Injection Molding Using a 3D Printer
Stefan of CNC Kitchen recently explored using 3D printers for injection molding (IM), a process typically requiring metal molds and specialized machinery. However, 3D printers can be leveraged for low-volume IM runs, suitable for limited production and prototyping before investing in costly IM molds. Stefan followed Form Labs’ guidelines to create molds from glass-infused Rigid 10K resin, noted for its high heat deflection temperature of 218°C and ceramic-like rigidity.
The injection process proved challenging as Stefan attempted to push the clamped-shut mold against the nozzle of an FDM printer to inject molten plastic. Using PLA at standard extrusion temperatures resulted in the plastic solidifying before fully entering the mold. He experimented with higher temperatures, alternative materials like PETG and TPU, and high flow-rate extruders, yielding mixed outcomes.
The primary difficulties appeared to stem from suboptimal mold design rather than inherent flaws in using an FDM printer for IM. The Form Labs document outlines essential design principles such as enlarging the injection gate to reduce internal pressure and adding air vents to improve material flow. Professional commentators on Stefan’s video highlighted these design considerations and suggested preheating the mold to enhance results.
Stefan’s experimentation with 3D-printed molds for injection molding illustrates the potential and challenges of this approach, emphasizing the need for proper mold design and process adjustments to achieve better outcomes in low-volume production and prototyping.
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