The influence of heat transfer coefficient on cooling time in injection molding

Powder Injection Molding of Ceria-Stabilized, Zirconia-Toughened Mullite Parts for UAV Engine Components

“…20 Viscosities also fall within the moldable range (less than 10 3 Pa s) for the shear rates typically experienced during molding (10 2 s À1 -10 5 s À1 ), indicating processibility over the entire melt temperature range. 20,21 Furthermore, the feedstock viscosity is comparable with that of other ceramic feedstocks based on a wax-polymer binder system. For example, for a shear rate of 1000 s À1 at 160°C, the viscosity of the zirconia-toughened mullite feedstock is $230 Pa s. This value falls within the range reported for silicon carbide and aluminum nitride feedstocks ($100 Pa s-500 Pa s).…”

“…A feedstock that exhibits dilatant, or shear thickening, behavior will experience powder agglomeration and subsequent powderbinder separation during the molding process. 19,20 Furthermore, shear-thinning behavior has been shown to ease molding and reduce the occurrence of jetting. 20 Viscosities also fall within the moldable range (less than 10 3 Pa s) for the shear rates typically experienced during molding (10 2 s À1 -10 5 s À1 ), indicating processibility over the entire melt temperature range.…”

“…19,20 Furthermore, shear-thinning behavior has been shown to ease molding and reduce the occurrence of jetting. 20 Viscosities also fall within the moldable range (less than 10 3 Pa s) for the shear rates typically experienced during molding (10 2 s À1 -10 5 s À1 ), indicating processibility over the entire melt temperature range. 20,21 Furthermore, the feedstock viscosity is comparable with that of other ceramic feedstocks based on a wax-polymer binder system.…”

Modeling of Flexible Polyurethane Foam Shrinkage for Bra Cup Moulding Process Control

“…The thermal conductivity controls the rate of heat transfer within the polymer and is relative to material composition, density, porosity, temperature, etc. [ 19 ]. During a high temperature manufacturing process, such as moulding, the polymer is first deformed and heated in a short period of time (e.g., 2 min), and then it is fully relaxed and cooled afterwards.…”

The Elastic Mold Deformation During the Filling and Packing Stage of the Injection Molding Process

“…In the case of good contact, which is assumed at the filling stage, he measured HTC values in the order of 10 3 -10 4 W/m²K. Calculations by Nylund et al [32] show that HTC values above 2-3 kW/m²K have little influence on the cooling time in the injection molding process. Hence, a heat transfer coefficient of 5000 W/m²K is assumed at the mold-cavity interface to address the non-perfect contact between polymer and mold during the filling stage.…”