Thread: Lubrication System

Originally Posted by eskimo

Howdy Dave
hope all is well

the bijur resistance metering units are one way...extract from their brochure below

"2) Resistance Fittings
A resistance fitting is the part of the system that proportions and dispenses oil to a friction point. It must be remembered that the amount of oil delivered to each point in the system is apportioned by a resistance fitting, not the lubricator. The lubricator controls the volume of oil available for overall system consumption.
Bijur Delimon offers ten different sized flow devices. Each one is designed for one-way delivery of a proportioned quantity of oil to a bearing or surface."

Hi Eskimo, thanks.

I agree with you there like I said above, but it will still pump whatever amount of oil into an axis depending on the jet size, which are said to come in 10 different sizes above.

Dave

Hello,

well I've been chipping away at this project for a while now. It's almost done and I have tested the system with the help of an oil can. It seems to work well but as expected the leadscrew nut oilers need further restriction in order to balance the flow. I have bough some inline flow restrictors as well as some other ones discussed earlier but they won't arrive for a week or so now .

Someone mentioned (can't remember who) about sliding wiper sniper line up the guts to prevent kinking. I'm gunna try this to restrict the flow. It's a cheap and easy fix if it works. I only have 2.5mm twine which is almost the exact ID so that's no good. I think 2.0 -2.2mm somewhere will do the trick.

I chickened out of drilling a hole in the nut and instead just squashed some line into the cut that has been made for the backlash adjustment. I may yet change this too..

Here's a pic of where I'm at:

Simon

Well the wiper sniper idea didn't work. It was actually too restrictive. I then realised that my stainless electrodes are 2mm. They would have been perfect fit for the 2.5mm ID but the loss of flexibility was an issue. I ended up with a short piece of electrical wire in there. A 2mm wire only required about 40mm length to provide the required resistance to flow.

So far so good!

Simon

Hi Simon,
Looks good. I like the wire idea, i may actually put some in the nut lines too just to restrict the flow a bit more. I just drilled and tapped an M8 hole in the nut, towards the top where there was some meat.
Actually i'm not finished yet, i still have to do the Z jets. Plus i didn't get sick like you.

Made some more progress with my system today. I finished the rear wiper. I had to put the mill table back together to do it. I'm reasonably happy with the result. Nothing too technical here, just bread and butter stuff. The wiper felt I have is too thick for this application but I think I can peel away a few layers to make it thinner.

Also my flow controllers came today. I think I may use them on the leadscrew oilers. They should fit under the mill table with the small manifolds I made. eBay Australia: Buy new & used fashion, electronics & home d

Now I'll have to take the table apart again to fit it.


Simon

Pretty much finished the saddle part of the lubrication system. I relented and attached a couple of flow restrictors for the X and Y leadscrew nuts. These make it a little easier to reduce and control any preferential flow to the nuts since they offer very little restriction to flow compared to the small oil pocket between the ways. I also gave in and drilled a small hole in the X nut to inject the oil into the nut instead of just poking the end of the tube into the small slit made for backlash adjustment.

You will see that the flow restrictors live under the X leadscrew. It looks like it obstructs the leadscrew but in fact there is a poofteenth of a gap to allow them to be glued in place and allows for a neater plumbing job.

The two 8mm oil lines will now be plumbed in behind the mill to another manifold where the Z axis lube line (yet to be done) will also be plumbed in.

There is also a pic of the rear wiper and rubber way cover. The last pic is the oil pump I plan on using to pump oil to the lube lines. I plan on using manual control values for the axis lube lines and a momentary button to supply power to the pump. I may get carried away and plumb in another lube line to another manifold to supply a one shot system to my lathe which lives next to the mill. Same oil, same pump.

Flow control to the individual axes can be achieved with inline flow control values or, by taking your finger off the button quicker. The flow relativities between the ways and the leadscrew nuts is already taken care of with the inline flow controllers under the table.

