L-Bar Sealer vs. I-Bar Sealer: Which Do You Need?

The short answer

An I-bar sealer has one straight sealing bar. It is the simplest and lowest-cost way to start shrink wrapping, and it suits occasional jobs, changing product sizes and items that are long or oddly shaped. An L-bar sealer has two sealing bars set at a right angle, so it closes the side and the end of a centerfold film pouch in one stroke. That makes every pack faster and more consistent, which is why L-bar sealers are the usual choice once you wrap the same products every day.

Both machine types only seal and cut the film. The shrinking is done afterwards with a heat gun, in the hood of a hood shrink sealer, or in a heat shrink tunnel. The sections below explain the differences with the machines we carry from AIE and Maripak, so you can decide which one fits your volume, your products and your space.

How the two machine types work

I-bar sealer: one bar, one seal at a time

With an I-bar system you place the product in a pouch of centerfold shrink film, close the open side with the bar, turn the pack and close the end with a second stroke. AIE's I-Bar Shrink Wrap System uses an impulse sealing bar: it heats only during the seal, so there is no warm-up time. AIE describes it as a three-step operation and ships it as a complete starter kit with the impulse bar sealer, a timer, a two-speed heat gun with holder, a film rack, a free 500 ft roll of 75 gauge centerfold PVC shrink film, an outlet plug and a parts kit.

The AIE-800PI portable I-bar system turns the idea around: the 32" impulse bar is hand-held, so you bring the sealer to the product. A micro switch fires the sealing and trimming wire, the temperature timer is adjustable, and an 8 ft cord connects the controller to the hand unit. AIE recommends it for large items and products with unusual shapes.

L-bar sealer: two bars, one stroke

On an L-bar sealer the product sits inside the centerfold film on a work surface, and the L-shaped bar closes over the open side and the end at once. AIE's L-Bar Shrink Wrap Systems are manual impulse machines with a dual sealing bar that seals and trims PP, PVC and PE film up to 0.025 mm thick with 500 W power; AIE gives an average seal time of 1–4 seconds. They come with a film rack dispenser, a timer, an outlet plug and a parts kit. Film and heat gun are sold separately.

Maripak's machines take the next steps. The Compack 5800 hood sealers seal and shrink in the same chamber when the operator closes the hood. The LMC semi-automatic L-sealers close the bar with an electric motor, and the TMC Pro adds a shrink tunnel in the same machine. The fully automatic RLS e-Pro detects the product length with a sensor and feeds packs on a conveyor.

I-bar vs. L-bar at a glance

Prices are as shown on the product pages; freight is quoted for each order before you pay.

When an I-bar sealer is the right choice

Choose an I-bar system when shrink wrapping is an occasional task, for example for gift sets, small batches, spare parts or items that change from week to week. Because the bar is straight and open at both ends, the product size is limited mainly by the bar length, not by a fixed seal area. AIE offers its I-bar systems from 13" to 40"; we carry the 40" AIE-2040I and the hand-held AIE-800PI with a 32" bar for items that are too large or too awkward to lift onto a table.

The trade-off is speed and consistency. Every pack needs at least two seals, and the operator positions the film by hand each time. If you wrap the same product all day, the extra handling adds up.

When an L-bar sealer is the right choice

Choose an L-bar sealer when you wrap the same kind of product regularly and want every pack to look the same. The question is then how far you want to automate.

Manual L-bar system

The AIE L-Bar systems are the entry point: a manual impulse L-bar with a film rack, in four sizes from 13" × 13" to 24" × 32". They need no warm-up, and AIE states 500 W power. You shrink the film with a heat gun, for example the AIE dual speed heat gun, which you can add on the product page.

Hood shrink sealer

A hood sealer such as the Maripak Compack 5800i combines the L-bar and the shrinking in one compact machine: you close the hood, and the film is sealed and shrunk in the same chamber. Per Maripak it handles about 5–10 packs per minute, needs no compressed air and no separate tunnel, and runs on single-phase 200–240 V. The 5800HC has a taller 16" chamber, and the 5800MC adds an automatic discharge conveyor.

Semi-automatic and automatic L-sealers

For higher volumes, the Maripak LMC series closes the sealing bar with an electric motor at about 10–15 packs per minute, in seal areas from 23" × 17" to 35.5" × 25.5". The sealed pack then passes through a heat shrink tunnel; the TMC Pro combines both in one machine. The RLS e-Pro is fully automatic, with servo drives, automatic product length detection and a conveyor speed of up to about 98 ft/min.

Shrinking the film: heat gun, hood or tunnel

Neither an I-bar nor a basic L-bar sealer shrinks the film by itself. With the AIE I-bar systems the heat gun is included; with the AIE L-bar systems it is sold separately. A heat gun is flexible and inexpensive, but the result depends on the operator. A hood sealer shrinks the film in its chamber. A shrink tunnel gives the most even result for regular production: AIE's infrared shrink tunnels heat from four sides with an adjustable conveyor, and Maripak's Diamond tunnels come in single and double chamber versions. When you plan a tunnel, size its opening to your package; our selector calculates it.

Which shrink film to use

Use the film types the manufacturer lists for your machine. AIE's L-bar systems seal and trim PP, PVC and PE film up to 0.025 mm thick, and its I-bar kits come with a roll of 75 gauge centerfold PVC film. Maripak's Compack and LMC machines run polyolefin (POF) and PVC within the gauge ranges on each product page, and the RLS e-Pro also handles PE, OPP, CPP and PP with knife changes. Our Shrink Film Calculator works out the centerfold width and the film per package.

How to size the machine

For an L-bar sealer, the seal area must be larger than your package plus the film around it; for an I-bar, the bar must be longer than the widest seal you need to make. Measure your largest package (length, width and height) and enter it in the L-Bar Sealer & Tunnel Selector. It calculates the seal area and tunnel opening and shows the matching machines. Also check the maximum product height: for example 6" on the Compack 5800i, 13" on the 5800HC (depending on the other dimensions) and 7" on the TMC Pro 5844-M.

Checklist before you order

• Volume: occasional jobs point to an I-bar or manual L-bar; daily production points to a hood sealer, an LMC with tunnel or a combination machine.
• Package size: largest length, width and height, including the height limit of the machine.
• Power: AIE states 500 W for its L-bar systems; the Maripak machines need 200–240 V single-phase or 220 V three-phase and do not run on a 120 V outlet.
• Compressed air: not needed for the AIE systems or the Compack, LMC (except the pneumatic LMC-P) and TMC Pro models.
• Shrinking: heat gun, hood or tunnel, and the space it needs.
• Film: type, gauge and centerfold width that the machine accepts.

If you are unsure, send us your package sizes and daily volume through Request a Quote or call +1 469-809-4363 (Mon–Fri, 9am–5pm CT). We reply with a written quote for a suitable machine.