Polylactic Acid, commonly known as PLA, is widely used in manufacturing and 3D printing due to its eco-friendly properties, versatility, and few limitations. PLA’s versatility is highly regarded because of its low melting point, which makes the material very easy to use.
The low extrusion temperature of PLA—about 130-180°C—makes it easy to print the material rapidly as it doesn’t quickly warp as it cools.
Having said that, PLA’s temperature-related attributes and strengths could also be its Achilles heel. There are multiple reports of incidents of poor quality and even failed prints at default temperature settings.
Whether you’re planning to buy or already have a 3D printer, we will guide you on how to use PLA filament in various temperature settings properly. Additionally, we’ll provide some practical tips and tricks based on years of offering 3D printing services in Toronto, Vancouver, and Calgary to maximize its strengths fully while minimizing print failures.
How Important is Temperature in PLA 3D Printing
PLA’s thermal properties are among the very important factors to consider during the 3D printing process. Let us discuss what these key thermal properties are and their significance in the success (or failure) according to the settings, equipment, and temperature range you’ll be using.
Melting temperature
This is the process in which PLA changes from its solid state to its liquid state. In its liquid state, a change in the viscosity of the material also occurs, which greatly affects the success of the printing process, as we will discuss later in the article.
The melting point is triggered at around 130°C to 180°C. Once the melting point has been reached, the machine still needs to be recalibrated with a temperature above 10°C, the identified melting temperature. This low melting temperature makes PLA the better option among other polymers.
Glass transition point
This is the temperature where the polymer, in its hard, glassy state, transforms into a soft, rubber-like state. PLA has a low glass transition point of 60°C. When the filament reaches its glass transition point, it starts to melt. However, at this state, PLA filament still needs to be totally molten before the user can work with it.
Such low-temperature ranges have huge significance when using PLA. Having low melting temperature and glass transition temperature has the following implications:
- Extrusion through using the printer nozzle becomes much easier.
- The user has better control of the printing process.
- The print and bed temperatures must be monitored accordingly, as any increase or decrease in the temperature settings has a direct effect on the molecular mobility of the thermoplastic monomer.
What is the Optimal PLA Printing Temperature Setting?
Let’s just clear things up and then get them out of the way: there is no such thing as “best temperature settings.” We’ll use the term “optimum” instead. Temperature settings often differ and vary according to the circumstances involved.
Finding out the optimal printing temperature settings when printing with PLA is a bit more complicated than it is perceived to be. Aside from the physical, chemical, and thermal properties of PLA, other external factors could also affect and thus influence the optimum thermal temperature settings.
Factors and Conditions That Guide Optimum Temperature For PLA Printing
In this section, we will show you what other features could affect the temperature for the PLA printing process and why the final number may be different for every scenario.
Nozzle diameter
The diameter of the nozzle can significantly affect the required print temperature since the mass of the fluid directly affects the changes to PLA’s thermal properties. A narrow nozzle diameter requires a lower print temperature and allows for higher detail in prints. These are ideal for creating intricate parts in your project.
On the other hand, a wider nozzle helps with faster printing by allowing more material to flow through. However, it does require a higher PLA print nozzle temp. Finding the balance between detail and speed is key in selecting the right nozzle for your project, especially when printing with materials like Polymaker PLA, which may need specific temperatures to achieve the best strength and surface quality.
Extruder distance
The further the extruder pulls the material, the higher the temperature needed in order for the PLA to melt quickly. The average starting print temperatures is usually at 230°C and is then adjusted lower at certain increments.
Test your setup regularly with a temperature tower to help identify the best settings for your specific printer configuration. With this, you can be sure that the PLA is perfectly melted and extruded, regardless of the part’s complexity or size.
Presence of a heated bed
You don’t need a heated bed when printing PLA. However, if your printer has one, the bed temperature must be monitored frequently as it can affect the overall temperature of the 3D printing process.
