Hi thanks for the question.
The removal of all cavities and gaps (no matter how small) coupled with the ability to increase the driving force applied to the filament were the original inspiration for the design.
The Flex Wheel has a 60 mm diameter (approx) drive wheel which has 2 x pre shaped flanges that envelope the print filament, these flanges are compressed against the filament by series of small bearings located on a hinged plate. These bearings in combination with the flanges spread the driving force over a large area (result no localiced high pressure point or filament deformation). When compressed the flexible flanges completely surround the filament thus eliminating the existence of any gaps.
Once the filament is travelling around the 180 degree arc inside the Flex Wheel the trick is to then get it back out !!! As the drive system produces an enormous amount of force this has
not been an easy task. To achieve this I developed (after many reiterations) a filament guide block which contains a high precision stainless steel tube with an outside diameter which has been milled in multiple steps. One end sits snugly inside the Flex Wheel flanges, the other you can see protruding from the unit on the pic 4.
The bearings and an additional slide clamp keep the flanges tight against the filament right up until the last moment when it enters the tube - The flanges being flexible they easily flow over the tube and move out of the way.
You can then drill a 3 mm opening into one end of your Bowden tube which can then slide over the outlet tube of the Flex Wheel. Once secured with a PTFE tube coupling and a mounting block this then creates one entire seamless path for your filament to travel to your hotend. This process is explained in little more detail in this
instructable
The following assembly guide may help to explain the design in more detail.
Flex Wheel Assembly Guide
The Flex Wheel / Filament guide / bearings etc. are mounted on a high quality milled aluminum base and top plates with the quality precision geared stepper the overall weight is a touch over 900 grams - so not light. It is definitely the ultimate filament control system for Bowden set ups and I have switched all my printers to Bowden (even when printing 1.75 mm flex!).
It can be used in direct drive situations, where the hot end is positioned and slides over the outlet tube and the Flex Wheel unit mounted upside down - I have used this set up to print ultra flexible filament (46A) video demonstration
Printing 46 A shore hardness To be used in this configuration there are some factors to be considered - the weight being one of them / hot end offset from center and mounting position on x axis rails, however these can be overcome.
We are really only starting to find out what the unit is capable of - recent video test showing the force that can be delivered
Power of the Flex Wheel
Any other question help to provide further details.
Edited 2 time(s). Last edit at 12/13/2018 02:08AM by Arnold Lane 1000.
www.flexwheelextruder.com