Fig。5 Sink index Fig。6 Clamp force

Clamp force。 In the injection process, due to expansion force of melt within the mold, mold parting surface may separate, resulting in the flying side, it is necessary for the injection mold machine to provide a locking force, and the force known as the clamping force。 With the force can offset the cavity expansion force generated by melt。 Usually clamp force should be as small as possible。 The smaller clamping force can not only save energy, reduce costs, but also to extend the service life of injection molding machines and mold, while the mold is also an exhaust can be carried out smoothly, so that the mold filling state is more easily controlled。

In injection molding the clamping force distribution is shown in Fig。6。 The maximum clamping force is 86kN, the results of the analysis can be used to help designers to choose different types of injection molding machine。 As can be seen from Fig。5, the machinery can meet the requirements and is capable of normal production。

Recommended ram speed。 Fig。7 is the recommended ram of the program graph, and its role in the regulation of ram into the cavity of the injection speed, speed of injection mold filling process to ensure consistent, will help to improve the surface quality of workpieces and to avoid excessive shear stress。 The injection speed is recommended to make a more uniform rate of flow front, which will help to eliminate the pressure peak, and at the same time can improve workpiece surface finish in Fig。7。 XY position by injection pressure map can easily show the changes in pressure。

Temperature。 Temperature mainly includes temperature at flow front and bulk temperature at the end of filling。 The integrated use of temperature at flow front and the weld line graph can be analyzed

whether weld-line quality is good or bad。 The narrower the size range of temperature distribution is at the end of filling, the better mold quality is。 Two kinds of thermal analysis results are shown in Fig。8 and Fig。9。

Thermoplastic polymer flow analysis is usually used to predict the flow behavior inside the die。 Moldflow simulation begins to melt from the injection site spread to the adjacent point of the flow front, until the flow front to spread and fill workpiece and the last point to complete the flow analysis and calculation。 The objective is to obtain the best packing stage set time, thereby reducing as much as possible cause of the workpiece by the holding pressure contraction, warping and other quality defects。 A reasonable temperature distribution at flow front should be uniform, and the model can not be much difference in temperature。 As can be seen from Fig。8, the model is more uniform temperature distribution model shows that the melt temperature in the flow of slow decline, which will help fill, and a smaller drop in the temperature of the product, which means that the surface quality of plastic parts will be guaranteed。

Figure 8 Simulation results for the flow front temperature。 As can be seen from Fig。8, material flow analysis can be seen that the maximum temperature the forefront is 230。6 ℃, the lowest temperature is 223。8 ℃, injection molded parts of the temperature difference is 6。8 ℃, the recommended values of the control value (20 ℃) within indicated that a smaller temperature difference, which means the quality of the surface of injection molded parts are guaranteed, workpieces can be filled。Fig。8 shows that when the material fusion temperature is 228。9 ~ 230。6 ℃, the lowest melt temperature is only lower than the injection temperature of 223。8 ℃。 So materials can be a very good fusion, and does not appear Weld。 Cavitations are seen in the fusion line and parting

surface, and exhaust ducts are set at the opening of weld line。 This is not only convenient to exhaust, but also increase the fusion line of fastness。 From the Fig。8 flow front temperature graph and Fig。4 weld line graph, we can see the formation of weld lines when the melt temperature is about 230 ℃。 The weld line is not obvious, and the results are best。