How to Recycle Your 3D Print Waste with 3D Filament Recycler

3D printing has opened doors to countless creative possibilities, but one of its most significant environmental challenges is waste. Failed prints, prototypes, and support material accumulate, leaving makers with a growing pile of 3D print waste. Recycling this waste into new filament is a sustainable solution that not only reduces plastic disposal but also gives a second life to failed prints and plastic leftovers. Here’s a step-by-step guide to recycling 3D printing waste into filament, a look at the necessary equipment, and answers to some common questions about the process.

Why Recycle 3D Printing Waste?

1. Sustainability: With plastic waste being a global issue, every effort to reduce, reuse, and recycle helps reduce the carbon footprint of individual makers and companies alike.

2. Cost-Effectiveness: Filament can be expensive. Recycling old prints can save money in the long run, especially for large-scale 3D printing operations.

3. Customization: Recycling filament allows for the customization of material properties by mixing different plastics or incorporating colorants.

Step-by-Step Guide to Recycling 3D Print Waste into Filament

1. Collect and Sort Your 3D Print Waste

Start by collecting all failed prints, supports, rafts, and any other 3D printing waste. It's essential to separate different types of plastic, as each type requires different extrusion temperatures. For example:

• PLA (Polylactic Acid) is commonly used in consumer 3D printing and can be recycled at lower temperatures.
• ABS (Acrylonitrile Butadiene Styrene)and other high-temperature plastics require a more robust extrusion setup.

Mixing different materials can lead to inconsistency and weaken the recycled filament, so ensure thorough sorting.

2. Shred the Plastic

Once sorted, break down the waste into smaller pieces. This can be done manually or with a plastic shredder. Consistently small pieces will melt evenly and extrude more reliably. Ideally, each piece should be around 5mm or smaller in diameter to prevent clogging and promote uniform melting.

Note: Plastic shredders can be costly, so a blender or strong pair of scissors can suffice if you're working with small amounts of waste.

3. Dry the Plastic

3D printing filaments can absorb moisture, which will later affect the extrusion process, causing bubbles and weakening the final filament. Dry the shredded plastic using a dehydrator or an oven at a low temperature (50-60°C) for a few hours.

4. Use a Filament Extruder

To transform the shredded plastic into filament, you’ll need a filament extruder. There are several options on the market here is a few examples:

• Artme3D Filament Extruder

• Price: €675.00 EUR
• Key Features: Compact, suitable for small-batch recycling, straightforward controls.
• Best For: Makers looking to recycle filament on a budget; compatible with PLA and other standard filaments.

• EX2 Filament Extruder

• Price: $2249.00 USD
• Key Features: High-capacity extruder, suited for multiple material types (PLA, ABS, PETG), advanced temperature and speed controls for precision.
• Best For: Professional users needing high-volume filament production; offers more control for multi-material setups.

These devices are specifically designed to handle 3D printing waste and turn it back into filament, and they come with controls for adjusting extrusion speed and temperature.

5. Set the Temperature and Start Extruding

Different plastics have different melting points:

• PLA: 160-200°C
• ABS: 220-250°C

Set the extruder to the appropriate temperature based on the plastic type and adjust the extrusion speed to achieve a consistent diameter, usually around 1.75mm or 2.85mm, depending on your 3D printer’s requirements.

Pro Tip: Experiment with the settings on test runs to find the best temperature and speed for consistent filament quality.

6. Cool and Spool the Filament

As the melted plastic exits the extruder, it should pass through a cooling system (such as a water bath or cooling fan) to solidify. A filament winder can help spool the filament neatly, ensuring consistent tension. If you’re extruding filament manually, be prepared to manage the spooling by hand to maintain filament uniformity.

Quality Control: Testing Your Recycled Filament

After creating a spool of recycled filament, test it with a small print to check its quality. Key factors to look for include:

• Diameter Consistency: A precise filament diameter (within ±0.05mm) is critical for successful printing.
• Strength: Weak or brittle filament may indicate impurities or improper extrusion settings.
• Printability: Watch for clogging, poor layer adhesion, and surface quality.

If the filament has issues, adjust the extrusion settings, reprocess, or try adding fresh pellets to improve quality.

The Importance of Keeping Filament Types Separate Before Recycling

Keeping different types of filament separate before recycling is crucial for achieving high-quality recycled filament. Each plastic type, such as PLA, ABS, PETG, or TPU, has its unique melting point, chemical properties, and printing requirements. Mixing these materials, even in small amounts, can cause significant issues during extrusion and in final print quality.

