As a common processing equipment, injeksan molding machine are widely used in many industries. However, during the operation of injection molding machines, uneven cavity filling is a common problem, which will lead to reduced product quality and reduced production efficiency. Therefore, this article will conduct an in-depth analysis of the uneven cavity filling in the plastic injection machine and explore some improvement methods.
Analysis of the causes of uneven cavity filling
Uneven cavity filling refers to the phenomenon that the plastic melt cannot be evenly distributed in the cavity during the injection molding process. There are many reasons for this problem, mainly in the following aspects:
1. Mold structure of injeksan molding machine:
The design and processing accuracy of the mold structure have a direct impact on the filling time. Reasonable mold structure helps to fill the raw materials quickly and evenly and shorten the injection molding cycle. At the same time, the mold processing accuracy will also directly affect the filling time. If the mold processing accuracy is not high, the filling time may become longer.
2. Injection molding material properties:
Poor fluidity: Different plastic raw materials have different fluidity. Raw materials with poor fluidity have large flow resistance in the mold cavity and are difficult to completely fill the cavity.
Insufficient drying of raw materials: Too high water content in plastic raw materials will reduce its fluidity, resulting in insufficient filling. For example, highly hygroscopic plastics such as polyamide (PA) need to be fully dried.
3. Injeksan Molding Machine:
Insufficient injection pressure: Injection pressure injeksan molding machine is the driving force for pushing the plastic melt to fill the cavity. Insufficient pressure will lead to incomplete filling.
Too slow injection speed: The injection speed affects the flow state of the melt in the mold. Too slow speed will cause the melt to cool and solidify during the flow process, resulting in insufficient filling.
Insufficient holding time: The holding stage is the stage for compacting and replenishing the mold cavity. Insufficient time will lead to insufficient compensation for material shrinkage, resulting in insufficient filling.
4. Other factors:
Improper equipment selection: The maximum injection volume of the small plastic molding machine must be greater than the total weight of the plastic part and the nozzle, and the total injection weight cannot exceed 85% of the plasticized amount
Insufficient feed: Failure of the feeding system or inaccurate metering will lead to insufficient material supply and cannot meet the filling requirements of the mold cavity
Cold material impurities blocking the material channel: Impurities or cold materials in the molten material blocking the nozzle or gate will cause poor feeding and affect filling
Product size: Product size has a significant impact on filling time. The filling time of small-sized products is generally shorter than that of large-sized products.
The impact of uneven cavity filling
The uneven cavity filling has an important impact on the quality of injeksan molding machine products, which is mainly reflected in the following aspects:
Inconsistent size: Uneven cavity filling will lead to inconsistent sizes of injection molded products, which may cause unqualified products in severe cases.
Internal defects: Uneven filling will also cause problems such as bubbles and defects inside the injection molded products, reducing the strength and stability of the products.
Poor surface quality: Uneven filling will cause sink marks, short indentations, discoloration and other problems on the surface of the product, affecting the appearance quality of the product.
Methods to improve the uneven filling of the mold cavity
To address the problem of uneven filling of the mold cavity, manufacturers can take improvement measures to enhance product quality and production efficiency.
1. Optimize mold design: Rationally design the structure of the mold, reduce the collision and deformation of the mold cavity, and improve the filling uniformity.
2. Optimize injection process parameters: By adjusting parameters such as injection speed, pressure, and holding time: enable the plastic melt to evenly fill the mold cavity
3. Select suitable injection molding materials: Select injection molding materials with good fluidity and stable melt index according to product requirements to ensure uniform filling.
4. Regular maintenance and care: Timely check and replace severely worn injeksan molding machine parts to ensure the normal working state of the injection molding machine.
5. Process optimization: Through simulation analysis and experimental verification, find out the problem, improve the production process, and improve the uniformity of mold cavity filling.
Uneven filling of the mold cavity is a common problem in automatic injeksan molding machine, which requires our attention and timely solution. By analyzing the causes of uneven filling of the mold cavity, we can find corresponding improvement methods. Only by ensuring uniform filling of the mold cavity can we produce high-quality injection molded products and improve production efficiency. Therefore, during the operation of the horizontal injection molding machine, we should pay close attention to the uniformity of cavity filling and take corresponding improvement measures.
FAQ’s
Your injection mold may not be filling due to low injection pressure, insufficient material temperature, poor venting, or improper gate design. Checking these factors can help resolve the issue.
The number of cavities in a mold depends on machine capacity, part size, material flow properties, cooling efficiency, and production volume requirements.
Balance of fill ensures that all cavities in a multi-cavity mold fill simultaneously, preventing defects like short shots, warping, or inconsistent part dimensions.
