PLA is made from biodegradable materials, which means that it will degrade over time.
That is the primary reason filament manufacturers supply the rolls sealed and place them in a small silica bag.
The environmental humidity, rainy weather, microbes and external temperature are the main things that affect the durability of the PLA printed 3D objects.
PLA will decay faster when the temperatures are high and the environment is rich with the presence of microorganisms.
Soil could be a perfect choice of the elements but to reach the needed heat, which is around 60 degrees Celsius, you will have to bury the print in the dirt.
It will take around 6 months for the object to develop cracks and to show signs of decay. The length of time depends on the condition of your soil sample.
Under room pressure and temperature, PLA will take a very long time to degrade. In a regular room, the object will endure for up to 15 years.
Sunlight will not speed up the biodegradation – apart from heat – but the direct sunlight might make the object to lose its colour and appear pale – the same thing that happens to the plastic if left outdoor for a long time.
Some people see the slow biodegradation of PLA as bad while others will see it as good. That depends on the purpose of the printed object. PLA is an ideal 3D printing material because it will return to nature eventually.
That is beneficial in situations where the printed object has to disappear after a short time. On the other hand, some people will design items that they want to see for many days. Fortunately, the objects will remain unchanged for several years.
As stated above, PLA material requires several conditions to biodegrade that might not be present in your indoor environment. For your 3D print to last for many years, you just need to keep it in a cool dry place.
Can PLA Printed Objects Break Easily?
PLA printed objects can break easily after you have placed them in environments with high temperature and moisture levels. A print that has lasted for many years will also break easily due to degradation.
None of the three-dimensional printing processes such as heating the object and cooling it down again will reverse the process.
Anything you do will make the object worse. Smaller prints are likely to break faster than the thick and big prints.
That is because the bigger and thicker prints are stronger and the stress will be divided over many layers.
If you need strong PLA 3D prints that will not break easily, you will have to make good design decisions and choose the printing material carefully.
A flimsy design or poor manufacturing will make the finished object weak regardless of the filament you choose.
How to Strengthen 3D Printed PLA Objects?
PLA 3D printed objects are not strong but you can make them stronger. That is because most of the objects are printed for use as toys and prototypes.
However, today, people are using 3D printing to create parts – the available parts strengthening techniques have made that possible.
But how do you strengthen your PLA 3D objects? You have many ways of doing that but their level of effectiveness varies widely. Perhaps you have tried some of them.
This might be the most obvious method of making your PLA 3D prints stronger. You just need to increase the density of each print.
Most three-dimensional slicing systems allow the user to select the interior density percentage, 0 percent being hollow and 100 percent being solid.
Choose a level that matches the level of strength you need. You might not need something that is completely solid, but that is possible and it will make a strong object.
3D printers use the extrusion process to print objects. So, the objects will have boundaries between the layers, which will make them very weak.
Changing the printing direction arbitrarily can be hard, so you may select the overall direction of each layer by orienting your model before you start printing.
The main idea here is to examine the direction of your object’s mechanical stress when using the object and orient the model properly to prevent exposure of the weak boundaries.
PLA filament producers use various materials to make them. One of the recent methods involves combining normal material with stronger materials.
For example, you can buy PLA filament infused with glass fibres or carbon nanotubes or any other strengthening material.
The resulting objects might not be very strong, but they will be stronger than those you get from the pure filament.
If your prints are hollow, you can inject them with strengthening agents after the printing part is over.
You just need to drill a few tiny holes on each side and use your hot glue gun to inject adhesives into the interior of the object. That way, it will be dry.
Electroplating will make your PLA 3D prints stronger. The method is inexpensive and offers an easier way of making some parts of the 3D print stronger than when it is in polymer form.
Some people use nickel or copper metal to plate their prints. Such metals will make the surfaces more attractive and impervious to the common environmental effects.
You can combine some of the above approaches to come up with an even stronger print. For example, you can use the interior injection and then electroplate the surface with nickel.
That will highly depend on how you want to use the object. Some items like the visual prototypes you place on your desk will need less strength. Others will need more strength to withstand various outdoor elements.
Can You Make PLA Objects Unbreakable?
PLA material is made to biodegrade with time, so using it to make an unbreakable print is nearly impossible.
However, you can strengthen the print and improve its waterproofness so that it lasts for many days. You can coat it with polyurethane and epoxy paints if you are creating them for use in moist places.
Can You Recycle Broken PLA Prints?
Yes. It is possible. However, you will need clean prints and ensure that they are made of pure PLA. The material should also be similar in size, chemical composition and shape if you need perfect results.
Shred the prints into tiny pieces – with a diameter around 0.7cm. A Filamaker shredder will work perfectly when shredding old prints. After shredding the prints, your next important step is to set up the recycler extruder so that the filament will come out constantly.
In professional setups, a spooling system, which has a diameter of the PLA filament, will reel the filament and adjust the pull to maintain a constant diameter.
In simple setups, that might not be feasible and you should opt for alternative ways of keeping the extrusion constant. For example, you can place the printer on your printing table and allow the filament to drop constantly to the ground.
Then allow the filament to curl itself into circles as it falls on the ground. For this method to work perfectly, you will need to push the filament to one side after it hits the ground.
Keep the printer’s extruder closer to the ground and ensure that it is horizontal.
After selecting a setup that works perfectly, it is the time to finetune the recycling process so that you can get the best results. Adjust the size of the extruder nozzle, extruding temperature and distance and power of your fan.
Adjustment of the nozzle is the toughest part because PLA stretches after extrusion. To get an extrusion diameter of 1.75 mm diameter, use a 1.95mm nozzle size.
The adjustment of extrusion temperature is easy but you will have to experiment with different setups to know the right temperature.
If the extrusion is very slow, you will have to choose a higher temperature. If the filament curls or stretches out much as it comes out of the extruder nozzle, you will need to reduce the temperature. Mostly, you will require 155 degrees Celsius.
The cooling fan is the final parameter to control. It controls the stretching out of the filament. More cooling will mean a large filament diameter.
But because you do not want to blow the filament away during extrusion, you will have to choose an optimal temperature level. For good results, start by choosing the nozzle size and then try to adjust the distance of the fan.
PLA stands as the most popular 3D printing filament material in the globe. The number of PLA printed objects is always increasing because PLA combines a very low melting point, low shrinkage and it is insoluble in the water something that makes it a good choice when printing some items like spoons and cups.
PLA will take around 1-6 months to degrade after composting depending on the material type and the temperature conditions. In an industrial setting, composting will take around 1-3 months and will take over 6 months at home.
People are confident about the compost-ability of the PLA 3-dimensional printed objects and they will, therefore, send them to composting facilities or landfills. However, recycling is the best alternative.