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Sid
10-04-2022, 12:07 PM
Hi,
I'm new the cnc world and have decided to build my own laser cutter.
Having watched numerious how to videos on Youtube I've noticed that CNC Router builds tend to use dedicated stepper motor controllers with a hefty power supply whereas Laser cutters from what I can tell just use a cnc sheild that then has an A4988 Stepper Motor Driver plugged into it.
Would I be right in assuming that routers require more oomph hence the larger power supply and dedicated Stepper Motor Driver Board, or could the stepper motors for a router be powered/controlled by the A4988 Stepper Motor Driver plugged into the ardunio shield?
Would a laser cutter benefit from a dedicated Stepper Motor Driver Board?
What is the general concensus on such things
Rgds,
Stuart

Doddy
11-04-2022, 07:13 AM
The Arduino-based controllers/drivers have been designed around the original 3d-printer designs, capable of driving the small NEMA-17 stepper drivers which provide relatively low torque. The firmware on the boards is limited, but optimised to this role with an incomplete G-code interpreter and limited in terms of the rate of step-generation. There is an element of these being "new" technology applied to new tech devices, vs the legacy controllers, as well as something that was once fairly basic but which is maturing with development/use and with a growing user base.

Higher power CNC machines require higher torque (=power) steppers, running at higher currents and voltages. For these individual stepper drivers are preferred and these offer better capability and higher resolution (not necessarily accuracy) with micro-step generation. Behind this, it's generally preferred to host a more capable and complete controller.

You can find examples of cards that sit between these - with high-power drivers integrated onto controller cards. These are generally frowned upon - high energy systems can suffer failures (as can the lower power machines of course) allowing components to be replaced (or upgraded) rather than replacing the system.

You could use the shield-boards, you could even hay-wire "proper" stepper-drivers from such a board if you so desired. That's your decision to make. The shields have a sort-of-advantage that it removes an element of complexity (and control) from the tool-chain in terms of the machine controller - that's all exported to the shield; in the more conventional design that controller is provided by PC-based software such as Mach/UCCNC etc.

I know/understand the shield-based designs, I use the same microcontrollers for any number of things. However, for my use-case (CNC lathe and milling machines), I'll stick with seperate controllers, drivers, etc.

A_Camera
11-04-2022, 01:31 PM
Hi,
I'm new the cnc world and have decided to build my own laser cutter.
Having watched numerious how to videos on Youtube I've noticed that CNC Router builds tend to use dedicated stepper motor controllers with a hefty power supply whereas Laser cutters from what I can tell just use a cnc sheild that then has an A4988 Stepper Motor Driver plugged into it.
Would I be right in assuming that routers require more oomph hence the larger power supply and dedicated Stepper Motor Driver Board, or could the stepper motors for a router be powered/controlled by the A4988 Stepper Motor Driver plugged into the ardunio shield?
Would a laser cutter benefit from a dedicated Stepper Motor Driver Board?
What is the general concensus on such things
Rgds,
Stuart

The simple answer is no, but it depends on the size of the laser cutter. If you plan to use steppers which require more than 2A 36V then yes, you should go for different drivers, but if not then the A4988 (or similar) tiny drivers are excellent. On the other hand, you can still use the Arduino, the A4988 can easily be replaced with dedicated drivers, like the DQ542MA or something similar. You just need to wire STEP, DIR, EN and GND signals and of course, the power cables. You can run the Arduino from the ordinary power supply of 12 or 24V commonly used for these, and connect whatever power supply is needed for the steppers directly to the stepper drivers + / - connectors.