What’s the Difference Between a Volumetric Doser and a Gravimetric Blender?

In the plastic processing industry, accurate dosing is key to consistent product quality and cost control. Two common dosing systems are volumetric dosers and gravimetric blenders. While they may seem similar, the difference between them can significantly impact your production efficiency.

🔹 1. Dosing Principle: Volume vs. Weight

• Volumetric doser: Measures and dispenses material based on volume (e.g., screw rotations or fixed cup size). It’s simple and low-cost, but not highly accurate, especially when material density changes.
• Gravimetric blender: Weighs materials using load cells before mixing. It provides ±0.5% or better accuracy, regardless of material shape or bulk density.

🔹 2. Typical Use Cases

🔹 3. Automation Compatibility

Gravimetric blenders integrate more easily into fully automated production lines, especially in central conveying systems. Volumetric dosers are typically used in smaller-scale or decentralized setups.

🔹 4. Long-term Cost Consideration

While volumetric dosers are cheaper upfront, their lower accuracy may lead to:

• Overuse of expensive additives
• Quality issues
• More material waste

In contrast, gravimetric blenders save money in the long run through precise control and repeatable results.

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✅ So, Which One Should You Choose?

If you’re managing a high-volume plastic manufacturing plant or aiming for Industry 4.0-level automation, a gravimetric blender is the smarter long-term choice. But if your process is simple and budget is tight, a volumetric doser still gets the job done.

👉 Want to learn how a gravimetric blender fits into a fully automated central feeding system?
Explore the full solution here:
🔗 Central Feeding System for Injection Molding – How It Works