Selective laser sintering (SLS) 3D printing technology enables exceptional quality and productivity while opening the door to high-performance designs not possible with injection molding. SLS additive manufacturing also eliminates the long lead times and upfront investment of injection molding tooling.
JR has used SLS 3D printing to provide customers with a variety of complex parts, such as shafts, frames, complex pipes, living hinges, clips, and other components. Let's introduce our production process.
3D Printing Shafts
Friction, fit and powder removal are three factors in the design of shafts manufactured by SLS. Apply a 1 to 2mm rail on the static side (the "unstressed" side of the assembly) to control friction. The gap between the guide rail and the axle tube is kept at 0.3mm. If there is a gap of 2mm or more in the area far from the guide rail, the powder can be easily and thoroughly removed by blowing compressed air into the powder removal inlet on the static side.
When removing powder, blow compressed air while rotating the shaft to blow the powder out of the shaft cavity. As a natural bearing material, nylon provides a smooth, low-friction mechanism for low-load, low-speed applications. In more demanding applications where friction can generate heat and cause wear, insert bearings can be considered.
3D Printing Baffle - Airflow Management
To place the mounting point through the baffle, elongating the baffle into an aerodynamic teardrop shape reduces where turbulence can form. This improves airflow efficiency and reduces noise.
Always design baffles with gently rounded corners to prevent cracking of the sidewall of the pipe, especially if the component is being used in a pressurized and/or temperature-cycled environment.
3D Printing Embedded Bearing
In this example, we describe the placement of a ceramic ball bearing into a groove (CAD modeled as an annular cavity between faces A and B). Think of it as an integrated hybrid hinge mechanism.
Nylon is a naturally good low-friction load-bearing material. However, in applications where you expect long-term repeated cycle loads, replacing the CAD-modeled ball bearings already in place with ceramic ball bearings (mounted through the manhole) can yield a very durable, smooth mechanism.
Once all the bearings are in the grooves, a pin can be secured to seal the grooves.
3D Printing Bellows
SLS technology can be used to manufacture functional "bellows" when the application's assembly or joining operations require a certain degree of flexibility. Note, however, that nylon does not perform well in applications that require repeated cycling, such as wire and hose boots in mechanisms. Therefore, nylon should only be considered for bellows in applications with a very low frequency of cyclic bending.
Circular bellows work best when the tensile stress points are evenly distributed across the cross-section. When transitioning from a rounded section to a square below, any downward movement from the rounded section will build up stress. In this case, a different approach may have to be taken: using a similar structure for the "Deardorff bellows", which is essentially a series of alternating cross-connected rectangles. Note that due to the smaller radii of the corners, this geometry is more sensitive to stress concentrations and therefore prone to fracture when the loop is stressed.
3D Printing Grille
Hexagons are specifically optimized for SLS technology, not only because they fundamentally manage stress and cell efficiency, but also because very few triangles (12) are required to accurately represent the hexagons. If circles are used to form the grid holes, expect a significant increase in file size.
While the weight of the final part may be reduced relative to a solid non-mesh part, cleaning time and the drawing time of the system are increased since the laser is now contouring and filling in numerous cross-sectional features.
As with hollow parts, the amount of unused powder is not very relevant to the extra material for recycling. This is due to the proximity to the thermal exposure of the components. In fact, mesh parts are more expensive to manufacture than solid parts due to the extra drawing time required.
SLS 3D printing can provide any complex parts, and JR has a professional engineering team that can provide you with better design solutions. We can provide plastic and metal 3D printing services, if you have 3D printing needs, please feel free to contact us.