<p>I've recently changed my Ender3's hotend to E3D v6 clone with Titan direct extruder, so I can print faster than on stock. But when I increased the speed up to 70 mm/s for walls and 80 mm/s for infill (PETG, nozzle temperature of 225 °C, bed temperature of 80 °C, 0.2 mm layer height, 0.4 mm layer width), I've faced this kind of issue:</p>
<p><a href="https://i.stack.imgur.com/ipyUr.jpg" rel="nofollow noreferrer" title="3D printer printing a model with errors"><img src="https://i.stack.imgur.com/ipyUr.jpg" alt="3D printer printing a model with errors" title="3D printer printing a model with errors" /></a></p>
<p>Here's how it looks in Cura:</p>
<p><a href="https://i.stack.imgur.com/668ki.jpg" rel="nofollow noreferrer" title="Screenshot of Cura's preview of model"><img src="https://i.stack.imgur.com/668ki.jpg" alt="Screenshot of Cura's preview of model" title="Screenshot of Cura's preview of model" /></a></p>
<p>The printer's head goes from left to right, counter-clockwise and I get issues on both exits from curved shape.</p>
<p><a href="https://i.stack.imgur.com/AMZUz.jpg" rel="nofollow noreferrer" title="Another Cura preview further into the print with arrows indicating problem areas"><img src="https://i.stack.imgur.com/AMZUz.jpg" alt="Another Cura preview further into the print with arrows indicating problem areas" title="Another Cura preview further into the print with arrows indicating problem areas" /></a></p>
<p>First of all, I thought, it is connected somehow with retraction, but according to Cura, both problem places are in the middle of the current layer. Later I thought it could be related to Linear Advance and disabled it on the next test print, but it did nothing:( Slowing the printer down to 60-65 % in mid print solved the issue, but it's not what I changed the hotend for:)</p>
<p>Maybe someone has any ideas, what's wrong with it?</p>

[{'answer_id': 17846, 'author': 'FarO', 'author_id': 2338, 'author_profile': 'https://3dprinting.stackexchange.com/users/2338', 'pm_score': 0, 'selected': False, 'text': '<p>In other words, your print exhibits issues when the hotend is accelerating, like if not enough filament were pushed in.</p>\n<p>It is advised to calibrate for linear advance after replacing the extruder.</p>\n<p>Check <a href="https://marlinfw.org/docs/features/lin_advance.html" rel="nofollow noreferrer">https://marlinfw.org/docs/features/lin_advance.html</a> and</p>\n<p><div class="youtube-embed"><div>\r\n                <iframe width="640px" height="395px" src="https://www.youtube.com/embed/n3yK0lJ8TWM?start=0"></iframe>\r\n            </div></div></p>\n<p>and check <a href="https://marlinfw.org/tools/lin_advance/k-factor.html" rel="nofollow noreferrer">https://marlinfw.org/tools/lin_advance/k-factor.html</a></p>\n'}, {'answer_id': 17850, 'author': 'Perry Webb', 'author_id': 15075, 'author_profile': 'https://3dprinting.stackexchange.com/users/15075', 'pm_score': 0, 'selected': False, 'text': '<p>PETG can have difficulty printing at higher speeds.</p>\n<p>See <a href="https://3dprinting.stackexchange.com/questions/13412/why-does-petg-require-slower-speed">Why does PETG require slower speed?</a></p>\n<p>Also, if the speed is too slow, it tends to have heat creep.</p>\n<p>See <a href="https://3dprinting.stackexchange.com/questions/15629/what-are-ways-to-avoid-heat-creep">What are ways to avoid heat creep?</a></p>\n<p>Higher nozzle temperatures should allow faster print speeds, but will also increase the chance of heat creep and increase the slowest required speed to prevent heat creep.</p>\n'}, {'answer_id': 17862, 'author': 'Kezat', 'author_id': 30645, 'author_profile': 'https://3dprinting.stackexchange.com/users/30645', 'pm_score': 1, 'selected': False, 'text': '<p>In my experience, 225\xa0°C is the lower range for PETG, that combined with a higher than normal printing speed of 70\xa0mm/s might be your issue. The lower your print temps the lower the maximum nozzle flow rate. I would recommend increasing the nozzle temperature.</p>\n<p>For a point of reference, on my printer with an E3D v6 clone and a generic extruder I print PETG at 235\xa0°C and 60\xa0mm/s and 24\xa0mm/s outer perimeter speed, with a 0.2\xa0mm layer thickness. Though admittedly not optimized for speed.</p>\n'}]
['https://3dprinting.stackexchange.com/questions/17844', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/30570/']