[cnc1921]

Hello,

I'm studying the excellent book by Smid on gcoding.

on a lathe When doing an independent (of movement) compensation how does the control know in what direction to move
to compensate for the tool nose radius comp amount stored in the R column in the machine tool offset table - activated by the last two digits of the T command,
Since no G41,G42 command is given?
for instance - N1 G00 T0202.

please see below snippet from chapter describing lathe offsets:

I

Independent Tool Offset

For an independent offset entry in the program, tool offset
is applied together with tool indexing:
N34 G00 T0202
This command is usually programmed as the first block
for each tool (in a clear position).
At this point, the tool is still at its indexing position.When tool
offset is activated, it will cause a physical motion by the
amount stored in the offset register.

page 304 Chapter 34 cnc programming handbook peter smid third edition.

Thanks in advance for any replies!!

[rcs60]

there is a tool tip Orientation that you will need
in the wear offsets you should see x z r t
r= radius of tool
t= tool tip orientation generally this will be 0-9 positions
this t code will move the tool when cutter comp is called in the direction

[cnc1921]

Thanks!
I meant that if I call T0202 for example, since I called the comp by not writing T0200, the turret moves slightly still while located at machine zero.
as I understand, this tiny jumpy movement is due to moving the tool since R,T were activated.
But since no movement coupled with G41/G42 was programed, how the controller knows to what side to slightly move the turret, whether to move the insert further to the right of the workpiece or to the left of the workpiece?
Thanks! and sorry by my newbie misunderstandings..

[sinha_nsit]

When T0202 is commanded, the machine shifts the coordinate system appropriately, to suit tool no. 2.
This can be done in two ways:
1. coordinate display remaining same and tool moves
2. tool does not move and the coordinate display suitably changes.
Both are equivalent. The selection of method is parameter dependent.
This has nothing to do with G41/G42.

[cnc1921]

When T0202 is commanded, the machine shifts the coordinate system appropriately, to suit tool no. 2.
This can be done in two ways:
1. coordinate display remaining same and tool moves
2. tool does not move and the coordinate display suitably changes.
Both are equivalent. The selection of method is parameter dependent.
This has nothing to do with G41/G42.

Thanks very much! :)