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However, 3d printer parts maker BigTree Tech, also known as Biqu (Shenzhen Biqu Technology), has recently released a 3d printer control board that includes four 8A 24-60V drivers – integrated right there on the board, with all the necessary heatsinking, alongside a powerful 32bit processor.
Called Kraken, it costs around £100, making it a bit less expensive than even a low-end control board and three or four reasonable quality separate drivers.
It is also much more compact, as 200 x 113, and has a host of other features.
The processor is a STM32H723ZGT6, which includes a 550MHz ARM Cortex-M7 – far more powerful than the Cortex-M3s mostly used in ’32bit’ control boards – and vastly above the 8bit ATmegas that are still good enough for most 3axis cnc machines.
It has eight TMC2160 stepper motor drivers, which are a type with that works with an external mosfet bridge, allowing Kraken to drive four 8A max steppers and four 3Amax steppers, all fed from a separate power input of 24-60V – the main board needs 12 or 24V.
And these drivers have all of the sophisticated drive algorithms Fabless German chip company TMC (now part of Analog Devices) is famous for.
The board also has a lot of interfaces, including USB, two CAN bus ports, SPI and UART (plus a whole bunch of temperature sensor inputs that might be less important for cnc).
Plus there are some chunky (many amp) mosfet switched outputs, normally used to control a 3d printers heat bed and extruder heater. The bed one has its own separate power input for 12V or 24V.
On top of this, it has two 5A dc outputs, 5V and 12V, to power further electronics.
Missing hardware-wise are opto-isolators for the end-stop inputs.
Now, it is possible that this board has some form of cnc show-stopper that I have not spotted, but I suspect that there is nothing that, for example, the clever folks behind grblHAL could surmount – there is already a grblHAL for STM32F7xx (although migrating from F7 to H7 (both Cortex-M7) cannot be like falling off a log or ST would not have written this document).
Hats off to Bigtree Tech – particularly as it is a Chinese company that plays a straight bat with regards its open-source obligations.
Kraken on GitHub
Update – look what I just came across on Bigtree’s GitHub – although it is Marlin and not grbl
