3D prints can be used in many ways, some of which require a sterile and clean environment. Some people advise against using 3D prints because of the challenges of ensuring it is properly disinfected.
3D printed objects can be sterilized by using methods such as Hydrogen Peroxide (H202), warm water and soap, alcohol, etc.
This article will try to answer the question of whether you can sterilize 3D prints, as well as how you would go about doing it, so keep on reading to find out more.
Can You Sterilize PLA & 3D Printed Parts?
PLA and other 3D printed parts can be sterilized with methods such as Ethanol, Hydrogen Peroxide, UV-C lamps, Isopropanol, a hot air dryer, and even soap and warm water. There are other methods such as Autoclaving and using Ethylene Oxide as well, but they are not recommended for materials like PLA and PETG.
There are several different sterilization techniques out there, but not all of them are suitable for 3D printing. There are only a few, such as using an Isopropyl alcohol and water solution, a UV-C lamp, or a hot air dryer, that can be used to sterilize 3D printed parts without heavily affecting their strength and structure.
PLA is a low-temperature material that is bound to melt or lose its shape at high temperatures. This is why you have to be careful when choosing a sterilization method for this filament.
Similarly, Stefan from CNC Kitchen has put together a host of filaments to test after having them disinfected using an Isopropyl and water solution.
He has explained in his video how different materials such as ABS, PLA, PETG, TPU, Polycarbonate, and even liquid resin react to disinfecting by going through strength tests. Check out the video below.
Can PLA Printed Parts Be Autoclaved?
No, PLA printed parts cannot tolerate an autoclave cycle because this process uses direct contact with steam and pressure at high temperatures such as 121°C and 132°C, both of which PLA cannot survive and will easily melt. It’s recommended to use another sterilization method for PLA.
An autoclave, on the plus side, is a highly effective machine that is capable of destroying microbes and their spores, thus leading to complete sterilization. It is also non-toxic to the environment.
However, since the mechanism used here involves high temperature and high pressure, it’s not suitable for parts printed with PLA and will alter the shape and mechanical properties of such filaments.
How Do You Sterilize PLA 3D Prints?
PLA 3D prints can be sterilized by using a disinfectant such as 70% Isopropyl alcohol mixed with water. You can also use a UV-C lamp to sterilize PLA parts by exposing them to ultraviolet radiation for about 15 minutes. Another method is to simply use soap and water and clean your PLA parts.
There are several ways you can use to disinfect and sterilize PLA printed 3D parts, but the most common out of the bunch is by using Isopropyl alcohol in a 70/30 ratio with water.
If you do not have anything else than soap and water, then the former is also a decent alternative to sterilize your PLA parts and is also the safest.
Simply begin by pre-washing your parts using hot water and then applying soap on all reachable surfaces. After applying soap, wash your part again with warm water at least for 2 minutes and wash all the soap away.
Repeat the process one or two times more to ensure through-and-through sterilization. Once done, let your PLA parts dry in a clean environment.
Before you sterilize your prints with other methods, make sure that you’re wearing the proper safety equipment for the procedure. Sterilization processes can often get messy and dangerous so a pair of gloves and a mask is a must-have, along with goggles.
What people also do is prepare a solution consisting of Isopropyl alcohol with water and submerge their PLA parts in it for about 5-10 minutes to ensure proper sterilization.
If some corners of the print are hard to reach, you can use a spray bottle with the solution inside to manually apply the disinfectant to your print.
Prusa3D has carried out large-scale research on this topic where they’ve enlisted methods that work and techniques that do not work on commonly used filaments. It is worth checking out for proven and tested methods of disinfection.
How Do You Sterilize ABS 3D Prints?
ABS can be sterilized by several different methods such as using a hot air dryer, Isopropanol, bleach, UV-C lamp, and Ethylene Oxide. It is a high-temperature material that can generally tolerate more methods of sterilization such as Ethylene Oxide as compared to PLA.
Let’s take a quick look at these methods.
Hot Air Dryer
A hot air dryer can be used on ABS to have it fully sterilized. Bacteria and viruses cannot withstand high temperatures so if you set your dryer to about 65°C, that should be good enough to take care of most pathogens on your print.
Isopropanol is a common disinfectant that has been reported to be effective against microbes. When mixed with clean water, the solution becomes highly effective and can be used to sterilize ABS and other filaments comfortably.
