Guide to printing PLA Filament

PLA (Polylactic Acid) is one of the most popular and user-friendly materials for FDM (Fused Deposition Modeling) 3D printing. It is a semi-crystalline plastic that offers great printing yield with minimal requirements and is available in a wide variety of colours. PLA is also biodegradable under specific conditions and recyclable.

TABLE OF CONTENTS

• Minimal Printing Requirements
• Feed Path and Spooling
• Changing Filament
• Nozzle Temperature
• Addressing Common Issues
• Bed Temperature
• Do You Need Rafts?
• Storage Suggestions
• Troubleshooting Filament Jams and Nozzle Blockages
  • Common Causes and Preventive Steps
• Heat Creep
  • Solutions to Prevent Heat Creep
• Strategies to Minimise Warping
• Poor Layer Adhesion
  • Causes and Solutions
• Parts difficult to remove from platform

  • Solutions for Easy Part Removal

Minimal Printing Requirements

• Minimum Extruder Temperature: 195°C (±10°C). The optimal temperature may vary based on your printer and selected color.
• Heated Bed: While not required for all machines, a heated bed significantly enhances print quality. Recommended temperatures:
  • Glass Surface: 60°C
  • PEI/Texture Sheets: 70°C
  • PolyTerra: 40-50°C
• Enclosure: Although PLA has good dimensional stability, using an enclosure mitigates the effects of drafts, reducing warping on larger prints.
• Part Cooling Fan: Control of the cooling fan is advisable for optimal results.

Feed Path and Spooling

PLA does not have specific feeding path requirements. However, to avoid filament drag, it's best to minimize long and complicated feeding paths.

Changing Filament

• From PLA to Another PLA: Unload the filament at 200-210°C and load the new filament, ensuring the previous color is fully purged.
• From a Higher Temperature Filament: Unload at the recommended printing temperature of the high-temp filament, then load the new filament until the previous color is completely purged.

Nozzle Temperature

PLA typically prints at lower temperatures, usually between 190°C - 240°C. For fine-tuning, consider using a Temperature Tower to determine the best printing temperature based on your specific application needs, such as high detail or bridging. Temperature Tower Generator.

Addressing Common Issues

• High Wisps or Stringing: Lower the printing temperature and calibrate retraction settings. If using an all-metal hot end or direct-drive extrusion setup, refer to the manufacturer’s recommended retraction settings. For minor wisps, a heat gun can effectively remove them, but limit exposure to 5-10 seconds to prevent deformation.

  • Retraction Tuning: Retraction Calibration Guide.

• Bad Layer Adhesion or Underextrusion: Increase print temperature, reduce print speed, or adjust the part cooling fan if adhesion issues occur after the initial layer. Additionally, recalibrating e-steps and filament flow can rectify under-extrusion problems.

  • Extruder E-step Calibration: E-step Calibration Guide.
  • Flow Calibration: Flow Calibration Guide.

Bed Temperature

A heated bed is not required for PLA, but optimal performance is generally achieved at 60°C-70°C. The success of printing without a heated bed is contingent upon the printing surface, environment, and model size. Note that 70°C is the maximum for PLA to avoid crystallization and warping issues.

• Glass: 60°C
• PEI/Texture Sheet: 55-60°C
• Cold Plates/Satin Build Plates : 35-40°C 

Do You Need Rafts?

Rafts are generally unnecessary with PLA. However, for larger prints, using a raft can enhance bed adhesion, particularly in drafty environments.

Storage Suggestions

Store PLA filament in the resealable bag with desiccant included with all Polymaker products and keep it away from sunlight. PLA is mildly hygroscopic and can absorb moisture from its environment over time, particularly in humid conditions. Using a dry box, while not critical, can help ensure consistent printing quality in humid environments. An active heated dryer is recommended if PLA has been left exposed for over a month in damp conditions.

Troubleshooting Filament Jams and Nozzle Blockages

Filament jams or nozzle blockages can occur during 3D printing for various reasons. If the extruder cannot push the filament through, it may begin to "chew out" the filament, often accompanied by a clicking or clunking sound. Ignoring these signs can worsen the issue.

Common Causes and Preventive Steps

1. Insufficient Extruder Temperature:

   • If your extruder temperature is too low, PLA filament won’t flow properly, making extrusion difficult.
   • Solution: Ensure the nozzle temperature is set correctly for PLA, typically between 190°C - 240°C.

2. Softening in the Hot End:

   • If the filament softens prematurely, the extruder will chew out the filament, leading to a nozzle jam.
   • Solution: Monitor the temperature and ensure proper heat management.

3. Excessive Friction:

   • Friction on the filament may hinder feeding. Spool holder placement can affect this.
   • Solution: Experiment with different spool holder positions (above, beside, or behind the printer).

4. Improper Nozzle Height:

   • If the nozzle height is too close to the bed, filament feeding can be restricted, especially at fine layer heights (0.1mm or 0.05mm).
   • Solution: Make precise adjustments to the nozzle height to ensure proper clearance for filament flow.

5. Warping or Lifting Parts:

   • Warped prints may push against the nozzle, limiting material flow and potentially causing jams.
   • Solution: Use proper adhesion methods and ensure a stable first layer.

