mill_canned.lyx

CNC 的开放码,EMC2 V2.2.8版

 Dwell for the given number of seconds.
 
\layout Standard

3.
 Stop the spindle turning.
 
\layout Standard

4.
 Retract the Z-axis at traverse rate to clear Z.
 
\layout Standard

5.
 Restart the spindle in the direction it was going.
 This cycle is very similar to g82 except that it stops the spindle before
 it retracts the tool and restarts the spindle when it reaches the clearance
 value R.
\layout Section

G87
\begin_inset LatexCommand \index{G87}

\end_inset 


\layout Standard

The G87 cycle is intended for back boring.
 
\layout Standard

The situation is that you have a through hole and you want to counter bore
 the bottom of hole.
 To do this you put an L-shaped tool in the spindle with a cutting surface
 on the UPPER side of its base.
 You stick it carefully through the hole when it is not spinning and is
 oriented so it fits through the hole, then you move it so the stem of the
 L is on the axis of the hole, start the spindle, and feed the tool upward
 to make the counter bore.
 Then you stop the tool, get it out of the hole, and restart it.
 
\layout Standard

This cycle uses I and J values to indicate the position for inserting and
 removing the tool.
 I and J will always be increments from the X position and the Y position,
 regardless of the distance mode setting.
 This cycle also uses a K value to specify the position along the Z-axis
 of the top of counterbore.
 The K value is an absolute Z-value in absolute distance mode, and an increment
 (from the Z position) in incremental distance mode.
 
\layout Standard

0.
 Preliminary motion, as described above.
 
\layout Standard

1.
 Move at traverse rate parallel to the XY-plane to the point indicated by
 I and J.
 
\layout Standard

2.
 Stop the spindle in a specific orientation.
 
\layout Standard

3.
 Move the Z-axis only at traverse rate downward to the Z position.
 
\layout Standard

4.
 Move at traverse rate parallel to the XY-plane to the X,Y location.
 
\layout Standard

5.
 Start the spindle in the direction it was going before.
 
\layout Standard

6.
 Move the Z-axis only at the given feed rate upward to the position indicated
 by K.
 
\layout Standard

7.
 Move the Z-axis only at the given feed rate back down to the Z position.
 
\layout Standard

8.
 Stop the spindle in the same orientation as before.
 
\layout Standard

9.
 Move at traverse rate parallel to the XY-plane to the point indicated by
 I and J.
 
\layout Standard

10.
 Move the Z-axis only at traverse rate to the clear Z.
 
\layout Standard

11.
 Move at traverse rate parallel to the XY-plane to the specified X,Y location.
 
\layout Standard

12.
 Restart the spindle in the direction it was going before.
\layout Standard
\added_space_top 0.3cm \added_space_bottom 0.3cm \align center 

\begin_inset Graphics
	filename G87pre.png

\end_inset 


\layout Standard

Example 6 - Backbore
\layout Standard

Example six uses a incremental distances from (0, 0, 0) so the preliminary
 moves look much like those in example five but they are done using the
 G87 backbore canned cycle.
\layout Standard

G91 G87 M3 S1000 X1 Y1 Z-0.4 R1.4 I-0.1 J-0.1 K-0.1
\layout Standard


\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "60col%"
collapsed false

\layout Standard

You will notice that the preliminary moves shift the tool to directly above
 the center axis of the existing bore.
\layout Standard

Next it increments that location by the I and J values.
 I offsets X with a plus value being added to the current X.
 J does the same for the Y axis.
 
\layout Standard

For our example block both I and J are negative so they move back from the
 hole axis along the path just made by the tool.
 The amount of offset required should be just enough that the tool tip will
 slide down through the bore.
\end_inset 


\hfill 

\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "40col%"
collapsed false

\layout Standard
\added_space_top 0.3cm \added_space_bottom 0.3cm \align center 

\begin_inset Graphics
	filename G87s1.png
	width 2in

\end_inset 


\end_inset 


\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "60col%"
collapsed false

\layout Standard

Next the canned cycle moves the tool down in z and at the bottom location
 represented in the block by the Z 0.4 value it moves the tool back to the
 center of the bore.
\end_inset 


\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "40col%"
collapsed false

\layout Standard
\added_space_top 0.3cm \added_space_bottom 0.3cm \align center 

\begin_inset Graphics
	filename G87s5.png
	width 2in

\end_inset 


\end_inset 


\layout Standard

Now the g87 canned cycle turns the spindle on and moves back up into the
 bore at the programmed feed rate.
 This is the real cutting action of this canned cycle.
 With the proper tool in a boring bar this cycle will produce a chamfer
 on the bottom side of the bore.
 G87 can also be used to produce a larger diameter bore on the bottom side
 of the bore.
 
\layout Standard


\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "60col%"
collapsed false

\layout Standard

When the tool has reached the K position it is returned to the bottom location,
 the spindle is stopped and oriented and follows the earlier path back out
 of the bore to the initial position above.
 
\end_inset 


\hfill 

\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "40col%"
collapsed false

\layout Standard
\added_space_top 0.3cm \added_space_bottom 0.3cm \align center 

\begin_inset Graphics
	filename G87s12.png
	width 2in

\end_inset 


\end_inset 


\layout Standard

This canned cycle assumes spindle orientation which has not been implemented
 in the EMC to date.
 The proper alignment of the tool tip to the oriented spindle is critical
 to the successful insertion of the tool through the hole to be backbored.
\layout Section

G88
\begin_inset LatexCommand \index{G88}

\end_inset 


\layout Standard

The G88 cycle is intended for boring.
 This cycle uses a P value, where P specifies the number of seconds to dwell.
\layout Standard

0.
 Preliminary motion, as described above.
\layout Standard

1.
 Move the Z-axis only at the current feed rate to the Z position.
\layout Standard

2.
 Dwell for the given number of seconds.
\layout Standard

3.
 Stop the spindle turning.
\layout Standard

4.
 Stop the program so the operator can retract the spindle manually.
\layout Standard

5.
 Restart the spindle in the direction it was going.
 It is unclear how the operator is to manually move the tool because a change
 to manual mode resets the program to the top.
 We will attempt to clarify that step in this procedure.
\layout Section

G89 Cycle
\layout Standard

The G89
\begin_inset LatexCommand \index{G89}

\end_inset 

 cycle is intended for boring.
 This cycle uses a P value, where P specifies the number of seconds to dwell.
\layout Standard

0.
 Preliminary motion, as described above.
\layout Standard

1.
 Move the Z-axis only at the current feed rate to the Z position.
\layout Standard

2.
 Dwell for the given number of seconds.
\layout Standard

3.
 Retract the Z-axis at the current feed rate to clear Z.
 This cycle is like G82 except that the tool is drawn back at feed rate
 rather than rapid.
\layout Section

G98 G99
\layout Standard


\begin_inset Note
collapsed false

\layout Standard

needs a diagram or something to clear this up also compare with trunk
\end_inset 


\layout Standard

G98
\begin_inset LatexCommand \index{G98}

\end_inset 

 - initial level return in canned cycles 
\layout Standard

G99
\begin_inset LatexCommand \index{G99}

\end_inset 

 - R value return in canned cycles 
\layout Standard

These codes are treated together because they behave very much alike.燳ou
 will recall that when Z is above R the preparatory move is from the current
 location to the X, Y values.
 If G98 is not specified, then the canned cycle will return to the R value
 rather than the Z value that was used on the approach.
\layout Standard


\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "60col%"
collapsed false

\layout Standard

N01 G0 X1 Y2 Z3 
\layout Standard

N02 G90 G81 X4 Y5 Z-0.6 R1.8 F10
\layout Standard

Adding G98 to the second line above means that the return move will be to
 the value of OLD_Z since it is higher that the R value specified.
\end_inset 


\hfill 

\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "40col%"
collapsed false

\layout Standard
\added_space_top 0.3cm \added_space_bottom 0.3cm \align center 

\begin_inset Graphics
	filename G81ret.png
	width 2in

\end_inset 


\end_inset 


\layout Standard

Neither code will have any affect when incremental moves with a positive
 R value are specified because the R value is added to OLD_Z and that result
 is used as the initial level for a G98.
 The same value is the computed R value so G99 will also return to the same
 place.
 
