Exploring the versatile world of 3D printing, engineers can use this technology to create torsion springs. These springs store and release angular energy, suitable for specific mechanical needs such as system safety in braking assemblies. This article is a step-by-step guide on how to 3D print torsion springs while looking into the crucial factors of material selection, and adjustments in spring design to match application requirements. The discussion encompasses managing deflection in plastic springs, a comparison between metal and plastic materials, and optimizing spring dimensions for your designs.
Calculating Deflection in Plastic Torsion Springs
During the process of 3D printing plastic torsion springs, recognizing the extent of deflection is vital. The term deflection indicates the degree to which a spring rotates or bends under a specific load. The range of rotation for the spring relates directly to its functionality. As an example, let's consider a situation where a plastic torsion spring is employed to reset a latch in a safety system. In this case, accurate measurements of deflection are necessary to ensure that the spring is capable of completely resetting the latch, thereby avoiding any potential failures in the system.
The evaluation of spring deflection involves assessing parameters such as the spring's diameter, the magnitude of the applied force, and the properties of the plastic material used in the spring. Different types of plastic materials have various attributes that can significantly affect torsional stiffness and deflection. For instance, if you employ PLA (Polylactic Acid) for your spring, it's important to note its relatively lower tensile strength compared to other materials such as ABS (Acrylonitrile butadiene styrene). A spring printed from PLA may thus present greater deflection under the same load as a spring printed with ABS.
Once you've ascertained the load that your spring is required to bear, you can use this information in conjunction with the properties of the selected plastic material to make an estimation of the deflection rates. For instance, if the load exerted on your spring is measured to be 10 Newtons and you've chosen to use PLA, you can compute a potential deflection rate. The outcome of this calculation will dictate the design specifications, which can be inputted into your 3D printing software. This enables the production of a spring that performs as expected under planned loads.
Differences Between Metal and Plastic Springs
Material Strength : Metal springs have high tensile strength, able to withstand significant forces without changing shape. Certain metals like stainless steel or chrome silicon are notably durable even in extreme temperatures. On the other hand, 3D printed plastic springs made of Polyetheretherketone (PEEK) or Polylactic Acid (PLA) achieve similar high strength levels, rendering them a suitable option where forces are not excessive.
Weight : Due to their material composition, plastic springs are lighter than metal equivalents. This character is advantageous in aerospace applications, where reducing equipment weight is beneficial. However, the plastic springs' lower load-bearing capacity must be considered.
Corrosion Resistance : The chemical makeup of plastic springs affords them better resistance to corrosion compared to metal springs, which could extend their lifespan in settings where they are frequently exposed to water or certain chemicals.
Flexibility in Design : Both metal and plastic springs can be produced with precision. A noteworthy characteristic of 3D printed plastic springs is their capacity to accommodate design modifications. For example, previously printed torsion springs that produce less force than needed can simply be recalibrated by modifying the coil diameter in the 3D design, improving the spring's functionality.
Cost : The volume and frequency of production are factors when deciding the more affordable spring type. In situations of low-volume or frequently changing designs, 3D printed plastic springs might be the better choice due to the lower costs per print iteration. For large production quantities and consistent designs, metal springs could be the better option due to the benefits of mass production.
Designing the Torsion Spring Features and Dimensions
When designing plastic torsion springs, attention must be given to features and dimensions. Start by deciding on the wire diameter as it is related to the strength of the spring. A spring with a larger wire diameter is stronger and can withstand greater torques, possibly extending its lifespan. The next dimension to consider is the spring's outer diameter, which determines the space the spring will occupy in the assembly. A larger diameter means the spring can support more load, but requires more space in the device.
The subsequent step involves determining the number of coils in the spring. Increasing the number of coils enhances the spring's flexibility and decreases the stress per coil. However, it also expands the spring's length, which may not be practical for devices with limited space.
The design and shape of the ends of torsion springs are crucial as they interact with other parts of the system. For instance, if a spring is to apply rotational force to a hinged part, an open-ended spring would be suitable. In contrast, a spring with closed and squared ends would serve well for a task requiring evenly distributed force, such as in a door hinge.
Plastic deformation, which can occur from persistent load or stressors such as overheating or bridging during 3D printing, should also be taken into account in the design phase. Modifying factors such as the print temperature or speed during design can help mitigate these issues. Digital simulations can also assist in refining the spring design prior to finalization.