Complete strategy for the adaptability of mold and injection molding machine parameters

In the field of injection molding, the perfect cooperation between molds and injection molding machines is the key to producing high-quality products.Among them, the adaptation of parameters such as clamping force, template size, and mold opening stroke directly affects the smoothness and success of the entire injection molding process.
1. Method of judging parameter adaptation
Clamping force evaluation: First of all, we must understand the cavity projection area of the mold. This data can usually be obtained from the mold design drawing or the mold manufacturer.Then according to the characteristics of the plastic material, find the required injection pressure.The required clamping force is estimated by the formula “Clamping force = projection area of the cavity × average pressure of the plastic melt on the cavity”.Compare the estimated value with the rated clamping force of the injection molding machine. If the estimated value is less than or equal to the rated clamping force, the general preliminary judgment is appropriate in terms of clamping force.For example, a small plastic toy mold with a cavity projection area calculated as 200 square centimeters uses common ABS plastic. The average melt pressure is about 30Mpa, and the required clamping force is calculated to be 600kN. If the rated clamping force of the injection molding machine is greater than or equal to 600kN, it is basically suitable.
Template size adaptation: Check the dimensions of the mold, including length, width, and height, and then compare the size of the installation space between the fixed template and the moving template of the injection molding machine.The installation screw hole position of the mold must also match the screw hole layout on the template of the injection molding machine to ensure that the mold can be installed smoothly and firmly on the injection molding machine.Generally speaking, the length and width of the mold should be smaller than the corresponding installation size of the injection molding machine template, and a certain gap should be reserved around it for installation, commissioning and possible maintenance operations. The gap is usually 5-10 cm. It is more appropriate.
Calculation of mold opening stroke: the thickness of the mold, the height of the product, and the space required for the ejection mechanism need to be considered comprehensively.The mold opening stroke should meet the “mold opening stroke = mold thickness + product height + ejection distance + safety margin".For example, if the mold thickness is 300mm, the product height is 100mm, the ejection distance is 50mm, and the safety margin is 50mm, then the required mold opening stroke is at least 500mm. Compare this value with the maximum mold opening stroke of the injection molding machine. If it is less than or equal to the maximum mold opening stroke, the mold opening stroke is adapted.
2. The consequences of forcibly using mismatched molds
Insufficient clamping force: If the clamping force required for the mold is greater than the rated clamping force of the injection molding machine, during the injection molding process, the cavity will be unable to close tightly due to the huge pressure of the plastic melt, causing the plastic melt to overflow from the mold parting surface, forming a flying edge.This not only seriously affects the appearance quality of the product, but also causes waste of materials and increases the cost of subsequent cleaning.Moreover, frequent flying edge problems will accelerate the wear of the mold parting surface and shorten the service life of the mold.
The size of the template is not suitable: When the dimensions of the mold are larger than the installation space of the template of the injection molding machine, the mold cannot be installed at all. Forced installation may damage the template screw hole and positioning mechanism of the injection molding machine, and even cause deformation of the template.Even if it is barely installed, if the mold is not installed firmly, the mold will shake during injection molding, causing the dimensional accuracy of the product to get out of control, uneven wall thickness, concentricity deviation and other problems, and the defective product rate will increase significantly.
Insufficient mold opening stroke: If the mold opening stroke is less than the actual demand, the mold cannot be fully opened, and the product is difficult to release smoothly, and it is easy to get stuck in the mold.This may cause the product to strain, deform, and even damage the cavity and core structure of the mold.Forced mold release may also overload and damage the ejection mechanism, increase maintenance costs, and delay production progress.
In short, before injection molding production, it is necessary to strictly judge the adaptability of the mold and the parameters of the injection molding machine, so as to avoid falling into production difficulties due to the forced use of mismatched molds, and to ensure that the injection molding process is efficient, stable, and the product quality is reliable.