43.2 NUMERICAL CONTROL (NC)
· The use of numerical data to drive a machine for processes such as,
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- milling
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- turning
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- drilling
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- grinding
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- shot peening
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- tube bending
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- flame cutting
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- automated knitting machines
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- automatic riveting
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- etc.
· Basic components of NC systems,
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- program
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- controller unit
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- machine tool
· Most suited to,
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- parts are processed frequently in small lot sizes
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- complex part geometry
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- close tolerances on workpart
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- many operations on part in processing
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- large amounts of metal to be removed
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- engineering design will possibly change
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- parts that are too expensive for mistakes
· The methods for developing NC programs include,
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- manual part programming
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- computer-assisted part programming
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- computer generated programs
· The manual and computer aided methods use various NC programming languages,
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- APT (Automatically Programmed Tools)
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- AUTOSPOT (Automatic System for Positioning Tools)
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- SPLIT (Sundstrand Processing Language Internally Translated)
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- COMPACT II
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- ADAPT (ADaptation of APT)
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- EXAPT (Extended Subset of APT)
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- UNIAPT
· These languages are used by a parts programmer to define the motion of the cutting tool.
· The languages may be preprocessed, and then used for a number of various control types, such as,
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- punched paper tape
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- Computer Numerical Control (CNC)
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- Direct Numerical Control (DNC)
· The automatic methods work with geometry created in a CAD program.
