You need an 8 bit board to run the steppers. Probably the most popular is a Rambo board but you can do some searching and find other boards. The firmware you load on this board can be either be Marlin or Klipper (assuming the board you choose is supported by both, which I recommend).
If you use Marlin, then there are numerous choices of systems that will feed it GCode including OctoPi / OctoPrint. You can connect to Marlin directly with the system you are generating the GCode on (i.e. the system running your slicer and CAD software, etc.
If you use Klipper, the choices for systems that will feed it are more limited. The Klipper project uses an RPi running OctoPi / OctoPrint along with the software that converts GCode into the commands that are sent to the Klipper firmware.
The 8-bit board interfaces with the stepper motors, the heaters, and the fans. It communicates using commands sent over a serial connection. In my opinion, this would be a slave as it doesn't do much without being fed commands. This is true with either Marlin or Klipper as the firmware.
If you choose an RPi to feed the 8-bit board, you could call this a master as it sends commands, but those commands (i.e. GCode) are usually generated on another system which runs a slicer and/or CAD software which would, IMO, make the RPi a slave to that system.
In conclusion, pick an 8-bit board that will support either firmware, and use an RPi 3B, 3B+, or 4 running OctoPi / OctoPrint to interface with it. IMO, this gives you the most flexibility.
the reason most of the boards have changeable steppers is that you can easy upgrade the board.
You can also produce it in larger badges because it has a larger selling time.
If a stepper driver is outdated like the 4988 it would be hard to sell the board with a profit when they are soldered directly on the board.
Hi Andi thank you for the explanation.
One last thing I want to confirm that I understood that right.
If I want to remote my printer with my smartphone or PC in both cases I need 2 Hardware: ARM System like RPI and a 8-Bit system like RAMBO, RAMPS or Panda PI.
Than I have the choice:
Marlin or Klipper on 8-Bit system
--> ARM System is only used to connect my printer wireless with PC o Smartphone. 8-Bit system runs the G-Code and the Stepper / Heater HW
Klipper ob ARM System.
-> ARM System used to connect my printer wireless + runs the G-Code calculation and coordinates the 8-Bit System to run the printer.
Marlin on 8-Bit system
--> ARM System is used to connect my printer wirelessly with PC or Smartphone and sends G-Code to 8-Bit system. 8-Bit system runs the G-Code and the Stepper / Heater HW
Klipper ob ARM System.
-> ARM System used to connect my printer wireless + runs the G-Code calculation and sends coordinates to the 8-Bit System to run the printer.
This is not true. There are many 32 bit 3d controller boards. You can also control a stepper-driver directly from a Raspberry Pi over GPIO, but you do need something to plug the stepper-driver and the stepper leads into.
Hey guys thanks for all replys.
I think that I will look for running my printer with RPI and klipper as main system and the control board with 8 or ??bit architecture as slave.
Do someone know where in the hundreds of pages I can find a actual list of all the newest 3d control boards (is this the right generic term for the RAMBO and RAMPS boards or is there a better one?) That supports marlin and either klipper? Than I will buy 3 different boards an play with the different features of them.
Thank you so much.
