Deep Well Pump for increased coolant pressure and improved chip clearing?

Hello everyone,
I recently started retrofitting my CNC Lathe to a more modern controller.

Since I am now already tearing into the wiring and programming anyways I tought I might as well upgrade the coolant system while I am at it.

While looking into DIY cooling solutions I stumbled across many people using sump pumps to circulate their coolant.
However, thes cheap ones typically only have a head of approx 30ish ft. which should only result in a max. coolant pressure of ~10psi.

Since there is no significant difference in price when you buy import quality, I was thinking one could use a deep well pump like this one instead: 370W 500W 750W Solar Water Pump DC 24V 48V 60V Submersible Well Pump With MPPT Built in Controller Stainless Steel Ship from ES|Pumps| - AliExpress

They are typically rated for 300+ ft. of head and have a peak flowrate of 8+gpm. They should thus be able to deliver plenty of coolant pressure. Some of them also have stainless meshes that keep potential chips out and are rated for use in sandy waters, so they should be able to handle any abrasive particles that are small enough to slip trough the meshes.

Pretty sure 100+ psi is overkill and might actually separate the loc-line if that kind of pressure really builds in the circuit, so I'd probably also need to hook up a pressure reducer of sorts somewhere in line. I'm also considering using a small-ish accumulator tank and a pressure switch as a possible solution.


Posting this because I'm wondering if anyone else has already tried this as I couldn't really find any references to it, tough that might be because deep well pumps are such a hotly discussed topic on the internet, or perhaps because this is a really bad idea

If you or anyone you know of has tried this, what were the results? Would you recommend going down this path?

Perhaps someone also sees something immediately obvious why this is a bad idea and can explain to me why nobody is doing this?

P.s. yes the lathe is in an enclosure, so aside from the finer coolant mist I should be able to easily deal with the increased messiness of using a "high pressure" coolant system.

Cheers
B

One issue would be sucking the sump dry. If that happens, you will damage the pump most likely.

I'm guessing your sump does not have enough capacity to support the capabilities of the pump.

submersible pumps have a flow curve which in sure you know. and maybe that pump will do it but it requires roughly 1 hp to lift 8 gallons per minute 300' so it might work for what your doing but the watts dont match up with standard deep well water pumps

Unless you are doing a lot of deep hole drilling, I would not try for higher pressure. It won't help with normal machining but it sure as hell will make a mess with your turret sealing. More problems for no benefit, eh.

EmanuelGoldstein said:

Unless you are doing a lot of deep hole drilling, I would not try for higher pressure. It won't help with normal machining but it sure as hell will make a mess with your turret sealing. More problems for no benefit, eh.

Click to expand...

It absolutely does help. High pressure directed coolant turning tools are not a gimmick.

I have two identical heavy duty lathes, the older one has basic flood coolant, probably like 15-30psi. When we bought the second one we specified the high pressure coolant option. It is like 300psi, so not super high pressure, but the difference is very easily noticable. Better tool life at higher surface speeds, massively improved chip control.

I wouldn't buy a new lathe without it now.

It's hard to believe that high pressure would help...but then, I haven't used it. I guess what you're saying is it acts like a pressure washer and blows the chips away?

As for the submersibile pump, I think they are really meant to do two things you don't need - lift water long distances, and fit in a small cylindrical space. I'd have to think there are better pumps out there for a sump.

GregSY said:

It's hard to believe that high pressure would help...but then, I haven't used it. I guess what you're saying is it acts like a pressure washer and blows the chips away?

As for the submersibile pump, I think they are really meant to do two things you don't need - lift water long distances, and fit in a small cylindrical space. I'd have to think there are better pumps out there for a sump.

Click to expand...

By itself it maybe doesn't do much. But used in combination with directed HP coolant holders, it makes a big difference to chip formation and edge life. The 300psi that I have in that machine is not sufficient to take full advantage, but it's noticeable nonetheless.

Video below explains in the context of superalloys, but the benefits are the same in any material. Sandvik video, but all the usual names make similar tools.

For boring and grooving the benefit is most noticeable of all.

