In order to achieve optimal results when printing 3D filament, it is not only important to select the right material and correct 3D print settings, but also to ensure that the filament is properly conditioned for processing. We summarized the most important information about drying and storing 3D printing filament for you in this post.
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Proper storage, drying and processing of plastic 3D filaments
Which 3D printing filaments should be dried?
3D materials like PMMA, PA (Nylon), PC, PET, PETG, TPU and all technical 3D filaments like CF-filled PA or flexible filaments should be properly dried before printing. It's important to note drying the filaments, that are not likely to be affected by moisture absorption during extended storage, can offer significant advantages and improved printing experience after drying them.
What determines the ability of a 3D printing filament to absorb moisture?
It depends a lot on the polarity of the main polymeric component, which means on their chemical nature. Non-polar plastics have a low surface energy compared to polar solvents and are therefore more difficult to attack chemically in this way. This group includes materials such as PP, PE, PS.
Polar plastics can be more easily dissolved by polar solvents. The most important protic solvent is water, which (simplified) into a proton and a Hydroxide ion dissociates. In connection with moisture, the plastic is dissolved by the high surface energy that enters into a connection with water, since the energy that holds the polymer chain together is smaller than the energy that comes from the polarity of the water. This means that the filament is chemically decomposed under the influence of temperature and a polar solvent. Therefore, those materials that fall into this group should definitely be pre-dried before processing. These are PET, PETG, PCTG, PC and also PLA.Â
Why is it so difficult to print not dried 3D printing filaments?
The main reason why excessive moisture has a negative effect when processing 3D printing filament is the so-called hydrolysis. This is the chemical breakdown of polymer macromolecules due to the reaction with water at high temperatures, in this case in the heated nozzle of a 3D printer.Â
How does moisture affect the 3D printing process?
In the context of 3D printing, high moisture content in the 3D filament can lead to the following 3D printing problems:
Formation of foam, bubbles, and opacity in transparent materials: at the high temperatures in the nozzle, water evaporates, expands and forms bubbles in the polymer melt, leading to poor surface properties and deteriorating the optical characteristics of the finished parts.
Stringing in 3D printing: Water reduces the viscosity of the polymer melts, making them more liquid and therefore easier to flow out of the nozzle and encouraging the formation of threads.
Warping in 3D printing: Prints made with not dried 3D material usually have poorer dimensional stability and are more prone to warping.
Poor layer adhesion, impaired mechanical properties: the hydrolysis splits the long macromolecule chains into shorter ones. This leads to compromised mechanical properties of the solid parts, which can lead to delamination during printing or even failure of 3D printed parts in service.
Color changes: Hydrolysis products often lead to color changes in the polymer.
Note: In our another guide, you can find more tips on how to improve printing with PETG 3D filaments here.
How does drying affect the quality of 3D printed parts?
The main benefit of using dried 3D filament is that it can significantly reduce the number of 3D printing defects caused by moisture. Furthermore, parts printed with dried materials can have more accurate dimensions than if they were not dried. So if the dimensional stability and fit of your 3D printed parts are important, we strongly recommend using a filament dryer.
In general, the use of dry or pre-dried filament increases the quality of the print results and makes the 3D printing process more stable, which means that the risk of failed prints can be significantly reduced.
How to dry filament for 3D printing?
In order to dry 3D filament sufficiently, it must be exposed to dry and hot air long enough. The easiest way is to dry the filament for a few hours at a low temperature (approx. 60-65°C) in the oven, preferably with the hot air function.
However, it is important to ensure that the set or displayed temperature and the actual temperature match, since the 3D filament can stick, clump together or, in the worst case, even melt at high temperatures.
A simple and inexpensive solution can also be to use a so-called dehydrator, which is usually used to dry fruit. These can be purchased cheaply in the white goods department of electronics stores or online.
In recent years, some manufacturers have also launched devices specially optimized for drying 3D printing filaments, which are now available from many large dealers of filaments and 3D printing accessories.
The best equipment and tools for 3D printing filament drying and storage depend on specific needs and your budget.
Here are some common options:
3D Filament dryer: A filament dryer is an apparatus specifically designed to remove moisture from 3D printing filaments. These can either be standalone units or attached to 3D printers. They typically use a combination of heat and airflow to dry the filament.
Desiccant Packs: Desiccant packs are small sachets filled with a moisture-wicking material such as silica gel. They can be placed in filament storage containers or bags to absorb any moisture that may be present.
3D Filament Storage Container: Airtight storage containers can help keep a 3d printing filament dry and free of dust and other contaminants. There are many options available including vacuum sealed bags, plastic containers with tight fitting lids and dry boxes.
