How can iQ weight control plus reduce scrap in injection molding?

For many years, iQ weight control has been successfully used to compensate for fluctuations in the injection molding process, such as those caused by changing material batches or temperature variations. The system compares each injection curve with a reference in real time and automatically corrects deviations.

However, production requirements are increasing, and the demands placed on individual production lines are becoming more specific. For example:

• more complex tools are increasingly difficult to replace,

• processes with a high proportion of recycled material are more difficult to control.

In the latter case, material behavior can change more significantly during operation, for example due to fluctuations in plastic viscosity. As a result, companies are often unable to fully utilize their production potential due to a lack of process stability. This is exactly where iQ weight control plus comes in.

First, it simplifies process setup more than ever. Instead of time-consuming optimization of an injection profile with up to 40 parameters, iQ weight control plus enables process setup through pressure-controlled process control using just two parameters:

• Injection pressure

• Switchover point

The ideal injection profile is determined automatically. The system is intuitive, easy to understand, and quick to learn. Especially for new operators or those with limited experience, it saves time and reduces the risk of errors.

This is one of the key advantages of iQ weight control plus.

With conventional volume-based injection molding using iQ weight control, the process is based on a fixed volume specification. If one or more cavities fail in an injection mold – for example, in a 48-cavity mold – the machine still injects the full volume. This can lead to overmolding and scrap.

With iQ weight control plus, injection is pressure-controlled. The machine automatically responds to an early increase in filling resistance by reducing injection speed.

The result:

• Component weight remains consistent

• Scrap is reduced

• No manual intervention is required

This significantly improves process stability, especially in high-cavity molds or during insert overmolding.

Pressure-controlled injection has been used in the past, but its application was limited as closed-loop speed control became more dominant with advance in measurement technology. While this enabled greater control, it also increased process complexity. In times when sufficient skilled personnel were available, this was manageable. Today, however, there is a shortage of skilled workers.

At the same time, ENGEL has developed iQ weight control plus, a system that automatically compensates for the previous limitations of pressure-controlled-processes – particularly their sensitivity to fluctuations in plastic material viscosity.

It is important to note that both injection methods -- speed-controlled and pressure-controlled -- have their advtantages. The most suitable approach depends on the specific component and application.

• Significantly simpler operation: Two parameters instead of more than 40 process parameters for injection molding setup. This greatly simplifies the machine settings. Ideal for new tools, frequently changing personnel, or short start-up times.

• Robust performance under material fluctuations: Even with batch variations or changes in plastic material viscosity, the system automatically adjusts – similar to classic iQ weight control – ensuring consistent part quality under varying conditions.

• Improved process stability, even in the event of cavity failure: The pressure-controlled control system automatically detects changes in filling behavior and dynamically adapts the injection process. Component weight remains consistent, and scrap caused by overmolding is reduced. This is particularly valuable for high-cavity molds or sensitive applications.

• Maintained productivity despite a shortage of skilled workers: With the simplified logic of pressure and time, the injection molding process can be reliably controlled without extensive expert knowledge. This helps ensure that process stability is maintained regardless of operator experience.

It is an extension of existing capabilities. With iQ weight control plus, customers can choose between:

• classic speed-controlled injection

• pressure-controlled injection

The optimal method is selected based on the application, molded part, material, and available expertise. Rather than an either-or decision, it offers greater flexibility and reduced complexity.