<p>I have two otherwise-identical machines (called &quot;Lefty&quot; and &quot;Righty&quot;), so I have a baseline to compare.  I am running Marlin 2.0.7.2 on both machines.  They are Creality CR-10 printers with BTT SKR e3 Mini v1.2 boards, with Marlin I compiled myself.  Both machines are (as far as I know!) running the same exact firmware binary.</p>
<p>When running <strong>the same G-code</strong> on both printers, Lefty prints fine.  But, Righty fires the plastic through -- I need to set the flow rate to 50 % (!) to be correct.  I have checked the esteps, both are identical at 415, and this produces 39.5 mm of 40 mm commanded when bumped through 1 mm at a time via the extrusion menu, even on Righty.  The XY movement on both machines is 100 % correct.</p>
<p>Volumetric extrusion is disabled in the firmware on both  machines, and disabled in the slicer.  Both machines are running TMC2209 drivers, set to Spread Spectrum at 650 mA for the extruder.  Both machines are set to 1250 accel. The steppers are rated for 1 A, and they are not skipping steps.</p>
<p>The machines were working side-by-side perfectly until I killed Righty's stepper driver with static, and replaced the board.  No other hardware was modified.</p>
<p>Why do both machines behave the same with identical G-code, until extrusion moves?  Why does Righty try and extrude nearly double what it should be, only during printing, when Lefty works perfectly?</p>

[{'answer_id': 15236, 'author': 'octopus8', 'author_id': 26170, 'author_profile': 'https://3dprinting.stackexchange.com/users/26170', 'pm_score': 1, 'selected': False, 'text': '<p>For both machines did you compare extruder\'s (E) steps/mm setting in Marlin and possibly stored in EPROM (so check from the LCD in Configuration&gt;Advanced settings) ?</p>\n<p>Also stepper motors ... I believe they are exactly of the same type? There are 1.8 degree and 0.9 degree stepper motors on the market - so exactly doubled flow could be related to rotation. Also the stepper driver board may be configured for mcrostepping (<a href="https://www.creality.com/blog-detail/10-v2-vs-cr-10-tmc2208-moto-driver-silence-print" rel="nofollow noreferrer">e.g. full steps agains half steps</a>), and this may equally influence the behavior. (I do not have CR-10, so I cannot advice in more details.)</p>\n'}, {'answer_id': 15257, 'author': 'Bryan Boettcher', 'author_id': 263, 'author_profile': 'https://3dprinting.stackexchange.com/users/263', 'pm_score': 3, 'selected': True, 'text': "<p>Annoyingly, this went away with a replacement board.  I don't have a better fix.</p>\n"}]
['https://3dprinting.stackexchange.com/questions/15235', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/263/']