I received some Cooler Master Jetflo fans. They are advertised as having "Fourth Generation" bearings made of polyoxymethylene (POM, otherwise known as Delryn).
The Jetflo POM bearing differs from the Sickle Flow X bearing I took apart previously. That one was essentially a sealed sleeve bearing, just like the original Sickle Flow bearing, but made with POM so it would last a long time. This . . . second generation . . . of the POM bearing (4th gen, Mark 2?) differs from that one. This one is supposedly water proof and dust proof. How is it made?
Here is Cooler Master's drawing of the POM bearing, Mark 2. The orange represents POM. POM in its natural state is black:
I took one apart to see what this bearing is made of. So let us start with the frame, and peel off the label. We can see a steel plug surrounded by what looks like a brass ring. It is actually a brass case, as we shall see later.
I pounded on the steel plug with a punch and never pushed it through. I pried and pried until the blade-and-motor assembly finally pulled away from the frame. Since we can see that the plastic was more soft than rigid, I should have taken a heat gun to it. Ah, well. Next time.
This shot shows where I pounded on the steel plug. No wonder I couldn't pound it through. Look at those cleats! The picture also shows one very scuffed circuit board.
Would the circuit board still work? I tried the fan, now that it was free of the frame. It wouldn't spin, but it did light up.
Now let us peel the Cooler Master label off the fan head. The blade disk (the blades are part of it) is a translucent plastic.
The blade disk did pull off.
And I was able to push the bearing out of the motor assembly.
A closeup of the 4th generation bearing, Mark 2:
I took my hacksaw and cut off the steel tip.
Clearly the steel is just an insert in the brass casing.
I reassembled the pieces so you can see how they relate:
Another attack with the hacksaw, and the retaining disk comes away. The mushroom top of the shaft pops through the retaining disk, which -- um - retains the shaft in the bearing assembly.
With the retaining disk off, the shaft comes out. Inside the brass case, the barrier ring faces us.
Pushing the contents out of the case, we see the POM bearing cylinder and the barrier ring:
I have assembled the pieces of the bearing:
The same picture, with the pieces numbered in the order they occur in the bearing:
1. The tip of the shaft that sticks into the plastic blade disk
2. The barrier ring and the part of the shaft that penetrates it.
3. The POM cylinder, the part of the shaft that penetrates it and the brass case.
4. The retaining disk and the end the shaft that penetrates it.
5. The end cap, with its steel plug.
The Cooler Master drawing again. The barrier ring is at the top, the retaining ring at the bottom:
I hope you have enjoyed our little tour through the innards of the Cooler Master Jetflo. BTW - look at those rubber corners. They really do dampen vibration.