[williamsmotower]

I'm using final version of Mach3 on a A and B axis trunnion table.

If I machine in 3+2 indexed 5 axis the trunnion works as it should. If I run a 5x simultaneous program, my B axis is losing or gaining "steps".

I put "steps" in quotes because I've verified it's not a mechanical issue with stepper and or table binding.

I don't believe it's my post and or CAM.

Anything to look at in Mach?

[awerby]

If it's really lost steps, you could try reducing the acceleration in the axis that's faulting. In Mach, that's under "Motor tuning".

[joeavaerage]

Hi,
I've not long finished building a fourth axis, and in the process of building a fifth axis trunnion.

I'd love to see some pics of your set-up.

I bought an introductory offer (still $1200USD!!! holy smoke!!!) for Fusion 360 Machining Extensions over and above my regular subscription. To date I've done both indexing and simultaneous
four axis toolpaths and had no issue.

Craig

[williamsmotower]

If it's really lost steps, you could try reducing the acceleration in the axis that's faulting. In Mach, that's under "Motor tuning".

I've sped up both velocity and acceleration many times thinking this axis is going too slow and maybe losing track of other axis with same problem. So it's definitely not losing steps from going too fast.

I worded that funny above... I've gone faster and it's no worse than before. I've gone probably 40% faster everywhere... it should have drastically lost steps if that were the case.

I'll post some pics shortly

In settings tab I've read to put 0.001" in rotary axis settings.... that didn't do anything.

I've tried a standard 5x simultaneous post, a 5x inverse feed post.... both have same issues with B axis being off at end of run.

[williamsmotower]

[joeavaerage]

Hi,
kool, looks good. I'm hoping mine will be as good.

I have used two Atalanta Drives servo reducers. The slightly larger of the two is currently configured as a fourth axis. It has a gear reduction of 19.5:1.
With the 750W Delta servo driving it it spins up to 150rpm. It has a manufacturers spec lash of <2 arc min. The chuck unbolts so that I can fit the trunnion table.

The other servo reducer has a 6.75:1 reduction, and it too has a 750W Delta servo to drive it, so in free running mode it will spin at 450rpm. It has a manufacturers
spec lash of <1 arc min.

Craig

[williamsmotower]

That's a bad pic... it is just 2 rotary tables. A 8" and 6" that I made a table coming off 8". It's surprisingly sturdy and accurate in indexing

[joeavaerage]

Hi,

it is just 2 rotary tables. A 8" and 6" that I made a table coming off 8"

Hey, when all said and done that is exactly what a 5 axis trunnion is.

It's surprisingly sturdy and accurate in indexing

That is the most important aspect of any on a CNC mill. As I say good work. I'm hoping mine will be likewise as sturdy.

Craig