CNC with Duet3
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Good evening from the UK!
This is my first post here, I bought a CNC machine online, I've have had nothing but hassle with a poor service. (He has now removed his website and no reply's to emails, seems to be a few of us in the same situation)
My machine is almost ready for the electrics (Its been a long 12 weeks getting to this stage)
I've got the motors in place (Nema23's)
I've got a Duet3 boxed and ready to go.I haven't got any limit switches yet but after reading up on proximity sensors, they seem to be the better option? My only questions is how can I get them to the 5V needed? Resistors?
Also can anyone recommend what cables I'm best using for motors and the proximity sensors?
Really appreciate any help, thank you!
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@hayden1993 i think that maybe if it's your first CNC with a duet, you should try with limit switches (this is what i have and i don't have to complain with the repetability),
and then once you're familiar with everything you can change the limit switches with either optical or other sensors. and for the limit switches it's really easier to use reprap ones:
https://aus3d.com.au/endstop-pcb
because they have a led that helps you know the wires are correctly connected and you see the trigger. -
@hayden1993 Can you post photos of your machine or a link to a description of it?
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@hayden1993 there is 5V available on each of the IO connectors that the limit switches will be connected to.
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Thanks for the reply, limit switches will be easier to mount, is there much wiring difference between them?
I'll add a picture of my build, please excuse the mess, its a small workshop.
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@hayden1993 said in CNC with Duet3:
Thanks for the reply, limit switches will be easier to mount, is there much wiring difference between them?
If you have a simple microswitch with nothing else you need two wires which are connected to the signal line and ground. "active" sensors like an optiocal or hall effect sensor, along with switches with indication LEDs also need power. Some of those work with 3.3V , others need 5V, either way an IO header on the Duet has both 3.3V and 5V on it.
More info here:
https://duet3d.dozuki.com/Wiki/Connecting_endstop_switches -
I have limit switches on my CNC and milling machine. They seem repeatable to .001" but generally I don't rely on that. The ones with LEDs are nice but the ones without don't require that third wire for power.
You asked about wiring. I use shielded copper cabling - 24AWG for indicator stuff and 18AWG for the 3A motors. After trying two different Amazon cables that were both garbage and would break if you looked at them, I went to my electronics distributer and bought General Cable (Carol) stuff, such as E2204S.41.86. If you use shielded cable make sure you only connect the shield to one end - usually the controller.
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In general, the accuracy of limit/homing switches is only a factor if there's something else on the machine that needs absolute registration to those switches... for example, fixtures, which are things bolted to the machine so you can put stock up against them (or clamping fixtures that hold the material themselves), assume their position is correct, and you can start the job.
Most CNC'ers place the material somewhere on the bed, secure it, and then using things like touch-probes to locate the piece and set work zero, and go from there. Working in this fashion isn't effected by the accuracy of the limit/homing switches.