Filament moisture sensors: Humidity sensors can be used to monitor humidity levels in your filament storage area. They can help you identify areas that may be too damp and require additional drying or storage measures.
It's important to note that while these tools can be helpful, they won't necessarily produce the desired result for all types of 3D filament. It's always a good idea to check manufacturers' recommendations for filament storage and handling before investing in additional equipment.
Chaosdrucker Christian presented a number of these dryers in this YouTube video and describes the advantages and disadvantages from his point of view:
How long does it take to dry 3D filament?
On average it takes about 3-4 hours at 50-80℃ to dry a 1kg spool of 3D printing filament. This mainly depends on the material to be dried and the initial moisture content. Please note that the drying parameters can therefore vary greatly, even for filaments made of the same material.
Why does the 3D filament drying take so long?
Moisture does not start to going out of the 3D material until the filament is fully warmed through. Because polymers are poor conductors of heat, it takes time for heat to penetrate the center of the filament and moisture to eventually reach the surface. How long this process takes depends on a number of factors, including the type of polymer and the drying temperature.
How long does it take for a dried 3D filament to regain moisture?
Moisture absorption times vary greatly from 3D filament to 3D filament and also storage conditions. With some 3D printing filaments, in extreme cases (e.g. high relative humidity and very slow print speeds), the moisture regain can be too fast that it is even necessary to transport the filament directly out of the dryer in a tube (PTFE tube ) to the printer to completely avoid contact with humid room air. Other materials can be printed without any problems even days after drying.
How should 3D printer filaments be stored properly?
3D printing filaments should always be stored dry, meaning in an environment with low humidity. The easiest way to do this is to use sealable vacuum bags or bags. They should be made of high-quality plastic and have a double zipper. Another variant is storage in so-called drying boxes.
One or more rolls can be stored in it airtight and with desiccant. Most of these also have a small device for measuring and displaying the relative humidity in the box. In addition to ready-made boxes that can be obtained from producers of 3D printing materials, there are also countless self-made variants for download. These can either be storage boxes that are completely self-printed, such as:
Source: Printables
In many cases, storage boxes from a well-known Swedish furniture store are modified for the purpose of a dry storage of 3D filaments. A frequently used solution how to build a simple and functional one with self-printed parts and few accessories can be found here:
Here you can see how the Rrobaki maker uses this method to keep the PCTG filament dried while printing:
In summary, it can be said that when in doubt, it is always advantageous to use dry or dried filament, especially when processing materials susceptible to hydrolysis such as PETG 3D Filament or PCTG 3D Printing Filament.
How to improve printing with PETG 3D filament and other 3D materials?
Here are some tips for drying 3D printing filament and storing it properly based on what we learned earlier.
Use a 3D filament dryer: A filament dryer is a device specifically designed to remove moisture from 3D printing filaments. You need it for the above mentioned types of 3D materials. There are many different models, so choose one that suits your budget and needs.
Use silica gel packs: Silica gel is a desiccant that can absorb moisture from the air. You can buy small packets of silica gel and put them in your filament storage container to keep the 3d printer filament dry.
Store filaments in airtight containers: To prevent moisture from getting to the filament, store it in an airtight container. You can use plastic bags or containers with tight-fitting lids.
Store the 3D filaments in a dry place: It is important to store filaments in a dry place so that they do not absorb moisture. Do not store the filament in rooms with high humidity, e.g. B. in basements.
Use a filament spool holder: A filament spool holder can help organize your filament and prevent it from getting tangled.
By following these tips, you can ensure that your 3D printing filaments stays dry and in good condition.
Conclusion
To achieve optimal results when 3D printing filament, it is crucial not only to choose the right material and print settings, but also to ensure that the 3D print filament is properly conditioned for processing.
3D printer filaments made of polar plastics such as PMMA, PA (Nylon), PC , PET, PETG, TPU and technical filaments such as CF-filled PA or flexible filament must be dried before printing to avoid failed prints due to excess moisture.
The ability of 3D printing filaments to absorb moisture depends on the polarity of the main component of the polymers. Non-polar plastics have low surface energy and are chemically more resistant to polar solvents, while polar plastics are more susceptible to moisture absorption.
Excess moisture in 3D filament during printing can cause various 3D printing problems such as blistering, stringing, warping, poor layer adhesion and color changes. Drying your 3D printing filament before using it can reduce the mentioned problems, and improve a print quality and mechanical properties of a printed part.
Therefore, proper storage, drying and processing of polar plastic 3D filaments are essential to achieve high quality 3D prints.
Hope this was a useful post for you.
Have fun printing!