The heated bed should be set between 20-70°C. We suggest starting at the lower end of the range and then adjusting if needed. Take note that the bed temperature settings differ according to the brand of 3D printer you’re using.
The following are the recommended settings as stated by the manufacturer of the following brands:
- Ultimaker: 60°C
- MatterHacker Build Series: 25-55°C
- Fillamentum Extrafill: 55°C
If you use 3D printers from Ultimaker, MatterHacker Build Series, or Fillamentum Extrafill, we recommend studying the manual for brand-specific bed temperature instructions for better adhesion and cooling.
Extruder type
Every brand of 3D printer has its own patented extruder design. Moreover, the type of your extruder plays a very significant role in determining the ideal temperature settings.
Bowden extruder
This type of extruder pushes the molten monomer into the nozzle with a plastic tube. There is a tendency for the PLA filament to slightly cool as it is being pushed. This is the reason why a higher hot-end temperature is necessary when using this extruder.
Recommended temperature: 200°C to 230°C
PTFE hot end
The extruder’s name is derived from the presence of a PTFE liner inside its heat break area. The purpose of this filament is to limit the maximum temperature of the nozzle. Setting the temperature a bit cooler can prevent damaging the filament.
Recommended temperature: 190°C to 220°C
Direct drive extruder
Most PLA filament users prefer to use the direct drive extruder due to its design. The extruder pushes the material all the way into the nozzle.
Recommended temperature: 190°C to 220°C
All-metal hot end
This type of extruder is infamous for its quick heat dispersion property—a.k.a. “The fast cooler”. When used with PLA, be careful not to exceed the maximum temperature limit of 290°C. At this temperature, the material starts to degrade and break down.
PLA Printing Temperature Settings for Best Results
To summarize all our points above, here’s the recommended temperature settings for PLA filament:
Experienced users usually start at the midpoint of the manufacturer’s recommended range and then adjust ± 5°C at a time. We also suggest having the cooling fan turned on during the whole printing process, along with the recommended temperature ranges mentioned above.
Common Temperature-related Problems in PLA Printing
You may have noticed that there is no exact temperature mentioned in the article. It is because there is no way it can be determined. The safest bet is to know the temperature ranges in which we can work with PLA materials.
Temperatures that are too low or too high outside of the suggested working temperature range could cause a lot of problems, thus causing the entire printing process to fail.
Here are some common problems users may encounter.
Clogging and inadequate extrusion
Low temperatures can cause the molten filament to be viscous. A high viscosity would result in the presence of small solid particles that can clog the extruder. A clogged extruder will result in a lack of extrusion.
Seam gaps, jams, and poor in-filling
Seam gaps, jams, and poor in-filling happen when not enough material is supplied during the extrusion. These problems point back to the increased viscosity and the poor flow of the filament.
Poor surface finish
The end-product of printing below the optimal temperature range leads to a rough and uneven surface of the prints. This is one of the common problems reported by users.
Low interlayer adhesion
Proper adhesion occurs when the interface between two layers is partially melted. This does not happen when the temperature is inadequate. A low interlayer adhesion increases the risks of surface separation and delamination once the object starts to shrink.
What Happens to Printers if the Temperature Is Too High?
High temperatures can cause many problems for printers, such as over-extrusion and stringing. Let’s dive deeper into what these are and how you can avoid these issues to get the best results from your printing projects.
Over-extrusion
While low temperatures can cause under-extrusion, working with temperatures above the safe range can lead to over-extrusion. Too much heat can affect the printer’s accuracy, resulting in uneven layers, blobs, zits, and decreased viscosity of the material.
Aside from lowering the nozzle temperature to under 290°C, you should calibrate the printer’s extrusion multiplier or flow rate to extrude the right PLA amount. Additionally, check and clean the nozzle regularly to prevent buildup that could contribute to over-extrusion.
