Motor upgrade

Was wars am Ende?

Thank you for the suggestion bmartens,
These videos were exactly the ones I followed, in order to tune my SC2/600, after having tried the instructions from Stepcraft.
Actually for instance, I only can achieve a speed of 1mm/s when cutting carbon sheets having 2mm of thickness, in one pass.
And this speed, I was able to reach it after having removed the grease delivered from SC, replacing it with a thinner lubricant (WD40/PTFE).
I think that speed could be better than 1mm/s on this machine.

I'm in the process of trying to convert my SC2/840 to dual Y stepper motors. I have designed a new controller with an extra driver for the second Y axis motor. I have also included my current configuration, with the parallel and 4th axis modules integrated.

I have tested it and so far so good, now I will have to order some parts to get the mechanical side of things ready.

In this thread, you've mentioned that the control card is too underpowered to control two NEMA 23 steppers, but would it be powerful enough to control two of the stock NEMA 17s (the 1.8A Nanotec motors)?

Failing that, is there any way to take the existing output from the y-axis controller and amplify it so that the current will be sufficient to power two motors?

Ideally, i'd like to directly drive the two y-axis lead screws with stepper motors without having to replace the entire unit controller (since the motor controllers are ingrained in the unit control PCB).

thanks

Answer is no. The good news is that since I published my mod, Stepcraft got in touch and they will release an upgrade pack with a new control unit and all the parts needed to have the two y-axis motors.

I would say yes ... but ...

I also think that it should be enough to drive Y with 2 NEMA 17 steppers. And the solution to add another driver for the additional stepper is to enhance the parallel board. Use one side for forwarding the signals to the driver board and the other side to add the additional driver. On the parallel board you have access to all important signals.

Downside is, that it won't work with the WinPC NC USB-board.

Definitely not. The driver is already under some strain just driving one motor. My board was brown under the Y axis motor from the heat. The driver is only good for 2A and each Y axis motor is 1.8A. Also the driver is current limited to 1.8A (resistor divider). If you hooked up two motors to one driver you would either blow the driver or end up with barely enough current to move them. Bad solution.
No need to do anything on the parallel board. I have made my own control unit with the extra driver, and now Stepcraft will release their own controller for the same purpose and it will work with both UCCNC and WinPC. Just hold on a bit longer and you can have that with warranty and everything.

I think you do not read careful enough ...

I don't say, that the one Y-stepper-driver-chip should drive 2 motors. I say that the space occupied by the parallel-board can be used to add another driver-chip listening to the same Y axis signals than the existing one (including Emergency-stop signal). Only thing which needs to be wired up there is a connection to the power-supply.

That said .. another solution would be to use the 4th axis-board space and add a stepper-driver-circuit there, which can handle both steppers. There you have power-supply and the room to add connectors. With the right software it's only a configuration-change. The old driver for Y can then be used as 4th axis driver, if needed.

DIY guys don't need warranty and everything, which basically means extra money ;o) And how long will this 'bit longer' be? A lot of old forum users already made their experience with SC announcements.

Routing the lines for the parallel port and a driver in that space, not sure that's a good idea, and like you said, WinPC users would be out of luck.
The 4th axis space would be possible, even modifying the 4th axis board by setting the correct micro stepping, but that would not be a good solution for those who use the 4th axis. I'm a DIY guy and I made my own board, if you have the knowledge to add a driver to either the parallel board space or the 4th axis, you can also make a new control unit. No need for any sacrifices.

A bit longer they said was before the end of the year. Haven't heard from them in a few weeks, so I'm not sure what's the progress.

Well ... life is a big optimization process ... and different people have different optimization goals.

Some might not like the idea of replacing a board which is not broken, some might not like the idea to spend money (we will see how much the upgrade-kit costs in the end), some have the opinion that 2 NEMA 17 are enough boost for such a machine .... ( in case the 2 NEMA 23 hit the end of the machine, how will the spindle nuts react? SC might like the idea of selling spindle nuts abos ;o)

I am only throwing in some ideas and avoid to say things like "definitely not" or "no way" ...

For me the backlash of Y and X seem to be a bigger problem ... and I don't have any hope that SC will do anything for SC1 owners here.

Nema 23 seems like an argument for different drivers all together. With the current output of the stepcraft control units being limited to 1.4A or 1.8A, I doubt you'd see enough gains from using Nema 23 with the same drivers...

My 840 is running fine with 2 Nema 17 on the Y axis. I know a guy from Finland who is running his with all Nema 23 motors in closed loop with a complete replacement of the electronics. So far it's working fine, but he had to limit the speed to way below the motor's capacity, or he might break it. And they look ridiculously big for the machine.
Do you mean the lead screw nuts when you say spindle nuts? Yeah, in the long run it might be more reasonable to use ball nuts with that kind of power...

Can't the new adjustable nuts be used on the SC1? I can't see it on the manual...

I thought you were mentioning the NEMA 23 steppers in the first place, but have mercy, I became 50 recently, so, too old to remember the details in the right context.

Adjustable nuts: "No way" ;o))

SC1 has an 8mm lead screw and lead screw nuts (SC calls them spindle nuts in their online shop). SC2 has 10mm ... and different slope as well. SC1 is more precise with 400 steps per mm vs. 300 steps per mm on SC2,

Oh ok, I don't know much about the SC1. I would guess between the steel screws and the brass nut, if anything wears out, it would be the nut, no? If so, just getting a replacement should be enough to bring the backlash to "new" or "almost new" condition.

Answer is no. The good news is that since I published my mod, Stepcraft got in touch and they will release an upgrade pack with a new control unit and all the parts needed to have the two y-axis motors.

Did they give any indication on time? The Y axis is so under powered with the single stepper and would do the upgrade in a heart beat.

Sorry to disagree here - if the machine is properly adjusted there is adequate power in the standard motors. I can achieve slew rates of over 3000mm/min on all axes on my 420/2.

I actually measured the torque required to move the Y axis once adjusted, and found it to be less than 10% of the rated torque of the stepper.