Choosing the Right Poly Film for Your Flow-Wrap Machine
Your flow-wrap machine is only as good as the film running through it. Choose the wrong poly film, and you end up with poor seals, film tears, excessive downtime, and wasted product. Yet many manufacturers in Tennessee and Mississippi have been running the same film for years without ever asking whether it is truly the right fit for their product, their machine, and their speed requirements. Choosing the right poly film for your flow-wrap machine does not have to be complicated—but it does require understanding a few key differences.
Why Film Selection Affects More Than Just Packaging
The film you choose directly impacts three areas: machine throughput, seal integrity, and product presentation. A film that runs at 150 packs per minute on one machine may cause constant jams on another depending on sealing jaw temperature range, film tension settings, and reel core dimensions. Beyond mechanics, film clarity affects shelf appeal, barrier properties affect shelf life, and gauge affects your per-unit material cost. Getting this right up front saves real money. A poorly matched film can reduce line speeds by 20 to 30 percent and increase seal failures that result in rejects and rework.
The Main Poly Film Types for Flow Wrapping
There are four film families that dominate flow-wrap applications in industrial and food processing environments:
BOPP (Biaxially Oriented Polypropylene) is the workhorse of horizontal form-fill-seal packaging. It offers excellent clarity, good stiffness, and strong moisture barrier performance. BOPP runs well on most flow wrappers and is widely used for bakery items, snacks, and confectionery. Some heat-seal grades initiate sealing below 85 degrees C, which allows higher line speeds without compromising seal quality.
LDPE and LLDPE (Polyethylene) offer flexibility and toughness that BOPP cannot match. These films seal over a wide temperature range, perform well at low temperatures for frozen or refrigerated products, and conform well to irregular shapes. Bread, fresh produce, and meat products are typical applications.
OPP (Oriented Polypropylene) is similar to BOPP but tends to offer even better moisture barrier properties and gloss. It is widely used in candy and snack segments where shelf appearance is a priority.
PET (Polyester) films are used where chemical resistance, thermal stability, or a superior oxygen barrier is needed -- especially for oily, acidic, or marinated products, and MAP applications.
Matching Film Properties to Your Specific Application
Selecting the right film means matching the film spec to your machine and product. Key variables to evaluate include:
• Gauge (thickness): Thicker film provides better puncture resistance but increases material cost. Standard flow-wrap films run from roughly 30-60 microns.
• Seal initiation temperature (SIT): Lower SIT enables faster sealing cycles. Always match the film's SIT range to your machine's jaw settings.
• Reel width and core size: Using incorrect dimensions creates tracking problems and film waste.
• Print compatibility: Confirm your film grade accepts the ink type you are using -- flexo, gravure, or digital.
Manufacturers in Jackson TN, Tupelo MS, and across the Southeast often discover these mismatches only after purchasing large inventory. Working with a knowledgeable distributor before you buy helps you avoid those surprises.
When to Request a Film Audit from Your Packaging Supplier
If your operation experiences frequent fin seal failures, film tear at the plow or former, inconsistent bag lengths, or seal quality that degrades at speed -- it is worth having a specialist review your current film. GenPac works with manufacturers throughout Tennessee and Mississippi to match the right poly film to each application.
Frequently Asked Questions
What is the difference between BOPP and OPP film for flow wrapping?
BOPP is stretched in two directions during manufacturing, which improves stiffness, clarity, and barrier properties compared to standard OPP. BOPP typically offers better dimensional stability at higher line speeds and is the more common choice for bakery, snack, and confectionery applications.
Can I use LDPE film on a high-speed flow-wrap machine?
Yes, but LDPE's softness requires careful tension control. Machines above 150 packs per minute may see tracking issues. LLDPE offers higher tensile strength and better film stability while retaining flexibility.
How do I know what gauge poly film I need?
Lighter products under 8 oz with smooth surfaces typically run well on 1.5 to 2.0 mil film. Heavier or irregular products may require 2.0 to 2.5 mil or higher. Your distributor can help you trial the correct gauge before committing to full inventory.
Does the type of poly film affect food safety compliance?
Yes. Film in direct contact with food must be FDA-compliant. Always confirm food-contact compliance with your supplier and request documentation.
Ready to Optimize Your Flow-Wrap Line?
Contact GenPac to talk with a packaging specialist about your specific application. We have been helping manufacturers across Jackson TN, Tupelo MS, and the Southeast find the right packaging solutions since 1982.