Issue 312 2026-07-23 Author : NAN YUN INDUSTRIAL CO., LTD. Suscríbete

Reasons for Unstable Discharge and High Waste Rates in LVT Extruders: Screw and Barrel Improvement Solutions

In the plastic extrusion process (LVT extrusion process), when problems such as unstable discharge, bubbles, voids, or inconsistent quality occur in products, many companies often first try to adjust the temperature, screw speed, or raw material formula. However, if the problems continue without improvement, what truly needs to be examined is whether the screw and barrel system meets the process requirements for raw material characteristics and feeding stability.

Customer Case Sharing: The Three Major Problems of Unstable Discharge, Bubbles in Products, and Short Screw Lifespan

A plastic flooring manufacturer encountered the following three major problems occurring during their production process:

● Reasons for unstable discharge in the LVT extruder:

Production output fluctuated significantly. Even if the screw speed remains unchanged, a phenomenon of surging occurs, and the flow of plastic within the machine remains unsmooth.

● Are bubbles and voids a screw problem or a temperature problem:

Gases generated by the heated raw materials cannot be effectively expelled, causing bubbles to appear in the boards, which affects density and subsequent grooving quality.

● Excessively high risk of screw breakage:

The customer had experienced extremely frequent screw breakage in the past. (some screws even broke less than a week after being installed).

Are these problems really caused by the raw materials?

In process using of high-filled calcium carbonate materials, a certain proportion of calcium carbonate must be added during production, while simultaneously using recycled plastic pellets for processing. However, high-filled calcium carbonate processing involves several challenges:

● Can calcium carbonate and the plastic base material be mixed evenly?

● Does the inconsistent particle size of recycled pellets affect feeding stability?

● Can gases generated after heating be discharged smoothly?

● Does the screw design match the material characteristics?

When facing different raw material characteristics and product demands, the evaluation for a screw and barrel design typically include:

● Improving feeding stability:

Ensuring the materials to continuously and steadily enter the plasticizing zone, reducing output fluctuation.

● Enhancing mixing uniformity:

Improving the dispersion of calcium carbonate and plastic base materials to achieve better product consistency.

● Optimizing plasticizing efficiency:

Ensuring materials to reach more stable melting quality during the plasticization and reducing the risk of quality fluctuations.

● Improving venting effectiveness:

Reducing residual gas released during material heating and minimizing bubbles and voids.

● Extending equipment lifespan:

Reducing abnormal wear and equipment damage risks through designs that meet process requirements.

Reducing the scrap rate is actually saving energy costs

Many people believe that energy saving simply means reducing equipment power consumption. However, for manufacturers, a more important factor is reducing ineffective production. When products are scrapped due to quality issues, raw materials, electricity, labor and machine operating time have already been invested, but they do not generate actual value.

Therefore, once material discharge becomes more stable, mixing becomes more uniform, and venting issues are improved, it not only increases the production yield but also decreases the waste, reduces the number of reworks and machine shutdowns for adjustment, and further lowers overall production costs and energy waste.

Choose a Professional Partner to Maximize Equipment Performance Value

Different materials, products, and process requirements may all require different screw and barrel. Nan Yun Industrial possesses years of experience in designing and manufacturing screws and barrels. With many years of experience in screw and barrel design and manufacturing, Nan Yun Industrial can evaluate the causes of processing issues and provide improvement recommendations based on each customer’s material properties, equipment conditions, and process requirements.

If you are facing issues with unstable discharge, bubbles, uneven mixing, abnormal screw wear, or other problems, please feel free to contact us to jointly find the most suitable improvement solution.