Computer-integrated injection molding

The computer-integrated injection molding (CUM) systems make it possible to target for (1) approaching a completely... 

CE cost effective CIIM computer-integrated injection molding... 

The ultimate result of Computer Integrated Injection Molding (CUM) in software packages is to translate the results of computer simulation of the molding of a specific part into machine settings for specific microprocessor-controlled machines (Fig. 2-16). CUM automates the entry of a large number of set points (Figs. 2-2 and 2-13) in microprocessor-controlled machines and maximizes their efficiency, on the basis of extensive development by Ernest C. Bernhardt (Plastics Computer Inc., Montclair, NJ 07042, USA), a world leader on this subject (110, 111). 

Fig. 2-16. Overview of Computer Integrated Injection Molding (CIM). Swiss machine manufacturer.

Figure 7-10. An overview of the Computer-Integrated Injection Molding (CIIM) machine from TMConcept, which includes shrinkage control (Metstal is a Swiss machine manufacturer).

Most computer-integrated systems have been developed for injection molding, since a much bigger market exists with IM. Other computer systems are available for the other processes. 

Developments. A variety of process modifications aimed at improving surface finish or weld line integrity have been described. They include gas assisted, co-injection, fusible core, multiple five feed, and push-pull injection molding (46,47). An important development includes computer-aided design (CAD) methods, wherein a proposed mold design is simulated by a computer and the melt flow through it is analyzed (48). 

Saxena, M., Irani, R. K., An integrated NMT-based CAE environment-part Application to automated gating plan synthesis for injection molding. Engineering with Computers, 9, 220-230 (1993). 

Zhou, Z.Y., Gu, Z. Zh., Shi, J. Y., Research on integrated design techiniques for injection mold runner system. Journal of Computer-Aided Design and Computer Graphics, 12(1), 6-10 (2000). 

Since this model is used to simulate the flow between thin gaps, such as in injection and compression molding, we are not interested in the detail of the flow field through the thickness of the part. Instead, we are more interested in the flow field and flow advancement in the planar (xy) directions. For this, it is convenient to integrate the velocity across the gap in order to compute the gap-wise average velocities,... 

Integral skin PUR foams are made by injecting the reactants into a closed (vented) or open mold. Reaction under fliese conditions produces a foam with a high-density outside skin layer and a soft foam interior. Common products such as steering wheels, footwear components, and computer housings generally employ integral skin PUR foams. 

The computations are begun by assuming an initial value of the average injection velocity and a constant initial temperature [35]. This allows us to locate the position Xp of the melt front a time instant At later. At time At, Eq. (15.3.9) is solved to obtain the pressure variation so that we can find the temperature variation from Eqs. (15.3.15) and (15.3.18). Similarly, the velocity components are obtained from Eqs. (15.3.5), (15.3.6), and (15.3.18). Integrating the x component of the velocity over the mold cross section yields the volumetric flow rate Q into the mold. The quotient QjWH is the new front velocity ... 

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