TMC drivers are definitely in the line-up for my own build.
Um, guys, beware with those TMC drivers.
I have upgraded my machine with TMC2130 recently and it has
not been smooth sailing, by far. In fact, unless you are annoyed by the "Terminator" noise the usual Allegro A4988 produce, I wouldn't bother. Only switch drivers if you have the TI DRV8825 or similar, which have known issues, requiring fudges like "smoothers" (= 4 diodes dropping the motor voltage to make the driver behave and sold for exorbitant prices).
The benefits of the Trinamic drivers are minimal - the fact that the driver supports 128x or 256x microstepping or step interpolation doesn't mean you will get smoother print! The machine tolerances will be a much larger factor and the stepper motor may not even be able to keep up with so fast pulse trains. So you end up with 16x or 32x microstepping as with the Allegro driver - but you have paid quite a bit more for it!
The only somewhat relevant thing you can't get elsewhere is the StallGuard feature, that could prevent damage to the machine if you manage to crash it. However, then on the Z axis the mechanical advantage of the leadscrews is such that the machine will get damaged way before the StallGuard triggers (and you can't turn the threshold so low to avoid it, otherwise it could trigger accidentally mid-print as well).
I wrote about my misadventures with the Trinamic drivers on my blog:
https://janoc.rd-h.com/archives/770But in short:
- The drivers do get hot, heatsinks and potentially a fan are a must otherwise the driver could start limiting current or even shut down mid-print. Never had such issues with the A4988.
- The Trinamic drivers are rated for less current - ok for lights machines but my Mendel90 throwing around a heavy Wade's extruder pushing 3mm filament gives them quite a workout. Running the machine from 12V doesn't help neither, many of the Chinese printers run from 24V, so less current is needed.
- If you have dual drive on the Z axis (each screw has its own motor), the silent "stealthchop" mode will most likely go completely haywire and could even cause breakage to the machine because the motors will be driven out of sync.
- StealhChop includes also step interpolation (the "MicroPlyer" feature), which has issues with missed steps (see here:
https://forum.raise3d.com/viewtopic.php?t=6013)
So given that the biggest selling points of these drivers either don't really work well or the benefit isn't all that great, I wouldn't rush into buying them. I certainly wouldn't have had I known this. Many people have used these successfully but don't rush into buying these expecting that they will make your prints better. They won't and they may not even work in your printer to begin with.
32bit MCU? Seems a bit ahead of the curve, but it's not something I would ignore. While I'm not against getting my hands dirty on the processor side, I'm not inclined to dive too deeply. This is not a development area for me - just one where I would expect a reasonably modest amount of configuration.
You definitely
want a 32bit CPU. The 8bit boards based on the various ATMegas are being pushed to their absolute limits with the current Marlin. Both in terms of memory (e.g. the reason for me replacing the electronics on my machine was that the Melzi board I had just couldn't fit Marlin compiled with bed leveling support!) and also in terms of computing power.
32bit CPUs have no issues doing complex bezier interpolations, leading to much less stress on the machine (vibration) and better quality prints, all the while driving an LCD, talking to the host computer and/or communicating over wifi, all at the same time. You just can't do that with a slow ATMega, those are being pushed to their limits just driving the stepper motors already.
If you are hoping to update the machine to support some newer features like the automatic bed leveling, definitely go for a 32bit board (or a machine that has one already).