Considerations for 3D printing threads

The rapid development of 3D printing technology has provided unprecedented possibilities for manufacturing complex thread structures. Traditional thread manufacturing usually requires the use of lathes or tapping tools, while 3D printing technology makes the thread manufacturing process more flexible. Whether it is an external thread or an internal thread, 3D printing can directly generate finished threads without the need for post-processing. This article will discuss the considerations for 3D printing threads in detail.

Terms related to 3D printing thread design

Pitch and helix angle

In the process of 3D printing threads, there are two main factors that affect the quality and function of the thread: pitch and helix angle.

The pitch refers to the distance between two adjacent teeth, which directly affects the fineness of the thread. Smaller pitches produce more threads, but require higher printing accuracy and resolution. Larger pitches are easier to print, but may sacrifice meshing accuracy. In design, it is recommended to select the appropriate pitch according to the 3D printing technology and materials used.

The helix angle refers to the angle of rotation of the thread around the axis. Threads with large helix angles are more likely to be offset or layered during printing, especially in high-resolution printing. Small helix angles are more conducive to printing stability, so when designing threads, choosing a moderate helix angle is the key to ensuring printing quality.

External and internal thread

External threads refer to threads located on the outside of a bolt or shaft, while internal threads exist inside a nut or hole. External threads are relatively easy to print because they can be directly exposed to the printer's nozzle and do not require too many support structures. Internal threads, on the other hand, have more complex geometries and are prone to material accumulation or support during printing, so extra care needs to be taken when designing to ensure that there is enough clearance space and matching tolerances.

Since 3D printing is not as precise as traditional machining, properly designed tolerances can ensure that internal and external threads can match smoothly. Generally, internal threads should be slightly larger and external threads should be slightly smaller to offset possible printing errors.

Thread diameter

Thread diameters are divided into outer diameters and inner diameters. The outer diameter refers to the maximum diameter of the external thread, while the inner diameter is the minimum diameter of the internal thread. When designing, the resolution of the 3D printer and the shrinkage rate of the material need to be considered to ensure that the printed thread size meets the requirements.

Tips for designing threads for 3D printing

In order to obtain high-quality threads, the following design tips are essential:

(1) Use an appropriate helix angle

Triangular threads, such as the standard 60° V-thread, are the most commonly used thread profiles for 3D printing because they are structurally stable and easy to print. In contrast, although square threads have good performance in traditional manufacturing, they may have problems such as insufficient printing accuracy and blurred edges in 3D printing. Therefore, it is recommended to use a more traditional V-thread design.

Source: https://www.researchgate.net/figure/V-profile-for-ISO-general-purpose-metric-screw-threads_fig2_260288511

(2) Adjust the printing direction

The printing direction of the thread affects the smoothness and fineness of the surface. For best results, it is recommended to design the thread to be printed along the Z-axis. This helps reduce layered textures and make the thread profile clearer. If the thread is printed in other directions, the layered texture between layers may affect the functionality of the thread.

(3) Matching layer height and pitch

Layer height is an important factor in determining resolution in 3D printing. Smaller threads are printed with thinner layers. When designing threads, it is recommended to set the layer height to 1/2 to 1/4 of the pitch, which can ensure that the layers of the threads are relatively uniform and reduce the impact of stratification on meshing.

Source: https://www.reddit.com/r/3Dprinting/comments/14kfn5q/testing_out_3d_printed_threads/

(4) Post-processing and polishing

Even when using high-precision printing equipment, the surface of the 3D-printed threads may still have a certain degree of roughness. To improve the meshing effect of the threads, slight post-processing can be performed, such as polishing or applying lubricants. This will significantly improve the smoothness of the thread engagement and extend the service life of the threads.

(5) Material selection

For thread designs with high load-bearing capacity, the choice of materials is very critical. Materials such as nylon and polycarbonate are suitable for printing high-strength threads due to their good mechanical strength and toughness. For large structures or metal connectors, it is recommended to use metal powder 3D printing technology to obtain higher durability. In addition, increasing the thickness of the thread root can effectively improve the load-bearing capacity of the thread.

JLC3DP helps achieve high-precision 3D printing threads

The design of 3D printing threads requires comprehensive consideration of key factors such as tolerance, pitch, helix angle, and reasonable optimization of printing direction and post-processing procedures during the design process. JLC3DP provides high-precision 3D printing services, supports a variety of materials and processes, and helps customers easily achieve high-quality thread printing. If you encounter challenges in thread design or printing, our team is always here to support you.