Why bubbles form on Extrusion Coating Lamination Machine

If you're considering an extrusion coating and laminating machine, you probably know that bubbles in the finished laminated product are more than just an aesthetic issue. They severely compromise barrier properties, affect sealing reliability, and reduce product yield. The root causes of bubble formation mainly boil down to four aspects: moisture or volatile substances in the raw materials, substrate surface contamination, mismatched process parameters, and equipment precision issues. This is how Winrich's customized equipment and services address these pain points at the source.

Raw material issues are the most common problem, especially in food packaging and medical device lamination. Many buyers overlook pre-drying resins such as PE or PLA, but the problem is that even 0.05% moisture content will turn into steam at the high temperatures of 200-300℃ in the extruder barrel. This steam forms tiny bubbles that get trapped in the molten film. I remember a coffee cup paper manufacturer who was plagued by persistent bubble problems until we finally traced the cause to insufficient drying of the PE resin. Another easily overlooked problem is volatile additives in the masterbatch. Low-quality colorants or antioxidants decompose at processing temperatures, releasing gases that get trapped between the layers. Winrich addresses this by combining the extrusion coating and laminating machine with a customized pre-drying system. Both temperature and drying time are adjustable, which is crucial for high-humidity regions or absorbent substrates like kraft paper.Substrate surface contamination is another major issue; you might think your production process is fine, but it's silently causing bubbles. Even if the paper substrate absorbs a small amount of moisture, it can lead to bubble formation during the lamination process.

Mismatched process parameters are usually caused by a "one-size-fits-all" approach, and frankly, many buyers make this mistake. They arbitrarily adjust temperature or speed without considering the material characteristics, and then wonder why bubbles keep appearing. For example, if the die head temperature is too high, the resin will undergo thermal decomposition. If the laminating roller pressure is too low, it won't be able to squeeze out the air between the layers—this is especially detrimental for multi-layer laminates such as aluminum foil composites. On the other hand, excessively rapid cooling can cause the film surface to solidify prematurely, trapping gas inside. Winrich's advantage lies in its precision control system. Their fully automatic extrusion coating machines utilize PLC-controlled gradient temperature adjustment and servo-driven pressure-balanced laminating rollers. These systems automatically adjust parameters based on the substrate type and coating thickness . For new customers, Winrich's on-site technical team provides 3 days of process debugging training to ensure your parameter settings match actual production.

While equipment precision defects are uncommon, their consequences can be disastrous. Uneven pressure distribution in the laminating rollers (due to bearing wear or poor calibration) can lead to localized air entrapment. Irregular die lip gaps can result in uneven film thickness and air accumulation. Unlike ordinary equipment, Winrich's machines undergo 12-point pressure calibration before delivery. Their laminating rollers are made of wear-resistant alloy, maintaining accuracy even at high speeds of up to 150 meters/minute. Furthermore, they offer a one-year free warranty and global on-site maintenance services. This is crucial for high-volume industries such as food packaging, where downtime means failing to meet order deadlines.

Solving bubble problems requires addressing four aspects: raw materials, substrates, process, and equipment. For buyers, choosing a machine that can be customized to their specific needs is crucial. Customization based on specific requirements is far better than troubleshooting after production. Winrich has 28 years of experience in the field of extrusion coating equipment, so they don't just sell extrusion coating laminating machines. They offer one-stop customized solutions: pre-drying modules for humid regions, multi-layer lamination systems for new energy battery packaging, and much more. Ultimately, the value of a laminating machine lies not only in speed and output, but also in its ability to consistently produce defect-free products. That is true success.
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