The demands placed on engineering thermoplastics in additive manufacturing (AM) are high and the areas of application are diverse, from prototypes in the automotive industry to small series production in veterinary medicine.
But even the best and most expensive material is only as good as its processing. To produce efficiently, avoid production losses, save costs and time, and achieve the best results with FFF 3D printers, you should consider the following five points.
1) Dry filament and store it optimally
Moisture in the filament affects the 3D printing result. This can be seen in bubbles which are increasingly formed during printing of the base layer and even in the subsequent printing process. Hair-thin threads (oozing, stringing) can often form on the component, or unevenness, so-called "blobs or zits", can appear on the surface. These imperfections result in components failing to meet their high-quality requirements and therefore the entire print must then be repeated, which is time and cost-intensive.
From left: Example: oozing/stringing and over-extrusion.
For this reason alone, it is worth drying the filament before printing, storing it in the best possible way and finally processing it at the right temperature and low humidity. A filament dryer such as the MiQ 5 from German RepRap is a suitable solution for this. It maintains a constant temperature of around 60 degrees Celsius and actively extracts moisture from the air. The material is dried reliably without affecting the material properties due to the softening temperature of filaments being higher than 60 degrees Celsius.
German RepRap filament-dryer MiQ 5.
Did you know?: Even if filaments are vacuum-sealed and look dry when unpacked, they may still contain moisture due to production. This occurs during production when the material is first heated to form it into the right shape. In some production processes it is then cooled down with fans or in a water bath. Although the filament is dried afterwards, very small water molecules often remain in the material.
2) Configure pressure of filament transport wheel
Only when the pressure of the filament feed wheel is adjusted to the type of filament used, can it be extruded in a material-compatible manner. If the contact pressure is too low, the material may slip through. If the contact pressure is too high, the filament screw will eat into the filament. This results in under-extrusion, which leads to an uneven print. A filament jam is also possible. With the FFF printer TiQ 5 from German RepRap, the pressure is adjusted in a few simple steps so that the correct amount of material is always applied.
3) Ensure optimum filament delivery rate
For a consistent print result, it is also necessary that the material is fed to the extruder without any tensile stress. As soon as the material is even minimally stretched, the filament thins out during the printing process.
FFF 3D printers from German RepRap combine a feeder with a direct drive extruder for this purpose. This ensures that the filament is always fed to the extruder at the right speed without subjecting the filament to mechanical stress on its way there.
4) Set correct temperature
ABS, polyamide, TPU, PETG: Each material has an individual glass transition temperature. This temperature must neither be undercut nor exceeded during printing. Therefore, the correct temperature of extruder, print bed and installation space is important.
If a filament is printed too hot, it burns. For a perfect printing result, the extruder temperature should be adjusted to the material. During the printing process, a sensor monitors the specified value and automatically corrects the temperature. Throughout the 3D printing process, the material should also be brought to its optimum temperature on the print bed to achieve the best adhesion.
The glass transition temperature also influences the printing result: a heated installation space promises that the component is built up without tension until it is sealed and can be cooled down in a controlled manner.
5) Adapt nozzle to the print job
Before each printing process you should clean the nozzle and remove any material residues. Otherwise, filament residues may come loose during the printing process and appear as uneven features or small dots in the new print. German RepRap printers allow the user to replace the hot end, nozzle and heating block as one unit with only one screw. In no time at all, the printer is ready to start a new job with a different material, giving users confidence that the material will be printed and processed cleanly.
Example: Material residues (black spot).
The philosophy of German RepRap's Open Material Platform also leaves the user free to choose the type of nozzle, whether it's Wolfram-Copper, stainless steel, or Olsson Ruby – all E3D compatible nozzles are possible.
If you take consider these five points for your next print job, you are a big step closer to achieving a perfect print result. In addition, it is also important to design your parts in an additive-compatible manner and think carefully about your material selection.
Especially when entering additive manufacturing, it is important to have an experienced and reliable partner like German RepRap at your side. Our goal is to not only set up the 3D printing system and train the user, we want to enable our users to achieve the best printing results, independently, regularly, and repeatably.
