Erratic behavior from Bridgeport Series 1 Mk2 with TNC155

[dbcooper99]

Hello everyone. I would first like to thank you again for helping me with my last problem. I am VERY new to CNC programming. I have written 4 simple programs so far and am starting to get the hang of the TNC155 control. My problem is that after I ran my latest program on a block of wood I decided to try it on some aluminum. After starting the program it looked good at first and then started on a totally random pattern. I stopped the machine, lowered the table, and started the program over deciding this time to only cut my pattern .002 deep just to check it. This time it followed the pattern as it should so I lowered my Z down a little more and tried again. Then it did the random pattern again. I lowered my table and tried the program 2 more times and it did different things each time. A couple times it gave me an error stating my tool radius is too large. I then powered off the machine for 10 minutes and restarted it. This time it ran my program as it should. I then raised the table and hit the start again and got another random pattern. At no time during any of this did I ever change the actual program. I only raised and lowered the table by hand. Any ideas?

[machintek]

I have seen older BOSS machines "hunt" for a start point if cutter comp math was not correct. Perhaps the TNC is doing the same thing.

George

[dbcooper99]

How could I check that? I am really new to all this so please bear with me. Thanks

[gus]

This has no relation to boss machines.

I am reasonably sure there is nothing random going on.

post your code

If you are working in tool comp, the starting position of the tool relative to the work becomes important. IOW, always start a program with a non tool comp move to a known point[IE X2 Y2 Z1 R0 F2000] If you are using datum shifts always start with a datum shift to zero so you don't start in the wrong location

[RKR]

Everytime you run your programm again you should load it in the automatic mode.

[dbcooper99]

Originally Posted by RKR Everytime you run your programm again you should load it in the automatic mode.

Thanks for the suggestions. The machine isn't at my house so I won't be able to try it until this weekend. What do you mean by the above quote? Can I not just push the start button to run the program again? What is automatic mode?

[RKR]

I have an ycm-40 supermax with tnc155b control. Every time I run the same programm again I have to select the programm in the programm list and then run it by pushing the start button.(in full automatic mode)

[dbcooper99]

Also - could anyone tell me the cheapest way to get the Z axis to move at the same time as X and Y? Thanks

[contractdesign]

It seem that from your description, the problem does not exist with a .002 deep cut, (low electrical load on the drive), but occurs only at a deeper cut, (heavier electrical load on the drives). It sounds like maybe the resultant load on the drive is creating a problem. I would say it's an electrical problem, maybe a setting in the drives. This is where my knowledge falls short, maybe someone can expand on this.

[greg b]

You should be able to program z axis in your program with x and y,I think the other member means to start your program in full sequence mode and not in manual mode .this means if you run in full sequence once you push the green button the program continues on its own where as manual mode you have to push the green button to make the machine move on each line of the program.

[dbcooper99]

Originally Posted by gus This has no relation to boss machines. I am reasonably sure there is nothing random going on. post your code If you are working in tool comp, the starting position of the tool relative to the work becomes important. IOW, always start a program with a non tool comp move to a known point[IE X2 Y2 Z1 R0 F2000] If you are using datum shifts always start with a datum shift to zero so you don't start in the wrong location

Yes, you are correct. It isn't random as I thought. I will have to get the code and post it so you can tell me where i messed up. It appears to run the first couple lines fine. They are straight lines with no tool comp. Then when asked to do the first arc it comes to, it decides to make a counterclockwise circle at the arc endpoint instead of making the arc. I am using the CT command as explained in the manual but it just doesn't seem to work for me.

[greg b]

Some times its easier to use the cr function with a circle centre but you should be able to use the ct function provided its set up correct.