Stringing on a 3D print

Stringing is a common problem in 3D printing that has existed since the dawn of this technology. Although great strides have been made in overcoming it, stringing still remains an unsolved problem. Stringing is the term used to describe the phenomenon of plastic strings forming between the layers of a printed object. This happens because some filament materials are not compatible with certain extrusion devices. Some printers are more prone to the phenomenon of stringing than others, depending on how they are designed and the type of material used.

Causes of stringing.

There are many causes of stringing: some can be quickly resolved by changing settings, others require more intensive work.

To begin with, the most obvious cause is temperature. The filament must be extruded at a sufficiently high temperature to prevent it from cooling before it reaches the print bed. If the temperature is too low, the extruder will try to move the filament, but will only push out a small amount before it becomes solid and stops moving completely. This phenomenon is known as ‘cold flow’ and can be solved by increasing the temperature limit setting in Cura Connect or Slic3r PE (by default it should already be set to 200°C).

The second is the type of filament used, as some filaments are more prone to stringing than others. The third factor is the calibration of the printer (if it is not set correctly), as this affects the amount of pressure applied to the extruder and thus the amount of filament that is pushed through it at one time.

If the stringing persists even after ruling out all the possibilities described here, then try one last method before deciding whether to discard everything: lower the extrusion multiplier settings until there is none left OR until all the strands disappear completely from the prints, but only do this after trying all the other things mentioned here first, as doing so may result in poor prints due mainly to increased friction between the layers of material.

However, don’t worry about this happening too often, because most people probably won’t even notice it unless they are looking closely at the surface detail levels of their model (which would mean they would need good lighting conditions).

Solutions to Stringing

If filaments continue to form on the parts, first try reducing the length and speed of retraction to 1 mm and 20 mm/s respectively. This will reduce the distance the hot filament has to travel, increasing the likelihood of it remaining in a molten state. This will reduce the amount of oozing that occurs during retraction (extraction of the filament from the nozzle). It will also reduce the speed of filament extraction, thus reducing the likelihood of filament breakage, spillage or oozing onto the part during printing.

If even these settings do not work for your chosen printer or material, you can try changing other parameters, such as:

• You can reduce the thickness of the initial line of this layer by changing its width to something less than 0.2 mm (e.g. 0.1 mm).
• Slow down the printing speed by 15-20%.

If there is little or no adhesion between layers, slow down the printing on this layer so that more time is spent at a lower temperature. By spreading each line over a wider distance, the extruded plastic material should have enough time to cool before meeting another extrusion and forming a uniform bond, even without increasing the fan speed!

Also reduce the filament extraction force from the nozzle by setting a lower extrusion multiplier to reduce the flow rate.

Conclusion

If you are still experiencing stringing problems, it may be time to take a closer look at your printer. Check the nozzle and make sure it is not clogged with plastic. It may be time to clean the nozzle or replace it completely if it is damaged. Also, check that there are no gaps between the plastic parts, which could allow air to enter the system and cause extrusion problems.