Guide for Creating 3D Printed Components with Consideration for Precision and Tolerance
In the world of FDM 3D printing, achieving consistent and reliable results can be a challenge. However, a video by Slant 3D offers a wealth of tips and tricks to improve parts design with tolerance in mind. Here are some key strategies to help you advance your FDM 3D printing skills.
Designing with Precise Clearance and Fit
When it comes to FDM printing, tolerances are typically ±0.2 mm. To compensate for shrinkage and print variation, it's essential to incorporate clearances of about 0.2–0.5 mm for mating parts. For tighter fits like friction or press fits, post-processing like drilling or tapping after printing can be beneficial [1][3].
Managing Material Shrinkage
To address material shrinkage, using thin walls instead of solid blocks can help reduce warping. Selecting appropriate infill patterns can also balance strength and reduce internal stresses. Annealing printed parts can relieve internal stresses and improve dimensional stability [3][4].
Incorporating Compliant Mechanisms and Part Flexibility
Designing parts with compliant features, such as flexible hinges or snap fits, can help tolerate slight dimensional variation. This can be achieved by adding slots or tapered edges, enabling controlled flexibility and reducing the need for exact print parameters, thereby improving assembly success [3].
Material and Process Tweaks
Choosing industrial thermoplastics like ABS, ASA, PC, and ULTEM can provide better repeatability and thermal stability. Adjusting layer height (127–330 microns) can balance surface finish and mechanical strength, with thicker layers improving strength but reducing surface smoothness [2].
Post-Processing for Fit and Finish
Post-processing plays a crucial role in FDM 3D printing. Sanding and primer can fill small imperfections, improving surface quality. Chemical smoothing, like acetone vapor for ABS, can reduce layer lines and improve dimensional accuracy. Annealing can improve mechanical properties and reduce part distortion after printing [4].
Additional Practical Design Tips
Avoiding sharp corners and using chamfers and fillets can ease assembly. Adding flexible slots or grip fins in mating parts can accommodate variation and provide a friction fit without over-reliance on printer calibration [3].
By implementing these strategies, you can tackle the mechanical challenges of FDM printing related to tolerance, shrinkage, and part motion, resulting in more reliable assemblies and functional 3D printed components with integrated flexibility. Eccentricities, like grip fins, are a strategic example for managing variability, particularly in the context of the opposite side of a part.
Technology plays a crucial role in addressing the challenges of FDM 3D printing, offering various strategies to improve the precision, shrinkage management, flexibility, and mechanical properties of printed parts.
By selecting appropriate materials like industrial thermoplastics and adjusting layer height, we can balance surface finish and mechanical strength in our FDM 3D printing projects.
