[Eddiep]

I'm building a simple coolant delivery system with 1/4" loc-line for my X2, and was curious as to what coolant pressure I should shoot for. The pump I've ordered flows 140gph, but has a max output pressure of 5.5psi - will this pressure be sufficient for the intended use?

What would you all consider an "ideal" pressure for this application (benchtop mill mainly cutting aluminum)? Is this an area where more is always better?

[Robin Hewitt]

Apart from the required lift I suppose the limiting factor is the filter on the pump. You don't want too much pressure or the flow control tap will be closed so far it may start filtering even smaller particles and get clogged up.

Any plans for the return piping? I used garden hose and I wouldn't recommend it, clogs up with aluminum swarf anywhere vaguely horizontal and I have to keep clearing it

[Skuzzy]

As I am about to embark on building my coolant system (finally finishing up the table/enclosure), I have to ask.

Why Loc-Line(sp?)? I had just planned on using copper tubing. And when flood cooling is the pressure really that important (as long as the pump can handle the rise from the tank to the flood line exit)?

Should the flood cooling be done using two lines, one on each side of the mill bit? Does it really make any difference?

I have built a strainer panel which sits on top of the support bridge where the mill is mounted. My hope is that it will catch most of the chips and then I am using a simple gravity filter in the drain tub (vertical walls mounted in the bottom with each one being slightly taller than the last).

Should that be sufficient for removing the metal bits from the coolant/lube? Or will the smaller particles float on the coolant/lube?

My return piping is a 1 1/2" PVC exiting straight down from the center of the basin. I have a 2" drop from the outer edge of the basin (48" x 28") to the middle. I hope that is sufficient.

[Eddiep]

Thanks for the replies. I chose loc-line because the stuff is really cheap, easy to use, and very modular (changing length, nozzle size, adding additional lines, etc. is litteraly a "snap") ... I've seen setups on cnczone with copper tubing/compression fittings, and I'm sure it would work just as well as the loc-line stuff. Went ahead and bought enough loc-line to do 2 or 3 coolant lines so I can hit the cutter from different sides... not sure if I'll actually need more than one, but I figure over-engineering it can't hurt (unless the pump I purchased can't keep up with multiple lines).

I plan on using a large stainless steel dark room sink directly under the mini-mill with a completely vertical ~3" PVC drain. The drain will dump into a cheap plastic storage tub (~15"+ wall height) with a fine mess screen set a few inches below the top. The little pump I have coming in also has a stainless mesh screen on the inlet - should be able to pass anything that makes it through the pickup screen without a problem.

I've bought all the parts, so I might as well hook every thing up and see how the pump does before ditching it for something bigger.

[Geof]

5.5psi theoretically gives you a maximum lift of about 10 feet above the pump. You must be lifting about 3 feet from the pump location so at the nozzles you will be getting around 3.5 psi if you are lucky. I think your pump is marginal; with several nozzles you may find the stream from each does not shoot far enough to be useful.

[Eddiep]

That's what I was afraid of. No harm in trying what I have, but I'm already thinking about a good replacement pump. Maybe a well filtered, high pressure automotive pump and a bypass regulator to control the outlet pressure?

5.5psi theoretically gives you a maximum lift of about 10 feet above the pump. You must be lifting about 3 feet from the pump location so at the nozzles you will be getting around 3.5 psi if you are lucky. I think your pump is marginal; with several nozzles you may find the stream from each does not shoot far enough to be useful.

[Robin Hewitt]

I have a DC motor driving the pump so I can control the speed with a conveniently placed knob. It's usually set quite slow, I think what you have may be plenty.

I try to keep the tool overhang a short as possible, so towards the bottom of the cut the oil has to squirt in from the side to avoid hitting the chuck, need enough pressure for that. OTOH if I increase the flow it sprays everywhere.

[Skuzzy]

So do you find you need to adjust the coolant flow direction often? It is not something I had considered. I figured I might have to adjust the angle to be sure the end of the bit was getting good flow, but that was about it.

I am mounting my mill in the enclosure this morning and will start working on the cooling system and getting all the cabling run to the controller.

I am also using a DC driven pump so I can control the flow. The head is rated for 300GPH @ 8psi into 3/8" ID @ 0" lift. I have two of these if there would be a reason to run a second flood line.

Anyone know of a reason why this would be required? I see some use two flood lines while others use one.

[miljnor]

Personaly i think PSI (or Gph) is way more important than flow..

i go for at least 50psi on a fully enclosed commercial machine but since we are talking hobby machines that may or may not be enclosed i would say at least 15psi.

And if your using a 5 gallon bucket like alot of people are using then the flow has to be in line with your source, as you cant flow more liquid than you have for supply.

As for your fine mesh screens, you will have to play with those, as the finer the mesh the sooner you have to clean them.

I use 1/8in hole mesh for my commercial machines and nothing for my hobby machine.

OH and really important what type of pump your using. Must be able to pass solids (impeller pumps are good for this) Gear pump is a NO_NO and diaphragm pumps need really good pre-filtering other wise diaphragm will get punctured.

[Robin Hewitt]

I adjust the direction as the work height changes, to clear my hold down clamps/bolts and to shove it out the way so it doesn't drip when I vacuum the bed.

With only one head I get good coverage on only 3 sides of the work piece, but it still seems to reach to tool on the blind side, heck it seems to reach everywhere. Stopping it reaching the places I don't want it to go is another matter

[Skuzzy]

Hmmm. Where is a good reputable online store to get the loc-line stuff?

The pump heads I have are magnetic drive impeller pumps rated for hazardous material. I happen to have a couple laying around from a previous project. I have pumped all manner of sludge/mud with them and they just keep right on working.

And thank you everyone. I hope to be good enough at this one day to be able to contribute back.

[Eddiep]

I got my loc-line stuff at modular-hose.com ... Depending on what you need, there is a bunch of it on ebay as well.

[Bubba]

My pump started life as a re-circulation pump in an ice machine. Worked quite well until my "filter" failed and a large piece of swarf decided to get between the vane and the housing. So I made up a new impeller to replace the plastic one and made the housing out of pvc pipe fittings. Diameter of the impeller is about 3.5" (Impeller diameter*rpm~= pressure output) in a centrifugal pump.
This combination has been working quite well for some time now. A 3.5" diameter impeller rotating at 3000 rpm is good (neglecting efficency) for about 31' of head (~13psi) and if it has a impeller depth of .5" will produce about 5gpm.
In my case, I use 1/2" poly line to feed my single nozzle on the mill/drill and drain back into the 5 gal. bucket. And I find that I am usually throttling the valve to keep coolant from going all over the shop as my mill is not enclosed. My primary filter is simply a piece of fiberglass window screen stuffed into a 4" piece of pvc pipe in the bucket. Every once in a while, I pull it out to flush the swarf off. So far, it works quite well for a hobby setup.