Stringing/oozing
Too high a temperature can lead to a phenomenon called “shrinking” or “oozing .”This is the result of a malfunction at the hotend displacements. The PLA filament’s high viscosity makes it difficult for the nozzle to hold during the non-extrusion phase properly, so you may need to use additional supports.
The high viscosity of the PLA filament makes the nozzle unable to hold it properly during the non-extrusion phase.
Configure your setting to increase retraction to pull the filament back when moving between sections of the print. This prevents PLA from leaking out of the nozzle during non-extrusion movements.
Poor bridging and overhangs
Bridging, or the building up of a solid layer between two surfaces without any support, is necessary in the printing process. An overhang, on the other hand, is a sloping print that doesn’t have anything underneath to support it.
In perfect conditions, creating both processes is already a challenge. A temperature that is too high can significantly affect the bridging process. It can also affect the angles and slopes of overhangs. The ability of the PLA material to cool in time can be hampered if the temperature is way above the working range.
If you notice some sagging or drooping from the printed object, this signifies the temperature is too high and can affect the success of the printing run. This problem may go unnoticed if the design does not require a lot of bridges and overhangs. You should watch out for that.
Use cooling fans to rapidly cool the PLA after it’s deposited. Adjusting print speed and support settings can also help achieve more stable bridges and overhangs by providing temporary support or slowing down to allow proper cooling.
Degradation and changes in color
PLA cannot take on too much heat. Temperatures above 290 °C will lead to the degradation of the molecular integrity of PLA. In short, PLA starts to break down if the temperature exceeds the tolerance level. You’ll notice the presence of discoloration on the printed product as it cools down.
The presence of such color changes is an indication that the filament composition has already degraded and its mechanical/physical integrity has already broken down. The finished product will be weak and brittle.
Use a thermometer or thermal camera to check for hotspots in your printer that may cause localized overheating. Regularly replace filament that has been exposed to high temperatures or humidity to ensure material integrity.
Heat creep
Heat creep is one, if not the most common, problem that 3D printing practitioners encounter. This can occur at any time during the printing process—may it be at mid print or during cooling down (after print). The most usual phase of heat creep happens during midprint when the temperature is at its highest.
Causes of heat creep
There are numerous causes of heat creep, all of them related to problems with inadequate temperature control. Heat creep is the result of one or a combination of the causes below:
- Hot end that is too hot – The heat block area is one of the hottest parts of the heat end. As the hot end assembly accumulates more heat, the possibility for the excess heat to travel to other parts is very high. You don’t want this excess heat to reach the PLA filament.
- The hot end design itself is not ideal with increased heat accumulation – Some hot end designs are not capable of dealing with prolonged heat accumulation. The undesired heat will then spread across the whole assembly, reaching the PLA filament.
- PLA filament stays at the hot end for too long – PLA, with its low melting point, tends to melt before it reaches the melt zone area. When this happens, the hot end’s temperature will increase, which leads to heat creep.
- Hot end fan couldn’t keep up – The cooling fan should handle the gradually increasing temperature levels during the printing process. However, if its cooling ability can’t keep up with cooling the heat sink and hot end assembly as the temperature rises, heat creep happens.
Prevent heat creep by increasing the printing speed. The idea behind this is that the fast-moving PLA filament won’t melt before it reaches the melt zone. However, this method is only effective when dealing with heat creep. If the increase in temperature is due to hot end jams, you should do the opposite.
Your fan should also be fast enough to prevent the flowing filament from melting before it reaches the melt zone. Set the fan at 100% speed to prevent heat creep from happening directly.
Just be mindful of cooling-related problems like warping, cracking, or an increase in the viscosity of the molten filament. If these show up, lower the fan speed bit by bit until you have the best output.
Lastly, if the heat creep still persists, you’ll need to replace the hot end assembly. Some types, like the all-metal hot ends, are known to be heat creep-prone. The PTFE hot end is a great replacement option since it has better insulation.
Do all types of PLA have the same optimal temperature ranges?