I agree that a borehole pump is not suitable. Plain stacked impeller pumps exist for this.

Why not use a pump that is fit to the purpose?

Grundfos Product Center | Grundfos product center

Omnimuller Inc said:

Hello everyone,
I recently started retrofitting my CNC Lathe to a more modern controller.

Since I am now already tearing into the wiring and programming anyways I tought I might as well upgrade the coolant system while I am at it.

While looking into DIY cooling solutions I stumbled across many people using sump pumps to circulate their coolant.
However, thes cheap ones typically only have a head of approx 30ish ft. which should only result in a max. coolant pressure of ~10psi.

Since there is no significant difference in price when you buy import quality, I was thinking one could use a deep well pump like this one instead: 370W 500W 750W Solar Water Pump DC 24V 48V 60V Submersible Well Pump With MPPT Built in Controller Stainless Steel Ship from ES|Pumps| - AliExpress

They are typically rated for 300+ ft. of head and have a peak flowrate of 8+gpm. They should thus be able to deliver plenty of coolant pressure. Some of them also have stainless meshes that keep potential chips out and are rated for use in sandy waters, so they should be able to handle any abrasive particles that are small enough to slip trough the meshes.

Pretty sure 100+ psi is overkill and might actually separate the loc-line if that kind of pressure really builds in the circuit, so I'd probably also need to hook up a pressure reducer of sorts somewhere in line. I'm also considering using a small-ish accumulator tank and a pressure switch as a possible solution.


Posting this because I'm wondering if anyone else has already tried this as I couldn't really find any references to it, tough that might be because deep well pumps are such a hotly discussed topic on the internet, or perhaps because this is a really bad idea

If you or anyone you know of has tried this, what were the results? Would you recommend going down this path?

Perhaps someone also sees something immediately obvious why this is a bad idea and can explain to me why nobody is doing this?

P.s. yes the lathe is in an enclosure, so aside from the finer coolant mist I should be able to easily deal with the increased messiness of using a "high pressure" coolant system.

Cheers
B

Click to expand...

What model lathe, and post some pix please.

gregormarwick said:

It absolutely does help. High pressure directed coolant turning tools are not a gimmick.

Click to expand...

Did you notice the OP is "retrofitting to a more modern control" ? Five'll getcha ten this isn't a GM supplier situation ....

EmanuelGoldstein said:

Did you notice the OP is "retrofitting to a more modern control" ? Five'll getcha ten this isn't a GM supplier situation ....

Click to expand...

Kind of glossed over most of his post tbh. He said is lathe was enclosed. It could be a real machine, but of course it could also be a Denford or Enco with a 4" chuck and steppers

gregormarwick said:

Kind of glossed over most of his post tbh. He said is lathe was enclosed. It could be a real machine, but of course it could also be a Denford or Enco with a 4" chuck and steppers

Click to expand...

Yes, and with the OP's linked pump, what doo you doo on a cloudy day, or at night ?

Walrus America Inc.

these people make a great assortment of low to high pressure coolant pumps also
plus reasonable price point

You do not need a deep well pump. A deep well pump is only needed if the water level is below about 25 feet. A shallow well pump will work fine. Do you mean a jet pump? Again not needed and the jet or venturi could clog with swarf.
Bill D

The reason for low pressure pumps for machine coolant is as much the environment they operate in as anything. Most of the old Gusher and similar pumps are technically cantilever pumps, same as used in parts washers. They are a centrifugal pump, but the impeller and volute are down at the end of a long shaft, keeping the seals and motor way up out of harm's way. Harm being in the form of chips, dirt, and other nasty things that do bad things to pump parts. They have extremely loose clearances so they don't clog or wear. Any pump generating 300psi is going to require some very special care and filtration to have a reasonable life expectancy.

Mike C. said:

The reason for low pressure pumps for machine coolant is as much the environment they operate in as anything. Most of the old Gusher and similar pumps are technically cantilever pumps, same as used in parts washers. They are a centrifugal pump, but the impeller and volute are down at the end of a long shaft, keeping the seals and motor way up out of harm's way. Harm being in the form of chips, dirt, and other nasty things that do bad things to pump parts. They have extremely loose clearances so they don't clog or wear. Any pump generating 300psi is going to require some very special care and filtration to have a reasonable life expectancy.

