Problem- coolant not turning off

[CORBIN92087]

We have a '07 haas vf-2 and periodically we have troubles with our coolant not shutting off during the tool changes. When the 'turn coolant off' code comes up it shuts the pump off but has pressure built up or somthing, then it sprays during the whole tool change. Then rust starts to show up on the taper of the toolholder that go's in the spindle. Any tips on how to get the coolant to quit sticking on????

[Donkey Hotey]

You're right, it's not 'sticking on', you just have residual pressure in the system.

You should change your programming so you shut off the coolant on the line before the tool change. That'll give it a chance to bleed down.

The bigger problem is that your coolant should not be causing rust--anywhere.

[CORBIN92087]

thanks for the reply. i actually have my coolant turning off right as its done with its cycle, with the tool still down by the part. and it pretty much stays at like 70% power thru the whole tool change until it turns back on for the next operation.

[Machineit]

The pump on a VF-2 can move a lot of coolant. If you are just using the small flex plastic coolant nozzle, the system itself can hold a large volume and it will keep spraying.

Your solution will be to use the larger programmable nozzle, or turn the coolant off even sooner.

I do agree with Donkey Hotey, that if your coolant is mixed properly, you should not be getting any rust on the tools.

Mike

[Geof]

All the Haas machines with the big coolant pumps do this and it is a bother because if your coolant is rich enough to prevent rust it leaves a gummy residue on the tapers when the water evaporates away.

On my Haas gantry machine I rigged a mechanical valve in the coolant line with a linkage that closed it when the spindle moved up to the tool change position.

Another though I have had but have not installed is to put a low voltage solenoid valve in the coolant line on the spindle nose and wire it in parallel with the pump through a transformer. This way the valve would close as soon as the pump turned off.

It has to be at the spindle so it is downstream of the plastic hose which is what keeps the flow going and it needs to be low voltage to be safe.

[HelicopterJohn]

it pretty much stays at like 70% power thru the whole tool change until it turns back on for the next operation

Are you saying the coolant pump motor is still running or are you saying that the pressure is still bleeding out of the system even the the coolant pump motor stopped on command from the HAAS control?

I have a HAAS TM-1P with the 3/4 HP High Output coolant pump and the PCOOL (Programmable Coolant Nozzle) and had the same issues. I tried several restrictor valves and while they helped some they did not completely solve my problem.

What I did was remove the FLAPPER Valve located at the output of the coolant pump. What that did was allow the coolant to drain back immediately after the command was issued to the coolant pump to stop. My first concern was that the coolant pump would not be able to get the necessary prime and deliver coolant in time for machining operations. As it turned out in my situation the coolant pump easily primes itself. What happens now is that the coolant stops flowing enough not to spray coolant all over the tool holder tapers and into the tool carousel.

This has worked for me and MAY?? be something you would like to try. I have been running my machine in this configuration for over a year. Try at your own risk.

John

[Haas__man]

Firstly - as everyone has aready said - coolant should not cause rust - either you need to change your coolant brand or the mixture is too weak.

Do you have an auxilary filter fitted? this would be a three foot high cylinder of around a foot diameter that is located on the floor behind the machine. It is usually used for TSC (Thru spindle coolant) but is sometimes used on regular coolant too.
Check at the coolant tank and around the pcool area for any shut off valves. These should all be fully open - if not then flow will be restricted and coolant will flow for extended periods of time even after it has been turned off.

If you do not have an auxillary filter then I think you may have a blockage. Firstly - the PCOOL nossle - unscrew the nossle from the unit - you will possibly find a piece of bent wire inside (only on machines made in the last three years or so). If you do find it then remove it and re-fit the nossle. It could be blocking the nossle. Another possibility is a blockage where the blue flexible pipes are. Remove the blue flexible pipes and remove the manifold from the machine ( the one that the blue flexible pipes screw into). Blow out the manifold to make sure there is no blockage and re-fit.

If you remove the flapper valve then you will definately stop flow immediatly - however you will probably find that coolant will take 5-10 seconds to turn on instead which is a whole new problem.

If you DO have an auxillary filter then there are more things we can do to fix this problem without removing the flapper valve.

Hope this helps.

[Pondo]

You can get a check valve that pops in line with the loc lines if you remove the flapper by the pump. It will keep the coolant from sucking back as fast back to the pump. That will work for a while, until it gets stuck open (which it will eventually). You will need to pop them off and back flush + clean them out periodically, but it will stop the problem of dripping coolant and the coolant flowing all back into the tank.

[CORBIN92087]

thanks for the replies...ive got plenty to try now!

[HelicopterJohn]

Hi,

I have attached a link to a video that demonstrates how my PCOOL nozzle works on my HAAS TM-1P with a 3/4HP High Output Coolant Pump with the Flapper Valve removed.

Sorry I filmed the video to try to show more of the cabinet area but in the process it shows the video in a horizontal instead of a vertical position. Hope you still get the idea.

http://s92.photobucket.com/albums/l2...rent=00006.mp4

John