Overview: What is PLA Filament?
Properties
Strength: Medium
Flexibility: Low
Durability: Medium
Ease-Of-Use: Easy
Pros
Low price
Excellent print quality
Easy to use
Variety of colors
Cons
Low heat resistance
Filament prone to moisture absorption
Not suitable for outdoor applications
Brittle
Polylactic Acid (PLA) is an environmentally friendly plastic derived primarily from renewable resources such as corn starch, tapioca roots, and sugarcane. It’s the most popular 3D printing material thanks to its low print temperature, excellent aesthetics, low difficulty, and minimal hardware requirements.
One of PLA’s most appealing aspects is that it’s industrial compostable. We say that PLA filament is industrial compostable because processing facilities can break down PLA plastics through industrial means. However, there’s no evidence that PLA is biodegradable in nature.
Outside of 3D printing, PLA plastics are used in bottles, plastic films, biodegradable medical devices like sutures, screws, and pins.
Thanks to its ease of use, low hardware requirements, high-quality prints, and low price, PLA filament has quickly become the most popular 3D printing filament. It’s especially popular among beginners and hobbyists, as achieving excellent print quality with minimal tinkering is easy. PLA also comes in a huge range of colors and styles, adding to its popularity.
The material’s rigidity, good tensile strength, and minimal warping make PLA an excellent choice for a wide range of printing applications—from detailed models and prototypes to cosplay and indoor applications.
PLA has a low printing temperature, between 180°C and 220°C. This low temperature means you can print PLA filament on almost any 3D printer, and you don’t need a heated bed or enclosure to print PLA.
However, PLA 3D prints are very brittle and shatter under stress. The material also becomes soft at temperatures as low as 60°C, making it unsuitable for outdoor applications.
Table of Contents
Hardware Requirements
PLA is a widely used 3D printing filament due to its ease of use and compatibility with most 3D printers, including budget machines. The low hardware requirements make it an excellent choice for beginners and those using budget 3D printers.
Bed
- Temperature: 20 – 60°C
- Heated bed: Optional but recommended
- Enclosure: Not required or recommended
Extruder
- Temperature: 180 – 220°C
- Hot-End: No Special Requirements
- Cooling Fan: Required
- Nozzle: No special nozzle required except for wood and metal-filled PLA
Build Surface
- PEI sheet
- Glass
- Painter’s tape
- Glue Stick
Material Properties
Exploring the material properties of PLA reveals why it’s a popular choice for a wide range of 3D printing projects. Here’s a detailed look at its key characteristics:
- Strength: PLA offers moderate strength but is more brittle compared to other thermoplastics, which can limit its use in load-bearing applications. You can increase the strength of your PLA-printed objects by using a higher infill density and layer height.
- Flexibility: PLA is generally rigid and offers minimal flexibility, making it prone to snapping under pressure rather than bending. The stiff plastic is prone to snapping when flexed.
- Durability: While PLA is biodegradable under industrial composting conditions, it is stable under normal usage conditions and offers a decent shelf life for indoor use. However, the low UV and heat resistance makes PLA unsuitable for outdoor use.
- Ease of Use: PLA is highly favored for its ease of printing. The 3D-printing filament does not require a heated bed, has minimal warp, and works well at lower temperatures, making it ideal for beginners and those with basic printers. Using default slicer settings without much tinkering or testing, you can easily achieve high dimensional accuracy.
- Temperature Resistance: PLA has a low melting temperature and softens at relatively low temperatures (around 60°C). While stable indoors, PLA parts deform when exposed to direct sunlight and higher temperatures.
- UV Resistance: Prolonged exposure to UV light can degrade PLA, causing it to become discolored and deform over time.
- Chemical Resistance: PLA is considered chemically resistant. The plastic isn’t soluble in solvents like acetone or isopropyl alcohol. However, you can use more powerful solvents to dissolve or layer smooth your printed objects for a smoother surface finish.
Printing Performance
PLA is the easiest filament to work with. Its low hardware requirements and high dimensional accuracy make it easy enough for beginners to achieve outstanding print quality. Yet experts can further improve dimensional accuracy by tinkering with slicer settings and carefully calibrating their 3D printers.
