1. The wall thickness of the product: The wall thickness of the product is related to the flow length of the melt, production efficiency, and use requirements. The ratio of the maximum flow length of ABS melt to the wall thickness of the product is about 190:1. This value will vary depending on the grade. Therefore, the wall thickness of ABS products should not be too thin. For products that require electroplating, the wall The thickness should be slightly thicker to increase the adhesion of the coating to the surface of the product. For this reason, the wall thickness of the product should be chosen between 1.5~4.5mm.
When considering the wall thickness of the product, you should also pay attention to the uniformity of the wall thickness. Do not vary too much. The surface of the product that needs to be electroplated should be smooth and free of unevenness, because these parts are easy to adhere to dust and difficult to remove due to static electricity. The fastness of the coating deteriorates. In addition, sharp corners should be avoided to prevent stress concentration. Therefore, it is advisable to use arcs for transitions at corners, thick and thin joints.
2. Demoulding slope: The demoulding slope of the product is directly related to its shrinkage rate. Due to different grades, different product shapes and different molding conditions, the molding shrinkage rate has a certain difference, generally 0.3~0.6%, Sometimes it can reach 0.4~0.8%, so its products have a higher molding dimensional accuracy. The demolding angle of ABS products is considered as follows: the core part is 31° along the demolding direction, and the cavity part is 1°20' along the demolding direction. For products with Bullet Proof Plate Kelvar complex shapes or with letters and patterns, the draft angle should be increased appropriately.
3. Ejection requirements: Since the apparent finish of the product has a greater impact on the electroplating performance, any tiny scratches on the surface will be clearly revealed after the electroplating, so no scratches are allowed on the mold cavity except for the requirement In addition, the effective area of ejection is also required to be large, the synchronization of the ejection process with multiple ejectors should be good, and the ejection force should be uniform.
4. Exhaust: In order to prevent poor exhaust during the mold filling process, causing melt burns, obvious seam lines and other problems, it is required to open an exhaust hole or exhaust slot with a depth of not more than 0.04mm to facilitate The gas generated by the melt is discharged.
5. Runner and gate: In order to make the ABS melt fill all parts of the cavity as soon as possible, the diameter of the runner is required to be no less than 5mm, the thickness of the gate is more than 30% of the thickness of the product, and the straight part (refers to the The length of the cavity part) is about 1mm. The location of Bullet Proof Plate Kelvar the gate should be determined according to the requirements of the product and the direction of material flow. For products that need to be electroplated, it is generally not allowed to exist on the adhesion surface of the coating.
Except for special grades or colored resins, most of the ABS resin used for injection molding is light ivory or porcelain white opaque particles. The resin's water absorption is not very high. For example, when the processing allowable value is less than 0.1~0.2%, the molding process can be performed without drying when the packaging is tight, the storage is proper and the product requirements are not too high. However, if the moisture content in the particles exceeds the specified value, they must be dried before they can be molded. For special grade particles or products that have higher requirements (such as electroplated products), they must also be dried before molding.
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2020 12/29