Rapid Tooling for Three-component Injection Moulding. Aim: Geometry and material qualification
Use Case: RAPID TOOLING FOR 3C IM
OUR MISSION
Testing and qualifying various injection moulding materials for multi-component compatibility and validating the tool's geometry for efficient production.
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Printer Used: UnionTech Pilot 250
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Layer Resolution: 100 µm
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Printing Material: Somos® Perfom Reflect
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Material Properties: High stiffness, mechanical strength, and heat deflection; suitable for Injection Moulding due to surface quality and durability
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Printing Duration: Approximately 30 hours per tool set
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Machine Used: Wittmann Battenfeld HM 800.
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Key Features:
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80 t clamp force for effective moulding.
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Injection Parameters:
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Pressure: 2000 bars.
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Mass Temperature: 300 °C.
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Mould Temperature: 80 °C.
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IM Components:
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Utilized 3 different types of Polycarbonate for a variation of additives in the 3-component part.
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IM Cycles:
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Per tool/component: ≥ 200
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DETAILED INSIGHTS
Addressing Light Scattering: The Need for Multiple Components
Multiple-component injection moulding is a time-tested technique, essential when a product must embody diverse properties. For instance, toothbrushes are classic examples where a hard material ensures stability during use, while a surrounding soft material offers enhanced user comfort.
Integrating Multiple Materials
In our specialized optical application, it was imperative to eliminate light scattering. This fundamental requirement drove the decision to encapsulate a translucent section within an opaque component, ensuring clarity and precision in the final product’s function.
Preventing Light Scattering
For our project, polycarbonate (PC) was the initial material of choice due to its robust mechanical properties (hardness and strength), chemical and heat resistance. The sheath, providing stability to our part, utilized this PC. Meanwhile, the inner disc, playing a crucial role in the optical application, demanded a PC variant with an enhanced refractive index. These two distinct, nearly transparent PC types were complemented by a third PC variant embedded with a light blocker to meet the application's nuanced requirements.
Selecting Polycarbonate for Optical Application
Material compatibility is crucial in this process. The polymers selected must possess similar functional groups in their chemical compositions to guarantee sufficient adhesion. Without this compatibility, there's a risk of the materials separating, requiring mechanical interlocking and introducing complications like undercuts in the moulding process.
Ensuring Material Compatibility
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Advantages of Printed Tools in Injection Moulding
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Prototyping Efficiency:
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Focus on the Tool: Traditional prototypes might not mirror the final product's functionality. With tool prototyping, anticipate the moulded counterpart's precise actions.
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Material Authenticity:
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Original Materials: 3D printing plastics often include additives; using the original materials ensures your prototype is representative.
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Feasibility Investigation:
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Rapid Adjustments: Efficiently modify geometries and wall thicknesses, preventing investment in non-viable steel tools.
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Application-Specific Benefits:
In certain scenarios, like in our case study, printed tools offer unique advantages.
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Cost-Effective Alternatives:
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3d-printed tools serve as affordable alternatives to steel for prototyping.
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Superior Control:
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For applications requiring thin-walled PC parts, plastic tools offer better thermal control, essential for the injection moulding process.
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Rapid Cooling Prevention:
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Metal tools can lead to too rapid cooling, detrimental for moulding flow-resistant materials like PC.
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