PLA (Polylactic acid) filament is the most popular filament due to its ease of use. It is produced from starch from the cultivation of corn, sugar cane or other starch-rich vegetables.
- Low melting temperature: This material extrudes at over 200ºC which makes it suitable for any type of 3D printer.
- Cold printing surface: It's not required to have a heated print bed to print this material, but it is recommended to utilise some kind of adhesive to help fix the first layer to the printing surface.
- Good mechanical strength: With the exception of temperature resistance, PLA is a hard and rigid material.
- It does not shrink, therefore there is no warping.
- No odour when printed.
- It does not give off toxic fumes when printed.
- Low temperature resistance: This material has a glass transition temperature of only 60ºC, but it starts to soften at 45-50ºC, which limits its use in situations close to heat sources.
- Hygroscopic: PLA is very sensitive to humidity, so it is recommended to store it in a dry environment.
It is essential to consider the extrusion device and the nozzle in order to get the best results when working with PLA filaments. The temperature range of this filament is quite large, ranging from 180°C to 230°C. For darker colours, a temperature increase of 3°C to 5°C is usually recommended.
In order to get the most accurate parameterisation for your 3D printer, you can perform a temperature test.
It is not crucial to use a heated bed when working with PLA, but it is strongly advised, especially for large prints, to improve adherence and prevent warping. The optimal temperature for these kinds of prints is between 50°C and 65°C. If a heated bed is not available, a lacquer or surface prepared for 3D printing such as magnetic strips with textured sheets or PEI sheets must be used. Kapton tape or masking tape may also be used for this purpose.
When parts have a lot of detail, it is important to help the plastic solidify correctly; otherwise, it will solidify too quickly. It is not recommended to turn on this fan in the first layers in order to enhance the part's adhesion to the surface.
Having a general idea of the optimum print speeds for a 3D printer is very important, as it is contingent on the whole set of components. Having said that, 35mm/s to 65mm/s would be an optimal range for most instances.
The layer height is determined by the nozzle's output diameter, with 50% being optimal but ranging from 75-80% and 25% respectively. A 0.4mm nozzle would have a layer height of 0.2mm and maximum values of 0.3mm and 0.1mm, for example.
The purpose of this parameter is to absorb the dimensional variations of the filaments, therefore a flow test must be conducted to determine the precise value for each material in the printer where it will be used. This parameter should not shift more than 5% in a normal print, meaning it must be between 95% and 15% in order to maintain consistency. If our extruder is badly calibrated after performing the flow test, we must calibrate it first in order to achieve the best results.
Using laminators, you can usually set the percentage at which the material is laminated to 120% of the nozzle diameter, which is a decent value. The nozzle diameter, however, cannot be set below the nozzle diameter. You may increase the thickness of the walls in a single pass to produce stronger parts without increasing the printing time by adjusting this value.
An optimal value must be determined through a retraction test when using this parameter, which depends on the hotend-extruder assembly. The following retraction values are provided as a starting point:
- Direct Extrusion (Prusa MK3S, Artillery X1 or similar): 1mm and 35mm/s
- Short Bowden (Ender 3 or similar): 4mm and 40mm/s
- Long Bowden (CR10, Tevo tornado or similar): 5mm and 40mm/s
Avoiding Jams & Clogs with PLA
Leaving the filament loaded in the printer and leaving the hotend at printing temperature is the primary cause of jams with this material. This deteriorates the material and eliminates its plastic properties, resulting in residues inside the hotend that are deposited on the next printing job, which results in poor quality results or even nozzle blockage.
Type of hotend
When printing with PLA, the hotend with a PTFE tube along its entire barrel is the finest choice in order to avoid friction between the material and the metal walls of the hotend itself. If you have an all-metal hotend, you may also print with PLA, but you must keep the melting temperature low and make sure the heatsink has a decent thermal shock in order to prevent the molten plastic from rising along with the barrel.
It's imperative to have a cooling system when creating a thermal shock in order to prevent the molten material from rising up the barrel. Typically, a fan is used which is turned on at the same time as the 3D printer and should not be switched off. There are also some hotends that utilise liquid cooling for this purpose.
The hotend will get clogged if the material cools down and adheres to the walls of the barrel if the retraction length is not well defined and excessively long. A shrinkage test should be performed as described above to prevent this.
It is important to clean the hotend if a material with a higher melting point than PLA has been used, so that the new material can flow without problems.
Storing the Filament
The filament must be kept in a dry location when it's not being used because it's hygroscopic (sensitive to moisture). Vacuum packing the spool with a silica gel bag is probably the best approach to store it, the same as you receive it at home. Although it would be costly, we send an airtight transparent bag with each spool so that the filament can be kept with its desiccant bag when it is not in use.