In the field of medical injection molding, poor blanking is one of the key issues affecting product quality and production efficiency. Medical products have stringent requirements for precision, cleanliness, and material properties, so any minor deviation in the injection molding process can lead to serious consequences. Poor blanking not only results in raw material waste but also extends the production cycle and even threatens patient safety. This article proposes solutions from the following four aspects.

Optimize Material Usage

Targeted treatments should be carried out according to the characteristics of different materials. For polypropylene (PP), which has low viscosity in the molten state and is prone to forming "flow marks" or "short shots," pre-treatment of the material can be done before injection molding to adjust its processing properties. For example, an appropriate amount of thickening agent can be added to increase the viscosity and reduce problems during flow. For polycarbonate (PC), a highly rigid material with insufficient fluidity, the preheating process can be optimized to raise the material temperature and reduce its viscosity, ensuring uniform filling. At the same time, strictly control the moisture content in the material, keeping it below 0.02%. Efficient drying equipment can be used to fully dry the material and prevent hydrolysis reactions during high-temperature melting, thus avoiding the formation of bubbles or silver streaks.

Improve Mold Design

Mold design needs to balance precision and structural rationality. Ensure that the surface roughness of the mold cavity meets the requirements, keeping it at Ra ≤ 0.8μm to reduce the flow resistance of the molten material and prevent underfilling or surface depressions. Precisely design the gate position and size, and optimize them through repeated experiments based on the fluidity of the material. This helps avoid problems such as "jetting" causing weld lines when the gate is too small and extended cooling time and increased internal stress when the gate is too large. In addition, reasonably design the mold's venting system to ensure that the gas in the cavity can be discharged promptly. This can be achieved by adding venting slots or optimizing the venting structure to prevent defects such as "burning" or "air trapping." Regularly maintain and service the mold, check for wear and tear, and promptly repair or replace damaged parts to ensure the mold's precision and performance.

Precisely Control Process Parameters

Establish a comprehensive process parameter monitoring and adjustment mechanism. Install high-precision sensors and monitoring equipment to monitor key process parameters such as injection speed, melt temperature, holding pressure, and holding time in real time. Develop detailed process parameter standard ranges according to different materials and product requirements. When the injection speed is too fast, causing excessive shear heating of the material and degradation discoloration, promptly reduce the injection speed. If the speed is too slow, resulting in premature solidification of the material and short shots, appropriately increase the injection speed. For the melt temperature, control it precisely according to the material's characteristics. Reduce the heating power when the temperature is too high and increase it when the temperature is too low to ensure suitable material viscosity. When setting the holding pressure and time, match them precisely with the material's shrinkage rate. Determine the optimal holding parameters through experiments to avoid problems such as sink marks or holes due to insufficient holding pressure and mold core shift and product deformation due to excessive holding pressure. At the same time, use advanced control systems to achieve automatic adjustment of process parameters and improve production stability and consistency.

Strengthen Environmental Management

Creating a stable production environment is an important aspect of solving poor blanking. Install a sophisticated environmental control system to monitor and automatically adjust the temperature and humidity in the workshop in real time, keeping the temperature fluctuation within ±2℃ and the humidity within an appropriate range to prevent changes in material properties due to environmental factors. Regularly maintain and inspect the injection molding machine to ensure stable hydraulic system pressure, no wear on the screw, and normal operation of the heating coil, reducing the impact of mechanical vibration and temperature deviation on the blanking quality. Strengthen the training and assessment of operators, improve their skill levels and sense of responsibility, and develop standardized operation procedures and parameter setting specifications to reduce human errors. At the same time, establish a strict quality traceability system to record each batch of products in detail, so that targeted solutions can be quickly implemented when poor blanking problems occur.