Shop vac setup

So I am going to add a dust shoe to my CNC soon. I will run my shop vac off it because I do not have a fancy dust collection system. I would prefer to run it for 30 seconds every 5 minutes just to periodically suck up the chips and dust:

is there an independent ac timer that can easily accomplish this? I really do not want to try and incorporate this into my ramps. I think that doing so would take me a lot of head scratching.

A bonus would be if it has the ability to 1) set a periodic interval but also a total shut off so I could have it run ever 5 minutes for the approximate duration of the project.

That would be a pretty simple code snippet for a separate arduino.

I’m a fan of the arduino beetles for little projects like this. One of those and a single channel relay board would be all the hardware you needed. You could use the fan on/off on the ramps to trigger the second board to ‘enable’ and then turn the fan off at the end of the gcode to disable it.

You need to be a little careful with this. A vac pulls a lot of power and I would consider it pretty dirty power so if you experience arduino reboots, you know why. Plenty of people have had there machine’s reboot because of garage fridges and compressors kicking on. Doing it every few minutes might really be asking for trouble unless you have multiple circuits to play with.

I dont think it will work the way you are thinking? I find if I start cutting and forget to start the vac there isn’t really a point to start it. The dust shoe doesn’t really pull chips in, it more so keeps them from getting flung out. My biggest problem isnt the big chips its the fine dust that covers the garage and my sinuses. As for power, my MPCNC is on a separate circuit from my vac(it probably helps that I have a 200amp service on my garage)

1 Like

Make sure you check the current rating of the relays. Vacuums have a higher starting current that may not be good for the relay contacts. Additionally, the relay current rating is typically based on a resistive load. Motors are not 100% resistive; I’d look for a relay with a current rating of about twice the running current just for that reason.

Running on seperate circuit is not a problem. I already do that. If it does not really have enough power to pull the chips already accumulated, then that would be my no go for this project. I just don’t think that my shop vac will handle many 3 hour + constant duty cycles.


Now here is another question: what are the draw backs of just letting the wood shavings accumulate until the project is done and cleaning it all at the end?

It depends on what you are cutting, mdf creates clouds of fine dust that coats everything and the dust gives me crushing headaches, solid wood isn’t as bad and the bit will clear any chips in the way. I use an old Rigid that my wife left outside in the rain for two weeks, if anything is going to die thats it and it runs like a champ for hours. I did build a cyclone that made a HUGE difference (the fine dust plugs the filter very quickly.

I’m going to disagree with the other statement.

I hate the extra loud sound of the shop vac, so I never run it the entire time my MPCNC is running.

I typically start my cut, and then every so often I’ll crank up the shop vac and run it across the project to suck up all the dust. My shop vac has more than enough power to pull sawdust off of the board from 1-2" away. The only thing you would notice is that the shop vac is only pulling up the dust from where the dust shoe is currently going over.

I can get away with doing it this way because my MPCNC is on wheels. I wheel my machine over to the garage door and put a box fan blowing across the machine. Any fine saw dust that gets kicked up gets blown out the front of the garage. The heavier stuff that accumulates on the board is what I have to suck up with the shop vac.

I still plan on building an enclosure for the MPCNC at some point with a hole on the back so that the shop vac can pull the sawdust out of it. This would go a long way in keeping the sawdust from getting on everything in the garage.

Honestly, I never leave my MPCNC running by itself. I’m always stopping by to check on it even if I’m doing something else in the garage. Every time I stop by, I’ll run the shop vac and clean off the work surface.

1 Like