glossary.lyx

CNC 的开放码,EMC2 V2.2.8版

#LyX 1.3 created this file. For more info see http://www.lyx.org/
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\language english
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\layout Chapter

Glossary
\layout Standard

A listing of terms and what they mean.
 Some terms have a general meaning and several additional meanings for users,
 installers, and developers.
 
\begin_inset Note
collapsed false

\layout Standard

This pattern uses the Description paragraph style
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rather than the standard style.
\layout Standard

It also uses each term as a Label so that one term can
\layout Standard

easily refer to another using a cross reference.
\layout Standard

Cross references need a space ahead and after
\layout Standard

so that they look good in the published documents.
\end_inset 


\layout Description

Acme\SpecialChar ~
Screw
\begin_inset LatexCommand \index{acme screw}

\end_inset 


\begin_inset LatexCommand \label{AcmeScrew}

\end_inset 

 A type of lead-screw that uses an acme thread form.
 Acme threads have somewhat lower friction and wear than simple triangular
 threads, but ball-screws are lower yet.
 Most manual machine tools use acme lead-screws.
\layout Description

Axis
\begin_inset LatexCommand \index{axis}

\end_inset 


\begin_inset LatexCommand \label{Axis}

\end_inset 

 One of the computer control movable parts of the machine.
 For a typical vertical mill, the table is the X axis, the saddle is the
 Y axis, and the quill or knee is the Z axis.
 Additional linear axes parallel to X, Y, and Z are called U, V, and W respectiv
ely.
 Angular axes like rotary tables are referred to as A, B, and C.
\layout Description

Backlash
\begin_inset LatexCommand \index{backlash}

\end_inset 


\begin_inset LatexCommand \label{Backlash}

\end_inset 

 The amount of "play" or lost motion that occurs when direction is reversed
 in a lead screw.
 or other mechanical motion driving system.
 It can result from nuts that are loose on leadscrews, slippage in belts,
 cable slack, "wind-up" in rotary couplings, and other places where the
 mechanical system is not "tight".
 Backlash will result in inaccurate motion, or in the case of motion caused
 by external forces (think cutting tool pulling on the work piece) the result
 can be broken cutting tools.
 This can happen because of the sudden increase in chip load on the cutter
 as the work piece is pulled across the backlash distance by the cutting
 tool.
 
\layout Description

Backlash\SpecialChar ~
Compensation
\begin_inset LatexCommand \index{backlash compensation}

\end_inset 

 - Any technique that attempts to reduce the effect of backlash without
 actually removing it from the mechanical system.
 This is typically done in software in the controller.
 This can correct the final resting place of the part in motion but fails
 to solve problems related to direction changes while in motion (think circular
 interpolation) and motion that is caused when external forces (think cutting
 tool pulling on the work piece) are the source of the motion.
\layout Description

Ball\SpecialChar ~
Screw
\begin_inset LatexCommand \index{ball screw}

\end_inset 


\begin_inset LatexCommand \label{Ballscrew}

\end_inset 

 A type of lead-screw that uses small hardened steel balls between the nut
 and screw to reduce friction.
 Ball-screws have very low friction and backlash, but are usually quite
 expensive.
\layout Description

Ball\SpecialChar ~
Nut
\begin_inset LatexCommand \index{ball nut}

\end_inset 


\begin_inset LatexCommand \label{Ballnut}

\end_inset 

 A special nut designed for use with a ball-screw.
 It contains an internal passage to re-circulate the balls from one end
 of the screw to the other.
\layout Description

CNC
\begin_inset LatexCommand \index{CNC}

\end_inset 


\begin_inset LatexCommand \label{CNC}

\end_inset 

 Computer Numerical Control.
 The general term used to refer to computer control of machinery.
 Instead of a human operator turning cranks to move a cutting tool, CNC
 uses a computer and motors to move the tool, based on a part program.
\layout Description

Coordinate\SpecialChar ~
Measuring\SpecialChar ~
Machine
\begin_inset LatexCommand \index{coordinate measuring machine}

\end_inset 

 A Coordinate Measuring Machine is used to make many accurate measurements
 on parts.
 These machines can be used to create CAD data for parts where no drawings
 can be found, when a hand-made prototype needs to be digitized for mold
 making, or to check the accuracy of machined or molded parts.
 
