nakamura-tome & lns bar feed problem

[e2499]

Am kinda new at this so don't ream me to hard.
We have a nakamura-tome tw250 with fanuc 18i, the company had a tech come in and interface an lns quick load bar feeder to it. He demonstrated manually that it works, and left.And I'm now left holding the bag. Which for most you guys isn't a problem, I'm sure.
I'm thinking I can write a sub program (not my strong suite) to get the loader to do what I need. However my problem lies in timeing to call up the sub program. Iwould like to use the parts counter from the Fanuc as it can be changed right on the screen (for a new part) but don't know it's parameter address. this would lead to the next problem, being how to "0" the part count out at the begin of the new bar. Then finally how to restart the original program. Hopefully I'm makeing sense of what I'm attempting. Any help would be greatly appericated, even if I'm told I can't do that.

[3T2SP13A]

Which LNS feeder do you have? If it's an S-2 or S-3 (Quick Loads) I can help.
The LNS has to be set up (positionally) properly - we found this out the hard way, as the set-up techs we had didn't get it right on four of them (WTS-150 with S-2 and S-3)over a five year span. They run on two different measurements, the top cut and end of bar. The easiest way to get the count right is to measure your stock length manually. Take that number and subtract what ever you feel is best for a drop length. Divide the result by the part length, plus cut off and facing stock. This is the proper count, but isn't necessarily what the PLC thinks. If your count and the PLC disagree, then a simple ratio multiplied by the part length will get you going - e.g. If your part count is 32, the PLC says 30, and you have a part length of 1.000" in the PLC, then you change the OAL in the PLC to read 0.938". (1.000 divided by 32/30) Back out of set up, and go to automatic mode, and tell it to start. The PLC should advance the pusher and check the existing stock, and return to it's home position and show a part count of 32. I don't happen to recall the code to initiate the bar change from the CNC, but I can find out for you if you still need it.

[3T2SP13A]

To continue with my explanation, this issue arises when the technicians set the LNS too far away from the main spindle. The pusher bar should be able to reach the back of the bar stock when the material length is down to the last part. This seems to arise from the techs using a different projection from the spindle head to the back of either the chuck jaws or the rear of your collet face when in the closer. Are you using chucks or closers? We used ATS zero-length 5C closers mostly, and they stick out further than the rear of the jaws would on the 6" Kitamura OEM chuck by about 3", which the techs use to set-up. When the LNS can't touch the bar stock when on the last part, the part count will be incorrect.
Hope this helps -

[CNC Enhancements Tech]

I also install bar feeders similar in nature to the LNS quick load servo. I am surprised the installer did not give you a sample program to use with it, as how it is interfaced can affects how you need to program the lathe. Usually the Bar feeder tells the lathe when it is out of material not the lathe telling the bar feeder. On the Nakamuras I have seen with Fanucs but not that particular model, the bar feeds end of bar signal turns the block skip (block delete) button off. So in the lathe program you put something like "/M99 P2000" or "/M98 P2000". The P2000 point to either a line number N2000 or sub-program number O2000. If you use the M99 it will jump to line number N2000 when the end of bar signal is sent from the LNS to the lathe. If you use the M98 then it will jump to a sub-program number O2000. Then where it jumps to you would need sufficient lines of code to allow the bar feed to load the new bar. These lines of code depend again on interfacing and the particular job you are running.

[e2499]

Thanks for the replies. The bar loader is I gather a quick load 2. Un like the quick load servo, it has no provision for altering bar diameter, or part lenght in it plc.(We have one of each). I don't have a problem with the lenght of "throw" of the barloader, as the push bar will extend past the face of the collet. If I were to let it. My biggest problem now it writting the sub-program, is just plain ignorance. I'm thinking that once the barloader pushes the new bar to the top cut position, the bar is then faced off, I'll then have to index the turret to a bar stop, position it relative to Z0, open the chuck, push bar,and close the chuck. As long as the top cut position is always closer to the chuck, then the Z0 I shouldn't have a problem. Thanks guys I think a light just came on.