[alan_3301]

This one was about 5 hours of cutting time. I don't remember more than 2 or 2.5 amps. Spindle did get warmer than ambient, but not by much.

https://www.youtube.com/watch?v=UhwZqgQjlak

[CNCMAN172]

Where you making a vacuum table? What was your depth of cut?

Russ

[alan_3301]

copied from the youtube description:

cutting aluminum on crp4848
Onsrud 65-025 Carbide
0.25" Slot cut @ 0.083" DOC 34IPM 11400RPM
Total cut time ~5hrs w/ profile, grid, and chamfer.

[JerryBurks]

You got lucky

130-140F is above what the temperature should be, 120F is normally around the max for reliability, the higher the temperature the grease will run from the bearing surfaces, Plus you have the motor coils that if to hot the insulation will break down

If you are measuring that temperature on the outside, on the inside the Bearings will be 10-20 degrees hotter

Maybe I should be more specific...130-140 is the maximum I have ever seen. That is on a nice California summer day with 100 degrees (I am working out of my garage) and cutting near full load (big bit, deep cut and high speed). I have a stick-on color changing thermometer strip on the spindle and usually run smaller bits (1/4 or 1/8") and even after hours of running the indicated temperature is normally about 5-10 degrees C (10-20F) above ambient. At some point I calculated the heat capacity for the 600 cuft/min of air is indeed higher than for the few gpm of water. Estimating the convective heat transfer is more difficult and so I just relied on my practical experience.

I have posted this method a few times in the past but I guess it is too far out of the orthodoxy having a water cooled spindle with air cooling ;-)

[Azalin]

My spindle is a 2.2kw Chinese. To cool it I'm using a car radiator. Dimension is 120x240mm so I glued two 120mm computer fans to it. The bucket is very small. I think capacity is 200ml max.

As for the pump, I use the cheapest brushless submersible I found.

Been using this setup for 2 years without a problem.

Sent from Shadowmoon Valley

[johnnyt74]

My spindle is a 2.2kw Chinese. To cool it I'm using a car radiator. Dimension is 120x240mm so I glued two 120mm computer fans to it. The bucket is very small. I think capacity is 200ml max.

As for the pump, I use the cheapest brushless submersible I found.

Been using this setup for 2 years without a problem.

Sent from Shadowmoon Valley

That sounds like a similar set up to what I'm going to end up with. I'm glad to hear that you've been using it without any issues.

Thanks all for the great advice in this thread. :-)

[1Jumper10]

Electronic Goldmine - Combo 12VDC Slimline Submersible Pump and Waterproof 15Ft Cable

This is the pump I've used on 2 machines. It's listed for about $26 plus shipping but it regularly goes on sale for $7-$10.

https://www.amazon.com/DROK-Control-...words=Drok+pwm

Pair it with this PWM speed controller and you've got a reliable pump with fully adjustable flow.

I've never used a large reservoir (5 gal etc.) type cooling system. I've always used a closed loop system and recirculated it through a fan cooled radiator. But I lean toward JeryBurk's experience in that the spindles run very cool. I think that just a simple loop of copper pipe in part of the recirculating loop would provide enough heat exchange to cool the spindle.

[Azalin]

Electronic Goldmine - Combo 12VDC Slimline Submersible Pump and Waterproof 15Ft Cable

This is the pump I've used on 2 machines. It's listed for about $26 plus shipping but it regularly goes on sale for $7-$10.

https://www.amazon.com/DROK-Control-...words=Drok+pwm

Pair it with this PWM speed controller and you've got a reliable pump with fully adjustable flow.

I've never used a large reservoir (5 gal etc.) type cooling system. I've always used a closed loop system and recirculated it through a fan cooled radiator. But I lean toward JeryBurk's experience in that the spindles run very cool. I think that just a simple loop of copper pipe in part of the recirculating loop would provide enough heat exchange to cool the spindle.

Looks like a nice pump.

Sent from Shadowmoon Valley

[aarggh]

My machine has had a simple tub with 6 or so litres of decent quality radiator coolant, undiluted, with a cheap (about $20) small submerged pond pump. No fans or anything else required. No noise, no mess.

In OZ we somewhat warm days in Summer and even when I've had the machine doing very intensive 3D machining of large panels with a 1mm ball nose, it can run for 8-10 hours non-stop on just one job and it's never gone above a little warm.

The trick I found to keep it clean and stop any growths or blooms is to keep it all sealed from light and any contaminants, I also place a bath towel over the whole tub to just really keep it clean.

I think it's been around 6 or so years now and the solution is good as new and has never been replaced or topped up yet. If your running long jobs or a much bigger spindle use a larger reservoir of coolant.

cheers, Ian