[Zuni]

I have no clue about hydrodynamics, so I was wondering if anyone sees any reason I couldn't pump spindle coolant through the two smaller internal chambers that run the length of a 3060 t-slot gantry, using the gantry as a big heat dissipator?

I think it would be pretty simple to pump the coolant into one of the ports on the end cap, pictured below, then out through one chamber and back through the other then to the spindle and finally back to the pump. This way, plumbing would be minimized and other radiators would be eliminated.

I know it's a bit of overkill pumping the coolant through 120" (60" out and 60" back) of aluminum, but I want the ports to be on one side of the machine only.

Thoughts?

Thanks,

--Mark



The end plate on the left would have one line connected to the pump outlet and the other line connected to the spindle inlet. The other end cap would be on the opposite end of the gantry and simply plumbs one of the smaller inner chambers inside the gantry to the other:

[Baxy]

It should work very nicely, although you need to be careful with the coolant selection to make sure that you don't have any corrosion issues.

[AssassinXCV]

If anything, the extra travel would be good. My above ground pool is heated by running water through a ton of black pipes that the sun rays heat up, and then the water travels back to the pool. It works quite well; so this should to.

[diyengineer]

Should work very nicely, as long as you can keep it leak free.

[restless1]

you might need rubber gasket material on the mating plates!

[Herbertkabi]

Perhaps I do not understand what you are doing but ...
My older cnc router there I did filled all these profile gaps and lacunas with epoxy/sand mix - machine did come much more rigid, less vibrations, no resonance.
Spindle cooling I decided also by own way - milling coolant (spec. oil/water emulsion) comes first of to the Spindle, cooling the Spindle and then through spindle to coolant nozzle. Coolant collector, filters, pumps are under the desktop. Filters are two, first is like sieve inside collector, second is fine filter, 20 micron water filter.
Works perfect!

[Zuni]

you might need rubber gasket material on the mating plates!

Yeah. I didn't show it, but I was thinking of a 4"x6" piece of flat inner tube rubber sandwiched between the end plate and the gantry on both ends.

Perhaps I do not understand what you are doing but...

I'm simply pumping coolant down one passage inside the gantry and back up through another passage to cool it:

Spindle cooling I decided also by own way - milling coolant (spec. oil/water emulsion) comes first of to the Spindle, cooling the Spindle and then through spindle to coolant nozzle.

That's quite a good idea, since you already have the coolant in the area of the spindle anyway.

Unfortunately, my machine won't have a cutting lubricant/coolant system, so I was just trying to come up with an extremely simple method to keep the spindle water cool using as few extra components as possible.

[Zuni]

It should work very nicely, although you need to be careful with the coolant selection to make sure that you don't have any corrosion issues.

Good point. What do folks do when they use those aluminum computer-cooling radiators with a spindle cooling system? They must have some sort of corrosion-inhibiting coolant that is suitable for running through aluminum radiators and steel spindles.

[wcarrothers1]

I would position the inputs and outputs of the tubes toward the bottom and top corner of the square opening to reduce air bubbles in that chaimber.

b.

[jsheerin]

You might want to figure out how much weight you'll be adding to the gantry with the liquid and make sure your motors won't mind pushing it around.

[Drools]

I have seen a companies use the internal chambers of 80/20 for compressed air lines so using them for a water reservoir should work fine.

[svanommen]

Neat idea but sounds a little overkill and could cause more problems than fix (weight, leaks, etc).

I thought I had read these Chinese spindles don't need much in the way of cooling. Most folks just circulate some water into a 5 gal bucket with a small pond pump. Right?

At work our water-cooler had a slow leak in the cold water tap so they were gonna toss it. I rescued it with the idea of possibly chilling my spindle water 'just for kicks'.

[diyengineer]

Fluid XP+ Fluids | Page 1 | Sort By: Product Title A-Z - FrozenCPU.com *

Any of these are aluminum safe.

Your idea will work very well.

[Zuni]

You might want to figure out how much weight you'll be adding to the gantry with the liquid and make sure your motors won't mind pushing it around.

