1. Wall thickness of the product
The flow length, production efficiency, and usage requirements of ABS plastic product melt have a significant impact on wall thickness. The ratio of the maximum flow length of ABS melt to the wall thickness of the product is approximately 190:1, which may vary depending on the product grade. Therefore, the wall thickness of ABS products should not be too thin. For products that require electroplating treatment, the wall thickness should be thicker to increase the adhesion strength between the coating and the surface of the product. It is advisable to choose a wall thickness of 1.5-4.5mm for this product.
When considering the wall thickness of the product, attention should also be paid to the uniformity of the wall thickness, and the difference should not be too large. For products that require electroplating treatment, the surface should be flat and free of bumps and depressions, because these parts are prone to dust adhesion due to electrostatic effects, which makes it difficult to remove and reduces the firmness of the coating. In addition, the presence of sharp corners should be avoided to prevent stress concentration, so it is recommended to use arcs for transitions at corners, thickness connections, and other parts.
2. Demoulding slope
The demolding slope of a product is directly related to its shrinkage rate. Due to different grades, product shapes, and molding conditions, the molding shrinkage rate varies to some extent, generally ranging from 0.3% to 0.6%, and sometimes up to 0.4% to 0.8%. Therefore, the dimensional accuracy of the molded product is relatively high. For ABS products, the demolding slope should be considered as follows: the mold core part should be at 31 ° along the demolding direction, and the mold cavity part should be at 4 (/1 ° 20 ') along the demolding direction. For products with complex shapes or with letters or patterns, the demolding slope should be appropriately increased.
3. Top out requirements
Due to the significant impact of the apparent smoothness of the product on the electroplating performance, any small scratches on the surface will be clearly exposed after electroplating. Therefore, in addition to requiring no scratches on the mold cavity, it is also necessary to have a large effective area for ejection, and to use multiple ejector pins with good synchronization and uniform ejection force during the ejection process.
4. Exhaust
In order to prevent the occurrence of poor exhaust during the filling process, such as burning of the molten material and obvious seam lines, it is required to open exhaust holes or exhaust grooves with a depth of no more than 0.04mm to facilitate the discharge of gases generated during the melting process.
5. Runner and Gate
In order to fill all parts of the mold cavity with ABS melt as soon as possible, it is required that the diameter of the runner is not less than 5mm, the thickness of the sprue is more than 30% of the product thickness, and the length of the straight part (referring to the part that will enter the mold cavity) is about 1mm. The position of the sprue should be determined according to the requirements of the product and the direction of the material flow. For products that require electroplating treatment, it is generally not allowed to have burrs on the coating adhesion surface.