Hairy 3D prints are caused by stringing, which occurs when the nozzle oozes filament while moving between different parts of the model. This can result in thin strands of plastic that resemble hair or spider webs on the surface of the print. Stringing can be prevented or reduced by adjusting the print settings, such as retraction, temperature, speed, and cooling.
Stringing is a common problem in 3D printing, especially with filament materials that have a low viscosity when melted, such as PLA and PETG. When the nozzle moves from one part of the model to another, it may leave behind a trail of molten plastic that solidifies into a string. This can happen for several reasons, such as:
Insufficient retraction: Retraction is a feature that pulls the filament back into the extruder when the nozzle is not printing, to prevent oozing. If the retraction distance or speed is too low, the filament may still leak out of the nozzle during travel moves.
High temperature: The temperature of the nozzle affects the viscosity of the filament. If the temperature is too high, the filament may become too fluid and ooze more easily. The optimal temperature depends on the type and brand of the filament, as well as the ambient conditions.
Fast travel speed: The travel speed is the speed at which the nozzle moves between different parts of the model. If the travel speed is too fast, the nozzle may not have enough time to cool down and stop oozing before reaching the next part. A slower travel speed may allow the nozzle to stabilize and reduce stringing.
Poor cooling: The cooling fan helps to solidify the filament as soon as it is extruded, which prevents oozing and improves the print quality. If the cooling fan is not working properly, or if the fan speed is too low, the filament may remain molten for longer and cause stringing.
Stringing can be avoided or minimized by tweaking the print settings and finding the best balance for your printer, filament, and model. Here are some tips to reduce stringing:
Increase the retraction distance and speed: The retraction distance is the amount of filament that is pulled back into the extruder when the nozzle is not printing, and the retraction speed is how fast this happens. Increasing these values can help to prevent oozing and stringing, but be careful not to go too high, as this may cause clogging or under-extrusion. A good starting point is to set the retraction distance to 2-5 mm and the retraction speed to 25-50 mm/s, and then adjust them according to the results.
Lower the temperature: Lowering the temperature of the nozzle can reduce the viscosity of the filament and make it less prone to oozing. However, lowering the temperature too much may affect the adhesion and strength of the layers, so it is important to find the optimal temperature for your filament. A good way to do this is to print a temperature tower, which is a test model that prints at different temperatures along its height. You can then compare the quality of the prints and choose the best temperature for your filament.
Slow down the travel speed: Slowing down the travel speed can give the nozzle more time to cool down and stop oozing before reaching the next part of the model. However, slowing down the travel speed too much may increase the print time and affect the quality of the print. A good starting point is to set the travel speed to 100-150 mm/s, and then adjust it according to the results.
Increase the cooling fan speed: Increasing the cooling fan speed can help to solidify the filament faster and prevent oozing and stringing. However, increasing the cooling fan speed too much may cause warping or cracking of the print, especially with materials that are sensitive to temperature changes, such as ABS. A good starting point is to set the cooling fan speed to 50-100%, and then adjust it according to the results.
Hairy 3D prints are not a desirable outcome, as they can ruin the appearance and functionality of the model. Fortunately, stringing can be prevented or reduced by adjusting the print settings, such as retraction, temperature, speed, and cooling. By experimenting with different settings and finding the best balance for your printer, filament, and model, you can achieve smooth and clean 3D prints. Happy printing!