\layout Standard


\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "60col%"
collapsed false

\layout Standard
\align left 
When the value of R is less than OLD_Z and incremental distance mode is
 turned on, G98 will return the tool to the value of OLD_Z.
 Under those conditions G99 will retract the tool to OLD_Z plus the negative
 R value.
 The return will be below OLD_Z.
\end_inset 


\hfill 

\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "40col%"
collapsed false

\layout Standard
\added_space_top 0.3cm \added_space_bottom 0.3cm \align center 

\begin_inset Graphics
	filename G81g98d.png
	width 2in

\end_inset 


\end_inset 


\layout Section

Why use a canned cycle?
\layout Standard

There are at least two reasons for using canned cycles.
 The first is the economy of code.
 A single bore would take several lines of code to execute.
\layout Standard

Example 1 above demonstrated how a canned cycle could be used to produce
 8 holes with ten lines of nc code within the canned cycle mode.
 The program below will produce the same set of 8 holes using five lines
 for the canned cycle.
 It does not follow exactly the same path nor does it drill in the same
 order as the earlier example.
 But the program writing economy of a good canned cycle should be obvious.
 
\layout Standard


\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "60col%"
collapsed false

\layout Standard
\align left 
Example 7 - Eight Holes Revisited 
\layout Standard
\align left 

\family typewriter 
\size footnotesize 
n100 g90 g0 x0 y0 z0 (move coordinate home) 
\layout Standard
\align left 

\family typewriter 
\size footnotesize 
n110 g1 f10 x0 g4 p0.1 
\layout Standard
\align left 

\family typewriter 
\size footnotesize 
n120 g91 g81 x1 y0 z-1 r1 l4(canned drill cycle) 
\layout Standard
\align left 

\family typewriter 
\size footnotesize 
n130 g90 g0 x0 y1 
\layout Standard
\align left 

\family typewriter 
\size footnotesize 
n140 z0 
\layout Standard
\align left 

\family typewriter 
\size footnotesize 
n150 g91 g81 x1 y0 z-.5 r1 l4(canned drill cycle) 
\layout Standard
\align left 

\family typewriter 
\size footnotesize 
n160 g80 (turn off canned cycle) 
\layout Standard
\align left 

\family typewriter 
\size footnotesize 
n170 m2 (program end)
\end_inset 


\hfill 

\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "40col%"
collapsed false

\layout Standard
\added_space_top 0.3cm \added_space_bottom 0.3cm \align center 

\begin_inset Graphics
	filename Eight.png
	width 2in

\end_inset 


\end_inset 


\layout Standard

Example 8 - Twelve holes in a square 
\layout Standard

This example demonstrates the use of the L word to repeat a set of incremental
 drill cycles for successive blocks of code within the same G81 motion mode.
 Here we produce 12 holes using five lines of code in the canned motion
 mode.
 
\layout Standard


\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "60col%"
collapsed false

\layout Standard


\family typewriter 
\size small 
N1000 G90 G0 X0 Y0 Z0 (move coordinate home)
\newline 
N1010 G1 F50 X0 G4 P0.1
\newline 
N1020 G91 G81 X1 Y0 Z-0.5 R1 L4 (canned drill cycle)
\newline 
N1030 X0 Y1 R0 L3 (repeat)
\newline 
N1040 X-1 Y0 L3 (repeat)
\newline 
N1050 X0 Y-1 L2 (repeat)
\newline 
N1060 G80 (turn off canned cycle)
\newline 
N1070 G90 G0 X0 (rapid home)
\newline 
N1080 Y0
\newline 
N1090 Z0
\newline 
N1100 M2 (program end)
\end_inset 


\hfill 

\begin_inset Minipage
position 1
inner_position 0
height "0pt"
width "40col%"
collapsed false

\layout Standard
\added_space_top 0.3cm \added_space_bottom 0.3cm \align center 

\begin_inset Graphics
	filename Twelve.png
	width 2in

\end_inset 


\end_inset 


\layout Standard

The second reason to use a canned cycle is that they all produce preliminary
 moves and returns that you can anticipate and control regardless of the
 start point of the canned cycle.
\layout Comment

Credits 
\layout Comment

This page is a rather direct rip off of the relevant portion of the RS274NGC/RS2
74VGER documents from NIST.
 Thanks also to Dan Falck, Ron Wickersham, and Jon Elson for their comments
 on portions of this page.
 
\layout Comment

This page is maintained by Ray Henry Your comments and criticisms are welcome.
\the_end