Material Guide: Polylactic Acid (PLA)

Polylactic Acid (PLA) is one of the most common 3D printing materials used. Almost all Fused Deposition Modelling (FDM) 3D printers are able to print in PLA and most of them are optimized to print PLA. PLA is a popular material due to several reasons. The most obvious reason is that PLA does not release much Volatile Organic Compounds (VOC) and the next being that PLA is one of the easiest materials to work with when it comes to FDM. However, despite being one of the easiest materials to work with, 3D printing with PLA still pose some challenges to inexperienced hobbyists or 3D printer operators. This article serves as a general guide to 3D print with PLA and specific details are omitted due to each brand of PLA varying slightly in optimised printing settings.

1. Glue Stick

It is always handy to have a glue stick as part of your 3D printing toolkit. The glue stick will help greatly for parts that are long and wide. Although PLA is not known for severe warping, if you are printing without a heated bed, it is best recommended that you apply some glue on the sharp corners of the 3D print as they are the areas that are most prone to wrapping. Sometimes, this tip is helpful even for 3D printers with a heated bed. Be careful not to apply too much as it will make removing the 3D print hard and might damage your print bed in the process.

2. Higher First Layer Temperature

Adhesion to the print bed is most often the issue that haunts most 3D printers. Using this simple trick can help to improve general print adhesion to the bed. If your slicing software allows, adjust the printing temperature of the first layer to be approximately 5 degrees higher than the rest of the layer. If the slicing software does not have this option, then you can adjust it manually while it is printing the first layer, subsequently turning it down from the second layer onward.

3. Maximum Cooling Fan During Bridging

The ability to bridge between 2 anchor points is one of the most interesting feature your FDM printer can perform. Some printers can bridge further and better than other printers due to several factors. This tip will help your 3D printer perform better bridging in general. Going back to your slicing software’s setting, take a look to see if you are able to set the cooling fan to maximum power during bridging. This will help the PLA that is extruded to cool as fast as possible, forming a solid that is strong enough to not sag, thus giving you a perfect bridged layer.

4. Print Support Structures with an Interlace Layer

3D printing with supports can be rather tricky especially when the quality of the surface finish in contact with the 3D print is of a significant concern. In most slicing softwares, there is an option for an interlace layer to be printed just before the main body of the model is printed.Usually, when enabled, the interlace layer will look like a raft that the main body of the model will sit on. The thickness of the interlace layer can also be configured. Generally, the thicker the interlace layer, the more support it will give, but it will also be harder to remove.

5. Use a Glass Bed

Using a glass bed is optional for printing PLA however, when a model is printed on a glass bed, it will tend to have an extraordinary smooth base. When choosing a glass bed, make sure it is of the material borosilicate as it’s impact resistance quality will help withstand the constant knocking when removing the 3D print.

6. Use a Skirt

Printing a skirt before the actual model will help to purge out any remnant filament that was part of the previous print or that was leaked out during the pre-heating process. This will ensure that the filament used to print the new model will be fresh and unused. This tip applies to most materials, when using the FDM technology, not only to PLA

7. Try to 3D Print Above 200 Deg

In many guides, you will notice that the lower the temperature the better it performs on overhangs. There is also a noticeable difference in surface finish with lower temperatures as well. However printing with lower temperature will compromise layer bonding and will not be recommended if your part will undergo heavy loading. Keeping print temperatures above 200 Degree Celsius will ensure complete layer bonding. Ensuring that the PLA melts properly will also reduce jams in the nozzle.

8. Use a Nozzle Not Smaller than 0.3mm

Using a nozzle that is smaller than 0.4mm allows the 3D printer to print models that are more detailed. However there are many concerns that comes with using a smaller nozzle. The first significant change is that the print time will be greatly increased due to less volume of material being extruded. Nozzle jam might also happen more frequently if the printing speed is too high. If the nozzle diameter were to go below 0.3mm, printing speed and frequency of nozzle jam would make it unfavourable for 3D printing.

9. Reduce Printing Speed During Bridging

During bridging, the material extruded is will need to be cooled as fast as possible so that the PLA would be able to change its state from liquid to solid rapidly. This will ensure a minimal sag as the 3D printer bridges from one anchor point to another. This tip comes in especially helpful when it comes to a long bridging distance.