A few months ago I installed a 2.2kw water cooled spindle on my EXT 30x48 MK1. At the same time I also upgraded to the new SLB. Everything is working fine except when I am doing large 3D carves. The z-axis drops ever so slightly, I am assuming because of the additional weight. On a small carve it is not noticeable but on a 25" x 12" carve I lose 1/4" to 3/8" in height by the end. Someone suggested in the Sienci Labs Facebook group to add spring on the z-axis to solve the problem. That helped but still have drops in z-height.
As suggested in other threads I have set $1=255 in the gSender Firmware. I am running the latest version of gSender, 1.4.9.
Can the SLB drive a stronger stepper motor like the links below? The first link seems to have almost identical specs but the Holding Torque is ~30% larger than the steppers supplied by Sienci Labs. The second link has more than twice the Holding Torque but seems to require more currant. Can the TMC2660C drivers provide enough currant for these larger stepper motors without affecting anything else?
Thank you for the suggestion @Spamming_Eddie, but based on the description in $210 - $212 these settings do not apply when $1 is set to 255 since it applies the torque to all motors
These settings are instead of the old solution.
They might prevent axis movement when the axis does not move but the machine is working.
Atleast thats what I get from the explanation in the document. I have no big beast spindel on my mill but if I had, I would play with them improved settings that are specific for, gasp, heavy spindles that can lower the z-axis over time, before grabbing a wrench.
Yes. Currently I’m running a larger NEMA 23 on my X axis 2.8Nm, 3.0A and a NEMA 23 on my Z axis 3.0Nm, 4.0A. The color of the wires will not likely match the wire colors of the NEMA 23 motors that come standard with the Sienci CNC. So, be sure to match up and connect your A+ A-, B+ B- correctly.
@aarseneault I’m not a stepper motor expert, but my understanding is that if the motor is better set up with its windings or coil pairings it’s possible to get more torque out of the same amount of current/voltage that the drivers can output. I can’t make any guarantees with the links you’ve listed, but it should be possible. There have been others asking the question of what range motors the SLB can support and that’s also a difficult question to be able to fully answer so I’m still working to see if I can give more insight there too.
In your particular case though, I’d agree with @Spamming_Eddie in checking out $37 and $212 for trying to keep your Z-axis in place. If that works, then you don’t have to bother getting new hardware and doing more assembly/disassembly but totally your call
Should I expect something different when applying $37 (z-axis) and $212 (100%) compared to $1 (255) other than the max force being applied to all motors rather than just the z-axis?
My understanding is that it has the same effect but offers more granular control to apply different settings for each motor rather than the same for all motors. If that is true, setting $37 and $212 will not change anything since I already have $1=255 and am still getting a drop in z-height on 3D carves.
I will try it out when I have some downtime to see if it makes a difference.
You’re correct that it has a similar effect, though I actually haven’t tried seeing what the holding current is of $1=255 compared to the current set by $212 through $37 so it’s still possible that if it’s dependant then increasing $212 and activating it through $37 might still be stronger
I am no expert. I built my own CNC, and am using the SLB as my current controller. I began with a pretty weighty 1.5KW water cooled spindle. I had also built the machine with 4.2A Nema 23 steppers with a 36v power supply with an Arduino-based controller using external Stepper drivers. So, there should have been plenty of torque to hold the Z axis up. This wasn’t the case though. I tried several things to combat gravity, but ultimately, I added a mechanical fix. It’s not elegant. It’s basically a bungee support on both sides of the Z carriage. It’s not perfect, but it keeps things within a tolerable range – for me. It assists the stepper when lifting the spindle. I was concerned switching to the SLB because the onboard drivers are not a high current as the external drivers I have been using – so probably not as much torque. A good thing about the bungee system is I can retention it if I find steps are missing. I know some industrial machines have electromagnetic, and spring systems. This is my cheap “cowboy” engineering solution.
) will be to try a stronger stepper motor similar to what 