Flow Cut Off K40

So I am looking to buy an OMTech K40. And I am looking to replace the board with a Cohesion3d laser board. That being said everyone thinks it should have a flow cut off to protect the tube, but as far as i can tell from reading here the board does not support (directly) a water flow meter cut off. So the question is does it them work if you install a cut off on the power supply to the tube itself? And if so how? I don’t seam to find any good info on what sensor to buy and how to install it. I see a lot of folks talking about it but either with out dated info or no wiring info… etc. So any advice?

Yes, the water flow sensor would be connected to the laser power supply itself. It doesn’t stop the job from running, it’ll just stop the laser from firing.

There is a terminal you can use on your laser power supply for this. In normal operation, the WP or Water or Protect (it has different labels depending on the version of power supply you hare) will be connected with ground if the laser is in a condition to fire. This, on a normal K40, is usually wired to a switch on the front panel that enables the laser. If you want to add a water protect to your laser, this is where it will go. All the switches connected to this terminal must be wired in series such that a failure of any one of them causes the loop to open and the laser not to fire. If you wire them in parallel, all of them have to be open in order for the laser to not fire.

An example of the correct wiring, with an arrow representing a piece of wire between each component:

G terminal on LPSU -> Lid switch -> water flow switch -> front panel switch -> WP terminal on LPSU

What you are proposing here is definitely a good modification. I’ve been planning on doing it to mine but haven’t gotten around to it, even though it’d be a really quick job. I’d just have to disconnect everything and get the laser to a point where I could get the tube compartment open and work on it, and that’s the part keeping me from doing it. Small room, not a lot of space … excuses excuses :slight_smile:

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yip burnt my tube out from loss of water put water sensor in wired too the same terminals that laser enable switch is connected just take those 2 wires out and out sensor wire in their place its wp and ground or p and ground on power supply