When an extrusion line experiences inconsistent feed, pressure fluctuations, gauge variation, or unexpected defects, attention often turns immediately to the extruder. But the source of the problem may begin much earlier in the process. During pneumatic conveying and granule handling, electrostatic charge can build up as plastic pellets move through pipes, contact equipment surfaces, and interact with one another. If that charge is not controlled, it can disrupt material flow before the resin ever reaches the extruder. 

The result? What appears to be an extrusion problem may actually be a material conveying problem caused by static electricity. 

How Static Builds During Granule Handling 

Plastic pellets are naturally insulating materials. As pellets travel through a pneumatic conveying system, repeated friction and contact between the pellets, pipe walls, and other system components can generate significant electrostatic charge. 

Once charged, pellets can begin to: 

• Adhere to pipe walls and equipment surfaces 

• Cluster together rather than flow independently 

• Attract dust and fine contaminants 

• Accumulate inside cyclones and conveying equipment 

• Bridge or rat-hole inside bins and hoppers 

These issues interfere with the consistent movement of material through the system and can ultimately affect how reliably resin is delivered to the extrusion process. 

Upstream Problems Create Downstream Instability 

Consistent extrusion depends on consistent material feed. When static disrupts conveying, small variations upstream can create much larger problems downstream. 

Upstream conveying issues can include: 

• Bridging and rat-holing in hoppers 

• Pellet adhesion to pipes and equipment 

• Feed starvation 

• Inconsistent dosing 

Once material reaches the extruder inconsistently, manufacturers may begin to see: 

• Erratic mass flow and unstable output 

• Pressure fluctuations at the die 

• Gauge variation and dimensional inconsistency 

• Melt defects such as gels, bubbles, and contamination 

Even relatively small disturbances can reduce throughput, increase scrap, and negatively affect Overall Equipment Effectiveness (OEE). 

Why a Short Conveying Problem Can Become Hours of Lost Production 

A conveying disruption doesn't necessarily end when material begins flowing again. For continuous extrusion processes, a one-hour feed issue can lead to significantly more lost production time. After the initial disruption, the line may need to be restarted, material conditions stabilized, and product quality verified before saleable production can resume. 

During that time, manufacturers may also generate startup scrap, purge waste, and off-spec material. This means the true cost of an upstream conveying problem can extend well beyond the original stoppage. 

Control Static Where It Is Generated 

Rather than addressing the symptoms once they reach the extrusion process, static control can be implemented throughout the material handling system to neutralize charge closer to where it develops. 

Potential areas for static control include: 

• Conveying pipes: In-line ionization can neutralize charge as pellets move through the system. 

• Cyclones: Static neutralization can help reduce wall buildup and separation issues. 

• Blending and dosing equipment: Ionization can support more consistent material movement and mixing. 

• Bins and hoppers: Controlling charge can help reduce pellet adhesion, bridging, and feeding issues. 

• Monitoring points: Static monitoring can help identify charge levels and verify continued system performance. 

By neutralizing electrostatic charge throughout the flow path, manufacturers can improve material handling consistency before conveying problems have the opportunity to disrupt extrusion. 

Improve the Stability of Your Granule Handling Process 

Pressure fluctuations, inconsistent output, gauge variation, and melt defects don't always originate inside the extruder. If plastic pellets are sticking, clustering, bridging, or moving inconsistently during pneumatic conveying, electrostatic charge could be contributing to the problem before the material ever reaches the extrusion line. 

Identifying and neutralizing static at these upstream points can help create more reliable material flow, reduce unnecessary disruptions, and support a more stable extrusion process from start to finish. Simco-Ion static control solutions, including the Blowflex Easy Ionizing Air Nozzle, can be integrated into granule handling and conveying applications to help neutralize electrostatic charge and improve material flow. 

Click here to discuss your process and identify the right approach for your application!