So this is about it for now. Next post from me on this will be once I have wired and plumbed the pump and done the Z axis.

Cheers,

Simon

More pics:

Well I finally got the last of my flow controllers today (5 weeks after paying for them) so I have finished the mill lubrication system. I thought I would post the photos of the finished project and finally put this thread to bed!

The Z leadscrew gets oil fed through the rear of the column via a steel gland. On the other side of the gland is another pneumatic tube fitting with tube tapping into the Z nut (pic 1 &2). The tube inside has enough slack to move up and down with the Z axis and is protected with some split conduit. There are non return valves on the Z axis to stop the oil flowing into the X and Y axes and there is also one on the Z ways to stop it flowing into the Z nut which sits a little lower.
Finally a non return valve also on the end of the dip tube into the oil reservoir to stop oil flowing back into the tank when not in use. The pump and flow controllers seem to work really well. I just need to make final adjustments to get the correct flow ratios to each axes and leadscrew nuts.

The oil reservoir will eventually sit in a basket attached under the pump. The pump switch is a mom switch housed in a die cast enclosure which just sits at the back of the mill electrical box ATM. I have made provisions for a selection toggle switch on the box too. With a couple of 12V solenoids I will be able to select lubrication between the mill and (later down the track) the lathe

Cheers,

Simon

I forgot to add. I took Jhovel's advice (thanks Joe) and changed the 110V AC motor on the pump to an more manageable 24V motor. I only run it on 12V from a printer power supply but it still works very well and delivers huge amounts of torque. This was a pretty straight forward conversion but I did need to fit the existing gear to the shaft of the new motor and then make an adapter plate to mount it to the existing gearbox that drives the pump.

Thanks again Joe for the idea!

Simon

Nice work well executed Simon. Well done.

Phil

Good work Simon I am yet to finish my Z......

Thanks Phil!

Hi Ewan, come on mate, pull ya finger out!

Now for the next project..... Hand scraper (finally) it shouldn't take anywhere near as long!

Simon

Looking pretty flash Simon,

Novel pump you have there, I have never set my eye's on one of those ?

Does it have or need valve's to pump ?

I assume it would rotate fairly slow but would have a fairly high displacement per rev at a reasonably low pressure ?

john

Hi John,

It's a type of pump classified as positive displacement. It will pump both liquids and gases. The rotor with the rollers that "squeeze" the tube and move the fluid in one end and out the other is driven through a gearbox. The rotor does about 60 RPM's (approx) while it does not pump huge volumes per minute* it is satisfactory for the job employed. It was actually from a treadmill and was used for the automated delivery of lubricant to the deck and belt so it's still doing a similar job. In terms of pressures, as long as the fluid is not too restricted in its flow the pressures are kept low. However, if you reduce the flow too much (ie with the flow restrictors) then it is able to build up very high pressures. I did this accidentally the other day while adjusting the flow controllers and it burst the hose! The DC motor already produces plenty of torque but when transmitted through the metal gear gearbox, it's a little weapon!

No valves are needed on such a pump because the rollers continue on a rotary fashion and keep moving the fluid in one direction so no chance of back flow unlike a diaphragm pump, which is another type of positive displacement type of pump.

* if you do the calcs then it would displace the internal volume of the hose per revolution, maybe a little less. The hose is 6mm ID and about 120mm long so about 3cc per revolution. I have since found that a 2 -3 second push of the switch is plenty to deliver very effective lubrication to all parts. I am also pleased to report that the system stays primed with no air bubbles appearing in between use. This is important to ensure that all areas are getting their 2 -2 seconds of a small amount of lube and not just moving air.

Edit: I just had a second think. There are 2 rotors moving producing 2 x 3cc per revolution, so 6 cc. looking at this figure probably a 1 - 1.5 second burst would be plenty.

Now for a second lube line to the lathe..... Perhaps a little later on...

Cheers and thanks for the interest

Simon