3D printing brings convenience and fun to people's lives, and hobbyists often use 3D printers to print all kinds of favorite dolls or decorations. However, in the process of 3D printing, there are all kinds of printing problems, one of which is the retraction setting which is a headache for people. Retraction settings play a crucial role in print quality.

1. What is retraction in 3D printing?

Retract or Retraction in 3D printing is a method of minimizing extruder nozzle overflow during the printing process to avoid drawing or stringing. It is accomplished by temporarily pulling the printed filament material, such as PLA, ABS, etc., from the nozzle back inside the extruder.

2. How retraction works

When the 3D printer is moving the nozzle but not extruding melted filament, such as between two models, retraction temporarily pulls some of the material back in, which reduces Stringing and avoids the nozzle from leaking material into filaments that are not in the print path. It also improves print quality by minimizing the buildup of excess material and preventing “burrs” or other imperfections. It also prevents spills and drips of material onto the surface of the model.

3. Important parameters for retraction settings

The Retraction Distance setting, which is the length at which the extruder pulls the material back, is typically shorter for Direct Drive extruders, typically set at 1-3 mm, and longer for Bowden extruders, typically 4-6 mm, as the material is transported through a longer line. A calibrated model is used to test the optimum retraction distance to avoid pulling the material too far and causing breakage.

The Retraction Speed setting, which is the speed at which the material is pulled back, is commonly recommended in the range of 20-100 mm/s. If the speed is too low it may result in less effective retraction, and too high a speed may result in plugging or material wear. Too low a speed may result in poor retraction and possible drawing. Too high a speed may result in material wear, extruder stepper motor jumping or plugging. Tests can be started at medium speeds, e.g. 40-60 mm/s, and then gradually optimized.

The Minimum Travel Distance setting refers to the minimum nozzle travel distance for the printer to trigger retraction. Short travel distances may not require retraction, saving time. Prevents wasted time and material loss due to frequent nozzle retraction. The minimum retraction distance is usually set to 1-2 mm to avoid triggering retraction for short travel distances.

The Extra Prime Amount setting, typically used for the amount of material re-advanced to the nozzle after retraction, is used to ensure proper extrusion. Avoids print defects caused by insufficient material supply after retraction and can be adjusted in the 0-0.2 mm range.

For the nozzle temperature, too high a temperature will increase the material fluidity, which can easily lead to drawing. So the temperature can be gradually reduced while observing the printing effect.

4. Retraction Setting Tips for Different 3D Printing Materials

The characteristics of different materials determine their different needs for retraction settings, which we present in the form of a table:

5. Printing retraction common problems and solutions

If the 3D printer retraction settings are not appropriate, may produce a variety of problems, causing a greater impact on the printing, the specific performance will vary depending on the deviation of the settings, the following are some common easy to cause problems, respectively, to give the solution:

Drawing problem:

In the path of the nozzle movement of filaments or thread-like material, usually like a spider web. This is due to the printer retraction distance is not enough, the material is not completely pulled back from the nozzle. As well as retraction speeds that are too low and material still flows out as it moves. There is also a nozzle that is too hot and the material is too fluid.

Solution:

Gradually increase the retraction distance or speed, then lower the nozzle temperature and optimize the path using the slicer's “combing mode”.

Clogging:

Printing may be interrupted or the nozzle may be completely clogged because the filament material is not extruding properly. Too high a retraction speed or too long a distance may cause clogging. Also use the appropriate nozzle temperature and clean the nozzle and piping.

Solution:

Reduce the retraction distance and speed at the printer settings, dry the material before printing, and clean the nozzles and feed lines regularly.

Insufficiently extruded gaps after retraction problem:

Small holes or lack of material during printing, especially in areas where the nozzle retracts and then reextrudes. Retraction distance is too long, resulting in too much material being returned, insufficient additional extrusion after retraction, and too high a retraction speed causing the extruder stepper motor to slip.

Solution:

Appropriately reduce the retraction distance, and increase the amount of “additional extrusion after retraction”, and ensure that the material supply is smooth, reduce the retraction speed.

I present the common problems of printer retraction in the form of a table:

6. Retraction Settings Summary

3D printer retraction settings are critical to the quality of 3D printing, and improper settings can lead to a variety of problems, including drawing, clogging, and under- or over-extrusion. By gradually adjusting the retraction distance, speed, temperature and other related parameters, and optimizing the settings for specific materials and model characteristics, the print quality can be significantly improved.

UJOYBIO3D filament with temperature labeling

In the case of UJOYBIO3D's filament materials, the optimal printing temperature for PLA+ filament is detailed on the product's packaging, making it easy for users to find the optimal setting temperature as soon as they get started.