Make sure you guys do a legit extruder calibrate before messing with the flow rate. Its simple just measure and mark 100 mm of filament from the top of your extruder and have the system feed 100 mm. See if the line levels out or if it come up short or feeds to much.
There's a slightly different extruder calibration procedure
here that works for over-feed and under-feed.
- Measure and mark at 120mm
- Feed 100mm
- Measure where the mark falls
-- If it is at 20mm, the setting is correct
-- If not, use the formula (Expected feed length / actual feed length) * current steps setting = new steps setting
For example, if you expected to feed 100mm, but only fed 96mm (120mm start position - 24mm end position) with a current steps setting of 150, you would need to adjust the steps setting to 156.25.
(100 / 96) * 150 = 156.25
Scott