Insufficient filling often occurs in the production of injection molds. Compressed air burns, high internal stresses inside the product, surface flow lines and fusion lines. In addition to these phenomena, in addition to the first adjustment of the injection molding process, it is also necessary to consider whether the mold gate is reasonable. When Plastic Injection Molded Automotive Parts both the injection molding process https://www.nbtianke.com/product/car-parts/ and the gate are eliminated, the exhaust of the mold is the main problem. The main means to solve this problem is to open the exhaust vent. Then I will introduce the exhaust vents for everyone. First, the venting groove design of thermosetting plastics: The exhaust of thermosetting materials is more important than thermoplastic materials. First, the shunt in front of the gate should be vented. The width of the venting groove should be equal to the width of the runner and the height is 0.12 mm. The periphery of the cavity should be exhausted. Each exhaust groove should be separated by 25mm, the width is 6.5mm, and the height is 0.075~0.16mm, depending on the material flow. Softer materials should take lower values. The ejector rod should be enlarged as much as possible, and in most cases, 3 to 4 planes with a height of 0.05 mm should be ground on the cylindrical surface of the ejector rod, and the direction of the wear scar should be along the length of the ejector rod. Grinding is carried out using a finer grinding wheel.
The end face of the ejector rod should be ground to a chamfer of 0.12 mm so that if a flash edge is formed, it will adhere to the part. Second, the role and design of the exhaust trough: 1, the role of the exhaust trough: the role of the exhaust trough mainly two points. One is to exclude the air in the cavity when injecting the molten material; the other is to exclude various gases generated during the heating process. The thinner the wall product, the farther away from the gate, the opening of the venting groove is particularly important. In addition, attention should be paid to the opening of the venting groove for small parts or precision parts, because it can avoid the surface burn of the product and the insufficient injection volume, and can also eliminate various defects of the product and reduce mold contamination. 2, exhaust method: There are many ways to exhaust the cavity, but each method must ensure that the exhaust groove is designed to prevent the material from overflowing into the groove while it is exhausting; secondly, it should prevent blockage. Therefore, from the inner surface of the cavity to the outer edge of the cavity, the length of the groove of 6~12mm or more is about 0.25-0.4mm. In addition, too many exhaust vents are harmful. This is because if the clamping pressure applied to the portion of the cavity part that is not opened is large, it is easy to cause cold flow or cracking of the cavity material, which is very dangerous.
In addition to venting the cavity on the parting surface, it is also possible to achieve the purpose of venting by providing a venting groove at the end of the flow of the casting system and leaving a gap around the ejector pin. 3, design method: based on years of experience in injection mold design and product trial mode; this article briefly introduces the design of several exhaust slots, as shown in Figure 1. For product molds with complex geometries, the opening of the venting groove; it is best to determine it after several trials. The biggest shortcoming of the overall structural form of the mold structure design is poor exhaust. There are several kinds of exhausting methods for the whole cavity cavity core: 1 using the groove or insert of the cavity to be the human part; 2 using the side insert joint; 3 partially forming the spiral shape 2 and installing the groove in the longitudinal position The slat heart opening process hole; 5 when the exhaust is extremely difficult, the use of the mosaic structure, etc., if some die dead angle is not easy to open the venting groove, firstly, the mold should be appropriately changed without affecting the appearance and precision of the product. Processing.
The end face of the ejector rod should be ground to a chamfer of 0.12 mm so that if a flash edge is formed, it will adhere to the part. Second, the role and design of the exhaust trough: 1, the role of the exhaust trough: the role of the exhaust trough mainly two points. One is to exclude the air in the cavity when injecting the molten material; the other is to exclude various gases generated during the heating process. The thinner the wall product, the farther away from the gate, the opening of the venting groove is particularly important. In addition, attention should be paid to the opening of the venting groove for small parts or precision parts, because it can avoid the surface burn of the product and the insufficient injection volume, and can also eliminate various defects of the product and reduce mold contamination. 2, exhaust method: There are many ways to exhaust the cavity, but each method must ensure that the exhaust groove is designed to prevent the material from overflowing into the groove while it is exhausting; secondly, it should prevent blockage. Therefore, from the inner surface of the cavity to the outer edge of the cavity, the length of the groove of 6~12mm or more is about 0.25-0.4mm. In addition, too many exhaust vents are harmful. This is because if the clamping pressure applied to the portion of the cavity part that is not opened is large, it is easy to cause cold flow or cracking of the cavity material, which is very dangerous.
In addition to venting the cavity on the parting surface, it is also possible to achieve the purpose of venting by providing a venting groove at the end of the flow of the casting system and leaving a gap around the ejector pin. 3, design method: based on years of experience in injection mold design and product trial mode; this article briefly introduces the design of several exhaust slots, as shown in Figure 1. For product molds with complex geometries, the opening of the venting groove; it is best to determine it after several trials. The biggest shortcoming of the overall structural form of the mold structure design is poor exhaust. There are several kinds of exhausting methods for the whole cavity cavity core: 1 using the groove or insert of the cavity to be the human part; 2 using the side insert joint; 3 partially forming the spiral shape 2 and installing the groove in the longitudinal position The slat heart opening process hole; 5 when the exhaust is extremely difficult, the use of the mosaic structure, etc., if some die dead angle is not easy to open the venting groove, firstly, the mold should be appropriately changed without affecting the appearance and precision of the product. Processing.
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