Risks of Contamination by Different Plastics

1. Inconsistent Melting: When different plastics are mixed, they melt unevenly since each type requires a specific extrusion temperature. This inconsistency can lead to clogs in the extruder, uneven filament, or weakened structural integrity in printed objects.
2. Weak Filament: Contamination weakens the molecular structure of the filament, resulting in poor layer adhesion and brittle prints that break easily. Mixed plastics also lead to unpredictable print quality and performance issues, which are especially problematic for functional parts.
3. Print Failures: Contaminated filament can lead to common print issues like poor layer adhesion, warping, and stringing, as well as clogged nozzles. These issues ultimately waste more time and material, counteracting the benefits of recycling.
4. Incompatibility with Printers: Some materials, like PLA and ABS, are chemically incompatible and cannot fuse properly. This incompatibility can produce uneven extrusion, lumps, or bubbling during printing, affecting the final product’s surface and strength.

How to Thoroughly Dry Filament Regrind Before Extrusion

Moisture is a common problem in 3D printing, especially when dealing with filament regrind (shredded or granulated 3D printing waste). If not properly dried, the regrind can absorb ambient moisture, which leads to steam formation during extrusion. This results in filament with bubbles, inconsistent diameter, and weak structural integrity. Here’s a guide to thoroughly drying filament regrind to ensure optimal quality before extrusion.

Why Moisture Matters in Filament Regrind

Most plastics used in 3D printing are hygroscopic, meaning they absorb water from the air. When these moisture-laden plastics are melted during extrusion, the water turns into steam, creating bubbles that weaken the filament and can cause nozzle clogging during printing. Effective drying prevents these issues, ensuring smoother extrusion and a stronger final filament.

Methods for Drying Filament Regrind

1. Oven Drying

• Temperature Settings: Place the filament regrind on a baking sheet and spread it in a single layer. Preheat a conventional oven to a low temperature suitable for the plastic type (50-60°C for PLA, 70-80°C for ABS).
• Drying Time: Allow the plastic to dry for about 2-4 hours, checking periodically to prevent any plastic from melting or deforming.
• Cooling: Let the regrind cool gradually before transferring it to the extruder. Rapid cooling can lead to condensation, reintroducing moisture into the plastic.

2. Dehydrator

• Setup: Food dehydrators are an effective way to dry filament regrind because they circulate warm air evenly. Place the regrind in a single layer on the dehydrator trays.
• Temperature and Time: Set the dehydrator to a low temperature (50-60°C for PLA, 70-80°C for ABS) and allow the plastic to dry for 4-6 hours.
• Benefits: Dehydrators offer precise temperature control, making them an excellent choice for drying filament consistently without risking melting or warping.

3. Filament Dryer

• Purpose-Built Solution: Filament dryers are designed to remove moisture from 3D printing materials and are especially effective if drying smaller batches of regrind. Some filament dryers have temperature and humidity controls to monitor the drying process closely.
• Method: Place the regrind in the dryer and set it to the appropriate drying temperature for your filament type. Drying time may vary, but typically it takes about 4-6 hours.
• Pro Tip: For optimal results, pair a filament dryer with a vacuum-sealed storage bag immediately after drying to keep the regrind moisture-free until extrusion.

Tips for Effective Drying

• Use Hygrometers: Place a hygrometer in the drying container to monitor moisture levels and ensure thorough drying.
• Avoid Overheating: Exceeding the recommended temperatures can cause the regrind to soften, deform, or even melt, which makes it difficult to feed into the extruder.
• Storage Matters: Once the regrind is dried, store it in an airtight, moisture-resistant container to prevent it from absorbing humidity before extrusion.

Ventilation and Protective Equipment for Extruding 3D Filament at Home

Extruding 3D filament from recycled plastics requires careful attention to safety, as the process releases fumes that can be harmful when inhaled over extended periods. Different types of plastics release different types of volatile organic compounds (VOCs) and ultrafine particles (UFPs) when heated, some of which may be hazardous in enclosed spaces. Ensuring adequate ventilation and wearing protective equipment are essential steps to maintain a safe working environment when using a 3D filament recycler.

Importance of Ventilation During Extrusion

During the extrusion process, plastics like PLA, ABS, and PETG emit fumes that can irritate the respiratory system or, in certain cases, pose health risks over time. Proper ventilation not only helps to disperse these fumes but also prevents buildup in the workspace, keeping air quality at a safer level. You can use local exhaust ventilation or exhaust fans to eliminate TVOCs from the filaments during extrusion.

