Is the lube making it to the ways?
Our mid-80's vintage Mori ZL-15SM w/ Fanuc 0TT-B has been a great machine since we bought it used about 2 years ago.
One problem that it's always had is excessive waylube consumption.
The (Showa) lube pump has a variable timer for ON time but apparently OFF time in AUTO cannot be adjusted. I've set the ON time from 30000 (30 sec.) to 10000 (10 sec.) with no appreciable change in the consumption - approx. 3/4 of the tank per day.
If one of the SHOWA piston distributors was stuck I would assume that the oil would simply take the path of least resistance and that particular distributor would take more than its share of oil - not cause greater overall consumption.
Can someone weigh-in on this problem with an explanation and a solution?
Thanks in advance.
Is the lube making it to the ways?
NEVER EVER change timers, that is not your problem. You either have a broken flex line, or your manifolds are stuck and need replacement. The manifolds work in the following way, at roughly 180PSI the oil pushes the pistons closed, this allows the system to come up to pressure, where the pressure switch inside the pump tells the control to shut off, after a specified timer. Once the pump shuts off, the manifolds (dester units) spring back to the open position, forcing the correct amount of oil to each line (usually .16cc). When one or more of these stick, the pump will pump right through it, causing excessive oil consumption, but worse, may not close the rest causing damage to the ways or screws.
Very common to have way lube pressure alarms, so people will change the pump first, almost never is it a pump problem.
Dear Mr. Tire,
Thanks for your response. You always give clear, concise answers to questions about machine problems in this forum.
I guess I never really understood how the Showa-type piston distributors worked. Your explanation made it clear.
I've followed all the flex lines to the distributor manifolds and none are cracked, broken, or leaking. This leads me to to believe that one of the piston distributors is stuck. I considered this a few weeks ago and got a quote on replacements. YIKES !!! Replacement units (with six pistons per manifold) were about $600 each !!! But this was from Devco and since then I've found that their prices are about triple what competing lube-parts distributors charge.
But these are Showa units and I wonder if there are cheaper knockoffs?
I remember disassembling a Showa piston manifold apart years ago and with springs, seals, and widgets shooting off in every direction, I promised myself not to do it again. Have you had any luck repairing these?
Is there anyway to tell which unit might be stuck? I have adequate waylube on all the sliding surfaces. The H1 X-axis has the most visible ways and there is copious (if not, "excessive"...) waylube dripping off them.
I'm going back out to the machine to change the timers back to their original values while I anticipate your response.
Thanks in advance,
First, I usually change all all of them at the same time. There are some hidden ones, not sure on your machine. Check in the spindle area, sub spindle slide etc.. Only way to see what individual one is leaking is to pull the lines off and pressurize the system.
And to save you, a little secret is about to be let out....
Allworld machinery parts. Tell them if they don't have them to order on there next stock order. I won't say how much my friend (an independant) buys them for, but it aint 600 each !
So you think that if I disconnect one line at a time I should see one of them "spurting", not trickling? Maybe I'll disconnect all the output lines at a particular manifold, then cycle the pump to see if one is stuck open.
Allworld Machinery is no secret to me. We've used them for years (machine tool distributors) with good results. In fact, many, if not all, of the Chicago-based builders use them too (then step on the prices...) before screwing...er...um....uh..."passing the savings" on to Mr. Customer. I'll give them a call and see what they can do for Showa piston distributors.
Thanks again for your knowledgeable responses. You're the best !
I was being sarcastic, allworld is very popular . What you really want to look for is the one that is pushing oil when the pump in actually running. Might take two people. And if the pump does not have the manual button (some do,some don't) you can press e-stop, then control on. Mori's always pump oil as soon as they come out of estop.
Mr. Tire and others,
I finally got around to trying to track down which of my waylube manifolds/pistons is sticking, thus allowing too much waylube to flow.
I made about 8 short waylube hoses with nuts, tube sleeves, and ferrules. Then, manifold by manifold, installed the short hoses into the ports. With the short hoses pointing upward, I had a helper push the manual PUMP ON pushbutton to cause the pump to make max pressure, then release the button after 10 seconds. As the pump made pressure, the column of oil in each short hose filled equally on all the manifolds/pistons I've tested. I have one more to test in the morning. I fear that the final manifold will not have a piston that delivers too much oil.
Mr. Tire: You explained in an earlier post that the pump builds pressure and the pistons closed. Then, when the pump shuts off and the pressure goes to zero, that's when the pistons should deliver their load. Correct?
My system (Showa pump with DPB-16 manifolds) causes oil to flow as the pump is making pressure. Once the pump pressure maxes out and holds, no more oil volume builds in my short, test hoses. Is this what you explained?
Yes, probably was a clear as mud on my first post. What you are looking for is one or two that keep running oil through. I have found over the years, it's either the headstock or tailstock ones for some strange reason. Re-reading the original post, is it 3/4 of a tank on one or two shifts? If on 2 shifts, thats probably about normal.
Your initial explanation was reasonably clear (I'm just not very bright....)
I'm going to test the final piston distributor this morning.(V-E-R-Y difficult to access on this machine. It's on the bottom of the Head 2 carriage and you have to almost disassemble the machine to get to it.)
When I test the distributors (as I mentioned....) I remove the hard lines from the pistons and install the 6 short hoses I made up in their place. Then, while I'm watching the hoses, I have a helper cycle the lube pump manually. (i.e. push the manual pump button and hold it in for 15 seconds until it builds pressure, then release.) In testing the other 5 distributors on the machine, all six lines output the same volume of oil in the short hoses in that time.
This machine has always consumed much more oil than any other we have. In my experience most machines go through a normal-sized waylube tank in about 30 to 40 hrs. of ON time. (Of course, modern machines often have the waylube cycle tied to SERVO ON TIME and are not cycling when the machine is idle, thus conserving waylube for when it's needed.) This mid-80's Mori ZL-15SM with Showa lube pump and distributors goes through a tank in about 10 hrs. which is excessive even though the ON time is set to 30 seconds and the OFF time is 20 minutes.
Wish me luck. Maybe one of the last 6 pistons I test will be a leaker. (But I doubt it.....)
Thanks for your responses.
As expected, once I removed all the covers to access the HEAD 2 carriage waylube piston distributors and tested them, all eleven piston distributors output the same volume of oil.
So now, having tested every piston distributor on the machine (approx. 40), each one outputs the same volume of oil as the pump is building pressure. None outputs anymore once the pump shuts off.
I've got to reduce the waylube output on this machine by some method. We've had the machine for over 2 years and the problem has been present since day one. I can't believe Mori designed it this way. (i.e. using a tank of waylube every 10 hrs.). But with the ON time and OFF time timers set to factory values, that's how much oil it goes through.
I know you're opposed to changing the timer values but I don't know what else to do. The ON time timer was set to "30000" (30 sec.). I noticed two things while doing my tests: (1.) the short hoses I installed into each piston distributor port filled in the first 5 sec. of the pump ON cycle and didn't increase any as the pump continued to run and build max. pressure in about 10 seconds. (2.) the pump pressure switch input signal (X2.1) didn't come on until max. pressure was made at the 10 sec. mark.
So................ I think I'll change the ON time to 10 seconds which will discharge whatever amount of oil each piston distributor will discharge and allow the pressure switch to close and generate its input signal to prevent the
LUBRICATION WATCHDOG ALARM that happens if the pressure switch signal is not seen every 24 minutes.
This may not change the total waylube consumption much, if at all, since it seems that the output of the distributors is maximized in the first 5 sec. of ON time. But maybe I'll be reducing the pressure in the lines so that when the pistons open, less oil is discharged.
What do you think?