Diagnosing VF-0E way lube problem

[James K]

Hi

The shop I work at has a 99 VF-0E that has been throwing alarm 121 recently, low lube or low pressure. Im fairly new to CNC machines and I am completely unfamiliar with the VF-0s way lube system. I played around with it a little on friday, so im hoping someone will be able to give me a little more insight on what to do next.

The first thing I did was manually pump the tank and watch the pressure reading. It went up to about 40 and then dropped to zero in less than a minute (just out of curiousity, what is the purpose of the hand pump?). I then wrote a little program to jog the axes back and forth and run the spindle while i watched the lube tank. The pressure never rose above zero and as far as i could tell the motor on the tank was not running.

Im guessing the fact that the system doesnt hold pressure very long indicates a leak in a line somewhere. Where in the world do I start looking for leaks?

Thanks

[Eagle View]

Lesson long learned. Call Selway and have them fix the problem and put your time into producing parts. You will end up doing calling them sooner or later and your machine is either running dry or not operational. It does't make busenss sense to mess with it.

I don't work for Haas or Selway but tried for years to maintain my own machines, it costs more in real money to do it the cheap way.

Eagle

[chmillman]

I wouldn't say that the pressure dropping to 0 in less than a minute necessarily indicates a problem (it might, but...). I don't know exactly what the time specs are, but what happens is the lube pump gives "shot" to the system at regular intervals (30 minutes?) which is distributed over 16 lube points, one of which is the air/oil mister for the spindle bearings. I would think the pressure would drop reasonably quickly to 0, as there is no real resistance in the system aside from the oil jets at the lube points. So I'm not sure there's a "leak" In fact, it is just probably "leaking" oil at the lube points... So check your system over a longer time.

It is more likely that you've got something clogged in the line somewhere (assuming the oil level is topped up in the tank). This can happen if you use crappy quality lube, for example. I was warned quite expressly by the service guy to use ONLY Mobil Vactra 2 (what Haas specifies), that other customers which had substituted oils had had problems, including catastrophic failure of spindle bearings because they didn't get any lube anymore. --ch

[ilbebach]

When you manually pump the lube ,the pressure should hold for atleast 4 or 5 minutes.

If it goes to zero like your case it surely means a leak , and most of the other areas are not getting oil...

I agree with Eagle ...better let the service guy handle this problem.. I'm a maintenance guy myself .. I dont mind the operators maintaining other parts of the machines themselves , but the lube portion is quite a messy issue ..

You need to remove all the x and the y and z way covers and look for any puddles of oil that will lead you to the culprit...



good luck
MJM

[lkenney]

Thought some more on this problem. first thing to check is the oil line filter mounted on the rear of the machine not far from the oil tank. It is a small metal can that comes apart and you can take the filter element out to clean it. They do get gunked up sometimes with funky oil or moisture in the oil lines.

Eagle

[M_D]

Averaged out, service guys have created more problems and cost me a lot more money over the years than they have saved, so I avoid using them. When new machines are still under warranty, we have to make a judgment call, are the "free" parts and "repairs" worth the risk, or are we better off to fix it ourselves in order to reduce the risk of damage. We usually have the problem fixed before the service guy could get here anyway.

This has been with various machines and service people. Granted some repair guys are very sharp, at least about certain aspects of machine repair, but many guys are learning on the job (your machine and money), and some guys are slow learners. If you have outside repair people available that can get get the job done correctly and in your timeframe needs, that's another matter.

Assuming that it is always better to hire a "professional" can cost you time and money. It's better to evaluate your skills and circumstances before deciding.

[lkenney]

I have been on both sides of this fence and as much as I like to fix things my self, I am choosing to use more service people. Yes they can cause problems but I found my costs went down when I left them alone and let them work. They got things done faster and better than if I was hanging over their shoulder. My wife and office manager pointed out one day that my "war stories" were costing us $125.00 an hour. We live away out in the sticks so calling support is always expensive costing us a couple hours of travel anytime someone comes. But I am still convincesed that if I need a machine up and I need to be machining I can't afford to fix it myself. Of course I don't have anyone else to put on it to chase down the problem either.

The pressure level does fall of to zero in a short period of time on the Haas oil system when hand pumped. If there is oil in the tank, then, as I said earlier, I would look at the oil line filter and if that did not fix it I would call Selway.

Eagle.

[serviceman]

when you lift up on the handle of the pump it manually cycles it and normally on most machines it should pump about 3 ccs of oil into the system this can be measured by disconnecting the line coming from the pump. normally when the filters are clogged the pressure holds or does not build up properly always check your filters there is one in the tank as well as the external and some machines now have the external filter inside the tank. there are 16 orifices on a vertical mill normally most are 3/0 and the spindle can be 4/0 or other depending on the speed. the distribution points are on the right side of the x axis under the table under the y axis in the front, the y axis in the rear behind the way lube tank and the hose to the air oil regulator, and in the z axis on the left of the ballscrew. normally i tell people to run the axis individually full stroke and watch the gauge sometimes when it hits the bad spot you will see a drop in pressure or a spike. the pump has a geared motor on it and only runs when the spindle is turning or the axis are moving. if you take the pump apart you can see if the motor is turning or check the voltage while the spindle is turning. or stand there while the spindle is turning and make sure the pump cycles at least every half hour or so the parameter is 108000 and that is 1/50 of a second i think 21.6 minutes the pressure should hold 3 or 4 minutes sometimes it will drop to 30 or 20 but it should hold for a while.

[Eagle View]

Serviceman;

thank you for your detailed input. I will file this for later use. I do appreciate the information so clearly written.

Eagle

[HuFlungDung]

Originally Posted by Eagle View Serviceman; thank you for your detailed input. I will file this for later use. I do appreciate the information so clearly written. Eagle

I second that motion!

[serviceman]

anytime, oh there is a pressure switch behind the tank and there is a float switch in the tank that are wired in series the pressure switch you can buy at napa auto parts op6616 or ps126

[JoBwan]

Good Info!!!