the world (disambiguation)
• Front end (disambiguation)
• Boundary (disambiguation)
• Telos (philosophy), a goal or final state
• Conclude (disambiguation)
• Terminate (disambiguation)

This disambiguation page lists articles associated with the same title. If an internal link led you here, you may wish to change the link to point directly to the intended article.

Look up mill in Wiktionary, the free dictionary.

Wikisource has the text of the 1911 Encyclopædia Britannica article Mill.

Mill may refer to:

• Mill (grinding), an equipment for the grinding or pulverizing of grain and other raw materials using millstones
• Milling machine, metalworking machine that operates by rotating a cutting bit while the workpiece is moved against the cutter on an XY table.
• Mill (computing)
  • Arithmetic logic unit, used in the context of Charles Babbage's Analytical engine, a 19th century concept of a computer
  • an early term for the central processing unit of a digital computer, especially in early British machines; the term is still occasionally used to refer to the CPU resources consumed by a program
• Mill (currency), a denomination used by some currencies, the equivalent of a tenth of a cent or penny, or a thousandth of the currency unit
• Diploma mill or degree mill, an organization which awards academic degrees and diplomas with very little or no academic study and without recognition by official accrediting bodies
• Nine Men's Morris, a traditional board game; the term "mill" may also mean "three (playing pieces) in a row" within the game
• Windmill (breakdance move) or mill, a power move in breakdancing
• The Mill (post-production), a visual effects company
• a manual typewriter
• the standard author abbreviation Mill. that may be used to indicate botanist Philip Miller's work when citing a botanical name
• a slang term for any internal combustion engine used on a hot rod, or other sort of customised personal vehicle.[1]
• Millage, a property tax
• Wet mill, a device that steeps a substance in water to remove specific compounds
• Cutting mill, a device commonly used in laboratories for the preliminary size reduction of materials
• Certain kinds of factories, such as steel mill, sugar mill, and cotton mill

People named Mill:

• Andy Mill (born 1953), a skier
• Frank Mill (born 1958), a German football player (World Cup winner, Summer Olympics bronze medalist)
• Harriet Taylor Mill (1807–1858), a philosopher and women's rights advocate
• James Mill (1773–1836), a Scottish historian, economist and philosopher
• John Mill (theologian) (c. 1645–1707), an English theologian and author of Novum Testamentum Graecum
• John Stuart Mill (1806–1873), an influential classical liberal thinker and philosopher of the 19th century, son of James Mill

Mill in geography:

• Mill, Netherlands, a Dutch village
• Mill en Sint Hubert, a Dutch municipality

MILL may refer to:

• Major Indoor Lacrosse League, the American indoor lacrosse league, rebranded in 1997 as the National Lacrosse League

See also[link]

• Mil (disambiguation)
• Mille (disambiguation)
• Mills (disambiguation)
• Miller (disambiguation)
• Milling (disambiguation)

This disambiguation page lists articles associated with the same title. If an internal link led you here, you may wish to change the link to point directly to the intended article.