Maintaining a Safe Workspace

1. Keep Doors Closed but Windows Open: Isolate the workspace to limit fumes spreading through the home, while ensuring that windows are open to maintain airflow.
2. Monitor Air Quality: Invest in a portable air quality monitor that can detect VOC levels, giving you an alert if concentrations rise.
3. Regularly Clean the Area: Vacuum with a HEPA filter and wipe down surfaces to remove any residual dust or particles, keeping the workspace as clean as possible.

Safety Precautions for Shredding Filament Waste

Shredding filament waste into smaller pieces is a key step in recycling 3D printing material, but it also comes with safety considerations, especially if you’re using a DIY setup like a blender or a larger plastic shredder. Shredding can create plastic dust and micro-particles that can become airborne, posing respiratory hazards. Whether using an old blender for small amounts or a commercial-grade shredder, it’s essential to follow safety precautions to protect yourself from potential hazards.

Safety Tips for Shredding with an Old Blender

If you’re using a household blender to break down small amounts of filament waste, take these safety measures:

1. Choose a Dedicated Blender: Use an old blender that you don’t need for food. Plastic particles from filament can adhere to the blades and container, contaminating the blender for other uses.
2. Work in a Well-Ventilated Area: Set up your shredding station in a space with good ventilation, ideally near an open window with an exhaust fan or in a garage with cross-ventilation. Shredding plastic creates small particles that can easily spread through the air if confined to an enclosed space.
3. Wear Protective Equipment:
   • Respiratory Mask: Wear an N95 or P100 respirator mask to filter out airborne plastic particles created during shredding. Even with small quantities, micro-particles can become airborne and pose respiratory risks.
   • Safety Goggles: Protect your eyes from any shards or dust that might fly out of the blender.
   • Gloves: Use cut-resistant gloves when handling plastic pieces and emptying the blender to prevent injury from sharp or jagged edges.
4. Cover the Blender with a Lid or Shield: Ensure the blender lid is securely in place to contain the shredded plastic. Additionally, consider using a clear shield (like a plastic barrier) around the blender to prevent any airborne particles from spreading when you open the lid.
5. Wait Before Removing the Lid: After the blender has finished shredding, give it a few seconds to settle before removing the lid to allow airborne particles to fall back down. Then, carefully pour the contents directly into a sealed container or bag to minimize exposure.

Safety Tips for Using a Larger Filament Shredder

For higher volumes of filament waste, a larger plastic shredder is often more efficient and safe, but it still requires careful handling.

1. Follow Manufacturer Guidelines: Larger shredders come with specific operating guidelines. Always follow the manufacturer’s recommendations on safe use, load size, and recommended PPE (personal protective equipment).
2. Use in a Controlled, Well-Ventilated Space: Place the shredder in a workshop or garage with adequate airflow. Ideally, use an exhaust fan or localized ventilation system (like a fume extractor) to capture any airborne particles at the source.
3. Protective Equipment:
   • Full-Face Respirator or Dust Mask: For larger shredders, a full-face respirator with a P100 filter is ideal to protect against both airborne particles and potential fume exposure.
   • Ear Protection: Shredders can be loud. Wear ear protection, such as earplugs or earmuffs, to protect your hearing.
   • Gloves and Safety Goggles: Gloves and goggles are essential, as they protect against accidental contact with moving parts and plastic fragments.
4. Minimize Exposure to Plastic Dust: Larger shredders may have a collection bag or container to catch shredded plastic. Ensure it’s properly sealed and emptied in a way that minimizes dust exposure. After each shredding session, vacuum the surrounding area with a HEPA-filtered vacuum to collect any stray dust particles.

Additional Tips for Managing Air Quality

• Avoid Breathing Air Immediately After Shredding: Whether using a blender or a commercial shredder, give the space some time to clear after shredding before re-entering without PPE. Fine plastic particles can remain suspended in the air for several minutes.
• Run an Air Purifier: If possible, place an air purifier with a HEPA filter in the room to capture any lingering particles and improve air quality.
• Storage of Shredded Filament: Place the shredded filament directly into airtight containers or bags. This minimizes the chance of plastic dust or particles escaping into the air during handling or transportation.

Shredding filament waste can be done safely with proper ventilation, protective gear, and good practices. By taking these precautions, you can reduce your exposure to airborne particles and enjoy a safer, cleaner filament recycling process.

