Fanuc Look Ahead

I have some questions about Fanuc look ahead. For reference I have a 0iMD control.

As I understand it there are a few different levels of look ahead which may be factory installed depending on what the machine tool builder has spec'ed out.

Using parameter 1604 one can turn on AICC so that the control is always looking ahead during milling moves (this is G05.1). Is there a reason not to leave this turned on all the time? (when enabled AICC flashes in the lower right corner of the display so I assume it is working)

Looking at some other information G05.1 is further modified by an R (or Q?) value which specifies defaulting toward speed or accuracy. If parameter 1604 is modified such that G05.1 is always on during feed what is its default R (or Q?) value? How does one modify the R (or Q?) value in this scenario?

G322 R4
Default was R3 on my Machine.

The R value for G05.1 is indeed set by the MTB, but only in the manner that Accell?Decell is affected. The MTB will set these values at the factory and are set in other parameters and can be changed. I'm not suggesting changing them. But there really is a very narrow range to set these to and most MTB's will be pretty conservative. You will know if they are set wrong because your toolpath will show it. When AICC is turned on without an R value, it will use the last value used unless you specify an R0. The Q value is only a switch, (1)on or (0)off, If you have the option installed, Q3 will turn on Nano Smoothing, which is an even higher level of AICC used mostly for full 3D or 5 axis machining.

The line of code should be G05.1 Q1 R?? where ?? is 1 through 10. Speed or quality.
To turn it off, G05.1 Q0.

There are some instances where AICC will cause a cycle time penalty because the look ahead will slow the machine down in circumstances such as acute angle changes and 3D contouring. So, no, you may not want to use it all the time. I do not use it on simple 2D contouring or when feeds are low enough that the machine can handle it no matter what.

There is a lot more to AICC, I suggest reading up on it to gain the most benefit.

Paul

LockNut said:

......There is a lot more to AICC, I suggest reading up on it to gain the most benefit.

Click to expand...

Because of this, some builders have implemented it as a range of M codes to assign different values depending on desired behavior.