Flow Wrapping vs. Overwrapping: Formats, Materials and Applications

A wrap chosen for appearance alone can miss the protection or opening requirement. Compare a film tube with end seals against a folded skin around a supported product, then verify the actual pack.

This comparison uses public equipment descriptions, not our own tests. The heat-sealed, underside-fin example below is a typical configuration; seal position, material and sealing technology need confirmation for the proposed machine.

How each format is built

The difference starts with the film path. A flow wrapper makes a tube around the product, and an overwrapper folds film around it.

Flow wrap (pillow pack)

A flow wrapper pulls film from a reel and forms it into a continuous tube. Products arrive in a line, usually on an infeed conveyor with lugs or a timed feed, and enter the tube one after another. A longitudinal seal joins the film edges along the tube. In the illustrated conventional configuration it is an underside fin seal; the proposed machine and pack drawing determine seal type and position. Rotating or reciprocating crimpers then seal across the tube at the leading and trailing edge of each product. Both end seals are made in one operation and a knife cuts between them, so each pack gets a trailing seal and the next pack gets a leading seal.

Because the tube is continuous, pack length equals the product length plus the film needed for the end seals. On printed film, a registration mark lets the machine place the cut and the end seals relative to the print. What each station of a flow wrapper does, and what it needs from the product feed, film, coder and downstream machines, is covered in our guide to the inside of a horizontal flow wrapper.

Overwrap (folded wrap)

An overwrapper takes a product that already has a defined shape, often a carton or rigid box, and wraps a sheet of film around it. The film is cut to length, laid around the product and joined along the body. The ends are folded into panels, much like wrapping a gift, and the folds are heat sealed. Some formats add a tear tape, a thin strip under the film where the consumer starts opening the pack.

The structure depends on the product holding its shape during folding. That is why overwrapping is associated with cartons, boxes and other rigid items, while flow wrapping can also handle soft or irregular products, as long as they can be fed in a line.

Why the seal layout matters

In a flow wrap, the fin seal runs the full length of the pack and the end crimp seals cross the tube. Leak investigations tend to focus on the points where the fin seal meets the end seals, because several film layers overlap there. In an overwrap, the sealed areas are the folded ends and any longitudinal overlap. The seal is made between layers of folded film rather than across a pressed tube, so sealing pressure and temperature act on a different geometry. Whether a seal is adequate for the intended use is settled by testing the actual film, not by the format name. One relevant reference is a standard test method for seal strength of flexible barrier materials. It defines how seal strength is measured, not what value is acceptable.

Conditional comparison

The table compares the two formats on the points that most often decide the choice. “Suits … when” means the format is a plausible fit under that condition, not that it is the only one.

Product shape and support

Flow wrapping is flexible about shape because the film tube forms around whatever is in it. The limits are feeding and spacing. The product has to enter the tube in a controlled way, with enough clearance and a consistent pitch. Fragile products can break at the infeed or at the crimp, so the feeding method needs attention. For cookies and biscuits, the cookie feeding trial checklist sets out how to describe flat, on-pile and on-edge arrangements and where to record breakage during a trial.

Overwrapping depends on the shape of the product. A carton with square edges gives clean folds, while a product with weak or uneven corners can crush or leave wrinkled folds. When the product is a carton, overwrapping typically sits downstream of a cartoner. Our guide to cartoners and case packers shows how that secondary packaging step is arranged.

Film and appearance

Flow wrap film is usually printed, because the film is the graphic surface and often the barrier layer. The machine reads a registration mark to position the print. If the film must also block moisture or oxygen, that is a film specification question as much as a machine question.

Overwrap film is often clear, because the carton underneath carries the graphics. Clear options include coated or laminated materials with different folding and sealing behavior. Cellulose-based film, often called cellophane, is a historical example associated with overwrapping. Whether it, a polymer film or another material suits a given job depends on the machine’s folding and sealing system and on the product. The guide on film and machine compatibility covers the film properties that affect running on either format: tension, coefficient of friction, sealing window and registration.

Where each format is used

These applications are examples, not rules.

Flow wrap is widely used for bars, biscuits, confectionery, bakery items, tubes, medical disposables and a range of non-food items. It is also used for multipacks of smaller packs.

Overwrap is common on cartons of cigarettes and similar products, boxed confectionery, stationery and other cartons sold with a film skin. For consumer products in cartons, the film overwrap sometimes serves as the tamper-evident or protective layer.

Either format may also appear as a secondary packaging step, for example wrapping a group of primary packs. That is why both appear in the secondary band of the line map in our packaging machine types overview.

Verification record to copy

Use one record per product, film and proposed configuration. Attach drawings and agreed test results; speed claims need product, pack and film conditions.

Use the RFQ checklist to retain these conditions when comparing proposals.

Protection, film reuse and opening

A wrap name does not establish airtight protection. Define barrier, seal-integrity and shelf-life requirements and record the actual pack tests; a folded outer wrap should not be accepted as hermetic on appearance alone.

Using one material on both formats is a trial question: compare the mating seal surfaces, folding behavior and the approved machine process before reusing a reel specification. Syntegon’s public flow-wrapper documentation includes hot, cold and ultrasonic sealing options, so heat sealing is not universal.

Tear tape is an opening aid in the manufacturer overwrap examples. Its presence alone does not establish opening force, complete film removal or tamper-evidence performance; retain an opening test against the pack’s requirement.

Worked comparison

Limits and on-site verification

This guide cannot settle which format your product needs. These points need confirming with real product and film on the actual machine:

• Sealing behavior. Fin seal, crimp seal and folded seals depend on film, temperature, pressure and dwell. The film supplier and machine builder provide acceptable ranges, and you confirm them with your materials. When seal faults appear in production, a structured seal defect investigation helps separate material, machine, product and method causes.
• Product feeding. Spacing, orientation and product damage at the infeed and crimper show up only in a trial with real product.
• Pack appearance and opening. The people who will run and sell the pack should judge fin position, fold neatness, tear tape behavior and ease of opening.
• Protection requirements. If the pack must meet barrier, shelf life or tamper-evidence requirements, define them first and check the pack against them with an agreed test.
• Regulations and labeling. Rules for markings, contact materials and tamper evidence vary by market and product, so check them for your case.

Related decisions

To see where flow wrapping or overwrapping sits in a whole line, the overview of packaging machine types shows the primary, secondary and tertiary stages. For carton-based secondary packaging, see cartoners and case packers. Film selection questions continue in film and machine compatibility.

Method and source review

Manufacturer mechanism review: October 8, 2026. These are public descriptions, not our test observations or recommendations:

• Syntegon, horizontal flow-wrapper documentation, process FAQ and “Sealing competence”: form/fill/fin-seal operation and hot, cold and ultrasonic sealing options.
• Marden Edwards, cosmetics overwrapping documentation, capabilities: supported cartons, folded ends and body-seal positioning.
• Marden Edwards, pharmaceutical overwrapping documentation, capabilities: folded wrapping and easy-open tear tape.

The blank record supplies evidence fields, with acceptance set by the product and pack specification.