[gmoreno_cnc]

Hi all,
I am planning to build a Protective Housing for my CNC-Router (1800x1000x570mm).

I was planning to make it with aluminium frames and double polycarbonate panels.

The thing is that I need the temperature to be constant when I am Milling aluminium molds, since I cannot allow myself higher tolerances than 0,015mm due to the thermal expansion.

What would you recommend me to do? Install a ventilator or air conditioning system that activates with a thermostat?

[joeavaerage]

Hi,
I'm a bit dubious that an air conditioning system is going to do the trick.

It would take many hours for a warm peice of tooling grade aluminum to cool to ambient temperature even if the ambient is controlled.

The real issue is that you are adding heat to the material much faster than could be removed by a temperature controlled air environment.
If your spindle is consuminng 2kW then its possible that about 500W of heat is going into the work material, you'll never remove that much with
air (gas) cooling.

The solution is to use flood cooling, and lots and LOTS and LOTS of it, well in excess of 20litre/min.

Craig

[gmoreno_cnc]

Thank your for your reply Craig.

Sorry for being so “newbie” but what’s the best cooling liquid for an Aluminium mold?

[Jim Dawson]

My prefered coolants are from Blaser Swisslube. https://www.blaser.com/en_US

[joeavaerage]

Hi,
flood coolant is largely water with (usually) a small addition of water soluable oil. There is a lot of discussion about what oil is best,
but the vast majority of the coolant volume is water.

From a pure cooling point of view it makes no difference whether there's any oil in it at all. Most oils have some sort of anti-fungal properties
which can suppress bad smells that can come from stale coolant and so a coolant oil is recommended, it will help with chip removal
and tool-life.

Unless you have some very specific requirement I think any water soluable oil that you can get in small quantities would be fine.

Craig

[mactec54]

Hi all,
I am planning to build a Protective Housing for my CNC-Router (1800x1000x570mm).

I was planning to make it with aluminium frames and double polycarbonate panels.

The thing is that I need the temperature to be constant when I am Milling aluminium molds, since I cannot allow myself higher tolerances than 0,015mm due to the thermal expansion.

What would you recommend me to do? Install a ventilator or air conditioning system that activates with a thermostat?

Depending on the rate that you are machining, ( metal removal ) as to how it will affect the work piece, you would rough out the mold let it cool down and then do you finish machining with coolant, the coolant is what will remove the heat when cutting, if you can keep you work area cool then your machine will be stable at that room temperature

The only thing that normally changes with a mill, ( depending on how hard it is being worked ) is with the Z axis, and that depth is easy to control, You said a Router so you most likely have a water cooled spindle so that won't be affected by heat expansion .015mm is a big number .00059" I cut molds with a tolerance .0001" or .0025mm, I doubt that your router would be able to hold .015 no matter what you did with trying to control the temperature

I suggest to machine a mold under size measure it see where it is from the programed cut size and then adjust your program to suit, you can get it the perfect size you want by doing it this way and no temperature to worry about only in the Z axes if you are not water cooled

[hfjbuis]

Like already said, use a lot of coolant. Cooling is more difficult and more expensive than warming up. Consider keeping the coolant at a relative high temperature like 35° C. Adjust the milling dimensions to have the part on spec when it is at room temperature.