sorry
 

I mean to go outside of the building manual / recipes..:o

/oopz

Congratulations Ken. Nice build.

Joe #53

Ken, congratulations on an excellent build. I tried a submersible pump and found that the pump was heating the water along with the spindle. Keep an eye on the temp for a while. You may have to move to a bigger reservior. Also, is that an ER-16 collet or ER-20?

I believe the chinese spindles come with the ER-20.

From memory and someone please correct me if Im wrong! the wattage of the pump will generate the same watts in heat back into the water / coolant.

Cheers
Tony.

I dont know why people are using submersible pumps in tanks of water. I know that the larger the volume of water is the longer it will take to heat up. Thats obvious. And most likely the water will never reach the same temp as the spindle. So you can run a cooling system like this. But the spindle will be running hotter than need be. Why not close the loop and throw in a radiator or heatercore to cool the water back down?

Took enough observation of my water cool "system"

My ambient temp is ~30C +/-2 day or night, 24/7, year round.

Pump wattage 7.2W

Operation Flowrate 310ml/min

Water temp in room =29.5C

water temp with pump on, spindle off = 30.5C

Spindle running over 1/2 hour cutting. = 45C & rising.

Spindle running over 1/2 hour w/o cutting =41.2C & stays.

To improve the operation temp, I recon either
1) a bigger reservoir, present is 2.5L
2) paint the reservoir black
3) use metal reservoir painted black
4) have a copper coil element as radiator but this will ass more restriction to the flowrate which really bothers me.
5) have a fan blowing the reservoir, but this defeats the use of water cool spindle don't you think so?

The water does reach the temp of my spindle which is not desireable hence I switched it off immediately, the cause of this particular case I presumed was because my cutter was rubbing more thrn cutting... created lots of smoke & charred the cutter as I kept pushing the test cut for an extended period of time because I didn't know you are not suppose to see smoke from the wood & make charcoal :)

Ken

Rule 1 - no smoke
Rule 2 - see rule 1

Cooling.
You can paint stuff black until you are blue in the face (hehe) but it won't cool things at all. If you got one degree improvement by painting a reservoir black I would be surprised, the reason being is the boundary effect, that is, the air is not moving around the black object so it fails to dissipate heat well. A fan blowing on the black object breaks the boundary and allows the object to transfer the heat to the surrounding air. Hope this helps.

Regards Ross

does the spindle have a built temp sensor? How do you know the water is the same temp as the spindle? I highly doubt it. Using a fan to cool the coolant does not defeat the purpose of watercooling. Fans are used all the time with watercooled applications. There are fanless cooling systems out there but depending on the app they just aren't as good as systems with fans. Or to be more specific, systems with a cooling element such as a radiator with air moving through it. Depending on the app it doesnt matter how much air is flowing through the rad but that there is some air to carry the heat away. You can have a massive amount of air flowing through but if the rad can only dissipate so fast the excess air is wasted and loud. Same goes for flowing coolant. Does matter how fast the coolant is flowing only that the cooling is flowing. The coolant spends the same amount of time within the spindle and radiator whether the flow rate is twice as fast or twice as slow. The whole system works together to achieve good results.

Having a large reservoir is good for the same reason for having a large wateblock, it takes longer to heat up the whole mass or volume. Waterblocks are used to remove heat from cpus or gpus within a computer just incase someone doesn't what I mean. The mount ontop of the cpu etc.

My recommendation is to close that loop with a good size rad with a fan or two or three. The cooler the better. Everything runs better when cool. Well most stuff atleast.

I have a IR thermometer. I measure the water temp & the spindle body temp.

