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In the world of automated packaging—whether for fresh meats, medical devices, or ready-to-eat meals—thermoforming technology is king. It is fast, efficient, and cost-effective.

However, a thermoforming machine is only as good as the materials you feed it. The process relies on a precise marriage between two distinct types of flexible packaging materials: the Forming Film (the bottom web) and the Non-Forming Film (the top web).

If these two don't "dance" together perfectly, you end up with leakers, curling packages, or compromised shelf life. At XHPAK, we specialize in coextruded solutions.

1. The Foundation: What is Forming Film?

The Forming Film (often called the "Bottom Web") is the workhorse of the package. It is fed into the machine, heated, and then pushed into a mold using air pressure or a vacuum to create a pocket or tray.

Because it undergoes significant physical stress, this film requires excellent thermoformability and deep-draw capabilities.

The Role of Material Structure: To achieve deep pockets without thinning or breaking at the corners, we use specific material structures.

• Strength: Polyamide (PA) is typically used for its puncture resistance and memory.

• Barrier: For food safety, we integrate EVOH (Ethylene Vinyl Alcohol).

Our PA and EVOH Coextruded High Barrier Forming Film is engineered to stretch uniformly. This ensures that even the thinnest point of the formed tray (usually the corner) still maintains enough EVOH thickness to block oxygen, keeping your product fresh.

2. The Seal: What is Non-Forming Film?

The Non-Forming Film (or "Top Web") is the lid. It does not stretch. Its primary jobs are to seal tightly to the bottom web and to display your brand.

Since it stays flat, this film is perfect for high-quality rotogravure or flexographic printing.

Key Characteristics:

• Clarity: It must be crystal clear to let the consumer see the product.

• Printability: This is where Laminated and Printed Film shines. At Xianghe, we can provide complex printed top webs that carry your branding, nutritional info, and barcodes, laminated to protect the ink from abrasion.

• Peelability: Depending on the user experience you want, the non-forming film can be engineered for "easy-peel" or "lock-seal" (permanent seal).

3. The Match: Why Compatibility Matters

The biggest mistake manufacturers make is buying top and bottom webs from different suppliers that aren't calibrated to work together. This leads to the "Curling Effect"—where the package bends upward or downward because the tension in the films is different.

How to Ensure a Perfect Match:

A. Sealing Layer Compatibility

Chemistry matters. If your forming film has a PE (Polyethylene) sealing layer, your non-forming film must also use a compatible PE layer.

• Pro Tip: For high-temperature sterilization (retort) applications, you might need a PP (Polypropylene) sealing layer on both sides.

B. Barrier Symmetry

If you use a High Barrier Forming and Non-Forming Film combination, ensure the barrier rates are balanced. A high-barrier bottom web paired with a low-barrier top web is a waste of money—oxygen will just enter through the top.

C. Specialized Functionality

Sometimes, you need the package to "breathe." For example, in medical sterilization (using EtO gas) or certain fresh produce applications, a complete barrier isn't what you want. In these cases, we recommend a PP/PE Coextruded Breathable Film as the top web. This allows specific gases to pass through while blocking bacteria, creating a safe, sterile environment.

4. Troubleshooting Common Thermoforming Issues

If you are experiencing issues on your line, check these common culprits:

• Corner Thinning: The forming film is too thin or lacks sufficient PA content. Solution: Upgrade to a specialized deep-draw PA/PE structure.

• Leakers: Often caused by contamination in the seal area or incompatible sealing layers between the top and bottom webs.

• Hazy Packaging: Using a lower quality recycled material or a film without anti-fog properties. Solution: Ask for Xianghe’s high-gloss, anti-fog formulations.

Conclusion: One Source for Both Solutions

The secret to efficient packaging isn't just the machine; it's the chemistry between the films.

At Xianghe, we don't just sell rolls of plastic. We provide a system. By supplying both the PA and EVOH Coextruded High Barrier Forming Film and the matching Laminated and Printed Film, we guarantee:

1. Consistent Sealing: No chemical mismatch.

2. Flat Packages: Optimized tension to prevent curling.

3. Visual Appeal: Crystal clear presentation that stands out on the shelf.

Ready to optimize your packaging line? Stop guessing with mismatched films. Contact Xianghe’s R&D team today to find the exact film structure tailored to your product’s depth, shelf-life, and sterilization needs.

FAQ: People Also Ask

Q: What is the difference between forming and non-forming webs?

A: Forming webs are the bottom films that are heated and molded into a tray shape. Non-forming webs are the top films (lids) that seal the package and usually carry the printed design.

Q: Can I use PA/PE film for both top and bottom?

A: Yes, but the structures are different. The bottom PA/PE will be designed for stretching (forming), while the top PA/PE will be rigid and flat.

Q: Do I need EVOH in my forming film?

A: If you are packaging fresh meat, cheese, or oxygen-sensitive food, yes. EVOH provides the high oxygen barrier necessary to extend shelf life. for frozen foods, standard PA/PE might be sufficient.