Hello everbody

First i would like to introduce myself and tell my story.

Fell free to skip the next part if u just want to help :-).

My name is Daniel and i started getting into CNC a while back. My first CNC Mill is the one shown in the first picture :-D. I build it entirely by hand out of Wood and parts from ebay. It did it job more or less (more often less xD) but at least it gave me the opportunity to mill parts for its successor. Since i found CNC-Milling to be extremly usefull and it is a lot of fun i decided to go all in. The result is the monstrosity shown in the second Picture :-). I'm trying to build a CNC-Mill that has it all: a lage working area (600x600mm), precision, (speed) and enough power to maybe mill some aluminum
sometime in the future. The build was long an full off setbacks most of them credited to the lack of precision and speed of the small wooden CNC-Mill. But i finally got it finished. The mechanics work a lot better then i expected. The sleds and the portal are easy to move around and the trapezoidal screws can easy be rotated by hand to move them around. The screws are driven with HTD tooth belts. Do to the fact that i was afraid any motor within my budget would lack the power to move the giant 30 Kg portal around all drives translation have of 2 to 1 to give the hole thing more power at the expanse of Speed. Few days ago i started testing the thing and thats when the problems started...

The electrical Set-Up:

The setup of the electronics is as shown in the third Picture.

I have a 24V 15A Power-supply

An "old" blue Chinese Tb6560 3 Axis 3,5A controller board (used to run the old mill in the past)
The dip Switches are all set to on (max current, fast Decay, no MicroStep)

and 3 Nema23 300oz 3A Motors; 200 Steps for 1 Rotation (Full Name: GB23H282-30-4A Additional Specs: see Picture No. 4)

and an old HP Laptop with MACH3 istalled (also used to run the old mill in the past)

The Problems i encounterd:

1) Speed: The Board is currently set to 1/1 Microsteps /no micro stepping. Which in my setup means 133.33 Steps per mm. Acceleratio is set to 200mm/sec^2 for the speed tests.

At 300 mm/min Motor runs nice and smooth but lacks tourque (i can stop i with my hand, its bareley anough to move the portal)

At 400 mm/min the motor starts turning and then stops shortly after making a buzzing sound and the shaft is jerking a little to the left and right but not turning.

At 500 mm/min the motor goes direktly into jerking and buzzing and turing extremly slowly with no tourque at all

2) Acceleration: as long as the max speed is set at 300mm/min i can turn the accelaration as high as i want to (for example 1000mm/sec^2 does not result in stalling). But i would explain that away with the fact that there is no load attached to the motor so the motor does not experience any resistance when accelerating.

All and all the motor are not only a lot slower then my old set up but also apear to have even less torque then the tiny Nema 17 Motors i used in my old CNC-Mill. My Old setup was running at 500mm/min and an acceleration of 300mm/sec^2 (the old mill also needed 133.33 Steps for 1mm and i used it with 1/8 Microteps, Motors also needed 200 Steps for one complete turn of the shaft). My goal was to build a better CNC Mill not one that is slower and weaker...

Observation and Measurement:

To monitor the Power usage i connected an Multimeter between the Powersupply and the Controllboard. The board itself draws 0.15A with no Motor enabled. I guess most of that runs the small fan and the rest is lost in the 12 and 5V Voltage-regulators. When enabling the one Motor connected to the board 1.5A are drawn from the Power supply. The Current drops down to 0.83A when the motor is run constantly in one direction. If i apply tourque to the shaft of the motor the Current goes up to 2.0A just befor i press down hard enough around the shaft to stop the motor. When the motor is supposed to be running but i stop it with my hand the Current reads 1.5A. All in all it does not draw close to 3A the motor is supposed to draw.

What i tried so far:

I read my way through most of this forum using the search. The "How I fixed my Chinese TB6560 controller (updated)" Thread was very usefull altough very very long :-).

I removed and bridge the Optocouplers as seen in the 5. Picture circled in green. I know it's not the safest thing to do but should it kill the LPT-Port on Laptop it would be sad but i do have other old (and basicly otherwise useless) Laptop to replace this one. The result: No improvement at all. The Laptops LPT is not damaged yet but it made no differnce at all.

I removed the 10k resistors that are supposed to reduce the current running trough the Motor while at a stop as seen in the 6. picture circled in yellow. Resulting changes: None what so ever.

I grounded the heatsink of the TB6560 chips as seen in the 6. picture circled in red. Resulting changes: None what so ever.

I removed the 1000pF capacitors and replaced them with the proper 100pf capacitors. Picture No. 6 circled in pink. Resulting changes: The anoying hissing sound when the motor is not moving is gone. Other than that no changes at all.

I set Mach3 to "Sherline 1/2 Pulsemode". Didn't not improve performance at all.

I varied the Step Pulse length between 0 and 14 µs with also did not improve or affect the performance in any way.

I am still going to try the hole 74HC14 thing to buffer the Clock/Step signal but i had none here and they are supposed to arrive here within the next couple of days. I'm not getting my hopes up...

So my question to all of you is:

Can you please tell me what else i could try?
Is there anyone else with a similar set up (3 Axis Board, 300 or more Oz, 24V Powersupply) who has any insight at all?
Are there any Modifications or Changes in Settings that could Improve the performance?
What do you thing is the Problem? Is it the controll board or the motors? And why?
Should i try another software?
Can the Controllboard not handle more than 600 Steps per Second at 24V? why did it work befor with 12V and Nema17 motors?
Can't the Steppermotors run faster than 180 rpm? Are there faster Motors? Can i make my motors faster?

And please refrain from suggesting i go and buy a gecko controller board unless you think it's the only chance i got because
i really don't have another 300$ to buy one.... :'(

Please Help :drowning:

Greetings from Germany