Compression molding simulation

Guiraud et al. (2010) integrated this rheology model into the finite-element code for SMC/BMC compression molding simulation. The mold geometry, the mesh and the boundary conditions are shown in Fig. 3.29. 

Today, the most widely used model simplification in polymer processing simulation is the Hele-Shaw model [5], It applies to flows in "narrow" gaps such as injection mold filling, compression molding, some extrusion dies, extruders, bearings, etc. The major assumptions for the lubrication approximation are that the gap is small, such that h < . L, and that the gaps vary slowly such that... 

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,... 

T.A. Osswald. Numerical Methods for compression mold filling simulation. PhD thesis, University of Illinois at Urbana-Champaign, Urbana-Champaign, 1986. 

To illustrate the effect of fiber orientation on material properties of the final part, Fig. 8.60 [5] shows how the fiber orientation distributions that correspond to 67 50 and 33% initial mold coverage affect the stiffness of the finished plates. The Folgar-Tucker model has been implemented into various, commercially available compression mold filling simulation programs and successfully tested with several realistic compression molding applications. 

In your university library, find the paper Barone, M.R. and T.A. Osswald, J. of Non-Newt. FluidMech., 26,185-206, (1987), and write a 2D FEM program to simulate the compression molding process using the Barone-Caulk model presented in the paper. Compare your results to the BEM results presented in the paper. 

T.A. Osswald and C.L. Tucker III. Compression mold filling simulation for non-planar parts. Intern. Polym. Proc., 5(2) 79-87, 1990. 

Now, let US consider a WPC deck. In a simple case, it is assembled with boards, made of a composite material. The boards can be solid or hollow, or of an opened, engineered design (see Figs. 1.1-1.25), which can be extruded (in a common case) or compression molded. Typically, but not always, WPC boards have a width of 5V2 in. (139.7 mm), height (thickness) of P/4, 1.00, 15/16, or 13/16 in. (31.75-20.64 mm), and—for standard boards—12, 16, or 20 ft. in length. The board s surface can be smooth (unbrushed), brushed, embossed, or having an exotic pattern, such as streaks, simulated wood texture, among others. 

Savastano H Jr, Santos SF, Radonjic M, Soboyejo WO et al (2009) Fracture and fatigue of natural fibre-reinforced cementitious composites. Cement Concr Compos 31 232-243 79. Rahman WA, Tin SL, Razak RA et al (2008) Injection moulding simulation analysis of natural fibre composite window frame. J Mater Process Technol 197 22-30 Toledo FRD, Andrade SF, Fairbaim EMR, Melo FA et al (2009) Durability of compression molded sisal fibre reinforced mortar laminates. Construct Build Mater 23 2409-2420 Pillai MS (2006) Applications of natural coir fibre, proceedings, natural fibres vision 2020, New Delhi 8-9th December... 

In the past, the engineering of part design in compression molding has been done in an empirical manner, that is, cut and try . However, numerical simulations may be useful for process optimization to improve the part quality... 

Experimental and simulation results of fiber orientation in compression molding (Kim eta ., 2009 Park eta ., 2001) (a) Component of the orientation tensor an and (b) representation of the planar orientation by ellipsoids. 

Kim et al. (2009,2011) proposed a structural optimization considering processing parameters in the case of compression molding process. While the conventional structural design and analysis has been based on the assumption of isotropic properties in the final part, they integrated the structural analysis with the simulation of fiber orientation and separation into the optimization scheme. This structure-process coupled optimization is useful to further improve the product quality compared to the conventional separate structural design and process optimization procedures. 

Advani, S. G. and Tucker III, C. L. (1990a), A numerical simulation of short fiber orientation in compression molding . Polymer Composites, 11(3), 164-173. 

Osswald, T. A. and Tucker IE, C. L. (1988), A boundary element simulation of compression mold filling, Polymer Engineering and Science, 28(7), 413-420. 

Chang C-Y. Simulation of mold filling in simultaneous resin injection/compression molding. Journal of Reinforced Plastics and Composites, 2006 25(12) 1255-1268. DOl 10.1177/0731684406060253. 

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