I'm working on a project, a scaled-up version of an older project. It has a lot in common with CNC-machines, this one has less power and is designed to handle different painting tools (airbrush, markers, brushes and such).
I decided to build this one in a more proper manner and i am planning to make a PCB for the stepper drivers Polulu stepper drivers (A4988). Design below.
I'm not really sure if this is OK, is the wiring of the decoupling capacitors ok like this? Or should i use one capacitor which is rated for decoupling all four?
Other question (this is the first time making a PCB); when exposing the PCB its the UV light that counts right? Did anyone try exposing with the lamps for exposing screens (in screen printing), if yes, is there any advise on the amount of units or length?
Technical drawing of the machine also attached.
The VMOT is 12V from an old PSU, the VCC from an Arduino Mega
Or should i use one capacitor which is rated for decoupling all four?
No such thing.
Each unit requires its own decoupling capacitor.
when exposing the PCB its the UV light that counts right?
Not just that, it is also the developer, concentration and temperature and also the opacity of the mask.
The only way it to experiment with your setup by doing a number of strips. Expose the whole thing for say 10 seconds, then have A piece of PCB material and cover a small strip and expose for another ten. Keep doing this covering up a bit more each time.
Then develop it and see what turns out the best. No need to do this full size.
Use wider traces for all power and high-current lines, you need low inductance and low
resistance, especially on the motor and motor power traces.
I think the Pololu modules have some decoupling on them, I'd add more on the motherboard
anyway for Vmot, in the 47uF to 330uF range to reduce noise going out the the rest of the system