Unlike materials like ABS or polycarbonate, which are versatile across various manufacturing processes, PLA is predominantly designed for 3D printing. It’s a purpose-built material that offers unmatched ease and quality.
One of PLA’s biggest draws is its low entry barrier regarding equipment requirements. You don’t need a heated print bed, enclosure, or direct drive extruder—components essential for printing materials like ABS, PETG, or TPU.
The simplicity of PLA 3D printing allows even the most budget-friendly printers to achieve excellent results. PLA is also one of the cheapest available filaments, with prices ranging between $10 – $40 per kilogram.
The popularity of PLA filament means you’ll find more variety in color and finishes. Thousands of colors are available to purchase to help you craft the perfect print.
You’ll find various filament options, including dual and tri-extrusion filaments that merge colors in one spool, wood and metal-filled PLA, glow-in-the-dark, transparent, and glitter materials.
PLA is far more forgiving than other filaments, making achieving high print quality easier. Most default slicer profiles are optimized for PLA and produce high-quality prints without adjustment.
You can further improve your prints with adjustments to the slicer settings and calibration of your 3D printer. A bit of tinkering leads to significant improvements without the extensive trial and error associated with more sensitive materials, making them ideal for those looking to fine-tune their outputs.
Troubleshooting Guide
Causes:
- Unclean Print Bed: Residue or oils on the print bed can prevent the first layer of PLA from sticking properly.
- Incorrect Bed Temperature: A heated build plate improves adhesion, although PLA does not necessarily require a heated bed.
- Improper Bed Leveling: An uneven print bed can cause parts of the first layer to be too far from or too close to the build surface.
- Inadequate First Layer Settings: Incorrect settings such as print speed, Z offset, and cooling prevent proper adhesion.
- Poor Surface Compatibility: Some print bed surfaces don’t offer good adhesion for PLA without using an adhesive aid.
Solutions:
- Clean the Print Bed: Regularly clean your print bed with isopropyl alcohol or mild soap to remove dust, grease, and filament residue.
- Adjust Bed Temperature: Set the bed temperature to around 50-60°C to help the first layer of PLA stick to the bed without warping.
- Level the Print Bed: Ensure that the print bed is properly leveled. A good rule of thumb is to adjust the nozzle at all four corners until a piece of paper can slide between the nozzle and the bed with a slight resistance.
- Adjust the Z Offset: Calibrate the Z offset to ensure the filament adheres correctly.
- Optimize First Layer Settings: Decrease the first layer speed to 50% of the normal print speed. Slower speeds allow more time for the filament to adhere to the bed. Additionally, set the first layer height 50% thicker than the rest of the print to help the plastic grip the bed. Use a first layer height of 0.3mm when printing with a 0.2mm layer height.
- Enable Build Plate Adhesion: Consider printing with a brim or raft to increase the surface area of your object’s base and increase build plate adhesion.
- Use Adhesives or Appropriate Surfaces: To improve adhesion, apply a thin layer of glue stick, hairspray, or blue painter’s tape. Alternatively, swap to a build surface designed for PLA. A textured PEI sheet is my build plate material of choice when printing PLA.
For more information, check out our full guide on what to do if PLA isn’t sticking to the bed.
Causes:
- Improper Bed Leveling: If the bed is uneven, the nozzle might collide with higher spots of the print.
- Warping of the Print: If parts of the print lift off the bed, the nozzle can collide with these warped sections.
- Mechanical Issues: Loose belts, worn bearings, or any slack in the movement mechanisms can cause the nozzle to drop or move unpredictably.
Solutions:
- Level the Print Bed: Ensure that the print bed is perfectly leveled. This is often the simplest and most effective solution to prevent the nozzle from colliding with the print.
- Address Print Warping: Improve bed adhesion (as previously discussed) to prevent the corners of the print from lifting. Consider using a brim or raft to stabilize the print.
- Inspect and Repair Mechanical Components: Tighten any loose belts and replace worn bearings. Ensure all moving parts are securely fastened and operate smoothly to maintain accurate nozzle positioning.
- Activate Z-Hop: Enable Z-hop in your slicer settings. This feature lifts the nozzle slightly when moving between print areas, reducing the risk of the nozzle dragging across or colliding with the print.
