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Author Topic: Mach3 Using 2 Axes both slow down?  (Read 280 times)

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Mach3 Using 2 Axes both slow down?
« on: December 20, 2020, 06:38:20 AM »

I am new with mach3.
I built a desktop cnc mill with grbl as controller.

Now I convert a mini lathe to cnc.
The lathe is a emco Unimat3.
Its a Toy:) and for me its a project to learn more about cnc turning.

I got one Problem!
If i drive 2 Axis in the same time both will slower if i drive only one Axis.
The Distance is correct! I dont loose steps! Only the speed goes down on both axis.


I drive the Axis over the Arrow Keys on the Keyboard.

I drive Z in - and hit then + X the Z axis speed goes little bit down.
when i release +x the Z Axis speed up.

My Setup:
A Thinkpad X61 with Dock and WinXp/Win7 in Standart-Pc config


Tb6600 drivers at 1/4 Steps and 1.5A/1.7A peek

Nema17 Steppers 1.7A with Gt2 belt Ratio 2:1

32V 5A Labor PPowersupply on 30V

Shielded wires between Tb6600 an Parallelport

Shielded wires between HomeSwitches and Parallelport

Shielded wires between IndexSensor and Parallelport

My Kernel Speed set to 100khz after testing with drivetest

My Motor Tuning is:
Steps/mm 1600 (microstep 1/4 ratio 2:1)

Velocity 300
Accleration 50
Step pulse 2us
Dir pulse 2 us

Step and Dir with 2us is incorrect or?
Tb6600 datasheet said minimum 2.2us.

Is this the failure? a change to 3us brings nothing.

thanks for help!

Offline Graham Waterworth

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Re: Mach3 Using 2 Axes both slow down?
« Reply #1 on: December 20, 2020, 05:19:17 PM »
I would drop the kernel speed down to 25khz and see if things respond better.
Without engineers the world stops
Re: Mach3 Using 2 Axes both slow down?
« Reply #2 on: December 20, 2020, 05:57:57 PM »
hi and thanks!
if i do this i got steps lost or the steppers do crap. and! my index speed is wrong.

i dont know