Only hot air, or is it actually critical to quality? The extended venting option shows the behavior of the air in the tool already in simulation.

Air entrapment in SIGMASOFT® - the simulation provides information not only about position and size but also about pressure and temperature within the air bubble.

The behavior of entrapped air in the tool is often opaque. Unexpected air inclusions occur, negatively impacting component quality. Their actual location, shape, and consequences usually only become visible in the finished component. With SIGMASOFT®'s process-oriented simulation, they can be reliably predicted from the beginning of the part and tool development. The newly expanded venting option allows for comparison of different venting solutions and an assessment of their effectiveness based on physical facts for thermoplastic, thermoset, elastomer, and MIM/CIM applications.

At the [wfb] from June 19 to 20 in Siegen, Germany, SIGMA Engineering GmbH, Aachen, will demonstrate at booth S06.04/05 how simulation helps to make the behavior of air in the mold physically transparent, enabling early detection and targeted avoidance of air inclusions and resulting defects. Entrapped air and its position within the part significantly influence the quality of injection-molded components. The negative effects are numerous: besides issues during filling and mechanical weak points caused by air bubbles inside the part, they are a common cause of visible streaks and burn marks on the surface for thermoplastics; in elastomers and thermosets, the high temperature of the entrapped air initiates premature cross-linking, leading to further part defects; in applications with complex inserts, trapped air can impair adhesion between polymer and insert or cause defects once they detach from the insert and are transported into other areas by the melt. Therefore, air inclusions should be identified as early as possible and actively eliminated.

Typically, the exact position and size of air inclusions can only be determined after the first parts are produced, and remedies can only be implemented through subsequent modifications to the mold. Process simulation with SIGMASOFT® enables reliable prediction of trapped air and bubbles, their potential transport through the melt into critical regions of the part, and an assessment of their impact on part quality. Countermeasures can thus be implemented early in the development phase, saving costs. For existing processes, simulation is also a valuable tool to identify the actual causes of burn marks or other defects. Vague assumptions are replaced with clear facts.

In addition to identifying potential air inclusions and their effects, SIGMASOFT®'s integrated venting option allows for the validation of vent placement and effectiveness. Solutions to avoid defects can be compared quickly before making changes to the process or mold. The influence of venting on the filling pattern is immediately visible in the simulation, and possible burn marks or other defects can be clearly identified in the results interpretation.