Adaptive Linear Advance

prusaprinters

<p>This is <i>not</i> another of those test models meant to help you <i>calibrate</i> the Linear Advance for your specific hardware. Rather, it is a bit of simplified G-code which takes standard 0.4mm-nozzle K-factor values and adapts them based on your actual nozzle size and extruder type.</p><h3>Explanation</h3><p>The provided code is meant to go in the custom G-code of your filament profiles. Rather than specifying several K-factor values in a long series of conditions as in the G-code of Josef Průša's filament profiles, you specify just one standard K-factor and an appropriate value is calculated for your nozzle size and extruder type. This is because I've found that suitable K-factors can be calculated based on the following formulas:</p><pre><code class="language-plaintext">k_factor = standard_k_factor / (nozzle_diameter / 0.4)</code></pre><pre><code class="language-plaintext">bowden_k_factor = direct_k_factor * 4</code></pre><p>You'll still need to determine the appropriate K-factor value for each material type, which you may base on <a href="https://help.prusa3d.com/article/linear-advance_2252">Mr Průša's recommendations</a> for a 0.4mm nozzle or on the results of your own experiments.</p><h3>Instructions</h3><p>My suggested <i>Start G-code</i> for the filament profile of a typical PLA filament, as used in the attached project, is as follows:</p><pre><code class="language-gcode">; Filament gcode M900 K{0.05/(nozzle_diameter[current_extruder]/0.4)*(printer_notes=~/.*PRINTER_(MODEL_MINI|HAS_BOWDEN).*/?4:1)} ; Linear Advance v1.5</code></pre><p>In the example above, 0.05 is the standard K-factor for PLA, the value used for direct extrusion through a 0.4mm nozzle. For printing with other materials, this is the only value that you need to change.</p>