Changing home position

[positiverake]

How do I change home position on a Fanuc OT and 18T this is for 3 nakamura lathes, we run some cut off tools that are a bit long for the machine and my operators are always indexing them into the sheet metal, I guess I could set the G30 and use that, but it still would not stop them from doing it in manual.

[tobyaxis]

Look in the Fanuc Manual for the G22 G23 Stroke Limit/Barrier. Setting this properly will keep the operators from hitting the walls in the machines.

I have never used it, but read about it a few times. It may work for your situation.

[guhl]

I'm not sure
may be grid shifting can help

[positiverake]

Does the Grid shift change the center line of the machine or just the ref. return point? I guess I can try it and find out, thanks for the info.

[Joemachine]

I believe that you can change the soft over travel limit with a parameter change. I have used this method to control the z travel limit when using an automatic work shift when making several ring type parts on 5-6 inch long blanks on Fanuc 10T and OT Nakamura lathes. Before each part ran, a false move was programmed in, to move the turret the total distance it would to make a part. With the soft limit parameter changed to limit travel .05 or so before the chuck, the machine would alarm out when the stock was used up. I'm sorry that I can't remember the specific parameter numbers, it has been over five years since I ran those machines. It was a several digit metric number that could be changed to predictably change the limit. Make sure that you write down the exact original number before you change any parameters if you decide to try this.

[stevo1]

The parameters for your “home position” or what you would call home if you programmed G0G90X0Z0 are based off of your machine origin position or the position that the machine is when you do a zero return at power up. On the Ot control they are parameters 708-711. These are set to the distance from “home” to “zero return” position. If you need more room you may not have it depending on how close these limits are already set to your hard over travel positions.

Be careful when changing your soft limits as these are usually set up to be just before your hard over travels. Your soft limit parameters are 704-707. Most times because they are setup based on your home position that they have to be changed if you change your home position with parameters 708-711.

Stevo

[Joemachine]

Thank you steveo1 for the useful information on the parameter numbers for changing the soft over travel limit. Obviously you are very familiar with this handy tool.
This forum thing is new to me. I think it's great the way people freely share their knowledge.

Joemachine

[stevo1]

Joe…you are more than welcome.

It is hard to determine how a person has there machine setup because a lot comes into play on preference of operator on to the MTB. There are several ways it can be setup and there have been many lengthy discussions even disagreements here on how they should be setup.

The soft limits and reference positions are something that really needs to be setup vs a tool.

Anyway welcome to the group you will learn a lot. I learn tons from here every day that is what I love best about the forums.

Stevo