Reactive Molding analysis

Reactive Molding processes, also called thermoset molding processes, use thermoset materials.

Characteristics of thermosets

• chemical reaction during the molding process.
• cross-linked polymer structure.
• simultaneous polymerization and shaping during the molding process.

Reactive processes

• Reaction Injection Molding (RIM)
• Structural Reaction Injection Molding (SRIM)
• Resin Transfer Molding for fiber reinforced plastic (RTM)
• Multiple barrel reactive molding (RIM-MBI)
• Thermoset injection molding
• Rubber compound injection molding
• Microchip Encapsulation
• Underfill Encapsulation

Advantages of reactive molding

• Thermosets' cross-linked polymer structure generally imparts improved mechanical properties and greater heat and environmental resistance.
• Thermosets' typically low viscosity permits large and complex parts to be molded with relatively lower pressure and clamp force than required for thermoplastics molding.
• Thermosets can be used in composite processes. For example, RTM and SRIM processes, which use a preform made of long fibers, offer a way to make high-strength, low-volume, large parts. Fillers and reinforcing materials can enhance shrinkage control, chemical and shock resistance, electrical and thermal insulation, and/or reduce cost.

The reactive molding analyses are integrated with the Autodesk material database, which offers more than 50 grades of lab-tested reactive molding materials. Specifically, Autodesk Moldflow Insight's Reactive Molding analyses can:

• Predict the melt front pattern to aid in part design and gate placement to optimize cavity filling for most reactive processes.
• Calculate the conversion (extent of cure) versus time at any location within the mold during filling and post-filling.
• Determine injection pressure and clamp force requirements for proper molding machine selection.
• Display injection pressure at any point within the cavity at any time during the filling stage.
• Graphically display the temperature change as a result of the reaction kinetics inside the mold at any point in time.
• Detect short shots due to pre-gelation conditions.
• Accurately identify weld (knit) lines based on part design and gate placement.
• Accurately identify air traps for proper mold venting.
• For RTM and SRIM analyses: allow users to define multiple anisotropic fiber mats with different orientations in the cavity.
• For reactive molding and microchip encapsulation analyses, predict part warpage.[1]

[1] To complete a Warp analysis for Midplane or Dual Domain analysis technology, you must select an analysis sequence that includes the Compressible solver.