13. Hot end heat management:
Place a heat shield in the form of a large aluminum washer between the hot end and the PEEK.
This would act as a heat shield, and heat sink which should radiate some of the heat away.
I would also try to add a piece of cork between the washer and PEEK.
13.1 Hot end design modification:
You could also minimize the contact surface area of the bearings by fluting the wall,
and adding channels to route the hot air out. If you wanted to get fancy, add an air port, and pump air into the flutes (fish tank air pump).
20. Equal length arms:
The Z axis is Zig Zaging down, and up, while the X, & Y maintain locational accuracy.
With equal length arms, the build envelope should increase in size.
I would think that symmetry of the delta system would be preferable.
If you decide to print equal length arms I'll buy you a roll of 1.75mm natural ABS.
I'll PM you my email address, and you can provide me with a shipping address.
21. Worm wheel specifications:
What is the throat diameter and outside diameter of the worm wheel?
Any over riding reason that you didn't use a smaller diameter?
The larger the diameter of the worm wheel the greater the resolution.
But a lager diameter can reduce the print envelope size.
I'm trying to figure out the sweet spot, as the stepper motor 200 steps or 400 micro steps,
the length of the arm, and the worm wheel diameter effects the output precision of the arm movement.
A2