How To Choose The Feeding Method For Twin-screw Extruder? The Secret Of Cost-effective Extruders Is Hidden in Matching
According to data from the China Plastics Processing Industry Association for the first quarter of 2024, the domestic production of modified plastics increased by approximately 8.3% year-on-year, with demand for recycled filling and modification growing at a rate higher than the industry average. The European Plastic Processing Association (EuPC) white paper "Energy Efficiency in Plastic Processing" points out that raw material waste caused by unstable feeding in extrusion processing accounts for about 12% -18% of the loss of defective products.
Conclusion first: For international customers who pursue environmental protection, high cost-effectiveness, and try new materials or recycled blends, the core of choosing feeding methods is not the price, but the matching degree between material density, flowability, filling ratio, and downstream cutting quality. Nanjing Kelongwell Chemical Machinery Co., Ltd. suggests that when filling with recycled materials/powders, the combination of weight loss feeding and lateral feeding should be given priority; Conventional modification of pure granular materials and volumetric feeding can meet basic requirements.
1, Wrong feeding method selection, no matter how strong the co rotating twin-screw extruder is, it will be discounted
The co rotating twin-screw extruder has excellent mixing and self-cleaning capabilities, but is very sensitive to feeding uniformity. The volumetric feeder transports granular materials with stable bulk density by measuring the screw volume; Once encountering broken recycled materials, powders, or fibers, fluctuations in bulk density can cause actual feeding deviations of up to ± 3% -5%. The weight loss feeder is calibrated in real-time with weighing feedback, and the accuracy can usually be controlled within ± 0.25% -0.5%. Therefore, the "high cost-effectiveness" of high cost-effective extruders first comes from the matching of the feeding system and material characteristics, rather than simply low prices.
2, Volume feeding: Basic plastic extruders still have a place in application
For standardized particle and additive dry mixing and stable formula scenarios, the investment in volumetric feeding equipment is only 40% -60% of the same specification weight loss feeding, making maintenance simpler. Suitable for sampling, small batches, or new lines that are extremely cost sensitive. COLOWE retains a volumetric feeding interface in the basic cost-effective twin-screw extruder solution, helping customers enter the modified plastics field with lower start-up costs. However, it must be acknowledged that once the material density fluctuates, the compensation capacity of volumetric feeding is limited, which will bring implicit risks to the subsequent melt quality.
3, Weight loss feeding: the key to stable consumption of recycled materials by cost-effective extruders
The revision of the EU Packaging and Packaging Waste Regulations in 2024 will promote an increase in the use of recycled plastics. The bulk density, moisture content, and particle size of recycled materials fluctuate greatly between batches, and weight loss feeding can compensate for these fluctuations in real time. According to the 2024 report by Plastics Europe's Circular Economy for Plastics, the use of weight loss feeding in regenerative modification production lines reduces melt pressure fluctuations by approximately 45% -60% compared to volumetric feeding. The COLOWE co rotating twin-screw extruder is recommended to be equipped with weight loss feeding, especially when the regeneration filling ratio exceeds 20%. This can not only stabilize production capacity, but also reduce screw torque jumps and shutdowns caused by feeding fluctuations.
4, Lateral feeding and liquid feeding: invisible lever for enhancing the blending efficiency of new/recycled materials
Lateral feeding is used for high filling of calcium carbonate, talc powder, fiberglass, etc., which can avoid bridging of the main feeding port, unstable feeding, and screw intake. In the PP/calcium carbonate filling system, using lateral feeding can increase the filling amount from 35% to 55% -70%, while reducing the wear of the main engine; Liquid feeding can accurately inject coupling agents, plasticizers, devolatilization aids, etc., with an error of less than ± 1%. The COLOWE plastic extruder is equipped with multiple lateral feeding ports and liquid injection ports, which are suitable for international customers to quickly switch between multiple formulas. It also allows one device to cover various processes from ordinary reinforcement to high filling regeneration modification.
5, Suggestions for selecting cost-effective extruders: COLOWE's "Three Matching" principle
Kelongwell suggests choosing from three matching options: material matching, process matching, and budget matching. For customers who are new to environmental protection and trying new materials, do not initially pursue high configurations or sacrifice feeding accuracy for the sake of saving money. The phased solution of using the COLOWE co rotating twin-screw extruder base platform, weightlessness main feeding, and reserved side feeding interface can be selected, which not only controls the initial investment but also leaves space for regeneration filling upgrade. This solution can reduce initial investment by about 25% -35% compared to a one-time full weight loss+side feeding, while maintaining the industry's mainstream level of production capacity stability.
6, Key Q&A: The 3 most concerning questions for first-time customers
Q: For the first time doing regeneration filling modification, with limited budget, can we use regular volumetric feeding first?
A: If the source of recycled material is stable, the particle size distribution is narrow, and the filling amount is less than 15%, volumetric feeding can be used first; But it is recommended to choose models with weighing feedback interfaces for later upgrades. If the recycled material comes from post consumer recycling, there is a large fluctuation in bulk density, and it is more cost-effective to directly feed it with weight loss because downtime and waste losses are usually higher than the price difference of feeders.
Q: What are the direct losses caused by feeding fluctuations in co rotating twin-screw extruders?
A: Firstly, the fluctuation of melt pressure leads to fluctuations in extrusion volume and uneven particle size; Secondly, fluctuations in screw torque may trigger alarms and shutdowns, resulting in a production capacity loss of approximately 5% -15%; It may also cause local over shearing, material degradation and yellowing, and exacerbate the odor problem of recycled materials. Therefore, stable feeding is not a "bonus point", but a basic indicator of cost-effective extruders.
Q: Why does Kelongwell emphasize the selection of "feeding system and plastic extruder host together"?
A: The actual accuracy is determined by the communication, response speed, feeding strategy, and anti-interference ability between the feeder and the host. Purchasing a separate feeder and connecting it to the main unit can easily lead to issues such as signal delay, feeding oscillation, and weighing interference. The COLOWE co rotating twin-screw extruder completes the feeding host joint adjustment before leaving the factory, which can reduce on-site debugging time by about 40%.
In 2025, when environmental regulations and cost pressures run parallel, efficient and cost-effective feeding is no longer a single equipment choice, but a system engineering around the process goals of co rotating twin-screw extruders and plastic extruders. Nanjing Kelongwell Chemical Machinery Co., Ltd. focuses on providing international customers with cost-effective extruder and feeding integrated solutions, allowing you to walk on a stable, energy-saving, and replicable path from the first ton of recycled modified materials.
