Prusa Mini Direct Hextruder Retro

prusaprinters

<h3>Update V1.1 (10/22/2021)</h3><ul><li>STEP file for v1.1</li><li>Extruder v1.1: some fix and more sturdy</li></ul><p>I really like the extruder of @Vez3D youtube channel and looking for it for a while. Finally @MAMSIH release his Hextruder which really impressive. I love his design but for me it have some problem:</p><ul><li>I don't have any heat insert</li><li>I don't have plastic PTFE coupler</li><li>His PINDA sensor holder integrated with X Carriage is weak and fragile</li><li>Air flow of cooling part fan is not exactly match with Vez3D design</li></ul><p>Therefore my design address this problems by:</p><ul><li>Replace heat insert required part to using nuts</li><li>Use M6 PTFE coupler</li><li>Seperated PINDA holder with hotend fan cover</li><li>Recreate XCarriage Fan airflow to match the design of Vez3D</li></ul><h4>BOM</h4><p>See @MAMSIH page for more detail</p><h4>Printing instruction</h4><h5>Print parameters</h5><ul><li>Material: ABS (recommended), PETG</li><li>Number perimeters: 4</li><li>Layer height: 0.2</li><li>Support: No need for support except for<strong> extruder parts</strong> need <strong>support on build plate</strong> only</li></ul><h5>Print direction</h5><ul><li>Extruder</li></ul><figure class="image image_resized" style="width:75%;"><img src="https://media.prusaprinters.org/media/prints/75582/rich_content/8ac7208d-2f50-485c-adc8-c0cff3bdb2db/screen-shot-2021-09-10-at-145538.png#%7B%22uuid%22%3A%22738f5357-c894-4577-ad24-df8d9cb52da4%22%2C%22w%22%3A911%2C%22h%22%3A859%7D"></figure><p>Note: Print with support on build plate only</p><ul><li>Adapter</li></ul><figure class="image image_resized" style="width:75%;"><img src="https://media.prusaprinters.org/media/prints/75582/rich_content/718a828b-2186-49cc-b1c7-4ec4b614a6c3/screen-shot-2021-09-10-at-145251.png#%7B%22uuid%22%3A%22018cef88-ba9d-4ac4-a564-12411b5d20b6%22%2C%22w%22%3A836%2C%22h%22%3A763%7D"></figure><ul><li>XCarriage</li></ul><figure class="image image_resized" style="width:75%;"><img src="https://media.prusaprinters.org/media/prints/75582/rich_content/8855ecf5-415f-43c2-9da5-d9a45b1c8f8a/screen-shot-2021-09-10-at-145420.png#%7B%22uuid%22%3A%22e18c4039-9472-467e-b44d-21e41f516437%22%2C%22w%22%3A864%2C%22h%22%3A779%7D"></figure><p>Note: with this direction there are some flaw in the model that it is not flat. You can use split model of prusaslicer and cut 0.5mm.</p><h4>Printer setting</h4><h5>Extruder setup</h5><p>Use this GCode in “Start G-Code” in <strong>printer setting</strong> section:</p><pre><code class="language-plaintext">M92 E705 ; Direct drive extruder steps M906 T0 E300 ; Extruder current ref</code></pre><figure class="image"><img src="https://media.prusaprinters.org/media/prints/75582/rich_content/ec4232c9-52ac-4115-bd8a-9d28e82176a4/screen-shot-2021-09-10-at-155459.png#%7B%22uuid%22%3A%22c62c8745-2e7d-4de9-9374-79efa928c61c%22%2C%22w%22%3A1664%2C%22h%22%3A218%7D"></figure><h5>Additional: Linear advance</h5><p>Beside configure step and motor current, you can callibrate “linear advance” K value (search google for it) for better result. For me, I user K value of “0.08”, insert this GCode in “Start G-Code” in <strong>filament setting</strong> section:</p><pre><code class="language-plaintext">M900 K0.08</code></pre><figure class="image"><img src="https://media.prusaprinters.org/media/prints/75582/rich_content/792ef097-906d-4691-a3c6-1097ff7df239/screen-shot-2021-09-10-at-160108.png#%7B%22uuid%22%3A%22642507a7-401a-4596-b96d-86f17a3cc2b1%22%2C%22w%22%3A1676%2C%22h%22%3A217%7D"></figure><p>Note: comment 2 default line of prusa.</p><h5>Additional: Retraction</h5><p>The default retract distance profile for the Mini is 3.2mm, this is considered to be pretty long for Direct extruder. I set it up to 1mm (or 0.8mm similar to MK3S)</p><h4>TPU performance</h4><figure class="image image_resized" style="width:75%;"><img src="https://media.prusaprinters.org/media/prints/75582/rich_content/2da74e88-531c-4a9d-beff-d411e4af1246/img_3669.png#%7B%22uuid%22%3A%2262f2e0fb-ad41-4433-acc1-f5fe4396155c%22%2C%22w%22%3A3024%2C%22h%22%3A3024%7D"></figure><p>Currently I'm very happy with my setup. I can print 2x faster with better quality and I confident I can print even faster.