- Decrease Flow Rate: Adjust the flow rate in your slicer settings. A higher flow rate can cause excess material to build up, leading to collisions. Lowering the flow rate helps maintain a more consistent and controlled extrusion, reducing the risk of bumps that the nozzle might hit.
Causes:
- High Extruder Temperature: Excessive heat causes PLA to become too fluid, leading to oozing as the nozzle moves between sections.
- Slow Travel Speed: If the nozzle moves too slowly between print sections, the molten filament has time to ooze from the nozzle, creating strings between open sections of your print.
- Improper Retraction Settings: Inadequate filament retraction when the nozzle lifts and moves results in excess filament flowing from the nozzle.
- Humidity: PLA absorbs moisture from the air, which can boil and turn to steam during printing, forcing small amounts of molten PLA out of the nozzle.
Solutions:
- Lower Print Temperature: Lower the temperature of your extruder to within the range specified by the filament manufacturer. When in doubt, lower the printing temperature in 5-10 degree increments until you print without strings. Note: Never go below the manufacturer’s lowest recommended temperature, or you’ll experience under-extrusion.
- Optimize Travel Speed: Increase the travel speed so the nozzle moves faster over open spaces. Faster travel speeds mean there’s less time for the filament to ooze from the nozzle and create strings.
- Tune Retraction Settings: Retraction is essential for pulling the filament back into the nozzle when moving between parts of your print and reducing unwanted extraction. Increase the retraction distance and speed in your slicer to reduce stringing.
- Store Filament Properly: Keep PLA filament in an airtight container with desiccants to minimize moisture absorption. If it has absorbed moisture, dry the PLA filament in a filament dryer or an oven at a low temperature.
- Enable Combing Mode: Combing mode in your slicer settings keeps the nozzle within the printed areas as much as possible when it moves. Combing mode reduces the amount of time your nozzle spends over open spaces and minimizes the amount of strings in your print. Note: Combing doesn’t fix stringing issues, but it does help reduce overall stringing in your prints.
- Enable Coasting: Coasting stops extrusion a short distance before the print move finishes, relying on the remaining pressure in the nozzle to finish the extrusion. This small adjustment reduces pressure in the nozzle before the print head travels to eliminate unwanted strings.
If you’re still struggling with stringing, check out our full guide on how to eliminate strings from your 3D prints.
Causes:
- Retraction: Too little, too much, too fast, or too slow retraction creates zits and blobs due to uneven pressure or filament oozing.
- Extrusion: Inconsistent or excessive extrusion is a direct cause of zits and blobs. If the printer extrudes more filament than needed, it accumulates on the print’s surface, forming blobs.
- High Nozzle Temperature: High nozzle temperature can cause the filament to melt too much and ooze excessively, even when extrusion isn’t actively occurring. The excess extrusion deposits on the model’s surface create unwanted print defects.
- Inconsistent Printing Speed: Sudden starts and stops caused by rapid changes in printing lead to surface irregularities like zits and blobs.
- Inadequate Cooling: Insufficient cooling can fail to solidify the newly deposited filament, allowing it to move or sag and form bumps on subsequent layers, resulting in zits and blobs.
Solutions:
- Lower Print Temperature: Reduce the nozzle temperature to minimize excess filament from leaking due to overheating. Check the side of your filament spool for the manufacturer’s recommendation and adjust your print temperature in 5-10 degree increments.
- Lower Print Speed: Decrease the print speed to give the filament more time to cool and solidify before the next layer starts, reducing the chances of blobs. Decrease print speeds in 10mm/s increments and monitor the effects on your print surface.
- Adjust Retraction Settings: Fine-tune the retraction distance and speed to effectively pull the filament back into the nozzle when it stops or changes direction.
- Enable Coasting: Turn on coasting to stop extruding filament just before the nozzle finishes a segment, relieving pressure in the nozzle and preventing unwanted filament flow.
- Increase Cooling: Improve part cooling by adjusting fan settings or adding more cooling fans to solidify the extruded filament faster and prevent oozing.
- Enable Wiping: Set the nozzle to wipe off excess filament on a portion of the print or on a wipe tower before moving to a new print area, reducing zits.
- Tune Printer Extrusion: Calibrate your extruder to ensure the right amount of filament is extruded, avoiding over-extrusion, which can lead to blobs.
