On Sat, 22 Dec 2018 at 23:50, Gene Heskett <ghesk...@shentel.net> wrote:
The only thing I could not find with any
search terms was a 1/2 to 1 gallon water tank to bury the water pump in.
I have a Chinese water cooled spindle on two different home built CNC
routers. I used a 5 gallon plastic bucket for the coolant tank on
each. They were free with a cat litter purchase. The plastic snap on
top is hinged. The back 1/3 stays snapped in place and the front 2/3
can be hinged open in case I ever need to dump the coolant, add to it,
etc. The lid keeps dust and debris out of the closed loop coolant
system. A small pump is submerged in the coolant and the power cord for
the pump and the coolant inlet and outlet hoses are routed through the
back third of the lid that remains snapped onto the top of the bucket.
You don't need a big pump regardless of the size of the spindle motor.
I use a small Little Giant pump that's often sold for fountains,
hydroponics, etc. I get the best version they make and it's still
inexpensive. Good brands include Superior and the upper end versions of
Little Giant. Here are a couple of possible examples.
https://www.ebay.com/itm/362400850664
https://www.ebay.com/itm/233055122922
I like the magnetic drive submersible pumps for reliability. I'd pay a
little more for a long power cord to get any electrical splices well
away from the coolant and a pipe thread outlet port so you can easily
find a fitting to connect to the weird metric sized very flexible hose
that connects to the spindle motor.
These small pumps don't produce much head pressure (aka "lift"). On the
larger CNC router, I tried to hide the coolant pump under the enclosure
and route the coolant lines on top of the enclosure and then down to the
spindle motor. That didn't work because the pump couldn't push the
coolant that high. I tried a much larger pump trying to power my way
through the problem and the head pressure was marginal. It barely
worked, most of the time, but the pump is cooled by the coolant and the
coolant temperature rose quickly. The coolant was cooling the pump more
than it was cooling the spindle. I finally gave up, went back to the
smaller pump, and put the coolant tank on top of the CNC router's
enclosure so it was pumping down to the spindle motor and back up to the
coolant tank. The pump only needs enough head pressure to clear the top
of the coolant tank. A possible down side is that a coolant leak could
siphon most of the coolant out of the coolant tank, but I used good hose
and it hasn't been a problem. On the small CNC router, I placed the
coolant tank on a shelf behind the CNC router, and it also pumps down to
the spindle motor.
I continue to be impressed with the Chinese water cooled spindle
motors. The quality is very good. They brag about the precision
"German" bearings and they are very smooth and have a very precise feel,
certainly much better than a Porter Cable or Bosch wood working router,
even though I suspect that "German" is the deliberately deceptive name
of a company or town in China. Still, good is good.
Using four gallons of coolant allows the larger CNC router to run pretty
much indefinitely now that the garage shop is air conditioned. When it
was hot in the summer, the coolant would get a bit warm in the summer
after five hours of hard use of the spindle motor. Less coolant means
it will get hotter sooner. More coolant is an easier and cheaper
solution than adding a radiator.
I use the pink RV safe antifreeze as the coolant. I don't think it will
corrode metals as readily as water and it won't freeze in your unheated
shop. Unlike some automotive coolant, this is used full strength.
I buy liquid LCD thermometer strips on eBay and I'll wrap one around the
spindle motor and I'll stick another in the electrical panel so I can
see the temperature at a glance. These are passive thermometers with no
electronics. They're sold for use in pet terrariums for lizards.
Direct reading with no batteries to replace. Be sure to get one that
goes as high as 40C or 104F. The selection isn't as good as I remember.
https://www.ebay.com/itm/253864383162
I wanted to measure the spindle motor temperature rather than the
coolant temperature to catch a fault where the pump stops pumping. I
still need to install a thermal switch on the spindle motor to E-stop
the CNC router if the spindle motor starts to overheat. I wired the
gantry for the thermal switch but never installed it... or I installed
the switch but never wired it into the E-stop circuit. These projects
all blur together in my old brain.
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
