PART 2 · Common Printing Problems
This part is for readers who have already started printing and need to solve a specific problem. Each chapter covers one symptom in full, and you do not need to finish PART 1 first. Go directly to the relevant chapter to work through the symptoms, possible causes, troubleshooting methods, and corrective measures.
Where to Start
If fine strands appear between parts of a model, start with Chapter 1, “Stringing.” If no material comes out or the extruder makes a clicking sound, see Chapter 2, “Nozzle Clogs and Feeding Issues.” If the corners at the base gradually lift, see Chapter 3, “Warping.” If the print turns into a tangled mass of strands, see Chapter 4, “Spaghetti Failure.” If colors do not match or light and dark bands appear on the surface, see Chapter 5, “Color Differences and Gloss Changes.”
Before You Troubleshoot
Record the printer model, nozzle specifications, filament model and color code, batch, main print settings, and how the filament has been stored and dried. Keep the model or slicer project file, photos of the failed print, and a record of when the problem occurred. If you have video, first look for the earliest point at which something went wrong.
Change one main variable at a time and keep a record of the original settings. Symptoms provide clues; photos alone cannot confirm or rule out filament, equipment, or other factors.
Chapter 1 · Stringing
1.1 How to Recognize Stringing
Web-like strands, hairs, or fine threads left between different features of a finished model are usually stringing. They often appear between two posts, tips, or small, separate features. Mild stringing mainly affects appearance. Severe stringing adds cleanup work and may occur alongside other extrusion problems.
Stringing is different from a spaghetti failure. With stringing, the main body of the model usually still forms in the intended shape. In a spaghetti failure, the extruded material no longer lands where it should be supported, and continued printing produces a tangled mass. Distinguish between the two before choosing a troubleshooting approach.
1.2 Why Stringing Happens
Think of printing as three actions: the nozzle prints at point A, travels to point B without printing, and then resumes printing. Ideally, no extra material should be left behind during that travel move. If molten material continues to ooze from the nozzle, the movement draws it into fine strands.
Factors that affect oozing include how the material flows, pressure inside the nozzle, retraction, temperature, humidity, nozzle condition, and the travel path. A model with many small, separate areas requires more travel moves, so stringing may be more noticeable even with the same settings. Stringing is therefore a symptom with no single cause.
1.3 What to Check First
| What to Check | Why It Matters | How to Verify |
|---|---|---|
| Temperature and filament profile | An unsuitable temperature can increase oozing. | Check the profile and adjust in small increments within the permitted range. |
| Retraction settings | Pressure relief before a travel move affects oozing. | Use settings suited to the current extrusion system. |
| Moisture in the filament | Moisture can make extrusion unstable. | Dry according to the material requirements, then compare results. |
| Model and travel path | Frequent moves across empty spaces can make stringing more pronounced. | Compare a simple test print with the target model. |
| Nozzle and residue | Buildup or leftover material can interfere with extrusion. | Inspect and clean according to the equipment procedures. |
1.4 Troubleshooting Sequence
- First, identify where the strands appear and record whether they occur on every model or only on certain features. Do not rely only on photos of a cleaned-up print; keep a record of the print before cleanup whenever possible.
- Second, check the printer, nozzle, and filament profiles. Start by checking whether an old profile was left in use after changing filament, or whether a project imported from someone else still uses a different printer model.
- Third, choose one variable to test within the limits allowed for the equipment and material. For example, adjust temperature in small increments and compare the amount of stringing, while also checking for new under-extrusion or insufficient bonding between layers.
- Fourth, check whether retraction is enabled and appropriate for the current feed system. Direct-drive and Bowden extruders have different retraction requirements. Do not simply copy someone else’s values or keep increasing retraction without limit.
- Fifth, if there are signs of moisture absorption, dry the filament according to the product requirements and compare the results. If it has already been dried appropriately, move on to the model, travel path, and nozzle rather than repeatedly carrying out the same drying procedure.
- Sixth, compare a simple test print with the target model. A successful simple print shows that those conditions work for that test; it does not prove that the material or equipment will work correctly for every task. If needed, optimize the travel path and the printing sequence for small features.
1.5 How to Assess Improvement
Whenever possible, compare the number and thickness of strands using the same test model, lighting, and camera angle. Also check detail, surface quality, and bonding. If lowering the temperature reduces stringing but makes the model brittle or causes under-extrusion, you need to find a better balance.
If severe stringing persists after basic troubleshooting, or the problem is concentrated in a particular spool or batch, keep samples and project records and contact technical support for further investigation.
1.6 Key Points
The key question in stringing is: “Why is material still oozing from the nozzle during travel moves?” Investigate temperature, retraction, filament condition, the model, and equipment together. Do not attribute all stringing to moisture, and do not immediately assign responsibility just because another spool prints normally.