- Clean Your Nozzle: Regularly clean your nozzle to prevent partial clogs that can disturb the flow of filament and lead to irregular extrusion.
- Keep Your Filament Dry: Store filament in a dry environment to prevent moisture absorption, which can boil during printing and create steam that causes irregular extrusion.
Check out our full guide on fixing zits and blobs in your 3D prints.
Causes:
- Excessive Bed Temperature: If the bed temperature is too high, it can cause the base layers of PLA to become too soft. High bed temperatures lead to spreading and bulging at the base of the print.
- Improper Bed Leveling: A bed that’s too close to the nozzle at the first layer creates too much of a “squish,” causing the first layer to squeeze out farther than intended.
- Over-Extrusion: Over-extrusion leads to excess filament accumulating around the base of the print.
Solutions:
- Decrease Bed Temperature: Lower the print bed temperature after the first few layers to help the material maintain its shape and reduce spreading.
- Level the Print Bed: Ensure the bed is level and set the correct initial nozzle height to avoid excessive squishing of the first layer.
- Calibrate Extrusion Rates: Check and adjust the extrusion multiplier to ensure that the printer is not pushing out more filament than required.
Causes:
- Poor Bed Adhesion: Inadequate adhesion can cause the corners of the print to lift and detach from the build plate.
- Rapid Cooling: If the printed layers cool too quickly, the top of the layer cools and contracts quicker than the bottom, pulling the edges of the print upwards.
- Improper First Layer Settings: Incorrect settings for the first layer, such as excessive speed or insufficient squish (the slight flattening of the filament against the build plate), compromise the bed adhesion.
Solutions:
- Use a Heated Bed (if not already): PLA doesn’t require a heated bed. However, using one set to the right temperature maintains an even heat throughout the printing process and prevents the edges from cooling too rapidly. Heated beds also provide greater bed adhesion, preventing warping at the edges of your print.
- Adjust Bed Temperature: Set the bed to an ideal temperature for PLA—typically between 50-60°C.
- Refine First Layer Settings: Reduce the speed of the first layer to ensure better adhesion and adjust the initial nozzle height to achieve a slight squish of the filament. This helps the first layer stick better to the bed.
- Apply Brims or Rafts: Adding a brim or raft increases the adhesion surface area, which helps anchor the object to the build plate.
- Optimize Bed Adhesion: Use adhesives like hairspray, glue stick, or blue painter’s tape on the print bed to improve grip. Ensure the bed is clean and free of debris or grease before printing.
- Improve Cooling Strategies: Control cooling fans to start slowly or after the first few layers. Sudden cooling causes the material to contract too quickly, leading to warping. I set my cooling to 0% for the initial layer to provide the filament with more time to set and adhere to the print bed.
Check out our full guide on 3D print warping for more information.
Causes:
- Under-Extrusion: Insufficient filament extrusion leads to gaps between layers and within the infill, weakening the overall structure of the print.
- Incorrect Print Settings: Settings such as low infill percentage, insufficient wall thickness, low print temperature, or too high a print speed can compromise the strength and durability of the print.
- Poor Filament Quality: Low quality can contain impurities or inconsistent diameters, adversely affecting print integrity and strength. Additionally, wet filament creates inconsistent extrusion, which can cause layer separation.
Solutions:
- Adjust Print Temperature: To improve layer bonding, increase the nozzle temperature within the recommended range for PLA (typically between 190°C and 220°C). This allows the filament to melt properly, ensuring stronger adhesion between layers.
- Calibrate Extruder: Ensure your extruder is properly calibrated to avoid under-extrusion. Check for any blockages in the nozzle and clean or replace it if necessary.
- Decrease Print Speed: Lower the print speed to allow more time for each layer to bond before applying the next one adequately.
- Use High-Quality Filament: Invest in good quality PLA filament to avoid issues with impurities and diameter inconsistencies. Store filament in a dry, dust-free environment to preserve its quality.
- Dry Filament: Use a filament dryer to dry wet filament.
- Improve Cooling Strategies: Adjust cooling fan settings to provide enough cooling to solidify the print without causing rapid temperature drops that inhibit layer bonding.
Check out our full guide on solving layer separation for more information.
Causes:
- Under-Extrusion: Occurs when the printer doesn’t extrude enough filament, leading to thin layers or gaps.
