Polymer Feeding in Compound Production

In PE- and PP-based polyolefin compound production lines, product quality depends on the correct raw material being fed into the extruder in the correct ratio and in a stable manner. VOLDE designs and manufactures complete extruder feeding systems for the closed-system conveying of polymers, mineral fillers, and functional additives arriving from big-bag, octabin, or bag packaging, their storage in intermediate bins, and their precise dosing into the extruder line via gravimetric feeders

| Controlled Storage and Transfer of Polymer and Filler Raw Materials

The main polymers used in polyolefin compound production are typically polyethylene (PE) (HDPE, LDPE, LLDPE) and polypropylene (PP) granules. These raw materials are mostly brought into the process in octabin or big-bag packaging. In VOLDE systems, polymers are drawn via vacuum pneumatic conveying from big-bag discharge or octabin discharge stations — which provide an enclosed, dust-free working environment — and transferred to intermediate bins or feed silos. Depending on the compound formula, other raw materials incorporated into the system may have different physical properties:

• Mineral fillers: Calcite (CaCO₃), talc
• Reinforcing fibers: Glass fiber, basalt fiber, mineral fiber
• Additives: Antistatic, UV stabilizer, antioxidant, flame retardant, coupling agent
• Processing aids: Slip agents, flow modifiers, wax, and process aids
• Color additives: Masterbatch- or pigment-based additives

These raw materials in powder or fine granular form are typically drawn via vacuum pneumatic conveying from bag dumping stations or big-bag discharge systems, automatically filling the intermediate bins located above the gravimetric dosing feeders. This way, raw materials are fed into the process continuously and in a controlled manner, without operator intervention.

| Gravimetric Extruder Feeding and Precise Recipe Control

In compound production, the final product quality depends on keeping the polymer, filler, and additive ratios stable. For this reason, gravimetric (loss-in-weight) dosing feeders are used at the extruder feeding points in VOLDE systems.

The feeders continuously weigh according to the flow rates defined in the recipe, automatically adjusting material flow and keeping extruder feeding stable.

The system is designed to be compatible with the following extruder types:

• Twin-screw compound extruders
• Co-rotating or counter-rotating twin-screw lines
• Side feeder or main feeding points
• High-filler-content compound processes (60–80% CaCO₃, etc.)

The upper bins of the gravimetric feeders are automatically refilled via the pneumatic conveying system. Refill management is controlled by the PLC in a way that does not disrupt the feeder's weighing stability.

| Automation and Extruder Communication

VOLDE extruder feeding systems are designed not merely as equipment supply, but with a complete process integration approach. Within the scope of the system, the following engineering areas are provided from a single center

• Gravimetric dosing feeders
• Pneumatic vacuum conveying systems
• Big-bag, bag, and octabin discharge stations
• Intermediate bins and feed silos
• Steel-construction platform and carrier structure above the extruder
• PLC control system and SCADA interface
• Recipe management and production reporting
• Communication and synchronization with the extruder control system

Thanks to the PLC-based automation architecture, the feeding system automatically adjusts speed according to extruder capacity, manages recipe changes, and records all production data. This approach minimizes operator errors while ensuring stable compound quality and high line efficiency.