Back to basic, heat travels in 3 mode, radiation, convection & conduction.
Painting black help in the radiation department, no matter how little, it helps.
Bigger reservoir give bigger surface for conduction, I'm not bothered by the seemingly small amount of heat transfering media (water), its the surface area that I'm after.
The cheap contianer was choose because of its very thin walls (less then 1mm) to make up for not so great thermal conductivity; Its also transparent so that I can see water flowing, no need to install flow sensor... Also a huge 4" lid. & cheap...
Changing plastic to metal always help in thermal conductivity, I can also add fins to it easily, but metal are not transparent...
Adding a copper coil in the inlet &/or outlet will work like a radiator, but that means the equivalent pipe length will increase significantly & hence the frictional head. We all know aquarium pumps are not built to handle static head & I can't find a fountain pump small enough to go into the container.... but this I'll try, I feel that I must have at least 300ml/min flowrate to safeguard my sanity.
Fan gives force convection but without a fan I have one component less to look after... & no fear of overheating when fan broke down...
I will have a huge 300W industrial fan in the shop to cool the occupant (me) & hopefully keeping dust in check. This will give some help in convection.

I can get 30W peltier cooler c/w heatsink for less then US60, but then again, I'll have to take care of it + added complexity in the electrical department which isn't really what I like...

Also I can buy a ~US90 1/8 hp coolant pump with a 24L/min flow 6m head. Pump from a 5gal steel tank through 6m of pipe to the spindle & get it over & done with, but its just not me...

Now that I had made dust, I learn a few real life situation... cutting without a dust collector is ... errrr.... dusty... as there are no partition in my shop :o I need to constantly clear the dust everywhere...
Came across a locally made dust collector w/o the cyclone in my local friendly hareware supply store. The blower has a 18" impaller & 3hp motor for ~US400, the correct hardware for a Billpenz cyclone;). Seriously considering the purchase to save some fabrication time....

Ken

Also thought of the peltier myself, even had someone incorrectly explain to me that it would not work as it had a hot side and a cold side !!! A strong opinion and no idea often is substituted for good advise hehe,

Might I suggest that you concentrate on the options that are likely to yield the biggest response. Using a car as an example, it has a radiator, a fan and a pump but it cools best of all when its moving. Air over the cooling radiator is the key and the more air the better as the temp is hotter while the car is stationary rather than ripping down the motorway at 100kph.

Regards
Ross

Radiator + fan sure will work, its another brute force method, it is also over engineering & complecating a simple task... Moreover, if any part of it fails, the spindle will burn along with it! It will also add weight on the y-car... totally contradict with my life philosophy.
My objective is to the reservoir temp 40~45C. no need to bring it below 30C which is lower then my ambient temp. Ultimate goal is running without a pump, just convection like a water tube boiler.... but my primary objective here is to build & run a MM...

Ken

Problem solved - Use a 44 gallon drum !!

Regards
Ross

Ken, I'm running a 3KW spindle and this is what my cooling system looks like. I used an old aquarium which cost me nothing. I purchased a coolant circulation pump for about $45 and that's that. The water temperature never gets above 36 degrees C, even when cutting 18mm stock single pass with a 12mm cutter for 4-5 hours straight. The only modification I would make would be to move the pump to the other side of the aquarium.

Ehh this is totally preference. I would rather have a small compact system on my ycar than have a huge bucket of water taking up space on the floor. Also the only thing that could fail on my idea of a cooling system that could cause damage to the spindle would be the pump. But your system has one too. You can try for a pumpless system so you don't have to worry about a failing pump. But if its not your pump failing will be be something else failing... spindle, stepper, etc.

Good luck.

OK I have a water bucket with a lid and a small hole for air to get in, then the pump outside - today I failed to notice that a foot and a half of teak wood saw dust was engulfing it and yet it was running fine - I was so worried when I noticed this - touch wood!

was this relevant??? :D

Guys, thanks for contributing solutions to my potentially lethal problem (at least to my spinbdle)

As resources dwindles.... cost is eating me alive...

David, Irfan, The 1/8 HP pump I mentioned is exactly the one in your pix, even comes with a strainer. They are build to run metal chips so it should have problems having thick teak shaving going through, only worry that would choke up the water passage within the spindle... but double the price which I feel its too pricy. Instead of a aquarium tank, I was thinking more of an empty 18L lub oil bucket which I normally use as dead weight but I like a fish tank better :D... if I can see one... Irfan, I recon you should have an in-line filter or seal the reservoir to keep wet wood fines choking up the spindle water passage, as we know spindle is one of the more expensive critical item on our MM even with good Chinese price.

