AcornSix accuracy issues.

[vincent-visser]

Hello,

The past few months we’ve build our first cnc 4x8 router with an AcornSix board.

Unfortunately we are experiencing issues with the accuracy of it. It keeps our head spinning for the last few months.

We got some part in the machine made from wood which we would replace by 15mm aluminum, Joint with hexagon m6 bolt and countersinked heads approx 7mm depth. We know wood is not best material for a rigid machine that’s why we replace is by aluminum asap.

Problem is very good visible at the moment the machine has made the holes for the heads of the bolts and then making the same holes but mill the centers completely thru the plate. Here the centre of the countersink holes and the centre of the 6mm thru holes doesn’t align anymore.

Dismantled the closed loop steppers of X Ymaster and YSlave and mounted a plate on it with a mark on the plate an the stepper axis so they align perfect. Now I’ve set machine coordinates at 000 and Work coordinates at 000.
Then we run a program of approx 30minutes. Max speed 3000mm/min and acceleration at 0,6sec. So nothing extreme. (made in aspire vectric).
After 30minutes the program is done and we move machine back to Work coordinates 000. The marks on the temporary mounted plates with marks on the stepper axis should align perfect when machine is back at WSC 000 but all 3 axis are 10-15degreed off.

While we did this, nothing else then only H16 logic power, H1 and H2 open collector axis drive and UTP cable to the PC are connected to the AcornSix board so nothing else could cause interference.


We have used shielded cables connected on 1 side of the cables.

We had al lot of contact with our Dutch centroid dealer en with Centroid America. After these problems with our first AcornSix board we got a second to try but accuracy problem is still there.

Lichuan LCDA86H stepper drivers with NEMA32 12nm closed loop 2phase motors.

I add some photos for more detailed info of the parts and problems.

Is there anyone who has had same problems like this or any thoughts of what’s going wrong here?

[vincent-visser]

https://centroidcncforum.com/viewtopic.php?f=60&t=9538

Here is the beginning of our problem. Is was solved for 99,9% after the firmware update but after a job of 30minutes we still notice a deviation of around 3millimeters.

[suntravel]

Why do you not connect the drivers to H13?

Uwe

[H.C]

Interessant...following: bought mine (hardware-cnc) 08/2023))
Also, when doing a adaptive toolpath for some time my X is off +- 0.8mm y spot on.
Still want to blame my router...(single stepper over x&y)

[ShawnM]

Those stepper drives and 99% of every other STEPPER drive needs to be wired to H14 and H13. The open collector outputs are for servo drives. Wiring stepper drives to AcornSix H1, H2 and H3 connectors is asking for missed steps. I'm sure your drive manual states they work on open collector outputs but they just aren't reliable as you are experiencing.

[vincent-visser]

Those stepper drives and 99% of every other STEPPER drive needs to be wired to H14 and H13. The open collector outputs are for servo drives. Wiring stepper drives to AcornSix H1, H2 and H3 connectors is asking for missed steps. I'm sure your drive manual states they work on open collector outputs but they just aren't reliable as you are experiencing.

Thanks for your reply Shawn.
I rewired the drivers today en run the same program again.
It looks way better now! Tomorrow I continue with testing.

Can you tell me the difference between 5V or 24V signals towards the driver? Why is 24V not reliable and 5V works good?