# Spindle feed link (FEED_LINK)

Normally, the speed of a spindle is only controlled by the program. In general, there are no other options to influence spindle speed depending on other parameters. For some special technologies (e.g. HSC milling, edge banding in wood machining) and to obtain a uniform milling profile on the workpiece surface, it is necessary to influence spindle speed by external variables.

The following command can link the spindle-specific speed dynamically to path feed by specifying various parameters. When set accordingly, the spindle speed then adapts automatically to various feedrates. This is necessary in particular for materials which may be damaged by unsuitable cutting parameters (e.g. scorch marks on wooden workpieces or melted plastic etc.).

## Attention

Spindle dynamic data are not considered. To avoid excessive deviation between the commanded and the actual link factors during active feed linking, the user must ensure that either the spindle dynamic is high enough or the path dynamic is reduced depending on the requirements.

Syntax for programming a spindle feed link:
<spindle_name> [ FEED_LINK [ON | OFF] [ [ [FACT=..] [CORR=..] ] | AUTO] [MAIN] SRC=.. ]

<spindle_name> | Name of the feed link spindle
FEED_LINK | Identifier for spindle feed link. Must always be programmed as the first keyword.
ON | Select spindle feed link
OFF | Deselect spindle feed link
FACT=.. | Synchronised link: Predefined link factor in [0.1%] between path feed (F word) and the basic spindle speed. The link factor can be reprogrammed at any time during active linking.
CORR=.. | Correction factor in [0.1%] to modify the link factor. The resulting link factor then results from the product of FACT and CORR (priority = FACT*CORR).
AUTO | Link on the fly: The link factor is calculated automatically from the current commanded spindle speed and the current path feed and it remains constant until the link is deselected.
MAIN | Spindle feed link is only effective if at least one main axis is involved in motion. The spindle speed is not influenced if only tracking axes are moved.
SRC=.. | Identifier of feed link source:

- FEED_VEL – path feed (default)
- EDGE_VEL – edge velocity for edge banding

- The keyword AUTO can only be programmed in combination with ON. FACT and CORR can even be reprogrammed while a feed link is active.
- The keyword MAIN can only be programmed in combination with ON.
- When the link is selected, the spindle must be in the state of endless rotation at a sped of !=0. The path feed must also be !=0 when the link factor is defined automatically.
- The spindle speed which is active when the feed link is deselected is retained as the commanded spindle speed. If necessary, the spindle speed must be redefined using the S word after the feed link is deselected.

## Attention

A spindle command via the S word has no effect when the feed link is active.

## Notice

A tool with dynamic parameters is to be defined and activated. The minimum speed of this tool (P-TOOL-00013) can in general prevent the spindle from coming to a standstill or jamming while milling with active feed link at path velocity = 0.

## Programing Example

Example 1

Manually programmed link factor, the effective link factor is changed by programming the correction factor

%feed_link1

N10 G00 X0 Y0 Z0

N20 G01 G90 X20 F2

N30 M03 S15

N40 G01 G90 X40

N50 S[FEED_LINK ON FACT=500]

N60 G01 G91 X5 F2

N70 S[FEED_LINK CORR=1100]

N80 X10 F2

N90 S[FEED_LINK CORR=900]

N100 X20 F2

N110 S[FEED_LINK CORR=1100]

N120 X40 F2

N130 S[FEED_LINK CORR=900]

N140 X80 F2

N150 S[FEED_LINK CORR=1100]

N160 X40 F2

N170 S[FEED_LINK CORR=900]

N180 X20 F2

N190 S[FEED_LINK CORR=1100]

N200 X5 F2

N210 S[FEED_LINK OFF]

N220 M30

## Programing Example

Example 2

Link factor is generated automatically from the current commanded spindle speed and the current path feed.

%feed_link2

N10 G00 X0 Y0 Z0

N20 G01 G90 X20 F1

N30 M03 S15

N40 G01 G90 X40

N50 S[FEED_LINK ON AUTO]

N60 G01 G91 X5 F1

N70 X10 F2

N80 X20 F4

N90 X40 F8

N100 X80 F16

N110 X40 F8

N120 X20 F4

N130 X10 F2

N140 X5 F1

N150 S[FEED_LINK OFF]

N160 M30

## Programing Example

Example 3

Link factor is generated automatically, feed link only acts with main axis motions.

%feed_link3

N10 M03 S200

N20 G01 X0 Y0 Z0 C0 F10

N30 S[FEED_LINK ON AUTO MAIN]

N40 G01 X50

N50 G01 X70 Y30

N60 G01 C45 ;Spindle speed remains constant

N70 G01 Z40 F15

N80 G01 Z60

N90 G01 C90 ;Spindle speed remains constant

N100 G01 C120 ;Spindle speed remains constant

N110 G01 X50 Y50 Z50

N120 S[FEED_LINK OFF]

N130 M03 S200

N140 G01 X10

N150 M05 S0

N160 M30