Full analysis of the clamping force of injection molding machine: Selection, influence and response

In the field of injection molding production, the clamping force of injection molding machines is as critical as the cornerstone, which is directly related to the quality of product molding and the stability of production.For every practitioner, an in-depth understanding of the relevant knowledge of clamping force is indispensable.
1. The exploration of the clamping force of the injection molding machine: How much do you know about the value?
The clamping force of injection molding machines of different specifications and models is different. The clamping force of common small injection molding machines may be between 50-200 tons. This type of injection molding machine is suitable for the production of small plastic parts, such as toy parts, stationery accessories, etc., to meet its basic requirements for mold opening and closing and holding pressure; medium-sized injection molding machines generally have a clamping force of 200-800 tons, which can cope with the manufacture of medium-sized products with certain structural complexity such as home appliance housings and small parts of automobile interiors; large injection molding machines have a clamping force of up to 800 tons or even thousands of tons, designed for large plastic products. Customized such as trash cans, industrial containers, car bumpers, etc. to ensure that the mold is tightly closed during the high-pressure injection molding process.
2. Selection of clamping force adaptation: depending on the product
The precise selection of the clamping force injection molding machine suitable for the product is the key to production.First of all, the projection area of the product needs to be considered, which is the core element of calculating the clamping force requirement.Through product design drawings, accurately measure the maximum projection area on the parting surface of the mold, combined with the injection pressure parameters of the plastic materials used (different plastic injection pressures usually range from 50-200MPa, such as polyethylene about 70-100MPa, polypropylene about 80-120MPa), using the formula “Clamping force = projection area × injection pressure × safety factor (generally take 1.2-1.5)”, the required clamping force can be preliminarily calculated.For example, to produce a home appliance shell with a projection area of 0.5 square meters, polypropylene material is selected, the injection pressure is 100MPa, the safety factor is 1.3, and the clamping force is calculated to be about 65 tons. At this time, a medium-sized injection molding machine with a clamping force of not less than this value should be selected.At the same time, the accuracy requirements and wall thickness distribution of the product cannot be ignored. High-precision products and products with uneven wall thickness often require more accurate and stable clamping force protection to avoid dimensional deviations or appearance defects caused by small mold displacement.
3. The impact of uneven clamping force: there are many hidden dangers
Uneven clamping force will bring many ills to the product.The most intuitive is the problem of burrs. When the clamping force in a certain area of the mold is insufficient, the plastic melt will overflow from the gap under high-pressure injection molding, forming burrs, which not only affects the appearance of the product, but also increases the subsequent process of removing burrs. Production costs.In terms of dimensional stability, the uneven clamping force causes the mold to be subjected to uneven force during the injection molding process, resulting in small local deformation, resulting in different wall thicknesses of the product, which in turn causes dimensional fluctuations. For products with strict tolerance requirements, such as precision electronic accessories, this dimensional instability will directly lead to product scrap.In addition, uneven clamping force may also cause stress concentration, causing hidden defects in the internal structure of the product, reducing the mechanical properties of the product, and shortening the service life. During long-term use or when subjected to external forces, the product is prone to serious problems such as cracking and damage.
The clamping force of the injection molding machine runs through the whole production process, from the source control of the selection of the injection molding machine to the monitoring and maintenance of the equilibrium of the clamping force in the production process, every step is related to the success or failure of the product.Only by accurately matching the clamping force and always preventing the hidden dangers of injection molding can we ride the wind and waves in the wave of injection molding production to create high-quality and competitive plastic products.