We have a 2000 Bridgeport EZ Track CNC 3 axes machine. We have been having an intermittant problem with the TLO in the z axis. Every once in a while a strange number seems to creep in and the tool crashes down into the part. Has anyone else seen this problem? Is there some obscure fact about the TLO that is not covered in the manual that you need to know? Crashes have already resulted in damage to belts (all replaced) as well as work.

Do you have 2 cables or one cable going to the Z axis motor?
There was an issue with the original design that relied on the linear scale for the Z axis position loop. They found that vibration could make it change where it thought it was (and correct for it). They thus went to the rotary encoder on the motor for Z axis position when in 3 axis. When in 2 axis, it still reads from the linear scale.
There are some other items to check. Your software may be corrupted and may need reloading. My records show that year 2000 we installed both machines with the Cutler Hammer control and the Computer Express controls. A hard drive was an option so CMOS settings should not be a concern. Connections should be checked.

George

We have two cables going to the Z drive motor. But what is the correct procedure to set TLOs? We may be dealing with operator error, although we have observed the same strange number on several different jobs. Its like 3.5 or 3.7 something like that. It just suddenly jumps in and if you are watching the pendant you might catch it in time if you look at the minor z readout, you know, the target number that is small on the right side of the display. I realize a problem gets much harder to diagnose if there is an operatore problem. A quick summary of the TLO procedure would be helpful if you don't mind.

Good to hear about the two Z axis cables.
Do you have the operation manual? I have to be in front of the machine and need to know which version of software you are using. I no longer get to play with these machines a lot. Also there is a problem if you use collets instead of solid end mill holders. With the solid end mill holders, you can preset all the TLOs. If you use a collet you have to set a TLO after you put the tool in. Not very efficient. The newer software supports multiple work coordinate systems (I am 99 percent sure of this).

George

Hi ya G. The TLO's can be set by touching off the tool and then setting a Z0. If the machine is in Third Axis mode I am pretty sure it will write the TLO to the currently active tool.

TM

TM,
Yes you can get out of the program and do a set of Z ZERO, which is a terribly inneficient way to run a CNC, and then go back to your program. But how to help Alan K? Is he doing something wrong, or is there a problem with the machine?

George
95X300

George,

If you are setting tools in 3X mode, the tool tables are active and will save the TLO's. You just need to change tools, set each tool and run the program.

Terry

And what if he is using collets?

George

If he is using collets it's a moot point.

Terry

To use the tool length offsets you will have to have your tools mounted in solid holders.

Go to the main screen where you can choose run, do event, or edit etc. You will also see "Tool F3" this is the function you use to set Tool length and make tool changes. Enter a tool number and press 0 to set. There is also a comment block where you can describe the tool. (This will show on the display and prompt the operator to insert the correct tool.)

Also on this same screen if you hit the edit function (5) , then at the bottom of the next screen that appears you will see an * that will say " tools" press + to select the tool.tbl file, this will take you to the tool length offset screen and the work shift screen. You will be able to see all of the different values that have been entered and you will be able to edit them here.

As to your crashes, make sure that when you are seting your tools that you have the proper work shift selected. It will apear on the main screen, Where the coordinates are displayed In the lower right hand corner where it normaly says ABS or INC. For example if workshift 2 is active when you go to the machine and you don't realize it and you then set your tool length. When you run your program it will usually call G54 and you could experience a crash. To activate or clear work shifts press "set XYZ" then press "/" acivate work shift. choose the one you want.

I hope this helps. Pete