文档介绍：英语原文
ＮＵＭＥRＩCＡL ＣＯNTＲＯＬ
Nuｍerｉｃal coｎtｒｏｌ（Ｎ／C)iｓ ａ form oｆ pｒｏgｒammaｂlｅ ａutoｍａｔｉoｎ ｉn wｈiｃh tｈe ｐrocessing ｅqｕiｐmeｎt is ｃonｔｒoｌled ｂｙ meanｓ ｏf nｕmbers, leｔｔｅrs, aｎｄ otｈｅr syｍbｏｌｓ, Tｈe numｂeｒs, letters, aｎd symｂｏls aｒｅ ｃoded in an appropｒｉａte ｆormat to deｆine a ｐｒｏｇｒaｍ of iｎｓtrｕcｔionｓ for a particulaｒ ｗｏｒｋ pａｒｔ or job. When tｈｅ ｊob chａnges, tｈe prｏgrａm ｏf ｉnｓｔｒucｔioｎs is changeｄ． Thｅ cａｐabｉlitｙ tｏ chaｎgｅ tｈe proｇｒam is ｗhat makes N/C ｓuitaｂlｅ ｆｏr low－ａnd mｅｄium-voｌｕme proｄuｃｔion. Iｔ is mｕch ｅasｉer tｏ wrｉtｅ proｇｒamｓ ｔｈan tｏ ｍake ｍaｊoｒ alteｒations oｆ tｈe ｐroceｓｓing eqｕｉｐmｅnt．
Ｔｈere arｅ twｏ bａsic typeｓ oｆ numericａlly cｏntrｏｌｌｅｄ mａchｉｎe ｔｏｏｌs:ｐｏｉｎt—ｔo—ｐoｉｎt ａnd ｃoｎtinuoｕs—pａth(ａlsｏ ｃａｌled coｎｔouring）.Ｐoint—ｔｏ—poinｔ machines ｕｓｅ ｕnsｙｎchｒonｉzｅd ｍoｔｏrｓ, wｉtｈ tｈe reｓｕｌｔ thaｔ thｅ positｉｏn oｆ tｈe machｉning hｅａd Caｎ ｂｅ ａsｓureｄ ｏnｌｙ ｕpｏn cｏｍpｌｅｔｉon of ａ movｅｍenｔ, or whｉｌe onｌy oｎe mｏｔｏr ｉs ruｎninｇ. Macｈines of this tｙpｅ arｅ pｒiｎｃｉｐalｌｙ used ｆｏｒ ｓtｒaｉｇht—liｎｅ cｕts oｒ for ｄriｌliｎｇ oｒ bｏriｎｇ．
Ｔｈe Ｎ／C syｓtem conｓiｓｔs of the fｏｌlｏwｉnｇ comｐｏnents:dａtａ inｐut, tｈe tａpｅ rｅaｄeｒ wｉｔh ｔhe cｏｎtrｏｌ ｕnｉｔ, ｆeedｂacｋ ｄｅviceｓ, ａnd thｅ meｔal—ｃutｔing machiｎｅ ｔool or other type of Ｎ/C equiｐｍｅｎt.
Ｄatａ inpｕｔ, alｓo ｃａｌlｅd “ｍan—ｔo—conｔｒoｌ link”, maｙ ｂe pｒoviｄｅd tｏ ｔｈe machinｅ ｔｏol ｍanuaｌｌy, ｏｒ enｔirｅｌy by auｔｏmａtic ｍeａnｓ. Maｎual ｍｅｔhodｓ when usｅd ａs tｈｅ ｓolｅ ｓouｒｃe ｏf inpuｔ data aｒe ｒesｔｒｉcｔｅd to a ｒelａｔivｅ