Sodium Hypochlorite, or better known as household bleach, can be used on the surface of ABS to rid them clean of harmful microbes and infectious agents. A small concentration of Sodium Hypochlorite is used, about 0.01% to disinfect ABS. The average duration for which the bleach should be applied is somewhere around 2 minutes.
UV-C lamps can work to sterilize ABS printed parts. Prusa Research advises using a 30W UV-C lamp that emits radiation below 280nm wavelength. In addition, the recommended exposure time is somewhere between 10-15 minutes.
The UV Light Sanitizer Wand Portable UV-C from Amazon is a good product that you can easily use to sterilize your 3D printed objects. However, do keep in mind that this technique of sterilization is not the most effective out there, and is only suitable for lightweight sterilization.
Exposure to Ethylene Oxide or ETO is a good method of sterilizing ABS prints. However, it certainly isn’t the most cost-effective and usually requires a specialized oven that exposes the filament to this gas.
Ethylene Oxide is a substitute for all those heat-sensitive materials that cannot tolerate high pressure steam, such as the process of autoclaving. ETO is generally used in healthcare facilities to sterilize a wide variety of items.
How Do You Sterilize PETG 3D Prints?
The best way to sterilize PETG is by using a 25% Hydrogen Peroxide solution and sinking your PETG parts in it. You can also use soap and water as a decent alternative to sterilizing your models without extra hassle.
PETG is more resistant to temperature than PLA but slightly lesser than ABS. It is for this reason that PETG like PLA cannot survive sterilization techniques such as autoclaving.
However, you can sterilize it with several ways, such as using a hot air dryer, bleach, an ethanol solution, and even Isopropanol.
One good method of sterilizing PETG is exposure to Ethylene Oxide which is used as a sterilizing agent in small amounts. This is also a great alternative to autoclaving which most filaments cannot withstand.
If nothing else, soap and water is always a good way to sterilize any type of part, let alone PETG. You can also use UV-C lamps since they do not affect the structural composition of parts.
Can You Sterilize or Disinfect PLA with Alcohol?
Yes, PLA can be sterilized with different concentrations of Isopropanol, ethanol, and rubbing alcohol and these are all forms of alcohol. Using a 70% Isopropanol alcohol and water solution is a great way to disinfect PLA and other thermoplastic filaments.
Rubbing alcohol is a multi-purpose substance and can be used to clean and disinfect 3D printed parts easily. What’s beneficial about using alcohol for sterilization is that it doesn’t affect or change the appearance of your part no matter how long you soak your print in it.
This blog reports that PLA was dissolved in alcohol for 24 hours, but no physical changes were obvious or visible. People have also said that they’ve frequently used alcohol to sterilize their parts and it has always been a good experience for them.
Which Methods Cannot Be Used to Sterilize 3D Printed Parts?
Sterilization techniques such as Hydrogen Peroxide Gas Plasma, autoclaving, and gamma radiation cannot be used to sterilize 3D printed parts. These methods lead to deformation of common thermoplastic filaments such as PLA, ABS, and PETG so be sure to watch out for these when looking to disinfect your models.
PLA is surely one of the most common filaments out there that is used by countless makers across the world. However, it is a material that cannot tolerate high temperatures and will definitely lose its shape when exposed so.
Therefore, a method such as autoclaving involves high temperature and pressure and direct exposure to steam. It goes past the limit of filaments like PETG and PLA and forces them to deform during the autoclave cycle.
In addition, Hydrogen Peroxide Gas Plasma requires a non-porous surface on objects it’s used on. Since 3D prints are widely porous, this is an option that’s simply ruled out for sterilization.
On the other hand, gamma radiation is expensive and is more suited to large-format sterilization. It is definitely not something you could do at home.
Furthermore, this case study reports that gamma radiation might be effective for sterilization, but it can also cause severe changes to the shape of the material thereby decreasing the part’s quality.
A more general explanation is that anything involving the use of high temperature should be avoided for sterilizing 3D printed parts. Most materials cannot survive too high temperatures and will only deteriorate should you choose to continue disinfecting them with such methods.
This is why it’s best to stick to methods that have been scientifically proven to work for filaments like PLA and PETG. The research conducted by Prusa3D is a great source to help you choose the correct sterilization techniques.