This tech tip will focus on the calculation of clamp tonnage. In order to keep the mold closed, this force must oppose the separating force, caused by the injection of molten plastic into the mold. How to calculate clamping force for injection molding icomold. Kim 22 clamp force pressure required total force projected area times injection pressure a x p rule of thumb 4 to 5 tonsin2 can be used for most plastics.
The clamp end of the machine is responsible for providing force to counter all of the pressure that is applied from the injection unit. Example, part is 10 in by 10 in by 1 in projected area surface area 10 in x 10 in 100 in2 injection pressure 15,000 psi for pc. First, we need to know the projected area of the entire shot. Schematic of thermoplastic injection molding machine. Injection molding machines are usually characterized by the tonnage of the. How to calculate clamping force injection mold design tutorial, technology and engineering loose core for ejecting undercut at injection mold picture above shows the loose core, or often also called slope ejectors or inclined pin, loose cores is one method to overcome the undercu.
Although a proportion of the pressure produced by the injection cylinder is transmitted to the cavity, various losses occurring in the heating cylinder, nozzle and gate. Clamping force refers to the force applied to a mold by the clamping unit of an injection molding machine. This is why injection molding machines are so large. The clamping force is proportional to the projected area of the molding, runner and must be opposed by the clamping force. How to calculate clamping force injection mold design. Injection mold design parameters calculation using pro. When a injection mold is fixed in a molding machine and molten plastic. Injection molding is one of the technique and methodology to create mold of various complex shapes with more detailed structure. At the time of designing a new mold, it is necessary to obtain by theoretical calculations what is the optimum required mold clamping force that the injection molding machine has.
How to calculate clamping force injection mold design tutorial, technology and engineering free download as pdf file. The required clamping force can be calculated from the cavity pressure inside the mold and the shot. The injection molding machine consists of the injection unit and the clamping unit, and their features are described below. How to calculate clamping force injection mold design tutorial. Clamping force indicates the amount of force that the clamping unit can apply to the mold to. The unit for the required mold clamping force is n newtons, or kfg, of tf. How to calculate clamping force for injection molding.
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