</p><h4>About filament changing</h4><p>It will be a little tricky when you need to load/unload or changing filament. While Prusa Mini use bowden extruder, the load/unload distance is 420mm long (the number is in the firmware) this is not good for direct drive (around 61mm with my setup). So, there are 3 ways to combat with whis:</p><ol><li>Heat up the nozzle and manual pull/push filament to load/unload filament.</li><li>Heat up the nozzle and use <code>M701</code> /<code>M702</code> to load/unload filament.</li><li>For advanced user, use can modify the firmware by tuning <code>ADVANCED_PAUSE_FEATURE</code> section, my configurations right now:</li></ol><pre><code class="language-c">#define ADVANCED_PAUSE_FEATURE #if ENABLED(ADVANCED_PAUSE_FEATURE) #define FILAMENT_UNLOAD_RAMMING_SEQUENCE \ { \ { 1, 100 }, \ { 1, 300 }, \ { 3, 800 }, \ { 2, 1200 }, \ { 2, 2200 }, \ { 2, 2600 }, \ { -2, 2200 }, \ { -20, 3000 }, \ { -30, 4000 }, \ } #define PAUSE_PARK_RETRACT_FEEDRATE 20 // (mm/s) Initial retract feedrate. #define PAUSE_PARK_RETRACT_LENGTH 2 // (mm) Initial retract. // This short retract is done immediately, before parking the nozzle. #define FILAMENT_CHANGE_UNLOAD_FEEDRATE 10 // (mm/s) Unload filament feedrate. This can be pretty fast. #define FILAMENT_CHANGE_UNLOAD_ACCEL 625 // (mm/s^2) Lower acceleration may allow a faster feedrate. #define FILAMENT_CHANGE_UNLOAD_LENGTH 80 // (mm) The length of filament for a complete unload. // For Bowden, the full length of the tube and nozzle. // For direct drive, the full length of the nozzle. // Set to 0 for manual unloading. #define FILAMENT_CHANGE_SLOW_LOAD_FEEDRATE 10 // (mm/s) Slow move when starting load. #define FILAMENT_CHANGE_SLOW_LOAD_LENGTH 30 // (mm) Slow length, to allow time to insert material. // 0 to disable start loading and skip to fast load only #define FILAMENT_CHANGE_FAST_LOAD_FEEDRATE 10 // (mm/s) Load filament feedrate. This can be pretty fast. #define FILAMENT_CHANGE_FAST_LOAD_ACCEL 625 // (mm/s^2) Lower acceleration may allow a faster feedrate. #define FILAMENT_CHANGE_FAST_LOAD_LENGTH 20 // (mm) Load length of filament, from extruder gear to nozzle. // For Bowden, the full length of the tube and nozzle. // For direct drive, the full length of the nozzle. //#define ADVANCED_PAUSE_CONTINUOUS_PURGE // Purge continuously up to the purge length until interrupted. #define ADVANCED_PAUSE_PURGE_FEEDRATE 3 // (mm/s) Extrude feedrate (after loading). Should be slower than load feedrate. #define ADVANCED_PAUSE_PURGE_LENGTH 50 // (mm) Length to extrude after loading. // Set to 0 for manual extrusion. // Filament can be extruded repeatedly from the Filament Change menu // until extrusion is consistent, and to purge old filament. #define ADVANCED_PAUSE_RESUME_PRIME 0 // (mm) Extra distance to prime nozzle after returning from park. // Filament Unload does a Retract, Delay, and Purge first: #define FILAMENT_UNLOAD_RETRACT_LENGTH 30 // (mm) Unload initial retract length. #define FILAMENT_UNLOAD_DELAY 5000 // (ms) Delay for the filament to cool after retract. #define FILAMENT_UNLOAD_PURGE_LENGTH 16 // (mm) An unretract is done, then this length is purged. #define FILAMENT_UNLOAD_PURGE_FEEDRATE 20 // (mm/s) #define FILAMENT_UNLOAD_PHASE1_LENGHT 35 // (mm)fast phase #define FILAMENT_UNLOAD_PHASE2_LENGHT 45 // (mm)slow phase #define PAUSE_PARK_NOZZLE_TIMEOUT 45 // (seconds) Time limit before the nozzle is turned off for safety. #define FILAMENT_CHANGE_ALERT_BEEPS 10 // Number of alert beeps to play when a response is needed. #define PAUSE_PARK_NO_STEPPER_TIMEOUT // Enable for XYZ steppers to stay powered on during filament change. // #define PARK_HEAD_ON_PAUSE // Park the nozzle during pause and filament change. //#define HOME_BEFORE_FILAMENT_CHANGE // Ensure homing has been completed prior to parking for filament change #define FILAMENT_LOAD_UNLOAD_GCODES // Add M701/M702 Load/Unload G-codes, plus Load/Unload in the LCD Prepare menu. //#define FILAMENT_UNLOAD_ALL_EXTRUDERS // Allow M702 to unload all extruders above a minimum target temp (as set by M302) #endif</code></pre>