How did Valrom reduce PVC scrap by 50% with iQ weight control?

Processing PVC in injection moulding is anything but trivial. Unlike many other polymers, PVC is particularly sensitive to fluctuations in plastic viscosity. Even small variations in temperature, raw material batches, or material degradation can lead to unstable filling behavior, inconsistent part weights, and increased scrap.

For manufacturers running high-volume production, these fluctuations directly translate into lost efficiency, higher costs, and unpredictable production performance.

Romania’s leading manufacturer of plastic pipe systems, Valrom Industrie, decided to address this challenge head-on. By implementing ENGEL’s iQ weight control, the company was able to transform an unstable PVC process into a highly consistent and reliable production environment.

The results speak for themselves:

• 50% lower scrap rate

• 90% less weight variation

• stable production despite material fluctuations

PVC is highly sensitive to:

• temperature fluctuations

• local material degradation

• batch-to-batch differences in raw material

• variations caused by regrind material

• external process influences

These factors frequently lead to plastic viscosity changes during production. For injection moulding operations, this often results in:

• fluctuating filling behavior

• unstable part weights

• higher scrap rates

• increased need for manual intervention

PVC (polyvinyl chloride) is widely used for pipe systems and plastic fittings due to its durability and cost efficiency. However, processing PVC in injection moulding comes with specific challenges.

For companies producing technical PVC fittings in large volumes, such fluctuations make production less predictable and less profitable.

Valrom was looking for a solution that could stabilise the process automatically without increasing complexity for operators.

During production, ENGEL’s intelligent process control iQ weight control analyses every injection cycle in real-time. The software continuously compensates for viscosity variations by automatically adjusting:

• the switchover point

• the injection volume

This allows the system to stabilise the part weight even when material or process conditions fluctuate.

To evaluate the potential of digital process assistance, Valrom tested iQ weight control in their injection moulding production while processing PVC.

The implementation followed a structured approach:

1. Training phase: Four setters from Valrom participated in a dedicated training programme at ENGEL’s training center in Bucharest (Romania). The team received both theoretical and hands-on training in a controlled environment to fully understand the functionality and benefits of the iQ weight control system.

2. Live production activation: After the training, the iQ weight control license was activated directly in Valrom’s production environment.

3. Real production testing: The system was evaluated under real manufacturing conditions using PVC.

The production results showed significant improvements:

• 90% reduction in weight variation

• 50% lower scrap rate

• stable quality across batch changes and temperature fluctuations

• reliable repeatability over long production runs

The tests at Valrom demonstrated clearly that iQ weight control works reliably with processing PVC, a material that is often considered difficult to stabilise in injection moulding.

During the production trials, no issues were encountered when running PVC with iQ weight control activated.

Even when filling fluctuations occurred, the root cause was traced back to low-quality regrind material, not to the control system. Despite these material variations, the process remained stable.

The real value of the technology became most visible after the test license expired. When iQ weight control was temporarily removed from the production process, Valrom observed an immediate impact: The scrap rate doubled.

This direct comparison made the benefits of the system unmistakably clear. The production team could clearly see how much stability the intelligent assistance system had added to their process.

As a result, Valrom is expanding iQ weight control to additional machines.