There may be some slight variations in the optimal temperature range for every type and brand of PLA, which may require you to tweak the numbers. Nevertheless, the optimal temperature range discussed is applicable to all.
The following are the three major types of PLA plastic. The main difference between these PLA types is how their molecular chains are structured.
PDLA (Poly-D-Lactic Acid)
This PLA has slower rates of biodegradation compared to the other types.
PDLLA (Poly-DL-Lactic Acid)
Commonly used in medicine coating, this type of PLA breaks down easily as it enters the body. This is the ideal plastic used in drug distribution.
PLLA (Poly-L-Lactic Acid)
This is the most common type of PLA used in 3D printing. It is also biocompatible, which means it can be used as an implant or applied to body parts that need to form collagen.
Additional Note: PLA+ is a variation of PLLA in which additives were added and mixed to produce a tougher version of the standard PLA. The PLA+ versions are different among the manufacturers and brands of this plastic. Different brands have different formulations, as they may add additives or dyes to their products.
The optimal temperature ranges of these types of PLA may vary slightly. To know more about the specific temperature ranges, check the manufacturer’s recommended values.
Summary
Printing with PLA is a simple and very easy process but requires diligence from the user to be mindful of the temperature settings. The ranges of temperatures are so narrow that a couple of degrees, both at the lower and upper limits, can affect the success of the printing process.
Although PLA melts within the 150 °C-180 °C range, proper printing requires a higher hot-end temperature. The other parts’ and components’ temperatures also have to be considered and included in the calculation of the overall working temperature.
The success or failure of PLA printing relies on the temperature settings of your 3D printer throughout the whole process. That is why you have to always monitor your settings at all times. Once you have mastered the process, we guarantee you that you’ll truly enjoy working with PLA materials and print like a pro.
FAQs
Why does my PLA print look stringy?
A stringy print is a typical sign of over-extrusion. The print temperature is probably above the recommended range. Decrease the temperature by 5 °C increments, then check again. In addition, look at the retraction settings to see if they are correct. String-like prints can also be caused by faulty retraction.
What is the best way to find the optimal print temp for my 3D printer and PLA filament?
The Temp Tower Method is the best way to find the optimal temperature range. You are going to print the same design at different temperature settings. Every user should use this method when new filaments are to be used or when replacing other parts or components of the 3D printer.
A Temp Tower is a vertical structure composed of vertical slabs stacked on top of each other. Each slab is printed at different temperatures that are set on the printer. The bottom is printed at the highest settings, while the succeeding ones are printed at 5 C decrements.
Once the prints are completed and stacked, observe for unusualities, errors, or undesired results on each slab.
You will also notice that several slabs will have perfect results. The values of the slabs with the perfect results belong to the optimal range of print temperatures.
Does bed temperature affect the PLA print?
PLA may not need a heated bed, but when you use one, it can surely affect the 3D printing process. A heated bed is used to print the first layer of the printed object. This first layer serves as the mold or foundation of all succeeding layers.
The first layer needs to have the right bed adhesion, or else the rest of the layers will fail. The success or failure depends on the bed’s temperature, among other factors. For the purposes of this article, we will only discuss the effects of temperature on the heated bed.
Too low or too high bed temperatures will be detrimental to the printing process. Temperature can affect the adhesion process. The ideal bed temperature should be between 50 °C and 60 °C. The values may vary according to the type of PLA filament and the brand that you’re using.
As you start printing with a heated bed, observe if the print properly adheres to the bed’s surface.
A print that does not stick properly indicates that the bed temperature is too low. You can fix this by slightly increasing the bed temperature by 5 °C. Check if the problem persists, then increase the temperature once again. Repeat the cycle until the paint properly adheres to the bed surface without overstocking.
On the other hand, if you’re having trouble removing the print from the build surface due to oversticking, the bed temperature may be too high. This can be fixed by slightly lowering the temperature by 5°C. Make sure that proper adhesion is maintained.