Craftbot enclosed air restrictor

The rear case fan of the craftbot tends to force a lot of air over the build area from the hole just above the Z stepper motor, this is great for PLA but could cause havoc with ABS printing.
This simple part will plug that hole causing the air to flow out the back handle hole instead.

Designed around the original Craftbot but should still fit the Craftbot plus, let me know if you have any issues.

Because the intake and exhaust are both on the back of the Craftbot with this mod make sure