How a continuous band sealer machine seals bags

A continuous band sealer machine seals bags in a single, uninterrupted process. Place the filled bag on the conveyor, which transports it to the sealing area. Sealing belts guide the bag opening through a heated block, softening the film.

Pressure then closes the softened film, followed by a cooling block that sets the seal. An embossing wheel marks the seal. The next bag is processed immediately, making this a continuous band sealer.

When placing a filled bag on the conveyor, ensure the open end is positioned between the two sealing belts. These belts grip the bag opening and move it through the heated block. The bag should remain upright as it enters the belts.

The belts operate continuously, allowing the operator to feed the next bag as soon as the previous one advances. Output depends on how quickly bags are placed on the conveyor and the belt speed setting. It is important to let the belts draw the bag through; pushing or restraining a bag during sealing can cause wrinkles, leading to leaks.

A single motor drives the conveyor, sealing belts and toothed guide belts, ensuring the bag opening and base move at the same speed. If the conveyor belt becomes loose, it may fall out of sync with the sealing belts, causing the bag to shift or the seal to misalign. In such cases, tighten the conveyor belt before continuing.

The gap between the two sealing belts at the heated and cooling blocks should be about the thickness of a single layer of bag film. If the gap is too narrow, the belts will drag and wear more quickly. If the press wheel is set too tightly, it may block or fold the bag as it passes. On the AS600F, filled bags enter from the right and exit sealed on the left, so plan your filling and removal stations accordingly.

Selecting a continuous sealer machine for your bags

Choose a band sealer based on the weight, height and film thickness of your bags. The FS150 and F150PM are suitable for bags up to 3 kg, while the AS600F can handle up to 5 kg per bag and 20 kg on the conveyor. The AS600F table can be set for bags between 120 and 600 mm in height.

Film thickness can be up to 0.08 mm for the FS150 and F150PM, and from 0.04 to 0.20 mm for the AS600F. If you need to print a date or batch code, select the F150PM. The AS600F is a vertical continuous band sealer for heavier bags and sacks.

Start by weighing your heaviest filled bag. If it weighs up to 3 kg, the FS150 or F150PM will be suitable. For heavier bags, up to 5 kg each, the AS600F is the right choice, and its conveyor can support a total of 20 kg at once. This is important in production environments where several bags may be on the conveyor simultaneously, such as when sealing sacks of granulate or bulk powders.

The AS600F features a conveyor table adjustable by handwheel, allowing you to seal bags from 120 to 600 mm high at the correct level. This is useful if you have bags of varying sizes or if your filling line changes product.

The FS150 seals films up to 0.08 mm thick in a single layer, including LDPE, MDPE, HDPE, PP and standard multilayer films. The F150PM seals LDPE, MDPE, HDPE and PP up to 0.08 mm thick. The AS600F accommodates a wider range, from 0.04 to 0.20 mm in a single layer, including laminates and composite films. The FS150 and F150PM operate on 220 V or 110 V, while the AS600F uses 220 V, 50 Hz. The F150PM measures 1000 × 400 × 450 mm and the AS600F 1195 × 500 × 1245 mm, so ensure you have enough space for feeding and removing bags.

Comparison table: band sealer models

The table below compares the three band sealers by sealing speed, temperature range, film thickness, bag weight, bag height and special features.

To use the comparison table, first check the bag weight and film thickness for your application, as these determine which model is suitable. Once you have excluded models that do not fit your bag or film, compare sealing speed, seal type and power supply. The heating section in the table shows the two heating tubes in the sealing block: 2 × 300 W for the FS150 and F150PM, and 2 × 400 W for the AS600F.

Printing a date or batch code on the bag

The F150PM band sealer with printer seals each bag and prints a date or batch code in a single operation. The printer is controlled by its own switch, and you can adjust the character spacing, delay and voltage for the print.

A code printed directly onto the bag will not come off like a label might.

With the F150PM, every bag is both sealed and printed in one go, ensuring that no bag leaves the packing station without a code.

There is no need to purchase, store or change label rolls during production.

The delay setting determines where the code appears on the bag. If you change the belt speed, the code position will shift along the bag, so you should check the print location after each speed adjustment. If you do not require a code, the FS150 seals the same bags: up to 3 kg, film up to 0.08 mm thick, at 0 to 13 m/min.

The printer on the F150PM is set using its own display. You can select the printing direction as forward or reverse. The printing speed setting controls how quickly the code is printed: a lower value prints faster and with narrower character spacing. The grey scale and pulse width settings affect the darkness and length of the print, with a larger pulse width producing a longer, darker code.

To change the code, enter the new text on the printer’s display and save it before starting the next batch. Printing starts when you press the Start button. After changing the batch or date, check the code on the first sealed bag to confirm the update. If you do not need a code on certain bags, you can switch off the printer and the F150PM will seal without printing, so both marked and unmarked bags can be processed on the same line.