Mixing Fresh PLA Pellets with Recycled Material

To improve the quality of recycled filament, it’s often beneficial to blend recycled PLA with fresh PLA pellets. This mixture combines the stability and strength of new PLA with the sustainability of recycled material, producing filament that’s more consistent and reliable for 3D printing. Here’s a guide to mixing fresh PLA pellets with recycled material, including the ideal ratios, benefits, and considerations.

Why Mix Fresh Pellets with Recycled PLA?

1. Improved Print Quality: Recycled PLA can degrade slightly in quality with each recycling cycle. Adding fresh PLA pellets helps restore strength, layer adhesion, and flexibility, making the filament closer to the quality of new PLA.
2. Consistent Extrusion: Fresh pellets help regulate the extrusion process, reducing issues like diameter inconsistencies and weak spots in the filament caused by degraded recycled material.
3. Better Color and Surface Finish: Adding fresh PLA enhances the filament’s surface quality, creating a smoother, more visually appealing result.

Recommended Ratios for Mixing Fresh and Recycled PLA

The optimal ratio of fresh PLA to recycled material depends on the quality of the recycled PLA and the intended use of the filament. Here are general guidelines:

• 50% Fresh Pellets / 50% Recycled PLA: This ratio is a balanced option that enhances strength and consistency without sacrificing too much sustainability.
• 70% Fresh Pellets / 30% Recycled PLA: For projects needing high-quality prints, this blend provides the structural integrity and reliability of fresh PLA while reducing material costs and waste.
• 30% Fresh Pellets / 70% Recycled PLA: This blend is ideal if you’re looking to maximize the use of recycled material. Although it may slightly affect print quality, it still offers an eco-friendly option with reduced impact on performance.

Steps for Mixing Fresh and Recycled PLA

1. Measure and Combine Materials:
   • Use a digital scale to measure out the exact amount of fresh pellets and recycled PLA regrind according to your chosen ratio.
   • Place both the pellets and regrind in a mixing container, ensuring they are evenly combined.
2. Dry the Mixture Thoroughly:
   • Both fresh and recycled PLA are hygroscopic and will absorb moisture from the air. Dry the combined mix in an oven or dehydrator at 50-60°C for 4-6 hours to remove moisture before extrusion. This step is critical for preventing bubbles and weak spots in the filament.
3. Feed into Extruder:
   • After drying, transfer the mixture to the filament extruder’s hopper. If your extruder doesn’t have a mixing capability, pre-mix the materials thoroughly to ensure a uniform blend.
4. Extrusion Settings:
   • Use the standard PLA extrusion temperature, typically between 180-210°C. Start with a lower temperature and gradually increase if needed, as the mixture may require slight adjustments based on the ratio of recycled to fresh material.
   • Monitor the extrusion closely to ensure a consistent filament diameter and color. If you notice inconsistencies, try adjusting the extrusion speed or temperature slightly.

Tips for Optimal Results

• Experiment with Ratios: Run test extrusions with different ratios to find the ideal blend for your specific recycled PLA quality and print requirements.
• Use Colorants Sparingly: If adding color to the filament, use it minimally, as too much colorant can impact the filament’s structural integrity. Colorants also tend to interact differently with fresh and recycled PLA, so small test batches can help achieve the right shade.
• Store Mixed Pellets Properly: If not extruding immediately, store the dried PLA mixture in airtight containers to prevent moisture absorption.

Diameter Measurements and Tolerances for Quality Control

Maintaining consistent filament diameter is crucial for producing high-quality 3D prints, as even small deviations can lead to print failures, uneven extrusion, and poor layer adhesion. When recycling filament, especially when mixing recycled and fresh PLA, quality control measures are essential to ensure a stable diameter and tolerance range. Here’s a guide to achieving and maintaining specific diameter measurements and tolerances during filament extrusion.

Common Filament Diameters and Target Ranges

Most 3D printers use filament in one of two standard diameters:

• 75 mm(commonly used for desktop 3D printers)
• 85 mm(typically used in industrial or large-format 3D printers)

The goal is to ensure that the recycled filament stays within a narrow tolerance range around the target diameter. Filament that strays outside of this range can lead to print inconsistencies, nozzle clogs, or weak layers.

Recommended Tolerance Ranges

For high-quality filament, a tolerance of ±0.05 mm around the target diameter is ideal. Here’s a breakdown:

• 75 mm Filament: Target diameter range of 1.70 mm - 1.80 mm.
• 85 mm Filament: Target diameter range of 2.80 mm - 2.90 mm.

