Closed Loop DIY Water Cooling System for Water Cooled Spindle

Water cooled spindles are great as they are quiet and run cooler than air cooled spindles. But having a bucket of water on your workshop floor next to your CNC router for the purpose of feeding water to cool your spindle is not ideal. At CNC Online South Africa we decided to try and create a closed loop water cooling system for our spindle. This worked great! We have have assembled a kit that our clients can purchase to create their own DIY closed loop water cooled system.

 

The components that are used are usually used for cooling high end computers. We sourced the following components to create this system:

1 x 240mm Aluminium Radiator

1 x Pump with reservoir and thermometer

2 x 120mm fans

1 x Flow indicator

1 x 12v Power Supply

2 x 16mm Compression Fittings

2 x 8mm Push-in Fittings

1 x 1 meter 16mm Hose

 

This kit is not specifically made for this purpose, therefore some basic DIY techniques are required to create your closed loop water cooling system.

 

Below is a pipe routing diagram.

 

Below is a wiring diagram:

 

Since the fans are RGB, they have 6 wires. We are not going to use the RGB function. The pump has variable flow control and therefore 4 wires, again we are not going to use that function as we will run the pump at full speed permanently. We have marked the + and – wires on the pump and fans that need to go to the power supply.

 

Please note that the pumps theoretical pressure head is 3 meters. This basically means that the pump must be placed less than 3 meters above or below the spindle. For maximum efficiency, try and have the pump on the same level as the spindle and avoid long pipe travel lengths. I highly recommend cutting a bracket on your CNC router and mounting the cooling system to the Z axis assembly, if you have the space. Keep an eye on the spindle temperatures after installation. If your spindle temperature is exceeding 60 degrees Celsius, consider moving your cooling system closer to the spindle.

 

Once installed, open the cap on the top of your reservoir see in the image below and fill up the system with a mix of distilled water and a little antifreeze. I South Africa, the antifreeze is hardly necessary, but it helps avoid algae. We used a syringe to make filling the system easier.

 

 

If you would like to control your cooling system from your controller, you can adapt the wiring to utilize a relay. Then using M commands in your post processor, you can switch cooling on/off when your cut begins/ends.

 

Note: When screwing the fans to the radiator, make sure the screws used are not too long. Screws that are too long will pierce and damage the radiator.

 

 

We have tested this kit, on a hot day during an 8 hour carve, our 2.2kW spindle never exceeded 40 degrees Celsius. Spindles can happily run 40 - 60 degrees Celsius above room temperature.