Requirements of injection machine and mold for the

  • Detail

Requirements of thin-wall injection molding on injection machines and molds

the demand for small and light parts has made thin-wall injection molding the most important performance of injection molding machines. "Thin wall" is usually defined by portable electronic parts with a wall thickness of less than 1mm. For large auto parts, "thin wall" can be 2mm. In short, thin-walled products require changes in processing technology: higher pressure and speed, shorter cooling time, and changes in ejection and gate arrangement. The following are the requirements of thin-wall injection molding for injection machines and molds

injection machine

the standard injection machine can be used to produce a variety of thin-walled products. At present, the performance of the new injection machine is much better than that of 10 years ago. The progress of materials, gate technology and design has further broadened the mold filling performance of standard injection machines for thin-walled parts. However, due to the continuous reduction of wall thickness, a more special injection machine with high-speed and high-pressure performance is needed. For example, for an electronic part with a thickness of less than 1mm, it is normal that the mold filling time is less than 0.5 seconds and the injection pressure exceeds 210mpa. The hydraulic injection machine for thin-wall injection molding is designed with a pressure accumulator, which can drive injection molding and mold closing frequently. All electric injection machines and electric/hydraulic injection machines with high-speed and high-pressure performance have also been introduced. In order to withstand the high pressure of the new injection machine, the minimum clamping force must be 5 ~ 7 tons/inch (projected area). In addition, when the wall thickness decreases and the injection pressure increases, the large template helps to reduce bending. The ratio of the pull rod of the injection machine for thin-walled products to the thickness of the template is 2:1 or less. When producing thin-walled products, the dead cycle control of injection speed, pressure and other processing parameters is helpful to control mold filling and pressure maintaining under high pressure and high speed

as for the injection volume, the large-diameter barrel is often too large. The recommended injection volume is 40% - 70% of the barrel capacity. The total molding cycle of thin-walled products is greatly shortened, and it is possible to reduce the minimum injection volume to 20% - 30% of the barrel capacity. Users must be very careful when injection molding, because for materials, a small injection volume means that the retention time of materials in the barrel is longer, which will lead to the decline of product performance


speed is one of the key factors for the success of thin-wall injection molding. Rapid mold filling and high pressure can inject molten thermoplastic material into the mold cavity at high speed, thus preventing the gate from cold solidification. If a standard part is applicable to the filling of plastic plates, pipes and profiled materials within two seconds, the mold thickness will be reduced by 25%, and the filling time may be reduced by 50%, just one second

One of the advantages of thin-wall injection molding is that when the thickness is reduced, less material needs to be cooled. As the thickness decreases, the forming cycle can be shortened by half. The reasonable setting of melt conveying device makes the hot runner and sprue not hinder the shortening of molding cycle. The use of hot runner and sprue bushing helps phthalates migrate to the drug solution or blood in the medical catheter or infusion bag, causing side effects on the human body and shortening the molding cycle to a minimum. In addition, we should also consider the material of the mold. P20 steel is widely used in the molding of traditional products, but due to the higher pressure of thin-wall injection molding, the mold must be made very strong. At present, FMG has a little more low-grade powder resources in the port spot. The H-13 and other 24 day dry bulk shipping markets rose sharply a few days ago. After yesterday's sharp decline, today's decline narrowed. Hard steel added an additional safety factor to thin-walled molds. However, the cost of solid molds may be 30% - 40% higher than that of standard molds. However, the increased cost is usually offset by improved production performance

Copyright © 2011 JIN SHI