Staying within these ranges ensures consistent extrusion flow, layer adhesion, and print quality. Tighter tolerances can be difficult to achieve with recycled filament but are worth aiming for to reduce print issues.

Tools and Techniques for Measuring Diameter

1. Digital Calipers:
   • Use digital calipers to measure the filament diameter at regular intervals during extrusion. Take measurements along several points of the filament length to ensure consistency.
   • Measure across different angles (90° rotation) to detect any ovality (flattening or uneven rounding), which can also impact print quality.
2. Laser Diameter Gauges:
   • Some filament extrusion systems come with built-in laser diameter gauges that monitor the filament in real-time. These gauges provide continuous, automated measurements, alerting you to any variations in diameter as extrusion proceeds.
   • This equipment is especially useful for maintaining tolerances in larger-scale recycling setups but can be a costly investment for hobbyist use.
3. Micrometer:
   • A micrometer can provide highly accurate diameter measurements, especially if precise tolerance control is required. Take readings at multiple points along the filament and adjust the extruder as needed to maintain the target diameter.

Steps for Quality Control During Extrusion

1. Set Up an Initial Test Run:
   • Before committing to a full extrusion run, extrude a test length of filament (typically a few meters) and measure the diameter. Use the digital calipers or micrometer to check for consistency.
2. Adjust Extruder Parameters:
   • Extrusion Speed: Slower extrusion can improve consistency, while faster speeds may introduce more variation in diameter.
   • Temperature: The extrusion temperature affects filament flow. Adjust the temperature in small increments (2-5°C) if you notice fluctuations in diameter, as too high or too low temperatures can lead to filament swelling or shrinkage.
3. Regular Monitoring and Calibration:
   • Take measurements at regular intervals throughout the extrusion process. For DIY setups, measure every 1-2 meters; for larger or automated setups, continuous monitoring with laser gauges is recommended.
   • Record the measurements to help identify any recurring deviations or patterns, which can be corrected by fine-tuning the extruder settings.
4. Post-Extrusion Quality Check:
   • Once the entire batch has been extruded, measure the diameter at random points along the filament length. Check that all points fall within the target tolerance range before spooling the filament for storage or use.

Troubleshooting Common Diameter Issues

• Thicker-than-Tolerance Filament: If the filament consistently measures above the target range, try reducing the extrusion temperature or speed slightly, which can prevent excessive material flow.
• Thinner-than-Tolerance Filament: If the filament measures below the target range, increase the extrusion temperature slightly to encourage smoother flow and prevent thinning.
• Ovality or Irregularities: If the filament has an inconsistent shape, inspect the nozzle for clogs or buildup. Cleaning the nozzle and checking for mechanical obstructions can help produce more uniform extrusion.

Storing Filament to Maintain Diameter Quality

After extrusion and quality checks, store the filament properly to prevent any diameter changes due to environmental factors:

• Keep in Airtight Containers: Filament can absorb moisture, leading to swelling that affects diameter and print quality.
• Avoid Stacking Heavy Items: Filament spools can deform under heavy pressure, so store them in a way that minimizes strain or bending.

FAQs

How to Turn 3D Printer Poop (Waste) into Filament?

To recycle 3D printer “poop” (failed prints, leftover supports, rafts, etc.), start by sorting, shredding, and drying the waste plastic. Feed it into a filament extruder like the Artme3D or Filabot EX2, which will melt and extrude it back into usable filament. Properly setting the temperature and cooling the filament are key to achieving high-quality recycled filament.

Can 3D Printing Waste Be Recycled?

Yes, 3D printing waste can be recycled, but it requires specialized equipment such as a plastic shredder and filament extruder. PLA and ABS, two of the most common 3D printing materials, can both be melted down and extruded into new filament. However, consistent results depend on careful sorting and processing.

How Do You Turn Failed Prints into Filament?

To turn failed prints into filament, sort the plastic by type, shred it into small pieces, dry it to remove moisture, and then feed it into a filament extruder set to the correct temperature. The extruded filament can then be spooled and used for new prints, provided the material quality is intact.

Can You Melt PLA Back into Filament?

Yes, PLA can be melted back into filament, provided it hasn’t degraded too much. PLA typically melts at temperatures between 160-200°C. Using a filament extruder, PLA waste can be heated and reshaped into new filament. Avoid recycling PLA repeatedly, as its properties degrade with each cycle, impacting print quality.