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How SLG ensures stable injection molding production with varying materials

Optimizing production

How SLG ensures stable injection molding production with varying materials

SLG shows how the iQ weight control plus digital assistance system compensates for material fluctuations and enables stable injection molding production. The result: improved part quality, less scrap, and up to 10% energy savings.

June 23, 2026

Image shows SLG and ENGEL employees in front of an ENGEL duo 2-platen injection molding machine

Author

Eva Wörnhörer

Marketing

Tag

digital solutions
technical molding

In industrial injection molding production, stable processes are crucial. Fluctuations in material, mold, or processing environment can quickly lead to quality issues, rejects, or unnecessary energy consumption.

In a recent production project, the plastics processor SLG Kunststoff GmbH from Buggingen shows how digital assistance systems can solve these challenges.

Together with ENGEL, SLG tested the production version of iQ weight control plus under real production conditions. The results were impressive: higher process stability, better part quality, and measurable energy savings.

The challenge: stable quality with complex molds in injection molding production

SLG produces large-volume packaging parts for the household goods industry using family molds. In a recent project, tray and lid components (2,100 g / 700 g) for a storage box were produced on an ENGEL duo 1700 two-platen injection molding machine.

Technical plastic injection-molded parts like these present typical challenges:

fluctuating material viscosity
changes in the mold’s filling behavior
high demands on weight consistency and surface quality
rising pressure on energy efficiency and production costs
sensitivity to even small process deviations, which can lead to rejects or unstable injection molding production

The solution: pressure-controlled injection with iQ weight control plus

ENGEL iQ weight control plus provides injection molders with an assistance system that intelligently controls the injection process. During production, the software analyzes the pressure curve of each individual shot and automatically adapts the injection volume to the current plastic viscosity. This immediately compensates for process fluctuations.

A key innovation: pressure-controlled injection molding.

Instead of a complex injection profile with numerous adjustment parameters, operators only need to define two values in the injection molding process:

Injection pressure
Switchover time

The system automatically generates the optimal injection profile from these values. The result: a significantly more stable process in injection molding production with reduced setup effort.

Real-world results: How SLG benefits from iQ weight control plus?

The field test at SLG was conducted under real production conditions. The goal was to improve quality and efficiency without changing the cycle time.

1. Improved part quality

Through pressure-controlled injection, several typical quality issues were eliminated.

The improved quality is evident in practice:

No flash formation on the components
Consistent part quality even with material variations
Reliable production restart after standstill

The system automatically responds to changes in the mold’s filling resistance and dynamically adapts the process.

2. Lower injection pressure

A particularly interesting effect was observed regarding injection pressure: a reduction of approximately 300 bars compared to the standard process.

This not only means lower mechanical stress on the mold and machine but also more efficient processing.

3. Measurable energy saving of around 10%

In addition to quality improvements, significant energy savings were also achieved.

A before-and-after comparison of energy consumption illustrates the effect:

Before: 0.407 kWh/kg
After: 0.383 kWh/kg

This corresponds to an energy saving of approximately 10% with no change in cycle time.

Image shows project planner at SLG Kunststoff GmbH

What’s particularly helpful is that the process is much easier to set up. With iQ weight control plus, we achieve stable results in injection molding production without having to constantly readjust. This significantly reduces the workload for our production staff.

Aytac Hatkoy, Project Planner at SLG Kunststoff GmbH

4. Economic Benefits for Injection Molding Companies

Beyond technical improvements, the project clearly demonstrates the economic value of intelligent assistance systems.

Initial calculations at SLG show that a single machine alone offers annual savings potential in the five-figure range.

The most important economic effects:

Less scrap
Lower energy consumption
More stable processes across shifts
Reduced setup effort
Less reliance on expert knowledge

Especially in times of skilled labour shortages and rising energy prices, this combination is a significant competitive advantage for many processors.

5. More process reliability even with recycled material

Injection molders benefit from iQ weight control plus, particularly when processing demanding materials.

Fluctuations in plastic viscosity – such as those caused by recycled materials or batch changes – can be automatically detected and compensated for within the same shot. This ensures that part weight and quality remain consistent.

This opens up new possibilities for economical, sustainable, and stable injection molding production.

Conclusion: iQ weight control plus enables stable injection molding production

The use of iQ weight control plus at SLG illustrates how material fluctuations in injection molding can be effectively compensated for and processes stabilized over the long term.

The important advantages at a glance:

Higher part quality – The digital software automatically reacts to changes in the mold’s filling resistance and dynamically adapts the process. Part weight remains constant and flash formation is prevented.

Reduced process complexity – In the injection molding process with iQ weight control plus, only two injection molding parameters are set instead of over 40. This simplifies operation and the training of new employees.

Measurable energy savings – SLG was able to save up to 10% on energy without changing the cycle time.

Stable injection molding production across shifts – With the simple logic of just two machine settings – injection pressure and switchover time – machine operators can reliably control the injection molding process even without in-depth expert knowledge.

With the iQ weight control plus digital assistance system, process stability in injection molding production is no longer determined by chance or experience any longer, but by intelligent algorithms.

Read more about iQ weight control plus in an interview with development engineer Matthias Hüttler: How can iQ weight control plus reduce scrap in injection molding?.

Fewer parameters, greater stability – find out in a personal consultation how iQ weight control plus can also optimize your injection molding production.

FAQ

iQ weight control plus analyzes flow time during each injection process and detects changes in material viscosity in real time. Based on this data, the system automatically adapts the injection pressure in the next cycle. This compensates for fluctuations, ensuring consistently high part quality and stable injection molding production, even with varying material properties or recycled materials.

With pressure-controlled injection, only two parameters need to be defined: injection pressure and switchover time. The injection speed profile is determined automatically. Compared to conventional processes with numerous machine settings, this results in fewer sources of faults, faster setup, higher process stability, and less reliance on the operator’s experience.

The set injection pressure is not exceeded during the filling process, and pressure spikes are reliably avoided. This reduces energy consumption and allows the required clamping force to be lowered. In practice, savings of up to 10% are possible while maintaining the same cycle time. In addition, rejects, machine load, and setup time are reduced, leading to measurable cost savings and more efficient production overall.