Hot end silicone sock is on of the best and cheapest upgrades you can do to your 3D printer.
This article applies to all 3D printers with a V5 J-Head, such as Kossel Pulley, Kossel Linear Plus, i3 Mega and so on…
As you can see in the picture below, the cooling fan affects nozzle (hot end) temperature.
On the left you can see unstable nozzle temperature without the silicone sock after the cooling fan turns on at 100%.
On the right you can see the same setup, just with a silicone hot end sock and fan at 100%.
More of these temperature osscilation problems are described in this article. Large drop or increase in the hot end temperature leads to thermal runaway and failed print.
V5 Hot End Silicone Sock
I highly recommend buying this one.
There is no need to remove heating element and thermistor.
You can just put it on the hot end with a hand or some pliers.
All of these testings were made with the same setup and PID values.
The biggest problem is that the original cooling duct performs even worse, than this upgraded cooling duct which was used for testing.
1.1. Without a hot end silicone sock
You can see in this graphs that after the cooling fan turns on at 100%, the nozzle (hot end) temperature goes to 224.4°C from desired 230°C and even after that oscillates around 230°C.
Please note that only the left side of the graph is without a silicone sock.
1.2. With a silicone sock
With a silicone sock, you can see that the temperature drops just to 226.3°C and does not oscillate after that.
Please note that only the right side of the graph is with a silicone sock.
More Kossel guides and upgrades
If you want to read more Kossel guides, navigate to Anycubic Kossel wiki