Advanced R&D Pilot Line: Bridging Compounding and Film Production

For R&D teams entering the world of polymer science, the transition from raw resin and fillers to a finished, functional composite film is a journey of precision. When working with challenging additives like carbon black (which tends to agglomerate) or metal particles (which are abrasive and heavy), the choice of machinery determines whether your research succeeds or stalls.
RobotDigg’s laboratory-scale extrusion lines, specifically the SJ30Twin-GL and the Coextrusion-FB35, are designed to bridge the gap between bench-top experimentation and industrial production.
1. The Compounding Foundation: SJ30Twin-GL Pelletizing Line
Your process begins with the SJ30Twin-GL. In polymer R&D, the most critical step is "dispersion"—ensuring that every micron of carbon black or metal is evenly distributed.
Why Twin-Screw? Unlike single-screw extruders, the SJ30Twin-GL utilizes co-rotating screws that create high-shear zones. This is essential for breaking down carbon black clusters and coating metal particles with the polymer melt.
Suitability for Fillers: The "GL" (High Torque) series is particularly suited for composite work. The modular screw design allows you to configure "kneading blocks" specifically for high-load filler incorporation.
Essential Recommendation: For metal particles, we recommend requesting bimetallic or hardened nitrided barrels. Metal fillers are naturally abrasive; a standard barrel may wear prematurely under heavy R&D use.

2. The Final Form: Coextrusion-FB35 Blown Film Line
Once you have created your composite pellets with the twin-screw, the Coextrusion-FB35 turns that material into a film.
The Coextrusion Advantage: For "polyethylene or polypropylene composite films," a coextrusion setup is a strategic choice. It allows you to produce a 2 or 3-layer film where the middle layer contains your expensive or sensitive filler, while the outer layers are pure PE/PP. This protects the fillers from oxidation and provides a smoother, more "commercial" surface finish.
Desktop Efficiency: The FB35 is designed for low-waste startups. In an R&D setting where materials may be expensive, the small internal volume of the SJ35 extruder means you reach "steady state" faster, wasting fewer kilograms of material during calibration.

3. Recommended Accessories for New Producers
As you are new to polymer production, the "unit" is only half the battle. To ensure a successful pilot line, the following accessories are necessary:
Vacuum Degassing System (for SJ30): Fillers often carry moisture or air. A vacuum vent on the barrel removes these gases, preventing "silver streaks" or bubbles in your final pellets.
Side Feeder: Instead of "pre-mixing" powders with pellets (which leads to separation), a side feeder introduces the carbon black or metal powder directly into the melt halfway down the barrel.
Hopper Dryer: PE and PP are not very hygroscopic, but carbon black is. You must dry your filler/resin mix before extrusion to prevent "fish-eye" defects in the film.
Air Ring and Tower Frame (for FB35): Ensure your quote includes the "Film Tower" with nip rollers and a winder, otherwise, you will have no way to collect the film.

The combination of the SJ30Twin-GL for masterbatch compounding and the Coextrusion-FB35 for film blowing provides a complete, professional-grade pilot line. This setup allows you to control the entire lifecycle of your composite—from the raw powder to the final rolled film.