Email Us

How to Properly Set Venting Slots in Injection Moldings?

During the injection molding process, there will not be a large amount of melt coming out of the vent hole because the melt will cool and solidify there, blocking the passage. The opening position of the vent should not be towards the operator to prevent injury from accidentally spraying molten material.


Function of vent groove in injection molding


The main function of the vent groove is to remove the air and various gases generated during the heating process of the material in the mold cavity during injection molding. The opening of the vent groove is particularly important for small or precision parts, in order to avoid surface burns, insufficient injection or product defects, and reduce mold contamination. Generally speaking, if the injection speed of the melt is the highest and no scorched spot remains on the product, it can be considered that the venting in the mold cavity is sufficient.


Venting methods for injection molding


There are many ways to vent the mold cavity, but each method must ensure that the size of the vent groove should be designed to prevent material from overflowing into the groove during venting, and to prevent blockage. Too many vent grooves are harmful; if the clamping pressure is high on the part of the split surface without vent grooves, it is easy to cause cold flow or cracking of the mold cavity material, which is very dangerous. Vent grooves can be set at the end of the material flow in the gating system, and a gap can be left around the ejector pin to vent the mold cavity. The choice of depth, width and position of the vent groove can affect the appearance and accuracy of the product. Therefore, the size of the gap is limited to prevent flashing around the ejector pin.


Design methods for injection molding


For molds of products with complex geometries, it is best to determine the opening of the vent groove after several mold trials. However, the biggest drawback of the entire structure in mold structure design is poor venting. There are several venting methods for the entire mold cavity and core, such as using a groove or insert block installed in the cavity, utilizing a side insert block joint, making it into a spiral shape locally, installing a slotted bar-type core in the longitudinal position, and opening a process hole.


If the vent groove is difficult to open in some dead corners of the injection molding and the venting is extremely difficult, using insert and splice structures, appropriate opening of the vent groove can greatly reduce injection pressure, injection time, holding pressure time and clamping pressure, making plastic molding from difficult to easy, thereby improving production efficiency, reducing production costs, and reducing machine energy consumption.

Precision Plastic Injection Molding News
  • Mold Parts Actively Expanding Domestic Market, Low Carbon RoadMold Parts Actively Expanding Domestic Market, Low Carbon RoadSeptember 16, 2022At present, the mold has strong competitiveness. Maximum advantages and strengths of both to private enterprise, but also the traditional industry. Enter the high-end market, inseparable from high-tec...view
  • China's Mold Industry All The More ToughChina's Mold Industry All The More ToughSeptember 16, 2022China's mold industry since its development, an average growth rate of over 15% per year, higher than the national GDP average more than 1 time. In recent years, due to electrical and mechanical, ...view
  • Considerations in Plastic Mold DesignConsiderations in Plastic Mold DesignApril 4, 2023Emphasis on Design of Inlet Channels for Plastic Moulded ProductsThe inlet should be located in the thicker part of the product to ensure smooth and complete mold filling. It should be placed where it...view
  • Precision Injection Molding Related KnowledgePrecision Injection Molding Related KnowledgeMarch 31, 2023Precision plastic injection molding, strictly speaking, refers to the dimensional accuracy of plastic products produced by injection molding equipment, which can achieve a precision of less than 0.01m...view
  • Homegrown HR Website Breaks Mold With New ModelHomegrown HR Website Breaks Mold With New ModelSeptember 16, 2022Dai Kebin, CEO of Lietou.com, said: “The firm, set up in 2006, has seen stunning growth since early 2011, but 2012 could be the best year in its history.”Last year, its user base quadrupled and reve...view
  • What is Injection Molding?What is Injection Molding?April 4, 2023With the development of society and the improvement of people's living standards, the demand for the quality of injection molds is also increasing. The number of injection molds produced by mold f...view