6. Filled PLA Materials:

   • Materials like carbon fiber or metal-filled filaments are more prone to causing blockages.
   • Solution: Use a higher diameter nozzle (0.6mm or greater) and consider using plated nozzles or harden abrasive resistant for these filaments.

7. Finer Nozzles:

   • Nozzle blockages are more common with smaller nozzles (e.g., 0.2mm). Avoid using these for filled filaments.
   • Solution: Adjust print speed and extrusion settings when using smaller nozzles, ensuring compatibility with your filament type.

8. Poor Quality Filament:

   • Filament that is oval-shaped or has inconsistent diameter can lead to jams.
   • Solution: Use filaments that meet industry-standard tolerances (±0.05mm for 1.75mm filament; an acceptable range is 1.70mm to 1.80mm). Opt for reputable brands that offer tighter tolerances (±0.03mm).

Cleaning a clog Nozzle

If your nozzle is blocked with PLA, one effective method is to feed a tougher, higher-temperature material (e.g., Polycarbonate) through the extruder. The higher printing temperature (around 250°C for PC) can help purge the clogged PLA.

Cold Pull: https://support.dremc.com.au/support/solutions/articles/51000285907-help-i-ve-got-a-clog-in-my-hotend-what-do-i-do-now- 

Heat Creep

What is heat creep?

Heat creep is a common issue encountered when printing PLA, where heat travels up the extruder toward the extruder gear, softening the filament. This prevents the gear from gripping and pushing the filament through the hot end, resulting in the filament being chewed out.

Heat creep primarily affects low-temperature materials like PLA, which has a low softening temperature of around 60°C. This issue is more pronounced in printers designed for high-temperature materials, dual extruder setups where filament sits idle for extended periods, or low-quality 3D printers with poorly designed extruders.

Solutions to Prevent Heat Creep

1. Ensure Cooling:

   • Confirm that the extruder fan is operational and cooling the extruder as intended. If the fan is making noise, consider replacing it.

2. Open Printing Environment:

   • If your printer is enclosed, leave the front doors and top hatches open during printing to prevent the filament from softening near the extruder gear.

3. Minimise Retraction:

   • Heat creep is more likely when printing models that require frequent retractions, as the filament will pass the extruder gear multiple times. Adjust your retraction settings to minimise this.
   • Retraction Tuning: Retraction Calibration Guide.

4. Use Simple Designs:

   • Printing simple parts with minimal or no retraction increases the chances of success, as the filament only passes through the gear once.

5. Opt for Specialised PLA Materials:

   • All Polymaker PLA materials (PolyLite™ PLA, PolyMax PLA, PolyWood™) feature Jam-Free™ technology, enhancing heat stability. These filaments maintain a high softening temperature (>140°C), preventing issues in the cold end while ensuring fast melting in the heating zone.

6. Inspect Heat Break:

   • If you're using an all-metal hot end and face heat break creep issues, ensure your cooling fan is adequate for the cold end. For K1 printers, it’s recommended to print without the top cover or with the front door closed.

If you continue to have problems, feel free to contact our support for further troubleshooting. Please note that we can offer limited assistance for filaments not supplied by us or for non-recommended parts.

Strategies to Minimise Warping

1. Utilise a Heated Bed:

   • Set your heated bed to 60°C to improve adhesion and warm the environment, reducing warping and enhancing print consistency. Avoid setting the bed temperature higher, as it can cause PLA to crystallize and warp. Consider cleaning build surface if you haven't done so in while, using some dish soap and warm water. 

2. Ensure Proper Adhesion:

   • The most common cause of warping is insufficient bed adhesion or incorrect nozzle height. Ensure your nozzle height is accurate and the bed is levelled properly, using appropriate printing surfaces for PLA.

3. Control Environmental Conditions:

   • Drafts, cool air from air conditioners, or low winter temperatures can create internal stresses in your material. An enclosure with a closed front can maintain a stable printing environment.

Poor Layer Adhesion

Causes and Solutions

1. Under-Extrusion:

   • If the filament is under-extruding, there will be gaps between layers, compromising mechanical strength. Ensure that the nozzle temperature is correctly set for consistent flow and reduce tension to allow for proper filament feeding.

2. Moisture Issues:

   • Printing with moisture-absorbed PLA can result in bubbles forming in the extruded plastic, weakening the part. If moisture exposure occurs, the filament can be dried, but proper storage is crucial to avoid future moisture issues.

Parts difficult to remove from platform

While good bed adhesion is essential for successful prints, excessive adhesion can make part removal challenging.

Solutions for Easy Part Removal

1. Test Removal Conditions:

   • Some print surfaces are designed to release prints when cooled. Experiment with removing models from a hot bed or a cold bed to find the best method for your surface.

2. Adjust Temperature Settings:

   • If your heated bed is too hot, or the nozzle temperature is too close to the bed, consider slightly lowering the bed temperature or adjusting the nozzle height to improve the removal experience.

3. Use a Release Agent:

   • While not necessary, some users find that applying a glue stick or similar release agent to their print surface makes part removal easier, especially for certain materials.