View Full Version : contour pre-calculation in G41 mode

Bertram BKZ
12-05-2011, 04:39 PM

How is the Heidenhain command M120 LA30 called on a Siemens 840D ?
With Heidenhain, the user is able to enter a desired number of contour elements for the pre-calculation “Look-Ahead” with M120 LA30 ( here 30 -99 blocks).

How do I program that function with Sinumerik 840D milling?

12-11-2011, 09:10 AM

First of all M120 is a PLC macro- so a machine function and with the sinumerik its in the hand of the machine manufacturer...
LookAhead depends on the size of the interpolation buffer (IPO buffer) and should have a reasonable value which the manufacturer already set up.

In the optimal “mould making packet”. There are several possibilities to optimise quality, accuracy and dynamic.
If that option is not paid for, then you can also do it manually. You should have a read in the manual basic function in the chapter “path control mode” about the benefits and disadvantages of a manual change of the IBO buffer size.. and have a look what other speed optimisation methods are available.