Doosan Lynx lube issue?

Hi all,

Don’t know if I really have a problem but suspect I do. Normally, if I do a full day of machining I would typically get at least 3/4 of my coolant skimmer tank full. I can’t remember how long it’s been since I’ve emptied it…at least a couple of weeks and I’ve been hitting it pretty hard. It’s about half full.

I’m using way lube, but not much. Maybe 1/2” from the tank over an 8 hour day. If I push the manual button on the lube pump the pressure does go up but then immediately goes back down. My foggy memory remembers it staying pressurized for at least a little bit after actuation.

Are my linear rails not getting enough lube now? Is the pump dead, plugged, or? I’m guessing it’s not an open line somewhere as the lube would all leak out or my tramp oil would fill even quicker. How to diagnose?

Thanks for any and all help,
Eric

Eric U said:

Hi all,

Don’t know if I really have a problem but suspect I do. Normally, if I do a full day of machining I would typically get at least 3/4 of my coolant skimmer tank full. I can’t remember how long it’s been since I’ve emptied it…at least a couple of weeks and I’ve been hitting it pretty hard. It’s about half full.

I’m using way lube, but not much. Maybe 1/2” from the tank over an 8 hour day. If I push the manual button on the lube pump the pressure does go up but then immediately goes back down. My foggy memory remembers it staying pressurized for at least a little bit after actuation.

Are my linear rails not getting enough lube now? Is the pump dead, plugged, or? I’m guessing it’s not an open line somewhere as the lube would all leak out or my tramp oil would fill even quicker. How to diagnose?

Thanks for any and all help,
Eric

Click to expand...

Hello Eric,
Your description of the manual operation of the pump is normal. There are two Timer parameters found in the Diagnostic Parameters; one for the duration between the pump being turned on and the other for the duration its turned on for. As soon as its turned off, the pressure shown via the gauge will drop to Zero.

There is also a pressure device and an alarm will be raised if oil pressure is low during the time the pump is running. If you were to disconnect a main feed pipe to one of the distribution manifolds and wait for the PMC to cycle the lubrication event, you should see a low oil pressure alarm raised.

In each of the outlets of the distribution manifolds, there is a two piece, spring loaded plunger arrangement; these can get stuck and inhibit the flow of oil. When I'm concerned about various parts of the machine getting oil, I locate the manifolds and disconnect the oil lines from the manifold outlets and observe if oil is coming out each outlet when the pump is actuated manually.

Regards,

Bill

Your machine is adequately lubed and running as it should.
However, if you want to check -
A)Clean machine interior THOROUGHLY.
B)Remove X axis way covers
C) Write a short program to move X up and down at a brisk, but not rapid pace, say around 80 to 100 IPM.
D) Depending on how the Lynx is configured you'll either see "snot" - the way grease from the grease pak, on the linear guides, or you'll see oil running down.

You can also do the same for Z and tailstock.

Make sure you clean everything and button up correctly.

DouglasJRizzo said:

Your machine is adequately lubed and running as it should.
However, if you want to check -
A)Clean machine interior THOROUGHLY.
B)Remove X axis way covers
C) Write a short program to move X up and down at a brisk, but not rapid pace, say around 80 to 100 IPM.
D) Depending on how the Lynx is configured you'll either see "snot" - the way grease from the grease pak, on the linear guides, or you'll see oil running down.

You can also do the same for Z and tailstock.

Make sure you clean everything and button up correctly.

Click to expand...

My Lynx is a Y-axis machine, so the X and wedge rails are exposed. I just ran an axis warmup program I have for about 5 minutes. No sign of extra way oil coming off the trucks. When I used to run this program without coolant I would see clear signs of extra oil dripping down the ways. This is both regular running and when manually activating the lube pump.

Eric U said:

My Lynx is a Y-axis machine, so the X and wedge rails are exposed. I just ran an axis warmup program I have for about 5 minutes. No sign of extra way oil coming off the trucks. When I used to run this program without coolant I would see clear signs of extra oil dripping down the ways. This is both regular running and when manually activating the lube pump.

Click to expand...

OK, if that's the case, then the next step would be to drop the lube tank and check for a plugged input screen. There is a VERY fine mesh screen on the pickup tube. Over time it gets plugged with an odd looking slime which is formed in the bottom of the lube tank. Clean in solvent and give a spritz of air. Clean out the tank as well and refill with fresh oil. Check for flow once reassembled and primed.

From there, there is a distributor block and you can see the lines coming in and out of it.

DouglasJRizzo said:

OK, if that's the case, then the next step would be to drop the lube tank and check for a plugged input screen. There is a VERY fine mesh screen on the pickup tube. Over time it gets plugged with an odd looking slime which is formed in the bottom of the lube tank. Clean in solvent and give a spritz of air. Clean out the tank as well and refill with fresh oil. Check for flow once reassembled and primed.

From there, there is a distributor block and you can see the lines coming in and out of it.

Click to expand...

I cleaned the pickup screen and tank. No perceptible change. Next is the manifold. Any hints on what to look for there?

Eric U said:

I cleaned the pickup screen and tank. No perceptible change. Next is the manifold. Any hints on what to look for there?

Click to expand...

Yes, send some air thru it and see if one (or more) passages are blocked. Could be some of that "pond scum" that accumulates in the tank may have made it to the distributor block.

Pull some sheet metal off the back of the machine.

You should see all lube lines full.

Disconnect each lube line at the connecting point to each guide truck, then work the pump.

The open line should flow like crazy.

Do each line, one at a time.

The lube metering valves can clog over time. First thing I do when buying a used CNC is replace all of them.

Linear guides don’t need much lube, and can run a long time without it. But, obviously you want all the points getting lube over time.

Good luck!

ToolCat