Water cooled spindles in winter temps

[Aiph5u (Aiph5u (not affiliated with Onefinity))]

Hey David,

@cyberhiker

Some use auto antifreeze but over time that will cause corrosion

bullshit. Do you really think anyone would pour this into the cooling system of their car if it caused corrosion? It is precisely the similar conditions of the car cooling system and the spindle cooling system which is why car coolant is often used. It is if you don’t use the correct anti-corrosive and absolutely mineral-free (distilled = no electrical conductivity) liquid that you will harm your spindle.

@Aiph5u

My spindle manual says:

The coolant used must be a special coolant that provides corrosion protection for non-ferrous metals, does not attack rubber seals and has the lowest possible electrical conductivity. Only use coolants offered by the manufacturer.

Therefore I use this as coolant liquid.

@Aiph5u

the main component is distilled water, which has nearly no electrical conductivity (under 2 µS/cm). There is a concentrated version available that you mix 1:2.

Ethylene glycol is what most people know as antifreeze and is what you put in the radiator of your car to prevent freezing and what is sprayed in tons per year on airplanes to deice them.

Since the corrosion inhibitor is not mentioned in the material safety data sheet, it’s probably based on Molybdic acid, Triazole and a substance that ensures a high (alkaline) pH value which require no declaration.

@Aiph5u

my spindle manual says:

Water-cooled motor spindles:

When dimensioning the cooling system, it must be ensured that the temperature of the cooling liquid leaving the motor spindle does not exceed the permissible value of 30 °C in normal operation.

At least one flow indicator and one temperature sensor with temperature display must be installed in the cooling circuit so that they can be easily seen by the operator and used to monitor the cooling system. Temperature monitoring must take place after the motor spindle has left and before it enters the heat exchanger. If the cooling system is monitored manually, check every 15 minutes during operation whether the coolant is within the permissible temperature range and whether there is coolant circulation. If the coolant does not circulate, or if the temperature exceeds the permissible limit, stop operation immediately and correct the problem.

Use special coolant that ensures corrosion protection of non-ferrous metals, does not attack rubber seals and has the lowest possible electrical conductivity. Use only coolant offered by the manufacturer.

My spindle is this, my water chiller is this . My coolant liquid is this.

(30 °C is 86 °F)

By the way, do you correctly warm up your spindle?

@Aiph5u

in my spindle ’s manual (a 6,000–24,000 rpm 2.2 kW water-cooled spindle), it says:

10.2 Spindle run-in

A cold spindle must always be run in thoroughly before it is put into operation in order to gently bring the bearings up to operating temperature. The stated run-in times are to be doubled if the spindle has not been used for more than a week, is brand new, or the bearing has been changed.

When running in, the speed should be set to the minimum (6000 rpm) and maintained for at least 1 minute. The speed can then be increased in steps of 6000 rpm and must be maintained for a further minute each time. The speed is gradually increased until the desired operating speed is reached.

If you care that much of too cold coolant, how cold is ambient temperature in your workshop?