[bearer]

Hi everyone!

I've got a Chinese bought TS3040C-H80 machine with one of those flexible shafts to a router hanging above the machine, and just a spindle and chuck on the Z axis.

And like another post on the forum here, I've probably overloaded the chuck causing it to fall out of the spindle, so I'm wanting to replace the whole thing with a Kress FME800 or similar spindle if possible. (I've already ordered the Kress as I'll use it for a DIY build if unable to make use of it here).

The new spindle weighs 1.4kg, this is my main concern, and the offset of the weight. I've seen the same basic machine with a directly mounted spindle and the only difference is that some has a 12mm instead of the 10mm round linear bearings like I have, and that the Z motor is directly coupled to the screw instead of belt driven as in my case. Unless I get really creative the center of the tool will be 23mm further away from the X axis, lost Y work space is not a concern, but maybe the shifted extra weight?

I've tried to add 1,2kg to the Z axis and it didn't seem to care at all, but still, to start off with; if this is an insanely bad idea - please stop me now

Meanwhile I'll continue drawing up my two suggestions for a mounting bracket and upload for input later.

input will be much appreciated!

Bjorn

[bearer]

Just as an update; it seems that it's the flexible shaft that is the root problem - in some positions/angles the shaft is unable to transfer the rotation to the tool bit properly, and that results in lost steps, broken bits and chucks that falls out.

I've tried mounting it more directly above the machine so thats its more or less in a straight line, but it is now in such a state that its pretty much useless and I'm waiting for my German friends over at cnc-plus to ship the potential replacement spindle.

edit:
.. right - the good news is that my diagnose above was 100% correct; the bad news is that the wire inside the flexible shaft now is totally disconnected from the motor. Seems the crimp between the motor and wire came undone!

[aarggh]

Hi Bjorn,

Flexible shafts on CNC's are just bad news, but it looks like your machine has Nema23 steppers fitted, if so, the 1.4kg Kress should be perfectly fine. The only limiting factor will be the power supply, if it's one of the 24v ones, the stepper may be underpowered, which may reduce it's torque. But you'd find that out pretty soon anyway, try a really decent cut in wood as a trial.

cheers,
Ian

[bearer]

Thanks for your thoughts Ian, good to know I'm not trying to break the universe here!

The motors are powered by 24V yes, just measured the PSU. The current setup ran cuts fine with about 1kg extra strapped to the Z axis, I do mostly 2.5D work so maybe I didn't test the Z axis very well..

The X and Y axis are fitted with 2.4A Nema23 motors, while the Z axis is a 1.55A Nema17 motor. For some reason the spindle is interfering with the controller now so its skipping steps badly. With spindle disconnected it runs fine - so I'll probably get a Gecko G540+36V and solve that problem too, instead of starting to rewire and add grounding.

.. and suddenly the cheap Chinese machine isn't so cheap after all - but what else is new.

Back to the mounting however, the new spindle has a shorter distance from the mount to the bottom of the Z axis, so it needs a longer adapter on the Z slide and a new Ø43mm holder.


I'm currently thinking screws from the back of the Z axis through the plate and into the holder, as the alternative would be a wider Z axis and loosing Y travel.


or to fix the holder with screws from the front, and use the screw holes on one side to clamp the tool on one side (option 1). But don't like this approach much.


Or mount from the front through the block and clamp the tool from the side (option 2).


Would it also make sense to support the top of the tool?, or is the 25mm mounting flange sufficient, machine does 2000mm/m max - although that might change with a G540..

Dimensions for holes and screws are not definitive, will adjust to whats easiest to source. And I'll also want to make some attachments for camera and a shop vac/dust shoe etc. Machining is only a minor problem, we have a fairly large machine park at work and the operators are easily corruptible with alcohol and cigarettes one might think I 'work' in a correctional facility

[lleal]

Dear friend,
I have a machine like yours. I chenged the controller to a TB6560, all works well, but only without the spindle. In your post "For some reason the spindle is interfering with the controller now so its skipping steps badly. With spindle disconnected it runs fine - so I'll probably get a Gecko G540+36V and solve that problem too, instead of starting to rewire and add grounding." you was the same problem. The spindle signal output from the TB6560 is 0-24v and we used the original driver and spindle. It seems to run well, but it interfere on the other axis. Can you tell me how you solved the problem?
Best Regards
LLeal

[bearer]

The spindle only interfered with the original unbranded Chinese controller, after installing the Gecko G540 it was smooth (and able to run much faster).

Even when using the G540s VDF speed control output with two resistors to divide the voltage down to 0-5V and applying that to the original PWM speed control and original spindle it ran smooth. It was however only temporary while I made the holder for the new Kress spindle, which only has manual speed control - now I have no electronics from the original machine.

[lleal]

The spindle only interfered with the original unbranded Chinese controller, after installing the Gecko G540 it was smooth (and able to run much faster).

Even when using the G540s VDF speed control output with two resistors to divide the voltage down to 0-5V and applying that to the original PWM speed control and original spindle it ran smooth. It was however only temporary while I made the holder for the new Kress spindle, which only has manual speed control - now I have no electronics from the original machine.

Can you tell me what kind of "two resistors to divide the voltage down to 0-5V"?
Thanks again!

Picture of my new controller TB6560AHQ for the 3040 H80mm

[aarggh]

Can you tell me what kind of "two resistors to divide the voltage down to 0-5V"?
Thanks again!

Picture of my new controller TB6560AHQ for the 3040 H80mm

From memory the speed control output is 0-10v, so two resistors of any equal value in series will have the same current level flowing through them, so each will measure half of the sum across them, 5v, and combined they will measure the full 10v across both together. Just need to use OHM's law to make sure you spec the power capacity (in Watts) of the selected resistors to ensure they won't create too much heat. I=V/R to calculate the current. V=IR to calculate the voltage. R=V/I to calculate the resistor value based on the known volts and current values.

cheers,
Ian

[lleal]

I am not an engineer, I am a photographer... I will try it, later, I will tell you Thank you for your help and effort.

[m9g]

Hi

I have one of these machines and am interested in increasing the size of the Z axis spindle, you mention the Kress FME800 - apart from creating a new bracket to hold it in place can this not just be plugged into the original control box and run?

[m9g]

just a thought, wouldn't the 6040Z motor and spindle fit onto the 3040?