Before making a selection, it’s essential to gather and understand the following critical information: mold dimensions (width, height, thickness), weight, and any specific design requirements; the type and quantity of plastic materials needed (whether single or multiple types); the dimensions and weight of the injection molded product (including length, width, height, and thickness); as well as molding specifications such as quality criteria and desired production speed.
Given the extensive range of injection molding machines available, accurately identifying the type of machine needed for your product is vital, as well as determining if a series production process is necessary. For example, materials such as general thermoplastic bakelite or PET can be used, and these may come in configurations like single-color, two-color, multi-color, sandwich, or mixed options. Some products may also demand high stability, precision, energy efficiency, high pressure, or rapid production rates, requiring careful selection of the appropriate machine series.
1. The mold’s width and height must be smaller than the internal supports of the large columns.
2. The mold dimensions should fit within the specified template size.
3. The thickness of the mold should fall within the acceptable range of the injection molding machine.
4. The mold’s width and height must meet the minimum size recommendations provided by the injection molding machine.
The stroke of the mold should be at least double the height of the finished product, taking into account the length of the vertical gate (sprue) to ensure adequate ejection of the finished products.
Following formula:
Clamping Force = Projected Area of the Product in the Mold Opening Direction (cm²) × Number of Cavities × Mold Pressure (kg/cm²).
The projected area is defined by the external dimensions of the product. The internal pressure of the mold can vary based on the material, typically ranging from 350 to 400 kg/cm². The clamping force of the machine should generally exceed 1.17 times the expansion force generated.
After determining the specifications and the model of the unit, as well as estimating the required tonnage, the next step is to establish the necessary screw diameter for the injection unit.
The “injection capacity” should be selected based on the weight of the finished product and the desired number of cavities, along with an appropriate “screw diameter.”
To calculate the weight of the finished cavity (regardless of whether it’s for one module or multiple cavities), the injection volume should ideally exceed 1.35 times the weight of the finished product, which means the injection volume should be less than 75% of the finished item’s weight.
When producing plastic items, it’s crucial to assess factors such as the “screw compression ratio” and “injection pressure.”