Adjusting a continuous band sealer machine for your film

Begin with a low temperature setting on the continuous band sealer machine, then gradually increase it until the seal is secure. Adjust the speed to suit the film and bag type. For a new bag, start at a slower speed and check the seal before increasing speed.

Increase the temperature in small steps. Large adjustments can burn the film, so it is safer to make gradual changes.

Once the temperature is correct, adjust the speed. Slower belts keep the film in the heated block for longer. Faster belts reduce the heating time. If the seal is strong and even, you can increase the speed to match your production needs.

Always test the seal on actual bags by pulling it apart by hand and squeezing a filled bag. A good seal is even along its length, with no wrinkles or burnt areas. Each film type and thickness requires its own settings, so record the temperature and speed for every bag you pack. On the AS600F, the seal is positioned 10–20 mm from the bag edge by adjusting the table height.

The seal quality depends on three main settings: temperature, speed and pressure. The pressure is factory-set for most bags and usually does not need to be changed. If you cannot achieve a good seal by adjusting temperature and speed, increase the pressure in small increments.

The fan cools the seal after it leaves the heated block. Whether the fan is used depends on the film material and thickness. For standard single-layer polyethylene film, the FS150 manual recommends using the fan. Polypropylene film needs a higher sealing temperature than polyethylene, so you must find a new temperature setting when switching from PE to PP bags. The F150PM and AS600F manuals give reference sealing speeds of 6–10.5 m/min for LDPE, MDPE, HDPE and PP, which are well below the maximum speed of the machines. On first use or after a long break, warm the heater at a low temperature for a few minutes to remove moisture from the heating element. While the blocks are heating, run the belts at low speed to prevent damage.

Band sealer, pedal heat sealer or vacuum packing machine

A band sealer seals bags one after another on a conveyor, so production continues without interruption between bags. This is ideal for packing lines where many bags are filled and sealed in sequence. The conveyor and sealing belts move each bag through the heated block, so the operator only needs to place the bag on the conveyor.

Pedal heat sealers seal one bag per press of the pedal and are suitable for smaller quantities. Vacuum packing machines remove air from the bag before sealing, which is necessary for products that must be packed without air. Band sealers do not remove air: they seal the bag with the air remaining inside.

A band sealer is chosen when there is a steady flow of filled bags at a filling station, such as in a warehouse or on a production line.

A pedal heat sealer works differently. The bag opening must fit the length of the sealing bar, which is 300, 450 or 600 mm, depending on the model. In contrast, a band sealer can seal a bag opening of any length as it passes through the belts.

Both a band sealer and a constant heat pedal sealer, such as the ZONE300D, maintain their heated blocks at the set temperature throughout the shift. A band sealer therefore requires time to warm up before the first bag and to cool down at the end of the shift, with the belts running. In contrast, an impulse pedal sealer only heats when its jaws are closed, so it does not need a warm-up or cool-down period.

With a pedal heat sealer, both hands are used to hold the bag flat across the sealing bar while the foot operates the pedal, sealing one bag at a time. With a band sealer, your hands are free to prepare the next bag. If the bag opening is wider than the pedal sealer’s bar, you must seal it in two presses, and the overlap may be a weak point. A band sealer closes the entire opening in one continuous seal, avoiding this issue.

A chamber vacuum packing machine only accepts bags that fit flat inside its chamber and works in cycles: the lid closes, air is removed, the bag is sealed and the chamber is vented. A vertical band sealer seals bags standing upright on its conveyor, and the AS600F can handle bags up to 600 mm tall. For heavy bags, the width of the seal is important as a wider seal supports more weight. The AS600F produces a 13 mm embossed seal, which is wider than the narrow seal made by impulse pedal sealers.

Vertical band sealers for powders and liquids

With a vertical band sealer, the bag stands upright on the conveyor. This keeps powders, granules and liquids at the bottom of the bag and away from the seal area. The FS150 and the AS600F are vertical models, so they are used for products that would spill or leak if the bag were laid flat.

A vertical model is selected when the product must remain below the seal. Horizontal models are used for dry solids that do not move or spill.

It is important to keep the product below the seal, as any product in the seal area weakens the seal and may cause leaks.

When filling the bag, ensure the product stays well below the seal line. Allow powder to settle before the bag reaches the belts to prevent dust in the seal. If the bag is overfilled or the product is too close to the top, the seal may not hold.

At the machine entry, align the open end of the bag with the guide plate so it enters the belts straight. A crooked or wrinkled entry can cause the seal to leak. Check that each bag opening is flat and straight before it enters the belts.