\layout Description

Display\SpecialChar ~
units
\begin_inset LatexCommand \index{display units}

\end_inset 

 The linear and angular units used for onscreen display.
\layout Description

DRO
\begin_inset LatexCommand \index{DRO}

\end_inset 

 A Digital Read Out is a device attached to the slides of a machine tool
 or other device which has parts that move in a precise manner to indicate
 the current location of the tool with respect to some reference position.
 Nearly all DRO's use linear quadrature encoders to pick up position information
 from the machine.
 
\layout Description

EDM
\begin_inset LatexCommand \index{EDM}

\end_inset 

 EDM is a method of removing metal in hard or difficult to machine or tough
 metals, or where rotating tools would not be able to produce the desired
 shape in a cost-effective manner.
 An excellent example is rectangular punch dies, where sharp internal corners
 are desired.
 Milling operations can not give sharp internal corners with finite diameter
 tools.
 A wire EDM machine can make internal corners with a radius only slightly
 larger than the wire's radius.
 A 'sinker' EDM cam make corners with a radius only slightly larger than
 the radius on the corner of the convex EDM electrode.
 
\layout Description

EMC
\begin_inset LatexCommand \index{EMC}

\end_inset 


\begin_inset LatexCommand \label{EMC}

\end_inset 

 The Enhanced Machine Controller.
 Initially a NIST project.
 EMC is able to run a wide range of motion devices.
\layout Description

EMCIO
\begin_inset LatexCommand \index{EMCIO}

\end_inset 


\begin_inset LatexCommand \label{EMCIO}

\end_inset 

 The module within EMC that handles general purpose I/O, unrelated to the
 actual motion of the axes.
\layout Description

EMCMOT
\begin_inset LatexCommand \index{EMCMOT}

\end_inset 


\begin_inset LatexCommand \label{EMCMOT}

\end_inset 

 The module within EMC that handles the actual motion of the cutting tool.
 It runs as a real-time program and directly controls the motors.
\layout Description

Encoder
\begin_inset LatexCommand \index{encoder}

\end_inset 


\begin_inset LatexCommand \label{Encoder}

\end_inset 

 A device to measure position.
 Usually a mechanical-optical device, which outputs a quadrature signal.
 The signal can be counted by special hardware, or directly by the parport
 with EMC2.
\layout Description

Feed
\begin_inset LatexCommand \index{feed}

\end_inset 


\begin_inset LatexCommand \label{Feed}

\end_inset 

 Relatively slow, controlled motion of the tool used when making a cut.
\layout Description

Feed\SpecialChar ~
rate
\begin_inset LatexCommand \index{feed rate}

\end_inset 

 The speed at which a motion occurs.
 In manual mode, jog speed can be set from the graphical interface.
 In auto or mdi mode feed rate is commanded using a (f) word.
 F10 would mean ten units per minute.
\layout Description

Feedback
\begin_inset LatexCommand \index{feedback}

\end_inset 


\begin_inset LatexCommand \label{Feedback}

\end_inset 

 A method (e.g., quadrature encoder signals) by which EMC receives information
 about the position of motors
\layout Description

Feed\SpecialChar ~
rate\SpecialChar ~
Override
\begin_inset LatexCommand \index{feed override}

\end_inset 


\begin_inset LatexCommand \label{FeedrateOveride}

\end_inset 

 A manual, operator controlled change in the rate at which the tool moves
 while cutting.
 Often used to allow the operator to adjust for tools that are a little
 dull, or anything else that requires the feed rate to be 
\begin_inset Quotes eld
\end_inset 

tweaked
\begin_inset Quotes erd
\end_inset 

.
\layout Description

G-Code
\begin_inset LatexCommand \index{G-Code}

\end_inset 


\begin_inset LatexCommand \label{G-Code}

\end_inset 

 The generic term used to refer to the most common part programming language.
 There are several dialects of G-code, EMC uses RS274/NGC.
\layout Description

GUI
\begin_inset LatexCommand \label{GUI}

\end_inset 


\begin_inset LatexCommand \index{GUI}

\end_inset 

 Graphical User Interface.
 
\begin_deeper 
\layout Description

General A type of interface that allows communications between a computer
 and human (in most cases) via the manipulation of icons and other elements
 (widgets) on a computer screen.
\layout Description

EMC An application that presents a graphical screen to the machine operator
 allowing manipulation of machine and the corresponding controlling program.
\end_deeper 
\layout Description