I'm trying to build a laser engraver/cnc router with Arduino Uno, CNC Shield v3, A4988 step motor drivers. I'm newbie about electronics and Arduino so sorry if I'm asking non-sense things.
I've installed GRBL 1.1 on Arduino Uno, connected A4988 drivers and two stepper motors (link to datasheet below). I used LM317 power supply for powering CNC shield. I haven't done any setting with A4988's trimpot.
When I try to send commands with Universal Gcode Sender, step motors turning well for single-axis movements. For example when I command to move it on X-axis, it seems it works well.
Here my questions are;
1- When one motor steps, the other motor also starts to work and vibrates without turning. Is this normal behaviour? Does CNC shield makes it "ready" as receives GRBL commands?
2- When I click on "return home" on GRBL controller software, step motor turns for several times and then stops and I guess skips (doesn't turn shaft) with a weird sound. What can be the reason for that? Does it means LM317 doesn't supply enough current? (I set it to 12V) Also A4988 doesn't heat at all, I suppose it should, can it be related?
3- Sometimes motor vibrates too much even for single-axis movement. Can it be also related to not enough current from power supply?
and also I'm thinking about connecting TTL/PWM laser diode with 12V/2.5A specifications, should I also consider this when calculating enough power supply? Or shouldn't I connect it to CNC shield, what is the best practice about this?
I'm thinking about buying 24V/5A power supply. For two step motors (0.4A * 2) and 2.5A laser I suppose I need 3.3A and as step motors are 12V and they will act better with higher voltage, I will buy 24V. Is this correct calculation or should I consider some other things?
Thank you for your answer. I use LM317 power supply for both CNC shield and motors. I connected it to CNC Shield's power input (12V-36V). Arduino gets its power from USB. On the photo below, you can see the cnc shield I use and I'm connecting power (LM317) to blue input on the left bottom of card.
Probably I use "LM317" wrong here, what I'm exactly using is a "LM317 adjustable power supply" which you can see here:
But I'm not sure if it's supplying enough current when it's set to 12V, on some other forum someone suggested using "switching-mode power supply" so I also bought Mean Well LRS-100-24 power supply.
I suppose CNC shield and A4988 motor drivers (when pot set correctly) set voltage and current for motors here but I want to ask again, would it be any problem connecting LRS-100-24 power supply (24V, 4.5A) to this shield? My motors are 12V, 0.4A (I will use 2 motors)
Okay, I won't use LM317 power supply but I will use 24V, 4.5A power supply but I'm confused about these words:
"The LM317 should only be supplying current for the electronics on the shield. It should NOT be supplying the power for the stepper motors."
Should I also use two seperate power supply for CNC shield and motors? Because CNC shield has only one power input (but not sure if X.STEP/DIR etc. has same purpose). And I was thinking about connecting 24V, 4.5A power to that input and powering both CNC shield, motor drivers and motors.
