Acme Threading

[ndp]

I am trying to make 10 TPI acme threads ( External )on a 2 7/8" tube. I am having Puma 400 CNC Machine ( Fanuc 16T ) Control. My problem is that i am getting burr on the threads. To get rid of these burrs i have tried so many things----

1. I tried top notch insert from Kennametal ( NA3R10 & NA3L10 for right
hand & left hand threads )
2. I also tried Laydown profile insert (LT16ER10ACME) but no improvement
3. I am using 10 passes to finish the thread
4. I tried G32,G97 and G76 threading cycles but same result everytime.
5. On the same tubing when i use Top notch insert for "V" threads then there
is no burr coming on the threads
6. Cutting speed i tried from 400 - 550

I even called a Kennametal specialist in my shop to help me but he couldn't figure out the problem.

Any suggestions? pl help

[MrWild]

When does the burr start forming? With the first cut or after a few passes? Both sides of the thread, or just one side?

[ndp]

Burr start forming right from the first cut. It is coming on both the sides. I forgot to mention that i had even tried using modified flank cycle "A55" but no improvement.

[Fred the thread]

Sorry for late response, but what you need is profile generation for the thread, then you can generate a small radius at the crests as you progress into the form and this will prevent burrs occurring. Prevention is better than cure!
If you still ned help with this Acme or any other thread, please respond and I will sort it for you.

Fred the thread