Hi,
If it is any reassurance, I can tell you that I am experiencing the same problem as you do. Only not with cutting a circle but by doing an angled movement (the worst with a movement to the up and left). Halfway through the machine stops dead in its track and makes a lot of noise, after that it continues its program but Mach3 thinks it is way ahead so the whole thing is ruined. This behavior happens when moving in G0, in G1 movement this hasn’t occurred as far as I know. A solution or help to get to the solution will be appreciated by more persons than just the topic starter so if you guys know anything, please put it here
Thanks in advance and excuses for the bad English (I’m Dutch )

 This is a classic symptom of your motors not being tuned properly, you either have the velocity set too high or the acceleration too high. If it happens near the start of th G0 move then likely turning your acceleration down slightly would cure it. If it happens a bit later into the move then it could be the velocity thats too high.

The noise you are hearing is your motor losing steps.

Hood

Hello
Please excuses my bad English I'm American and to me English is still a difficult language.

Sounds like you are also losing steps, what type of machine do you have? What are the motors? A person on this forum that goes by the handle of Whacko is very knowledgeable of this and he can give you the run down on what to check as far as your power supply, motors and etc. You could also try going into Mach3 motor tuning and increase the step and direction pulse to 8 and that will give your stepper boards more time.

But I felt that my drivers are too old (1989 to 1990's) and not able to do the microstepping I need along with my motors are Disk type made by Portescap (Swiss made). So in the end I bought faster computer a Compaq Pentium 4 with 2GHZ speed, three new Gecko G203V controller boards and three PacSci NEMA - 665 in/oz. stepper motors with encoders.

Let me know if the step and direction change make an improvement and we can go from there.

Fred

Hello
Please excuses my bad English I'm American and to me English is still a difficult language.

Sounds like you are also losing steps, what type of machine do you have? What are the motors? A person on this forum that goes by the handle of Whacko is very knowledgeable of this and he can give you the run down on what to check as far as your power supply, motors and etc. You could also try going into Mach3 motor tuning and increase the step and direction pulse to 8 and that will give your stepper boards more time.

But I felt that my drivers are too old (1989 to 1990's) and not able to do the microstepping I need along with my motors are Disk type made by Portescap (Swiss made). So in the end I bought faster computer a Compaq Pentium 4 with 2GHZ speed, three new Gecko G203V controller boards and three PacSci NEMA - 665 in/oz. stepper motors with encoders.

Let me know if the step and direction change make an improvement and we can go from there.

Fred

Fred, thank you very much for your reply. I will try to change the step and direction this week and let you know the results.

Hello,

I have tried the solutions provided by Hood and ffulmer. I started off with the changing the step and direction pulse to 8, but this made the mill behave even worse, so changed that back to 6. After that i lowered the Velocity and Acceleration and hey presto! The movements are better! Changed it another bit and it seems to work fine now! So thank you guys so much!

Vincent

Glad you are sorted

Hood