Well, my first part, my first broken tool.

My .149 drill bit came loose in the chuck. That wasn't the problem, I paused the prog. , stopped the spindle and coolant then retracted the z axis. rezeroed the tool after tightening. resumed cycle, as the tool finished drilling and retracted then  moved to the next x, zing! the tool was about .200 to deep, milled a little curved slot and snap.

So, what is the proccedure for changing a tool mid program and getting the z height right?

thanks much for any wisdom,

jh

I'm new too...  I'd sure like to know.  I just scraped all my parts when this happened.

The BEST thing to do is back up to a tool change and press the "Set Next Line" button. The tool change SHOULD have all the data needed to restart the program safely.

I think part of my problem was changing it in the middle of the drill cycle and changing it. I just changed out the drill in the chuck while it was still in the spindle and rezeroed the tool. I guess it's best if I do as you suggest so the machine is back at zero for that tool at the begging of the cycle and then remove the tool holder and reset the new one to the exact same height?  The question is what if I can't get the height exactly the same? 

How would I then compensate for the differance? Also I was in teh middle of drillign 395 holes in a pattern.

Would I just edit the tool table for that tool? I don't think the new tool height will be accepted into the program once it has been run?

So does this make the best solution.

1 at hole 195 tool breaks/needs sharpening

2 back up program to that change tool line and "set next line"

3 take the tool holder out and change the tool and re-measure.

4 enter the new measurment into the tool table

5 replace the tool in the machine

6 begin the cycle then pause

7 move to the last line ran

8 run program from here button

? is this the right way of changing tools mid program?

john h

I havnt had to change a tool mid run b4, but the most import ant thing is if you dont have accurate homing swtches is to keep power up to your CNC machine so you dont lose position to your original stating points. Make sure even though the machine is still on, you turn power off to the spindle though.

Jog the machine to a point where its easy to change the tool. Replace the tool and jog the Z axis down to where zero should be. So that the tool is just touching the work or table depending on if zero is at top of the work or bottom. This must be done by eye and can be difficult to get right. If you are just cutting shapes out the accuraccy isnt as important as if you are doing multi level work.

Once you have the tool bottom touching zero, press "set to zero" for the Z axis.
Then jog the Z to a height above the work piece. ( We dont want it rapiding through your work)
Then use the run from here stuff as you previously mentioned.

You will notice when you run the run from here line that it takes a while b4 the machine starts to move depending on how far into the code you were.

Its probably a good idea to run a few lines back from where it stoped b4. This will ensure you  have a seemless continuation of your cut.

"Once you have the tool bottom touching zero, press "set to zero" for the Z axis"

I guess you mean in the offsets page? not on the main run program screen

jh

This is how I do it:
1. See that you need to stop the mill and press FEEDHOLD
2. Press the Stop and rewind buttons
3. Load the new tool and set the tool length offset
4. go to the tool change just before I broke my too OR where I have a safe startup block on my program
5. Press cycle start


The tool change SHOULD have a safe startup block or blocks that have things like the fixture offset nd the tool length offset info as well as  a G80 G40 G50 G90... This will make it so you never have a crash!

Is that any help?