• 3D Printing
  • What is the reason for 3d printing wavy lines?

The sides of the 3D print are made up of hundreds of separate layers. If everything works fine, these layers should behave as a smooth surface. Then, as long as even one of the layers in the layers makes a mistake, it is usually seen clearly on the facade of the print. These erroneous layers form lines or textures on the side surfaces of the print. Many times this cycle occurs, meaning that the lines appear to be a repeating pattern (for example, every 15 layers). The following sections will look at the usual causes of such problems.

Inconsistent extrusion: The most common cause of this problem is the poor quality of the consumables. If the outer diameter tolerance of the consumable is not tight, you will see the change on the side of the print. For example, even if your bundle of consumables has a diameter change of only 5%, the width of the plastic extruded from the nozzle may vary by 0.05 mm. This extra extrusion produces a layer that is wider than the other layers and ultimately looks like a line on the side of the print. To produce a perfectly smooth side surface, your printer needs to have very good extrusion consistency, which requires high quality consumables. For other possible factors that cause extrusion inconsistencies, please read the "Extrusion inconsistencies" section of this article.

Temperature changes: Most 3D printers use a PID controller to adjust the temperature of the extruder. If the PID controller is not properly adjusted, the extruder temperature will continue to fluctuate. Due to the inherent nature of the PID controller's operation, this fluctuation will appear periodic, meaning that the temperature will change in the form of a sine wave. When the temperature becomes higher, the fluidity of the plastic will be different than when it is cold. This will result in a difference in the extrusion between the layers, producing a visible texture on the side of the print. Proper tuning should stabilize the extrusion temperature to within +/- 2 degrees. During the printing process, you can use Cura's machine control panel to monitor the temperature of the extruder. When the change is greater than 2 degrees, you may need to recalibrate your PID controller. Please consult your printer manufacturer for instructions on adjustments.

Mechanical problems: If you feel that there is no problem with extrusion consistency and temperature changes, the cause of the lines and textures on the sides of the print may be mechanical. For example, the print bed may sway or vibrate during printing, which may result in a change in the position of the nozzle. Then some layers will be slightly thicker than the other layers. These thick layers will form a texture on the side of the print. Another common reason is that the Z-axis screw is not positioned. For example, backlash problems or stepper motor controller settings. Even small changes in the position of the hot bed can have a big impact on the printing of each layer.