Ross, 44 gal barrel.... I would keep the barrel for a BBQ pit project... ;)

Charles, In today's world, everyone had learn that Everything will fail... someday... somehow...
No one is expecting anything to last till eternity...
I am still observing the reliability of my present setup, its certainly cost effective & robust enough for this application BUT the aquarium pump is not exactly industrial component...

Ken

The most simple solution is running a pipe directly from the town water supply and out the other side of the spindle. This solution has no pump, no reservoir, is always cool and uses the head pressure already supplied by the city water supply. We buy water here in kiloliter increments so running a machine for hours is it not that expensive. An example is running the machine using a slightly greater flow to the "Beer Glass Test" at 400ml per minute for 6 hours will use 144 liters of water. Some will say wasteful however the water is still available for other uses after it has run through the spindle, it has not gone anywhere.

PS I was kidding about the 44 Gallon drum but it served to highlight how to quickly solve your water temp issue by increasing storage volume to ridiculous levels. To explain it in other terms that is why one bar heater will never warm a whole house no matter how long it is turned on.

Very impressed by your back to fundamentals on how heat is dissipated but good scientist is always mindful of the relative size of the effects to each other. You have a very good tool in your non contact thermometer to measure the effects, so blaze away and have the facts speak for themselves. It is often very illuminating just how loudly facts do speak over pure theory or strong opinions.

PS Nice Penguin !!

Regards
Ross

This place is special because most members are hands on people, taking the effort to build a MM says it all.
Its an occupational hazzard to obtain numbers by simulation models & taking measurements as much as I could. It helps cut down many wasteful hours debating what works & don't.
Flowing tap water is a good option but some how feels wateful to me even though I don't subscribe to tree hugging. I did consider making an evaporative air conditioner using the water but as wet temp in my place is not really great (26C) I won't get meaningful cooling effect.
The system which David & Irfan using is IMHO far more practical. I will go that way when production picks up & mm starts paying for herself.
This aquarium based system is something I must have a go at to cure my amneasia & curousity. Will continue to keep an watchful eye over its closely...

Just a warning on municipal water: we used water to cool drawing dies and we had two sources: municipal water and mill water. We ran the tests and contrary to popular belief, the mill water was much cleaner than the municipal water, which in fact was very corrosive. Would it not be better to have a recirculating system through a big plastic tank? I would add some inhibitor to counteract the corrosive effect of the water.

I totally agree. You guys are running distiled water through your cooling systems right? Also you guy should be using anti-corrosive and anti-microbial additives in with the distilled water. Regular tap is very harmful to the water cooling components.

Not to that extend, I use tap water, leave them over a few day for the chlorine to evaporate the add a few drops of car shampoo as anti-corrosion & anti-microbial agent ;)

LOL. Your actually better off adding a bit of green antifreeze as an anti-corrosive/ microbial to some water. I stopped using tap water as part of a 50/50 mixutre of green antifreeze with my truck. Because the tap water literally corroded my heatercore which took me a good amount of time to replace. No I buy the 50/50 bottles which are premixed. Straight up.

Ken, I don't think the concept "anti-freeze" is well-known in Malaysia! :D

LOL. Well he's got to have something other than car soap. That doesn't cause a ton of bubbles to form?

LOL, Anti-seize would be more appropriate. :)
No worries, 1stly there are only 2 dorps & 2ndly the water trickle rate cn't stir up much bubbly.
I may pour some anti freeze in for the color then anything else... Apart from car shampoo, I also like adding a few drops of bleeching solution for laundry to take care of algae problem.

Ken, did you had time to check the ebay proximity sensors? quality? thanks!

Pablo,
The switches arrived within a week & they don't look like poorly made, tested with 12V power supply % they all worked.
That is all I have time for at the moment.

The aquarium tank pump failed one me... realised it only trickle through the transparent reservoir located on the y-car.
Did some leg work & found this nice little 3 phase 1/10 hp (75w) pump & a heavy-duty PE tank as reservoir.
Attachment 10009
with a total of some ~30m or 6mm pneumatic PE tube the flow rate is now ~360cc/min.
now I need to get some coolant to add to the water for better visibility & corrosion protection.