Introduce about Shell Moulding

In recent years, the financial crisis makes the slump, but the portable electronic products in the day and night to practitioners, but a lot of people are in short supply. Short and thin portable electronic products, pay attention, when shell thin to almost 1 mm, or less than 1 mm, the material suppliers, product and mould designers, mould factory, moulding plant and machine equipment manufacturer and subsidiary is a challenge. In this paper, shell moulding from material selection, product and mould design, CAE analysis, mould forming machine and equipment settings to choose the highlights. Period to initiate a total creative machine.

Fixed electronic products, the shell enable cost reduction, cycle time, thus increasing productivity. For portable electronics, the lighter weight shell allows the size reduction. Demand for portable electronic products grew by 30% per year, growth will be faster the next decade. With this product were also very few – less than 5% in the United States, less than 1% of the world – the market is amazing.
Typical shell thickness ratio of flow length on the range of 100:1 to 150:1 or more. To achieve such a high ratio without increasing the gate, they have high melt temperature, high injection pressure and the high rate of fire.
C-Mould simulation of injection moulding using the Cross-WLF model viscosity is as follows:
This model can be moulded in a wide range of conditions appropriate description of viscosity, one of the benefits is a better deal viscosity on the temperature and pressure sensitivity (viscosity The sensitivity of the pressure increases as temperature decreases). In the Cross-WLF viscosity model, the pressure on the viscosity to D3 show. In the traditional moulding conditions, the pressure had no significant effect on the viscosity, D3 can be set to 0. Under high pressure, the pressure on the viscosity becomes important, D3 must decide to make the simulation results can capture the effects of stress. D3 to obtain a reasonable value, the viscosity of special test procedures and data analysis is necessary.
Without taking into account the impact of pressure on viscosity, when the system pressure increases, the forecast error will be greater and greater pressure. The figure of the flat plate model is a good example of non-zero entry pressure on the viscosity of D3 can improve the filling and post-filling simulation of pressure prediction. Flat plate with polycarbonate (PC) material, the average thickness is 1mm, flow length is 170mm. Pressure on the viscosity of item D3 into the calculation, the predicted pressure was significantly increased, and quite consistent with the measured pressure.
Through the sprue gate, pin point gate, the second hot runner poured directly into the gate so thin, you should use the gate well, in order to reduce gate stress, to help fill, and products in time to the gate damage to a minimum. When the wall thickness less than 1.2mm, the diameter often greater than the thickness of the gate used to help flow, and coagulates in the gate before the completion of the appropriate tamping.
In order to have enough pressure to fill the thin cavity, flow pressure drop preferably not more than the machine can provide 15% of injection pressure. Great use of more traditional flow from 1.25 to 1.4 times the flow. Select more entrants with valve gate hot runner to effectively reduce the pressure to expectations.

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Edited by Leafly Mould Provides Injection Mold, Die Casting Mold, Stamping Mold

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