RUNNING IN FROM NEW
The Flex Wheel has been designed to achieve extremely tight tolerances which is essential to handle the increase in driving force that the unit produces particularly when extruding flexible filament.
In order to achieve these tolerances a new Flex Wheel requires a running in period which allows for the flexible Flex Wheel to ‘mate’ with the stainless filament feed tubes, these constraints will quickly abate and the unit will run smoother and more optimally after the first hour or two of operation.
METHOD
When you finish assembling the unit and before you tighten up the 4 x tension screws connect the Flex Wheel to your printers control board and extrude and reverse the unit a number of times to check for any issues. No need to insert filament at this stage. As your E step have not yet been calibrated test a number of speed settings to get the wheel turning at about two revolutions per minute.
Swing the 4 x tension screws into the corresponding position within the top hinge plate. Alternately tighten the tensions screws so a small amount of pressure is applied to the flanges of the Flex Wheel, once again control the unit forwards and backwards to check for smooth operation, if the unit starts to bind back off tension or temporarily reduce speed.
Once the unit is turning freely with a small degree of pressure applied via the tension screws insert a length of filament into filament feed tube and extrude approximately 300 mm of filament at a slow speed, you should feel the Flex Wheel grab the filament. A short time later the filament will exit from the unit through the other side. A small amount of debris may be produced.
Once the filament is travelling through the unit –check for holding capacity by physically grabbing hold of one end of the filament and resisting the extrusion forces – if the filament slips inside the mechanism continue to nib up individual tension screws until you cannot hold onto the filament anymore and it slips through your grip. Note if you over tighten the mechanism it may start to bind.
This process is not an exact science but more of a feel – But do not worry there is a lot of leeway between the upper and lower limits and the unit will compensate for fluctuations in filament diameter.
Once the Flex Wheel is “bedded in” this process will not be required and the unit will be easy to calibrate quickly (if at all) when changing filament in the future.
As the Flex Wheel goes through the bedding in process a small amount of material will be worn off the wheel, this material is basically a fine TPU powder and will not present a problem if it was to pass through your hot end and will quickly dissipate after the first few hours of use.
You are now ready to Calibrate extruder steps per mm.
As the Flex Wheel has a larger drive wheel circumference in conjunction with a geared stepper motor the extrusion rate will differ from your existing small hob gear. Refer to users guide for calibration guidelines.