How to Assemble 3D Printed Pieces

While 3D printing has made great progress over the past few decades, there are still limits to the shapes and sizes of objects that 3D printers can produce. If your project exceeds the size limit of your printer or requires modular components, you will need to print it in pieces, assemble and connect the parts after they are printed. This article will introduce the methods and precautions for assembling and connecting 3D printed parts.

Adhesives

Adhesives can be used to quickly connect parts. Choose super glue or e6000 adhesive for a very strong, long-lasting bond; if you need strong adhesion but want to split it later, hot melt glue is recommended. The advantage of using adhesives is that you usually don't need to change your 3d model, you just need to use design software to separate the model into multiple bodies. Split design means using design software to separate the model into two or more bodies. Taking Fusion 360 as an example, you can select the cutting surface through the "Split Body" tool to divide the model into multiple parts. Then, you can edit and export the split parts separately for easy printing and assembly.

Related reading: https://jlc3dp.com/blog/how-to-glue-3d-prints-complete-guide-for-seamless-connections

Snap Fit Joints

Snap Fit Joints are a method of connecting parts together using the mechanical properties of plastics. It is designed by designing a structure that can "snap" to each other: a raised part cooperates with a groove, and the connection is achieved through elastic deformation, so that the two parts can be easily connected and fixed together. The advantages of snap fit joints include no need for additional tools, quick assembly, detachability, and saving materials and time. It is an efficient and convenient connection method.

Snap fit joints have certain requirements on the elasticity and toughness of materials. Commonly used materials include PLA, ABS, PETG, etc., especially ABS, which has good toughness and wear resistance and is suitable for making durable snap fit joints. In order to ensure that the snap fit can be assembled smoothly, a certain tolerance needs to be considered in the design, that is, to ensure that the size of the snap fit part is neither too tight nor too loose, to avoid assembly difficulties or loose connections. In addition, when designing snap fit joints, it is necessary to avoid excessive stress concentration to prevent the snap fit part from breaking easily.

Threaded connection

In 3D printing, threaded connection is a common assembly method, especially for situations where detachable connections are required. This method requires special attention to tolerances and printing directions during the design phase to ensure the reliability of the threaded connection. When designing threads, you can choose to add internal or external threads directly to the part. Fusion 360 and other modeling software provide built-in tools to help quickly generate threads and automatically handle tolerances.

However, the strength of 3D printed plastic threads is not enough to support large torques, or in some cases, a stronger connection is required. The nut insertion method can be used. This method embeds nuts directly into the part during the printing process to provide a more stable connection. When designing a part, you can add nut embedding cavities at appropriate locations, pause the printing process, insert nuts or other connectors, and then resume printing. When using this method, you need to configure the slicing software to pause when printing to a specific layer, insert nuts or magnets, and then continue printing. In this way, the risk of weak threads can be avoided while ensuring the stability of the connection.

Related reading: https://jlc3dp.com/blog/considerations-for-3d-printing-threads

Key Considerations

Model splitting: Consider natural joints or symmetry (for example, splitting a figurine at the waist) to split it to reduce the difficulty of later assembly.

Tolerance control: Different types of connection methods have different tolerance requirements. For example, when using threaded connections, tolerance control is crucial. Too loose threads will result in loose connections, and too tight threads may cause assembly difficulties or damage. In addition, it is necessary to consider material shrinkage or printing defects during printing, and a certain amount of space needs to be reserved.

Post-processing: Grinding and trimming can make the connection surface smoother, which is conducive to subsequent connection.

Material selection: Plastic materials are suitable for snap fit joints and lightweight components, among which ABS and PETG have better toughness and heat resistance.

Durability and load requirements: When designing 3D printed assemblies, especially threaded connections and snap fit joints, the use environment and load requirements of the components should be considered. Some parts may need to withstand large torques or external forces. At this time, you need to consider strengthening the design of the connecting parts, such as increasing the wall thickness, choosing more durable materials, or using nut inserts to enhance the strength of the connection.

By using adhesives, snap fit ​​joints, threaded connections and other methods, you can choose the most suitable connection method according to the needs of the project to ensure that each component can be firmly combined. If you have difficulties in making complex assemblies or need industrial-grade precision printed products, JLC3DP can provide you with comprehensive support from design to realization to ensure the smooth completion of your project.