On the F150PM and AS600F, the centre of the seal is set 10–20 mm below the edge of the bag, so leave enough empty space at the top.

Set the conveyor so the bag stands upright under the belts. On the FS150 and F150PM, adjust the table height and move it forward or back to suit the bag size. Powders and liquids are often filled in areas that may be dusty or wet, but the F150PM and AS600F manuals require a location without corrosive or humid air.

What determines the price of a band sealer

The cost of a band sealer depends on features such as an integrated printer, conveyor load capacity, adjustable bag height and the range of film thickness it can process. Ongoing expenses are mainly for consumable parts like sealing belts and motor brushes. The price for each model is displayed on its product card.

The price is influenced by features such as the printer on the F150PM, the conveyor load and adjustable bag height on the AS600F, and the range of film thickness each model supports.

Ongoing costs are primarily for electricity and consumable parts, including sealing belts and guide belts. For the F150PM, printer ink is an additional expense. Each product card includes a Get offer button for quotations and an Add to inquiry button to group several products in one request.

The FS150 product page advises keeping spare sealing belts, guide belts, heating tubes and motor brushes available at the packing line.

Most of the electricity used by these machines is for the heating elements. The motors consume much less power: 50 W for the FS150 and F150PM, and 120 W for the AS600F.

Maintenance and safe shutdown

Band sealers require daily cleaning of the sealing belts to maintain strong seals. Inspect the sealing belts and toothed guide belts for wear every month. Check the motor carbon brushes regularly and replace them when worn to prevent unplanned stoppages.

The sealing head becomes hot during use. Keep hands clear of the belts while the machine is running. For the AS600F, switch off the heating first, allow the cooling fan to run until the blocks are cool, then switch off the power.

Clean any film residue from the sealing belts and wipe down the conveyor every day.

If a belt breaks, it will mark the seal and must be replaced straight away. For the AS600F, the product page also recommends checking the heating tubes, rubber wheels and temperature controller.

The sealing head is hot, so always switch off the machine and let it cool before cleaning.

Clean the sealing and guide belts with a brush and the conveyor table with a damp cloth. Never use a pressure washer, and ensure no water enters the control panel. The exposed gears should be greased every six months to keep them operating smoothly. If film adheres to the sealing belt or heated block, stop the machine and remove the film only once the block has cooled.

The F150PM and AS600F manuals state that a new heating tube is needed if the block takes more than ten minutes to reach the set temperature. The FS150 and F150PM are shut down in the same sequence as the AS600F, and on all three models the belts continue running until the blocks have cooled. For the FS150, wait until the temperature drops below 100 °C to protect the sealing belt. For the F150PM and AS600F, wait until it falls below 50 °C. A sealing belt that fails prematurely is often too tight, running on its edge, creased, or contaminated with film or dirt. Too small a gap at the heated blocks or excessive temperature can also cause early failure. Never wear gloves or jewellery near the belts, and always switch off the power before leaving the machine.

Checklist before purchasing

Before placing an order, check the film type and thickness, the weight and height of your bags, your daily sealing volume, whether you require code or date printing, the available space at your filling station, and your power supply. The comparison table above provides the specifications for each band sealer model.

Identify the film material and thickness of your bags and compare these with the film thickness row in the table above. Weigh your heaviest filled bag and measure the tallest one to ensure they are suitable for your chosen model.

Count how many bags you seal each day and decide if each bag needs a date or batch code. Plan the space at the end of your filling station, leaving enough room for the bag to exit after sealing. Check your socket: 220 V, or 110 V for the FS150 and F150PM.

Choose a location for the machine where it stands level, with at least 10 cm of clearance around it for ventilation. Keep it away from heat sources and steam, and ensure there is enough space to change the belts when necessary.

The F150PM and AS600F manuals specify a room temperature of 5–30 °C for correct operation. All three machines require an earthed socket with a protective earth wire for safety.

Questions about band sealers

What does continuous sealing mean on a band sealer?

Continuous sealing means the band sealer seals bags one after another without interruption. The conveyor moves each filled bag through the sealing area, ensuring steady production.

How heavy a bag can a band sealer handle?

The FS150 and F150PM can seal bags up to 3 kg. The AS600F can seal bags up to 5 kg each, with a total conveyor capacity of 20 kg.

Which films can these band sealers seal?

The FS150 seals films up to 0.08 mm thick in a single layer: LDPE, MDPE, HDPE, PP and common multilayer films. The F150PM seals LDPE, MDPE, HDPE and PP up to 0.08 mm thick. The AS600F seals films 0.04–0.20 mm thick in a single layer: LDPE, HDPE, PP, laminates and composite films.

Can the machine print a date on the bag?

The F150PM can print a date or batch code onto the bag during sealing. The printer settings are adjusted separately from the sealer.