Molding Solver - Stop Criteria

Filling Simulation Stop Criteria

Solver allows the filling simulation to stop under a variety of conditions. This is an advanced topic.

Default option is “percentage_filled_volume” = 100%. Solver considers any value above 99.3% as 100%.

Filling will stop as soon as the cavity is filled or when it encounters short-shot before any of the following conditions. All the following options are provided to study the filling process under a variety of what-if conditions and purposes of research.

• “fill_time”: simulation will stop if simulation time reaches this given time. This value has to be greater than 0.0.
• “percentage_filled_volume”: simulation will stop if cavity is filled at this given percentage by polymer. This value has to be between 0.0 and 100%.
• “max_injection_pressure”: simulation may stop if average pressure at injection BC reaches the given pressure. This pressure is used with maximum injection pressure given in “machine_data” packet settings.
• “max_clamp_force”: simulation may stop if clamp force reaches the given force. This stop criteria is used with maximum clamp force allowed by machine given in “machine_data” packet settings.
• “max_injection_flowrate”: simulation may stop if injection flow rate is higher than this limit.
• “min_injection_flowrate”: simulation may stop if injection flow rate is lower than this limit. Default value is equal to 1.0E-04 times initial flow rate.
• “all_fill_criteria”: this type gathers all other above criteria. Simulation will stop when first first criterion is reached.

In addition to the above list, another stop criterion is automatically called “no_exit_nodes” is automatically added. This comes into play only when user defines vents and does not use automatic vents. The simulation will stop if all vents defined by user are closed (if user has defined any vents).

Conditions for V/P Switch Over

During filling process, injection switches from velocity driven flow to pressure driven injection. This is called V/P switch over. The condition for V/P switch over is given in the fill driver settings and it can be one of the following.

• “percentage_filled_volume” : V/P switch over will occur when a given percentage of cavity is filled with polymer. This is the default option and default value is set to 85%.

• “specified_pressure” : V/P switch over may occur if this specified pressure is reached on injection BC.
• “percentage_max_injection_pressure”: V/P switch over may occur if this percentage of maximum injection pressure allowed by machine is reached. The maximum injection pressure allowed by machine is defined in “machine_data” packet settings.
• “percentage_max_clamp_force”: V/P switch over may occur if this percentage of maximum clamp force allowed by machine is reached. The maximum clamp force allowed by machine is defined in “machine_data” packet settings.
• “all_switchover_criteria” : V/P switch over will occur once one criterion is reached.
• “none” : there is not any switch over defined, so it will be driven by velocity during whole filling simulation

Once the V/P switch over limit is reached, pressure on injection BC can be prescribed with “injection_pressure” packet settings. It can be specified using one of these types.

• “pressure_value”: pressure at injection BC will be equal to this pressure value. This is option is prone to error and you have to certain of the pressure value before using it.
• “percentage_fill_pressure”: pressure at injection BC will be equal to last pressure at inlet times this given percentage filling pressure.

• “percentage_max_machine_pressure” : pressure at injection BC will be equal to the maximum machine pressure defined in “machine_data” times this given percentage.

How packing simulation stop?

The stop criteria settings is directly defined in “stop_criteria_settings” in “pack_settings”. The “type” can be defined as: