automatic shutdown

[cydrollinger]

I would like to know the best way to shutdown CNC operation when a Haas machine runs out of coolant? Seems like their is plenty of resource to implement a solution as a hardware or software solution? Any direction to this problem would be appreciated

Cy Drollinger

[Geof]

You should have put this thread in the Haas forum. There has been some discussion on this topic there.

I have thought about it several times and have figured out a system that I am confident would work, but I have never implemented anything.

I don't think you want to shut the machine down if the coolant level is low or if the flow stops. My approach was to devise a system that puts the machine into feed hold so it can resume running the program as soon as the coolant is topped up.

Also I don't think the coolant level is as critical as monitoring the coolant flow. We have had coolant pumps malfunction stopping the flow and level monitoring is not going to detect this. However, my system would do both.

The sensing units would be a (low pressure) pressure switch with NC contacts and a float switch also with NC contacts. The pressure switch would be plumbed into the coolant lines just downstream of the main shut-off valve on the spindle nose and the float switch installed in the coolant tank.These would give open circuits when pressure was present and when the coolant tank level was okay and both switches would be switching low voltage low current circuits.

A 208/240VAC coil, time delay ON, relay would also be needed.

The relay would be mounted inside the cabinet and wired across the coolant pump outlet.

A circuit would be connected across the Feed Hold button via the relay and have the pressure switch and float switch in parallel in it.

The operating sequence would be:

Coolant pump is turned on. This closes the relay contacts after a short delay. The delay is needed so the coolant system comes up to pressure before the relay contacts close.

If coolant is present in the tank and if pressure is present then both switches are open so the circuit across the Feed Hold button is open; the machine runs.

If either the coolant pressure drops or the coolant level drops, the circuit across the Feed Hold button is closed and the machine goes into FeedHold.

This system gives protection against (some) operator error: if the main valve is left off there will be no pressure so the machine would hold. However, it would not protect against a missing M08. But it would remind you to remove any M08s that were not needed because you wanted to machine dry and had turned the coolant valve off.

[cydrollinger]

Geoff, Thank you for your response and will have a look at the Haas section. If I implement your solution I will let you know!

Cy