This guide provides a systematic approach to diagnosing and resolving under-extrusion, often seen as missing or inconsistent layers in your prints on the Vision Miner 22IDEX. Addressing under-extrusion is crucial for achieving structurally sound and visually complete parts.
Under-extrusion occurs when the printer fails to extrude the required amount of filament for a given section of the print. This can result in gaps between layers, weak parts, and overall poor print quality. This guide outlines the most common causes specific to the 22IDEX and provides a step-by-step troubleshooting process, starting with the most frequent culprits.
Prerequisites include basic familiarity with printer operation and access to the printer's mechanical components and potentially the slicer software settings.
- Metal Brush (supplied with the printer, for cleaning extruder gears)
- Flashlight (optional, for inspection)
- Filament Sample (known good quality, dry)
Warning: The nozzle and hotend assembly can reach high temperatures (up to 500°C). Always allow components to cool or use appropriate heat-resistant gloves before touching.
Warning: Ensure the printer is powered off before performing mechanical inspections or adjustments unless otherwise specified (e.g., for hot tightening or live extrusion tests).
- Filament Quality: Ensure you are using high-quality filament known to be dry and consistent in diameter. Wet filament can cause various extrusion issues.
- Nozzle Size & Material Type: Be aware that abrasive materials (carbon fiber, glass-filled) significantly increase the likelihood of clogging, especially with smaller nozzle diameters like
0.4 mm. Consider using larger diameter nozzles (0.6 mm or larger) for these materials.
Before proceeding with detailed hardware inspections, review these common causes of under-extrusion:
Incorrect extruder tension is a primary cause of inconsistent filament feeding.
- Verify the extruder lever tension is set according to the recommended specifications. Improper tension (too loose or too tight) directly impacts filament grip.
- Reference: For detailed instructions on how to inspect and adjust the extruder lever, please consult the dedicated guide:
Link to Extrusion Lever Position Guide
A partial or complete clog physically blocks filament flow. This is especially common when using filled materials with smaller nozzles.
- If you suspect a clog (e.g., filament extrudes thinly, curls excessively, or not at all), follow the procedures in the Clog Troubleshooting Guide.
Important: Filled materials (carbon fiber, glass) require careful handling during clog removal.
- Reference: For detailed clog diagnosis and removal steps (cold pulls, needle use, etc.), see:
Link to Clog Troubleshooting Guide
Exceeding the hotend's melting capacity, often limited by the slicer's volumetric flow rate setting, can cause under-extrusion, particularly at higher speeds.
- Check the Max volumetric speed setting in your slicer (Filament Settings > Advanced in PrusaSlicer). A safe value is typically around
10 mm³/s.
- Remember that steel nozzles generally have lower effective flow rate limits than brass due to heat transfer differences. Printing faster than the hotend can melt will result in under-extrusion.
- Reference: For a deeper understanding of how this setting impacts print speed and quality, see:
Link to Volumetric Flow Rate Guide
If the initial checks above do not resolve the issue, proceed with these steps:
Physical restrictions or excessive friction can hinder filament movement.
- Check Spool: Ensure the filament spool rotates freely and the filament is not tangled.
- Inspect PTFE Tube:
- Examine the tube for sharp bends, kinks, or pinch points.
- Disconnect the tube at the extruder and manually push filament through it. It should move smoothly. Replace the tube if there's significant drag or damage.
Printing too cold increases filament viscosity and restricts flow.
- Confirm the nozzle temperature in your slicer profile is appropriate for the material.
- Steel Nozzle Consideration:
Tip: When using a steel nozzle, increase the print temperature by at least 20°C above the filament manufacturer's recommendation to compensate for lower heat conductivity.
- Monitor the actual nozzle temperature via the Web Control interface during printing to ensure it's stable.
- Q: Under-extrusion only happens on faster sections of the print. What should I check?
- A: This strongly suggests you might be exceeding the Max volumetric speed (see Initial Check #3) or printing slightly too cold for the speed (see Step #2 above). Try reducing print speed overrides or increasing temperature slightly.
- Q: I checked everything, but still get intermittent under-extrusion. What else?
- A: Re-check filament quality – moisture is a common cause of inconsistency. Inspect the extruder drive gear closely for plastic dust or wear; clean it with the Metal Brush. Intermittent issues could also point to a failing thermistor or heater cartridge (less common).
- Q: Can incorrect retraction settings cause under-extrusion?
- A: Yes, excessive retraction distance or speed can sometimes cause heat creep or filament grinding, indirectly leading to under-extrusion or jams. Ensure retraction settings are within reasonable limits (refer to standard profiles).
By systematically working through these checks – prioritizing extruder lever tension, nozzle clogs, and volumetric flow rate limits – you can effectively diagnose and resolve most cases of under-extrusion. Remember the specific considerations for filled materials and steel nozzles.
Run a test print after making adjustments to confirm the issue is resolved.