Do you want to avoid waste and defects? Discover the 6 most common mistakes in two-component resin dosing and the technical solutions for consistently efficient systems.
In the landscape of industrial automation, the use of two-component resins (epoxy, polyurethane, and silicone) has become essential to ensure electrical insulation, structural bonding, and component protection. However, the transition from manual dispensing to an automatic dosing system is not without its pitfalls.
An error in the mixing or dispensing phase does not only result in material waste, but can also compromise the integrity of the entire finished product. In this article, we will examine the most common issues encountered in production lines and how proper system design can help prevent them.
1. Incorrect mixing ratio (Mix Ratio)
It is the most common and the most critical issue. Two-component resins (Part A and Part B) require a precise mixing ratio, which can be specified by volume or by weight.
- The error: using non-proportional or unmonitored dosing systems, where a change in viscosity caused by temperature alters the amount of hardener dispensed.
- The consequence: a resin that does not cure correctly remains tacky or, conversely, becomes too brittle, losing its mechanical or insulating properties.
- How to avoid it: implement plants equipped with precision gear pumps or volumetric piston pumps. The integration of flow sensors and pressure transducers makes it possible to monitor in real time that the set ratio is constantly maintained.
2. Air bubbles in the compound
Air is the invisible enemy of precision dosing. It may already be present in the original drum or introduced during plant loading.
- The error: neglecting the degassing stage or using feeding systems that create turbulence.
- The consequence: structural voids in the cast part, which can cause mechanical failure or short circuits in electronic applications.
- How to avoid it: use vacuum feed tanks with integrated agitators. Slow agitation helps bubbles rise to the surface, while the vacuum removes them completely before the material enters the dosing circuit.
3. Incorrect choice of static mixer
The static mixer is the small spiral tube where the two components meet. Not all static mixers are the same.
- The error: choosing a mixer with too few elements or a diameter that is too large for the required flow rate.
- The consequence: streaked mixing, where areas of pure resin alternate with areas of pure hardener, leading to uneven curing.
- How to avoid it: correctly calculate the number of mixing passes required according to viscosity and the ratio difference between A and B. In extreme cases, consider using dynamic mixers with a motorised chamber for materials that are especially difficult to combine.
4. Inadequate sedimentation management
Many industrial resins contain fillers such as silica or metals to improve conductivity or resistance.
- The error: leaving the plant idle, for example over the weekend, without a recirculation or agitation system.
- The consequence: heavy fillers settle at the bottom of tanks or inside pipes, clogging the plant and altering the density of the dispensed material.
- How to avoid it: programme automatic material recirculation cycles and use shaped-blade agitators that keep fillers evenly suspended even during periods of inactivity.
5. Ignoring pot life
Pot life is the time during which the mixed resin remains workable before curing inside the plant.
- The error: stopping production for an extended break without washing or purging the mixing head.
- The consequence: the resin cures inside the mixer or, worse, in the dispensing valve, causing total system blockage and requiring costly maintenance.
- How to avoid it: set up timed automatic purging systems. If the plant detects inactivity exceeding 50% of the resin’s pot life, it automatically dispenses a small amount of material to keep the flow fresh inside the mixer.
6. Underestimating the impact of ambient temperature
Resin viscosity changes dramatically with temperature: a cold environment makes the material extremely dense, while a warm environment makes it more fluid.
The error: calibrating the plant in the morning and expecting identical performance in the afternoon, when the workshop has warmed up;
- The consequence: variations in dosing pressure and dispensed volume accuracy.
- How to avoid it: use temperature-controlled pipes and tanks. Keeping the material at a constant temperature for example 25°C or 30°C ensures stable viscosity, making dosing repeatable regardless of external climate conditions.
Conclusions: the importance of custom design
Avoiding these errors is not only a matter of good management, but of choosing the right technology from the outset. A two-component resin dosing plant should not be a standard catalogue purchase, but an engineered solution based on the chemical specifications of the material and the production line’s operating rhythm.
At AB Consulting, our experience allows us to analyse these critical issues in advance, offering systems that integrate vacuum control, thermal management and electronic mix ratio monitoring. Only in this way does automation become a real competitive advantage, eliminating waste and ensuring maximum final product quality.
Have you encountered one of these problems in your production?
Our technicians are available to analyse your process and recommend the most suitable plant configuration for your needs.
