Laryngoscopes are crucial medical instruments used for observing the laryngeal and vocal cord structures in the medical field. Their manufacturing precision and quality directly impact the accuracy of clinical diagnosis and patients' usage experience. Injection molding processing is a key technology for producing the plastic components of laryngoscopes. However, burr (flash) problems often occur during actual production. Burrs not only affect the appearance quality of products but may also have negative impacts on the sealing performance, assembly accuracy, and operational performance of laryngoscopes. In severe cases, they can even affect medical safety. Therefore, conducting an in-depth analysis of the causes of burr formation during injection molding processing of laryngoscopes and taking effective solutions are of great significance for improving the quality of laryngoscope products and reducing production costs.

Analysis of the Causes of Burr Formation in Injection Molding Processing of Laryngoscopes

Mold Factors

1. Insufficient precision of the mold parting surface: The mold parting surface is the surface that comes into contact with each other when the mold is closed. If the parting surface has wear, unevenness, or unreasonable design, during the injection molding process, the molten plastic will extrude from the gaps in the parting surface, forming burrs. For example, the parting surface of a mold that has been used for a long time may wear out due to repeated mold opening and closing, resulting in reduced sealing performance and an increased likelihood of burr formation.
2. Poor ventilation of the mold exhaust system: During the injection molding process, the air inside the mold cavity needs to be exhausted in a timely manner. Otherwise, high pressure will be formed when the molten plastic fills the cavity, causing the molten plastic to overflow from the mold gaps and form burrs. If the exhaust slots in the mold are too small, improperly located, or blocked, it will affect the exhaust effect and increase the probability of burr formation.
3. Wear of the mold core and cavity: The mold core and cavity are the key parts for forming the components of laryngoscopes. With the increase in the number of uses, their surfaces will gradually wear, leading to a decrease in dimensional accuracy. The increased clearance between them and the molten plastic makes it easier for the molten plastic to overflow and form burrs.

Injection Molding Process Parameter Factors

1. Excessive injection pressure: Injection pressure is the driving force that pushes the molten plastic into the mold cavity. If the injection pressure is set too high, exceeding the bearing capacity of the mold, it will force the molten plastic into the tiny gaps of the mold, resulting in burrs. At the same time, excessive injection pressure may also cause mold deformation, further exacerbating the burr problem.
2. Excessive injection speed: A fast injection speed will cause the molten plastic to form turbulence in the mold cavity, increasing the impact force of the molten plastic and making it easier for the molten plastic to overflow from the mold gaps. In addition, an excessively fast injection speed may also prevent the air inside the mold from being exhausted in a timely manner, forming high pressure and triggering burr formation.
3. Excessive melt temperature: An excessively high melt temperature will enhance the fluidity of the plastic and reduce its viscosity, making it more likely to extrude from the mold gaps. At the same time, an excessively high melt temperature may also cause the plastic to decompose and generate gas, further increasing the possibility of burr formation.
4. Improper holding pressure and time: The holding pressure and time have an important impact on the molding quality of products. If the holding pressure is too high or the holding time is too long, the molten plastic will continue to be squeezed in the mold cavity, causing the excess molten plastic to overflow from the mold gaps and form burrs.

Raw Material Factors

1. Excessive fluidity of raw materials: Different types of plastics have different fluidities. If the selected raw material has excessive fluidity, it is more likely to fill the tiny gaps in the mold during the injection molding process, resulting in burrs. For example, some low-viscosity plastic materials are more prone to this situation during injection molding.
2. Impurities in raw materials: If the raw materials contain impurities such as dust and particles, it will affect the fluidity and molding quality of the plastic. Impurities may block the exhaust slots of the mold, causing poor ventilation. At the same time, they may also form scratches on the mold surface, increasing the possibility of molten plastic overflow and burr formation.

Measures to Solve the Problem of Burrs in Injection Molding Processing of Laryngoscopes

Mold Aspect

1. Repair and improve the mold parting surface: Regularly inspect and maintain the mold parting surface, and promptly repair the worn parts to ensure the flatness and sealing performance of the parting surface. For unreasonably designed parting surfaces, optimization and improvement can be carried out, such as adding locating pins and locating blocks to improve the positioning accuracy of the mold and reduce the gap in the parting surface.
2. Optimize the mold exhaust system: According to the structure of the mold and the characteristics of the plastic material, reasonably design the location and size of the exhaust slots. Regularly clean the exhaust slots to ensure their unobstructed passage. For some parts with difficult exhaust, methods such as exhaust steel and vacuum exhaust can be used for improvement to improve the exhaust effect of the mold.
3. Repair or replace worn cores and cavities: Regularly detect the mold cores and cavities. When the wear exceeds a certain limit, repair or replace them in a timely manner. Technologies such as electrical discharge machining and laser cladding can be used to repair the worn parts and restore their dimensional accuracy and surface quality.

Injection Molding Process Parameter Aspect

1. Reasonably adjust the injection pressure: According to the structure and size of the laryngoscope components, the characteristics of the plastic material, and the actual situation of the mold, determine the appropriate injection pressure through experiments. Generally, on the premise of ensuring that the product can fully fill the mold cavity, try to reduce the injection pressure to avoid burr formation due to excessive pressure.
2. Control the injection speed: Adopt multi-stage injection speed control. According to the structure of the mold cavity and the filling situation of the molten plastic, reasonably adjust the injection speed at different stages. At the initial stage of filling, a relatively fast injection speed can be used to quickly fill the cavity; when approaching the end of the cavity, reduce the injection speed to reduce the impact force of the molten plastic and avoid burr formation.
3. Optimize the melt temperature: According to the recommended processing temperature range of the plastic material, combined with the actual production situation, determine the optimal melt temperature through experiments. On the premise of ensuring that the plastic can be fully plasticized, try to reduce the melt temperature to reduce the fluidity of the plastic and the possibility of burr formation.
4. Reasonably set the holding pressure and time: According to the structure and size of the product, determine the appropriate holding pressure and time through experiments. The setting of the holding pressure and time should not only ensure the dimensional accuracy and surface quality of the product but also avoid burr formation due to excessive holding.

Raw Material Aspect

1. Select appropriate raw materials: According to the usage requirements and technical requirements of laryngoscope components, select plastic materials with moderate fluidity and stable performance. When selecting raw materials, fully consider their processing performance and molding quality to avoid burr formation due to improper raw material selection.
2. Strictly control the quality of raw materials: Strengthen the inspection and quality control of raw materials to ensure that the raw materials do not contain impurities. Before the raw materials enter the warehouse, conduct strict inspection to check whether their appearance, particle size, moisture content, and other indicators meet the requirements. Unqualified raw materials should not be allowed to be put into production.

Conclusion

The formation of burrs during injection molding processing of laryngoscopes is the result of the combined effects of multiple factors such as molds, injection molding process parameters, and raw materials. To solve this problem, comprehensive measures need to be taken from aspects such as mold design, manufacturing, and maintenance, optimization and adjustment of injection molding process parameters, and selection and quality control of raw materials. Through continuous practice and improvement, improve the quality and efficiency of injection molding processing of laryngoscopes, produce high-quality laryngoscope products that meet medical requirements, and contribute to the development of the medical industry. At the same time, enterprises should also strengthen the management and monitoring of the production process and establish a perfect quality management system to ensure that every product can meet quality standards and improve the market competitiveness of enterprises.