Click to expand...

yep
the high pressure stuff is generally prefiltered

Okay, so for some reason i was under the impression I would get a notification of sorts when someone replies to this thread. That wasn't the case, hence my long inactivity.

The machine is an Ecoca El-4610E. I usually fill the sump with ~ 13 gallons of liquid if I fill it with a new coolant charge. That gets it to about 2/3 of max capacity. So I'm not really worried about running the sump dry.

I currently don't have access to the machine, so I can't really provide any meaningful pictures of it, but will do so next week.

I also heard that high pressures might improve surface finishes and am curious to see what that is about, but mainly wanted to convert to high(er) pressure to have it at my disposal when I am doing the occasional deep bore. I am also considering to play around with trough tool coolant at some point down the line, in which case higher coolant pressures might come in handy once again.

The currently installed pump seems to be an underpowered unit which got installed by the previous owner of the machine. There is plumbing for two separate coolant outputs on this lathe, and one of them is currently blocked off. Still, I only barely get a dribble from the other output. So some sort of replacement is due anyhow, the question that now remains really is what it is going to be.

Yes there are coolant pumps specifically designed for this purpose and I am sure they would fullfill all my requirements, but those cost about 5 times as much as the proposed deep well pump, and are designed for continous operation and can handle a lot of abuse. I am more of a "use the machine at the most 4-5 hours a week" kind of person, so perhaps a 300+$ pump is a bit overkill. I am aware that the deep well pumps are not really designed for this purpose, but since it is designed to operate in muddy/sandy waters I figure there might be enough overlap between their originally intended use scenario and this application that it might work anyways.

I was thinking of putting a T behind the pump and feed one of the lines directly back into the sump trough a valve of some kind. That way I can control output pressure of the coolant and not have the pump working under full load all the time. I'll also probably install a sediment filter with a 10 micron cartridge on the output, so that I'm not recutting any chips that make it trough the pump.

As far as pre-filtration is concerned, I plan on putting a 200-mesh screen in the drain of my chiptray and perhaps wrapping the intake of the pump with a 500 mesh screen.


Genreal consensus currently seems to be that the pump doesn't really seem suited for this situation, but other than that I don't see any real objections to trying this apart from potentially messing up the turret seals.

Part of the reason for upgrading the controls is that I currently have to rely on manual toolchanges like some sort of savage because the machine came without a toolchanger installed and/or appropriate software to edit/backup the ladder. (machine is about ~20 years old, but has surprisingly few hours on it)

However, fitting a turret really is stage two of this project, and I haven't done a lot of research into them so far, since I've never had the luxury of using a machine that had one.

Because of this I am not really aware what exactly was meant by the post of EmanuelGoldstein, and what the potential issues are that he has raised. Could someone please clarify this?

So you have a small, semi-enclosed centre lathe with a teach style control, currently equipped with a manual toolpost, and probably equipped with the original coolant pump, as a dribble of coolant is about all you get on a machine like this.

Any bigger pump that you put in there, you're going to have a very hard time keeping the coolant in the machine, and out of places it's not supposed to go. Machines like that are just not designed to have any volume of coolant flying around inside them. Exposed ways with basic wipers, minimal spindle sealing, servo motors and cabling inside the working area etc. etc.

At the very most, a 30psi single stack impeller pump, and even that would probably require flow restriction to keep the coolant contained. Completely new piping would almost certainly be necessary also.

Re. the turret, you have less than 130mm centre height from the cross slide - that's a very small envelope for any kind of vertical turret. A four position horizontal automatic toolpost might exist that's small enough, but I am not aware of one.

What do you intend to use a reservoir for your coolant? A deep well pump is typically about 2+ feet long and designed to have a continuous supply of cooling water going past it to cool the motor. Recirculated water will get warm and overheat the pump. Also, a pump sleeve is really needed to provide proper cooling.

My well pump might run 15 minutes a day, probably less, 45 seconds at a time

I would not think your average well pump is rated for continuous operation