Plastic-plastic friction vs. plastic-steel friction
Plastic-plastic friction vs. plastic-steel friction
(OP)
I am redesigning a micro-hydro educational tool that is essentially a Pelton wheel runner spinning in a polycarbonate enclosure. Our current design uses a steel axle spinning inside a boss in the enclosure.
We're considering changing that to a polycarbonate axle so we can reduce our part count and simplify the design. I theorize that we are going to see more friction with the new design. I've tried to find representative friction coefficients on the web but can't seem to find what I need.
Presumably, resin manufacturers are reluctant to list specific coefficients for their materials, since friction varies with texture, etc., but I'm just looking for ballpark figures, for feasibility. So does anybody have representative dynamic friction coefficients for:
1) Polycarbonate - Polycarbonate, and
2) Polycarbonate - Mild Steel?
Bonus points if these values reflect the materials being wet!
In the absence of numbers, intuition-based responses are welcomed.
We're considering changing that to a polycarbonate axle so we can reduce our part count and simplify the design. I theorize that we are going to see more friction with the new design. I've tried to find representative friction coefficients on the web but can't seem to find what I need.
Presumably, resin manufacturers are reluctant to list specific coefficients for their materials, since friction varies with texture, etc., but I'm just looking for ballpark figures, for feasibility. So does anybody have representative dynamic friction coefficients for:
1) Polycarbonate - Polycarbonate, and
2) Polycarbonate - Mild Steel?
Bonus points if these values reflect the materials being wet!
In the absence of numbers, intuition-based responses are welcomed.





RE: Plastic-plastic friction vs. plastic-steel friction
Acetal on polycarbonate may be a better choice.
Also take a (close) look at the bearings using pointy axle ends on model railroad car trucks.
Mike Halloran
Pembroke Pines, FL, USA
RE: Plastic-plastic friction vs. plastic-steel friction
RE: Plastic-plastic friction vs. plastic-steel friction
This is a water turbine; the enclosure is consequently full of water splash. No need for cooling, but any lubrication effects will be bonus.
Thanks!
RE: Plastic-plastic friction vs. plastic-steel friction
H
www.tynevalleyplastics.co.uk
RE: Plastic-plastic friction vs. plastic-steel friction
RE: Plastic-plastic friction vs. plastic-steel friction