This publication deals with the study of the mechanical properties of injection-molded polypropylene parts depending on the process parameters and the distance from the gate location in which the mechanical properties were investigated. Due to the fact that the mechanical properties of injection-molded parts are not the same at all locations, this research was designed to investigate the inhomogeneity of the properties of injection-molded parts along the length of the product. The inhomogeneity is affected by various influences, including distance from the sprue mouth, melt and mold temperature, injection pressure, crystal structure, and others. It was demonstrated that mechanical properties are not uniform over the entire injected product. Contrary to popular belief, mechanical properties can vary along the flow length due to uneven cooling and process parameters. Injection pressure and mold temperature significantly affect the mechanical properties of the injection-molded parts. The limiting injection pressure is 40 MPa and the mold temperature is 40 °C. The difference in individual spots in an injected article was up to 37%. Changes in mechanical properties are closely related to changes in morphology (crystallinity measured by DSC) caused by different injection molding process parameters. As is evident from the aforementioned results, the possible benefits of this work for injection molding of polymer products are apparent. Suitably chosen gate location, surface of the cavity, and process parameters can ensure targeted improvement of mechanical properties in stressed parts of a product.

• Klíčová slova
• indentation hardness, injection molding, injection pressure, mechanical properties, mold temperature, polypropylene,
• Publikační typ
• časopisecké články MeSH

This research investigates the adaptation of conventional injection-molding techniques for producing thick-walled polycarbonate optical components, specifically targeting their application in automotive light guides. With the automotive industry's growing demand for reliable yet cost-efficient optical products, the study examines how traditional injection-molding processes can be refined to enhance dimensional accuracy and reduce defects. Simulations and experimental trials were conducted to evaluate the impact of critical process parameters, such as melt temperature, mold temperature, injection pressure, and gate design, on the overall quality of the final components. The results show that by carefully optimizing these parameters, it is possible to significantly reduce common defects like warpage, surface imperfections, and dimensional instability. This research highlights the potential of existing molding techniques to meet high industry standards while maintaining cost-effectiveness, offering valuable guidance for manufacturers aiming to produce high-quality optical components for demanding applications like automotive lighting.

• Klíčová slova
• injection molding, light guides, polycarbonate, process evaluation, quality enhancement, thick-walled parts,
• Publikační typ
• časopisecké články MeSH

This study investigates the challenges and potential of conventional injection molding for producing thick-walled optical components. The research primarily focuses on optimizing process parameters and mold design to enhance product quality. The methods include software simulations and experimental validation using polycarbonate test samples (optical lenses). Significant parameters such as melt temperature, mold temperature, injection pressure, and packing pressure were varied to assess their impact on geometric accuracy and visual properties. The results show that lower melt temperatures and higher mold temperatures significantly reduce the occurrence of dimensional defects. Additionally, the design of the gate system was found to be crucial in minimizing defects and ensuring uniform material flow. Effective packing pressure was essential in reducing volumetric shrinkage and sink marks. Furthermore, we monitored the deviation between the predicted and actual defects relative to the thickness of the sample wall. After optimization, the occurrence of obvious defects was eliminated across all sample thicknesses (lenses), and the impact of the critical defect, the sink mark on the planar side of the lens, was minimized. These findings demonstrate the substantial potential of conventional injection molding to produce high-quality thick-walled parts when these parameters are precisely controlled. This study provides valuable insights for the efficient design and manufacturing of optical components, addressing the growing demand for high-performance thick-walled plastic products.

• Klíčová slova
• injection molding, optical lenses, polycarbonate, process evaluation, quality improvement, thick-walled parts,
• Publikační typ
• časopisecké články MeSH