[JMcDonald]

I am building mill to CNC, and I had an idea pop into my head. What if you encased the table in such a way that the entire table could be completely submerged constantly, with water coming up to .5" . 1.5" above the surface of the table? It wouldnt be pure water of course, but probably still something strait-forward like a bandsaw coolant or something (with a standard ratio of maybe 15:1). The X and Y motors would be mounted on the outside of the "bathtub" assembly, rather than on the table itself. The purpose of doing this would be of course cooling. I am building the mill in hopes that I can leave it alone for possibly hours at a time, and I thought it might be neat to literally just fill it up.

I really thought of this because I was thinking how messy it is to use coolant on my drill press, since by the time I get through a piece of .25" steel with a 2.5" hole saw, half my work bench is soaked. I also thought about how much higher and wider the tray on my bandsaw would have to be to really not lose any coolant (I have to add 8 cups of water every week or so of daily work, from it splashing out onto the floor). And in thinking of actually building a tray like that, I kindof wandered into this new territory of simply building it high enough that you could actually fill it with water and leave it.

The water would do a great job of cooling (think how long it would take to heat a bathtub full of water with a lighter...), but obviously wouldnt do much in the way of chip clearance.

So, do you guys think it would be worthwhile to try? The mill will travel 24"(x) x 6"(y), with a fully-supported table, so the box would likely be made so that it just butts up against the front of the column, rather than going around behind it, so the box would only have to be around 48"x12" (plus a few around the edges).

The alternative is building a somewhat more complicated tray of the same size, but with sloped bottoms so the coolant runs back to a smaller area to be picked up again.

*edit*

Other downsides include the water being pretty much useless if I have a vertically mounted rotary table mounted to the mill's table (like if I was milling lengthwise down a rod or tube), since it would be lifted off the table by a few inches. Another downside would be that it would have to be drained if I were to mount a rotary table on it horizontally, or else the motor would be submerged.

[dertsap]

the purpose of coolant is to lubricate the tool and not just to cool the tools or parts,you would still need to use the proper consentrate for milling and drilling
why not build a tray under the mill ? or some type of enclosure
measuring under water can proove difficult as well as checking surface finishes , you'd probably find more disadvatages having your parts submerged than its worth

[Mcgyver]

well thats thinking outside the box, or rather in it - i like to see it because breakthroughs have to be something no ones every done before, right ?D: unfortunately i have to pile on with the naysayers on this one though; tough to clean out chips, surface height will change with different pieces and it'll float away all the way and screw oil and a lot of weight. if you are going from scratch, would an enclosure for flood be easier?

[Geof]

As you describe it possibly the nattering naysayers have a point or two . As a concept for a dedicated machine design though it could have merit. Don't just have a static bath have a high volume flow through to actively flush chips away; making all the bits and pieces of the machine waterproof so you didn't wash away lubricants could be a serious challenge but possibly solvable.

On the scale you are thinking about I think you might find that the spinning tool throws the water/coolant around so much that you do not get any benefit of less mess.

[JMcDonald]

Well, that 15:1 concentration is pretty pretty slick feeling (getting it on your fingers feels kinda like Silicone spray, Id say). 20:1 is actually the normal concentration, but the instructions say you can go down to 15:1 for a little more protection. It also prevents rust, which is another big reason for it.

*edit*

Didnt see the last few replies.

Yeah, you are definately right that it would be both heavy (didnt think about that; probably looking at a good 30 gallons :O), and possibly messy still. I suppose Ill look into it after I actually get the mill together.

[dertsap]

as long the rust inhibitor is enough to avoid rust as you had meantioned then that kind of concentrate would probaby be ok , ive only got my handy dandy can of WD for at home , its hard getting out of the 8hr/day way of thinking at times ,
i can see some benefits to the idea but the disadvantages outway it in my eyes , the extent of the table would be limited to within the box size , which would mean no overhanging long parts , even simple things such as cranking the vise handle within a confined space can be troublesome.

im not trying to kill your idea at all ,it may work to your liking , but take all things into concideration , take all the factors you will be facing when it comes to fixturing or what have you , and try to work that into your design so that down the road your not faced with something that should be so simple being near impossible to accomplish

[DJPLAST]

Carry a tub of water across the shop (at a good pace) and see how much fluid gets splashed out in the process. Water weighs 8 lbs per gallon. Do you have enough stepper motor capacity to handle the extra weight? What stops the slosh at the end of the rapid move? I have run static tankfuls of EDM fluid for many years. Cranking a full tank at a rapid pace and then abruptly stopping can get the shoes a little wet with fluid.

[JMcDonald]

I was actually thinking of having the table move through the water, rather than carry the water. However, I did later think of doing what you are describing, which would be have the table carry the water, but then it would have the effects you are speaking of.

[HuFlungDung]

Having cut a few molds that tended to fill up with coolant as the cavities got deeper, I must say that I don't like submerged machining. The chips cannot get away. If you've got enough water pressure to blast through standing water to move the chips, then I think you will get splashed a wee bit, too.