Context: Advanced Materials Engineering
Modern engineering constantly seeks maximum efficiency. Therefore, the main objective of this project is the effective metal to engineering plastic replacement in industrial components. Traditionally, manufacturers produce these parts using steel or aluminum. However, we propose a different approach. We use FDM additive manufacturing (Fused Deposition Modeling).
In many applications, extreme loads are not the only factor. Here, polymeric materials can fully meet the rigorous design requirements. It is true that they do not have yield strengths as high as metals. They also lack the same Young’s modulus. Yet, they are a highly effective option to drastically reduce weight.
The density of plastics is far lower than that of metallic materials. For this reason, metal to engineering plastic replacement is a strategic option to study. It is vital for industries where every gram counts, such as aeronautics or the automotive sector. This strategy offers a clear competitive advantage.
At Atreydes Engineering, we analyzed parts originally made of 5083 aluminum. These components must resist tensile stresses of 2000kg. The challenge is modifying their geometry. We aim to manufacture them with 3D printing using advanced technical polymers.
Challenges in Metal to Engineering Plastic Replacement
The mechanical properties of polymers are generally lower than those of metals. This fact forces us to redesign the part completely. We require more support surface to transmit the load effectively. We also need to reach a lower contact pressure at the joints.
Furthermore, we seek a better load distribution in the anchors. This step will provide structural stability to the new plastic geometry.
Another critical factor is anisotropy. The FDM manufacturing process produces elements that are not isotropic. They have different resistance depending on the load direction. Therefore, in any metal to engineering plastic replacement, orienting layer deposition is crucial. We must align the fibers in the best direction. This allows the part to support the main stress with guarantees.
This anisotropic behavior requires careful planning. Unlike isotropic metals, printed parts have a grain. We must respect this during the design phase.
Material choice is essential to comply with load requirements. If we consider high-performance polymeric materials, polyamides (nylon) stand out.
When joining nylon with fiber reinforcement, its properties skyrocket. We use glass, carbon, or aramid fibers. This increases its yield strength and Young’s modulus notably. Thus, we manage to approach the behavior of traditional metallic materials. This makes metal to engineering plastic replacement feasible for high-stress parts.
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Tensile Strength: 345 MPa
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Yield Strength: 215 MPa
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Tensile Modulus: 7000 MPa
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Tensile Strength: 134 MPa
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Yield Strength: 87 MPa
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Tensile Modulus: 8164 MPa
To validate metal to engineering plastic replacement, simulation is the first step. CAE simulation predicts the behavior of the part under load. In metals, linear elastic behavior is very predictable. It fits perfectly until reaching the yield limit.
However, polymer behavior is not so linear. Its stress-strain curve is more complex. As a general rule, we accept its yield limit at 0.2% deformation.
Due to this, polymer simulations require a larger safety margin. They are slightly less exact than pure metallic ones. That is why a subsequent physical test of the part is necessary. This test dispels any doubts about the final performance.
The FDM additive manufacturing process deposits layers of molten material. It builds geometry layer by layer. We can consider that the material in the same layer is very resistant. It has almost the same properties as the raw material filament.
However, the union between layers (Z-axis) is the weak point. It shows strength values below the original material. This is inherent to the FDM process and vital in metal to engineering plastic replacement.
During the manufacturing phase, we must orient the part strategically in space. The goal is for all layers to work homogeneously. They must resist jointly against the main tensile stress. Proper orientation prevents delamination.
The tensile test is the litmus test. It guarantees that the designed part meets the real design loads. The load is applied through a precision hydraulic cylinder.
We control the exact pressure through a calibrated pressure gauge. We use a safety valve to avoid accidental overloads. Furthermore, we measure millimeter deformations by means of a digital dial indicator.
The test bench consists of 3 main custom-designed systems:
- Metal structure that defines the bench.
- Hydraulic power system.
- Electrical control system.
The engineering team designed all these systems entirely.
Our Optimization Process
To execute a successful metal to engineering plastic replacement, we follow a rigorous methodology. First, characterizing the behavior of the original part is necessary. This gives us a reliable starting point. From there, we can begin topological optimization.
CAE simulations define the new geometry. We cross these data with the restrictions of the additive manufacturing software (Slicing). Thus, we obtain the modified design for the new polymeric material.
Finally, the new part must pass the physical tensile test. This ensures that design requirements are met. It also validates that simulations have been exact.
If you are interested in other success stories, visit our Project Portfolio. Or if you have a similar challenge, contact Atreydes Engineering for a personalized study.