- Incorrect Slicer Settings: Fast print speeds, low extrusion multiplier, and low print temperatures result in insufficient filament being laid down.
- Nozzle or Extruder Issues: A clogged nozzle or problems with the extruder gear, such as wear or slipping, can reduce the amount of filament extruded.
- Filament Diameter Variations: Inconsistencies in filament diameter can lead to erratic extrusion rates, causing gaps. This is only an issue with low-quality filaments.
Solutions:
- Calibrate Extruder: Calibrate your extruder’s E-steps to ensure your printer correctly extrudes filament during printing.
- Check and Clean Nozzle: Regularly inspect and clean your 3D printer nozzle to prevent clogs that can lead to under-extrusion. Consider using a needle or acupuncture pin to clear out any debris, or perform a cold pull with nylon filament.
- Decrease Print Speed:
- Increase Print Temperature:
- Use Quality Filament: Choose high-quality filament with a consistent diameter and no impurities. You can use a digital caliper to check the filament’s diameter consistency or use our guide on the best 3D printing filaments.
- Monitor and Replace Extruder Components: Check the condition of the extruder gear, belts, and other components. Replace any worn parts to maintain optimal function and prevent slippage or other issues that could affect filament feeding.
Causes:
- Loose Belts or Pulleys: Belts that are not tight enough can cause the printer’s axes to slip during movement, resulting in layers that do not align correctly.
- Print Speeds Too High: Printing too quickly exerts excessive force on the printer’s mechanical parts, causing them to skip or lose position.
- Obstructions: Any obstruction in the printer’s movement, such as dirt or debris in the guide rails or rods, can hinder smooth motion and cause layer misalignment. Other objects can also block the printer bed and print head movement.
- Software Errors: Incorrect firmware settings or software glitches can result in erroneous movement instructions to the printer’s motors.
Solutions:
- Tighten Belts and Pulleys: Check and adjust the belt tension and ensure that all pulleys are tightened and secured to prevent slippage.
- Calibrate Stepper Motors: Adjust the current settings on the stepper motors to ensure they have enough power to move accurately without skipping steps.
- Adjust Print Speed: Lower the print speed, especially for layers with high detail or quick directional changes, to reduce the strain on the printer’s mechanical systems.
- Clean and Lubricate Mechanical Parts: To ensure smooth operation, perform regular maintenance on your 3D printer. Regularly clean all moving parts and apply appropriate lubrication to guide rails and rods.
- Update Firmware and Software: Ensure your printer’s firmware is up to date and check for any software updates that might fix known issues with layer shifting.
- Reduce Acceleration and Jerk Settings: Lowering the acceleration and Jerk settings in your slicer software reduces the forces exerted on the printer during direction changes, minimizing the risk of layer shifting.
Causes:
- High Print Speeds: Excessive speeds can lead to vibrations or resonance in the printer, especially during sudden direction changes, causing ghost images or echoes beside details.
- Mechanical Instability: Loose components, insufficient frame rigidity, or worn-out parts can amplify printer movements, leading to ghosting.
- Accelerations Too High: High acceleration settings can cause the printer to shake when starting or stopping movement, creating ripples in the print.
- Poor Bed Leveling and Calibration: An unlevel bed or poorly calibrated Z-axis can lead to uneven print layers, contributing to ghosting.
Solutions:
- Lower Print Speeds: Reducing print speeds, particularly on layers with complex or detailed features, can decrease vibrations and improve print quality.
- Stabilize Printer Frame: Ensure the printer frame is stable and all bolts and connections are tightened. Consider upgrading to a more rigid frame or adding stability enhancements if needed.
- Adjust Acceleration Settings: Lower the acceleration settings in your printer’s firmware to reduce the impact of sudden movements.
- Enhance Bed and Axis Calibration: Perform thorough leveling of the print bed and ensure all axes are properly calibrated for smooth, consistent movement.
- Add Dampeners or Upgrades: Install stepper motor dampeners or upgrade to better quality motors to reduce vibrations. Adding vibration-absorbing feet or a heavier base to the printer can also help.
- Optimize Movement Paths: Use slicer settings that optimize the path of the print head to minimize sudden direction changes and reduce the need for high-speed movements.
