UPDATE: An additional .stl file (5G+ Std Guide Tube.stl) has been added for 5th Gen owners with a Smart Extruder+ wanting a shorter filament feed path and less filament feed resistance. This type uses the standard filament guide tube which can be shortened by approx. 30% and will be a straighter feed path. No extruder cap fitting is required with this version. Just follow the filament drawer modifications. shorten the guide tube and your ready to go...
Please read the following overview / instructions:
The filament feed system on the 5th Generation Replicator is not a free or smooth as on the earlier Replicator 2's. Having as little resistance along the feed route ensures the right amount of filament is delivered on demand and also that there is no resistance that could affect retraction. In addition, this may improve reliability and reduce wear within the Smart Extruder due to reducing the internal stresses caused through pulling filament into the Smart Extruder (i.e. may improve service life).
This modification was developed to reduce the resistance along the 5th Generation filament feed route. (The route travels up from the spool then out of the filament drawer via a small hole followed by a fairly tight bend, along the back of the machine, through another bend then out through the front of the drawer before travelling through a considerable length of guide tubing before angling into the top of the Smart Extruder). In addition, the 5th Generation guide tube is considerably smaller so more restrictive than the tubing used on the earlier Replicator 2.
After this modification is carried out the filament route will essentially be 'straight up and over' like on a Replicator 2. The tubing used is from a Replicator 2 (although a fraction longer Teflon tube would be better).
The modification is relatively easy to carry of but does require drilling two holes in the drawer of a 5th Generation Replicator. Once drilled the printed parts can be installed in a matter of minutes along with a Replicator 2 guide tube (or similar) and use of 10mm cut from the original 5th Generation guide tube.