Hmm...Now you've got me wondering. I just STARTED to add up the gantry weight and find that just the 3"x6"x72 1/2" T-slot gantry plus the 1/4"x7"x60 1/4" cold rolled steel rail alone weigh in at 75 lbs total! That's not counting the entire z-axis and spindle hanging off there or the x-axis carriages or the y-axis rack and pinion drive setup.

What's all that add up to...110-120 lbs maybe??

It all has to be moved along the x-axis rails by (2) 380in/oz steppers powering ring and pinion drives. I wonder if this is gantry is too heavy even without 2 of the small inner chambers filled with water...?

[jsheerin]

Mine's over 140 pounds and works fine using motors that aren't as good (425oz*in).

[CarveOne]

Hmm...Now you've got me wondering. I just STARTED to add up the gantry weight and find that just the 3"x6"x72 1/2" T-slot gantry plus the 1/4"x7"x60 1/4" cold rolled steel rail alone weigh in at 75 lbs total! That's not counting the entire z-axis and spindle hanging off there or the x-axis carriages or the y-axis rack and pinion drive setup.

What's all that add up to...110-120 lbs maybe??

It all has to be moved along the x-axis rails by (2) 380in/oz steppers powering ring and pinion drives. I wonder if this is gantry is too heavy even without 2 of the small inner chambers filled with water...?

Moving it along the rails isn't the issue. It's accelerating the additional mass and reversing directions quickly.

If it were me I would daisy chain all available cavities. The added water weight won't be so bad. A little over seven pounds per gallon, and you will be sealing all of the cavities with gaskets anyway. If it gets too heavy just reconnect the fittings, and then blow the water out of the unused cavities with an air compressor hose at low pressure.

CarveOne

[Zuni]

If it were me I would daisy chain all available cavities. The added water weight won't be so bad. A little over seven pounds per gallon, and you will be sealing all of the cavities with gaskets anyway. If it gets too heavy just reconnect the fittings, and then blow the water out of the unused cavities with an air compressor hose at low pressure.

OK..I finally sat down and did the water weight math for my 72.25" long gantry:

The small chambers contain about 46.96 cubic inches each x 2 chambers = 93.93 CuIn of water.

The big chambers contain about 306.5 CuIn of water each x 2 chambers = 613 CuIn of water there.

There are 231 Cubic inches in a gallon of water so:

The smaller chambers combined will hold .4 gallons at 8.3 pounds per gallon comes to 3.38 pounds of water in both small chambers.

The larger chambers combined will hold 2.65 gallons at 8.3 pounds per gallon comes out to 22.03 pounds of water in both large chambers.

Put all 4 chambers into play and you've 25.41 pounds of water weight added to the gantry.

Needless to say, had a little free time on my hands tonight...

[CarveOne]

8.3 pounds is more than I remembered, but it's correct. 20 pounds of water will be dead weight but will also help dampen gantry resonance. I didn't know that your gantry is that wide. I would still try filling all cavities and see what happens.

CarveOne

[RomanLini]

Pay attention to the heat pathways. If you run water down and back the 2 smaller diamond tubes, you will have what acts as a heat exchanger.

That means final water at the end of tube 2 will be in close thermal contact with the hottest inlet water, a worst case scenario trasnfering the heat back into the water before it exits!

I would run the hot water in both tubes at one end, then extract the cooler water from both tubes at the far end, this will be much superior.

Also I would add 2 small fans (40mm?) to the 2 larger diamond tubes, and pump air the reverse way up the tubes, so the cold air enters at the end where the cool water exits.

Fans work better in extraction so put them at the hot end, extracting the air.

Hope that makes sense!

[CarveOne]

Plumb the cavities in parallel then. Feed all four from one end and collect them back to one hose at the output end.

"General Overkill" would prefer to use an array of Peltier devices along the extrusion's full length and a bridge circuit controller to vary the current through the devices to automatically regulate the water temperature within one degree C (or F) of a desired setting, and a big power supply to run it.

It could also double as a shop heater when not running jobs. Just reverse the dc polarity to the devices.

CarveOne