Tabs in Moldex3D Material Wizard

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Tabs in Moldex3D Material Wizard

Viscosity

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Viscosity is the index of the resistance of fluid to flow. The viscosity of simple fluids, e.g., water or oil, is usually a constant value at constant temperature. These fluids are generally referred as Newtonian fluids. The viscosity of plastic is complicated. Unlike simple fluids, the viscosity of plastic depends on its chemical structure, composition and processing conditions. With a given chemical structure and formulation, viscosity of plastics depends on temperature, shear rate and pressure.

 

PVT

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Plastic generally undergoes a significant volumetric change over temperature and pressure. It’s therefore essential to characterize its Pressure-Volume-Temperature (PVT) relationship in order to calculate the compressibility of material during packing phase, and its final part shrinkage and warpage after ejection.

 

Heat Capacity

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Heat capacity is the amount energy required to heat up a unit mass of the material for one degree. If one neglects the effects of possible chemical or physical transformation in the material, the internal energy of the material is related to the material temperature through heat capacity.

For further information about Heat Capacity, refer to Material in Reference.

 

Modify the heat capacity based on multiple data sources

Allow the input tabulated data up to 25 points in heat capacity for data modification through Material Wizard. Following is an example to display the modification procedures.

1.Select the material you want to change, and right click it to activate pop-up menu. Click Modify in the pop-up menu. Material Wizard window shows.

2.Click Next on Material Wizard till Step 4: Heat Capacity. Select the model from the dropmenu as Tabulated Data, and input data on the table.

3.Click Next to the last step. Click Finish to exit the wizard. The chart of heat capacity changes accordingly.

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Thermal Conductivity

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Thermal conductivity plays critical roles in melt cooling calculation during filling and packing, cycle time estimation and part temperature distribution…etc.  However, thermal conductivity of thermoplastic appears to be a weak function of temperature, independent of molecular weight, and does not vary significantly from one thermoplastic to another. The thermal conductivity of thermoplastic is generally relatively low as compared to the mold metal. The low thermal conductivity reduces the heat transferred to the surroundings. Considering the heat dissipated by viscous forces of high viscosity thermoplastic, the temperature distribution across the thickness of thermoplastic is therefore quite non-isothermal.

 

Modify the thermal conductivity based on multiple data sources

Allow the input tabulated data up to 25 points in thermal conductivity for data modification through Material Wizard. Following is an example to display the modification procedures.

1.Select one material, ABS_POLYLAC PA757_CHI-MEI from Moldex3D Bank, right click it, and click Add to User Bank.

2.Switch to User Bank, select the material you just added, and right click it to activate pop-up menu. Click Modify in the pop-up menu. Material Wizard window shows.

3.Click Next on Material Wizard till Step 5: Thermal conductivity. Select the model from the dropmenu as Tabulated Data, and input data on the table.

4.Click Next to the last step. Click Finish to exit the wizard. The chart of heat capacity changes accordingly.

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Viscoselasticity

Viscoelasticity of polymeric fluids or melts is very complicated. This feature shows very important effects in our real life, such as normal stress effects, elastic effects, and so on and they can be significant sometimes. In order to have injection products of better quality, it is necessary to understand what the physical behaviors of viscoelasticity are during the processing.

 

Modify Viscoselasticity parameters

Moldex3D provides five viscoelastic models, White-Metzner model, White-Metzner model (Modified), PTT model, Giesekus model and Oldroyd-B model, which you can select for the material viscoelastic parameter change. Following is an example to display the modification procedures.

1.Select the material you want to change, and right click it to activate pop-up menu. Click Modify in the pop-up menu. Material Wizard window shows.

2.Click Next on Material Wizard till Step 6: Thermal conductivity. Select the model from the dropmenu as Tabulated Data, and input data on the table.

3.Click Next to the last step. Click Finish to exit the wizard. The chart of heat capacity changes accordingly.

 

Mechanical Properties

It shows the mechanical properties, including Poisson’s ratios (PR), the elastic modulus (EM), and the CLTE (Coefficient of Linear Thermal Expansion) when users click the Mechanical tab. If the material is mixed with fiber or flake, the property information of fiber or flake will show as well.

 

Content

It shows the summary properties of the selected material. It contains basic information, MFI information, and the general conditions for melt and mold temperatures when users click the Content tab.

 

Revision Log

It is only available in User Bank where any material modification made by users is recorded.