We use extremely high pressure to insert the plastic resin into the cavity of the mold during the process of injection molding. The quantity of tonnage necessary is rated by a clamping force which we calculate in tonnage. It’s the amount of force needed to fixate the two halves of the mold together. The tonnage needed for a certain part is relatively easy to discover: the bigger the part, the more tonnage necessary. In many industries you will find large molded products such as large box containers and pallets. The automotive industry needs products like bumpers and car seats. You will also see these products in our home appliances such as air conditioners and washing machines.
Sometimes we talk about injection pressure and sometimes we talk about clamp tonnage. What is the difference and what is the relationship between these two terms? When we talk about injection pressure, we calculate the PSI, pounds per square inch. This number of PSI is required to inject the melted plastics into the cavity. When the pressure is just right, the products roll out with high quality. When we talk about ‘the clamp’ on an injection molding machine we talk about the two halves of the mold. In simple words, we want to keep these halves together with a lot of force while we inject the plastic resin. So, when the pressure of injection is high, the clamp tonnage must be adequate.