Good Injection Molders are in charge of combining fast manufacturing cycles with a high level of process stability. But there are a lot influences that can throw a production over the pile:
- changes in the material behavior due to different transportation environments until it arrives at customer’s site,
- the storage on the customer’s site,
- machine failures like pressure loss,
- temperature deviations inside the mold between the first and the last component of one batch or due to defects in the heating of the mold.
In-mold pressure and cure behavior at a glance for a complete process insightReactive injection molding with epoxy molding compounds (EMC’s) is a widespread process for electronics packaging for the automotive or aviation industry. One or more electric circuit boards are put into a closed mold and are encapsulated by the epoxy molding compound softened at elevated temperature, usually 140 – 180 °C. For this mass-produced article, every cent saved increases the competitiveness due to reduced rejects and reduced cycle times. The NETZSCH and KISTLER package is the package that distinguishes a highly efficient manufacturer from a standard producer.
Reference Curve under normal process conditionsFig. 1 shows a reference cycle of an electronic packaging process. On the upper half of the graph the cure signal of the NETZSCH sensors and on the bottom the pressure signal of the KISTLER sensors can be seen. The red boxes define areas which – under normal conditions – must not be crossed by the cure signal or have to be crossed when a green entry and exit is given. The green entry shown with the pressure signal indicates the normal arrival of material inside the mold.
Process failure – no material availableFig. 2 represents abnormal conditions if no material arrived inside the mold because the tank is empty or the snail is not working. Based on the sensor response the machine control system can be informed about the missing material and the current cycle will be stopped.
Abnormal process – temperature is too lowA temperature loss inside the mold will lead to a slower curing of the resin, so the cycle time has to be extended. Fig. 3 shows the sensor responses of the NETZSCH and KISTLER sensors of an abnormal cycle due to a temperature loss compared to the reference cycle. The pressure signal is not influenced by the temperature loss, so the reference and abnormal shot show the same behavior. The NETZSCH sensor detects the slower curing due to the temperature loss inside the mold and can therefore be used to adapt the process to avoid waste production. This makes it obvious why just a combination of both – pressure and dielectric sensors – can provide a complete insight into the manufacturing process and thus be able to increase process efficiency. The combined package of NETZSCH and KISTLER provide the most powerful sensor package that is able to sort good and bad parts during manufacturing and beyond that to make your process more efficient with avoiding waste production and lowering cycle times. You are interested to get more information? Please contact us!
Alexander has more than 6 years of experience in various production processes and the characterization of polymer materials and composites. He worked at the Application Center for Materials and Environmental Research (AMU) at the University of Augsburg and the Department of Functional Lightweight Construction at the Fraunhofer Institute for Chemical Technology ICT before being recruited by NETZSCH Analyzing&Testing. At NETZSCH Analyzing&Testing he was one of the drivers behind the founding of the Business Field Process Analytics and became its Manager. Process Analytics focuses on real-time sensors and model-based algorithms for intelligent manufacturing of polymers and composites, automated and robust production to contribute to the factory of the future.