How a continuous band sealer closes a bag

A continuous band sealer closes bags in a single, ongoing process. The filled bag is placed on the conveyor, which moves it to the sealing area. Sealing belts guide the bag mouth through a heated block, where the film softens.

Pressure closes the softened film, then a cooling block sets the seal. An embossing wheel marks the seal. The next bag follows without stopping, which is what makes it a continuous bag sealer.

When you place a filled bag on the conveyor, make sure the open mouth is positioned between the two sealing belts. These belts grip the bag mouth and carry it through the heated block. The bag must stand steady as it enters the belts.

The belts run continuously, so the operator can feed the next bag as soon as the previous one moves forward. The output depends on how quickly bags are placed on the conveyor and the speed setting of the belts. It is important to let the belts pull the bag through; pushing or holding back a bag during sealing causes wrinkles in the seal, which can lead to leaks.

The conveyor, sealing belts and toothed guide belts are all driven by a single motor, which keeps the bag mouth and the bottom of the bag moving at the same speed. If the conveyor belt becomes slack, it can fall out of step with the sealing belts, causing the bag to shift or the seal to misalign. In this case, the conveyor belt must be tightened before continuing.

The gap between the two sealing belts at the heated and cooling blocks is set to about the thickness of one layer of the bag film. If the gap is too small, the belts drag and wear out faster. If the press wheel is set too tight, it can block or fold the bag as it passes through. On the AS600F, the filled bag enters from the right and the sealed bag exits on the left, so you need to plan the filling and take-off stations on the correct sides of the machine.

Choosing a band sealer for your bag type

Select a band sealer by the bag’s weight, height and film thickness. FS150 and F150PM handle bags up to 3 kg, while AS600F supports up to 5 kg per bag and 20 kg on the conveyor. The AS600F table adjusts for bags 120–600 mm high.

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

Begin by weighing your heaviest filled bag. If it is up to 3 kg, you can use the FS150 or the F150PM. For heavier bags, up to 5 kg each, the AS600F is the right choice, and its conveyor can carry a total of 20 kg at once. This matters on a production floor where several bags may be on the conveyor at the same time, such as when sealing sacks of granulate or bulk powders.

The AS600F has a conveyor table that you can raise or lower with a handwheel, allowing you to seal bags from 120 to 600 mm high at the correct height. This adjustment is useful when you have bags of different sizes or when the filling line changes product.

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 handles a wider range, from 0.04 to 0.20 mm in a single layer, including laminates and composite films. The FS150 and F150PM run 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 plan for space to feed and remove bags.

Comparison table of band sealer models

The table below compares the three band sealers by sealing speed, temperature, 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 decide which model you can use. Once you have ruled out models that do not fit your bag or film, compare the sealing speed, the type of seal, and the power supply. The heating row in the table shows the two heating tubes in the sealing block: 2 × 300 W on the FS150 and F150PM, and 2 × 400 W on the AS600F.

Printing a date or batch code on the bag

The F150PM band sealer with printer seals the bag and prints a date or batch code in the same pass. The printer has its own switch, and you can set the character spacing, delay and voltage for the print.

A code printed on the bag cannot come off like a label.

With the F150PM, each bag is sealed and printed in one pass, so no bag leaves the packing station unmarked.

There is no label roll to buy, store or change during production.

The delay setting decides where the code lands on the bag. If you change the belt speed, the code position moves along the bag, so you need to check the print location after every speed adjustment. If you do not need a code, the FS150 seals the same bags: up to 3 kg, film up to 0.08 mm, 0 to 13 m/min.

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

To change the code, type the new text on the printer’s display and save it before starting the next batch. Printing begins 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 some bags, you can turn off the printer with its switch and the F150PM will seal without printing, so both marked and unmarked bags can run on the same line.

Setting a continuous band heat sealer for your film

Set the temperature of the continuous band heat sealer low at first, then raise it until the seal holds. Adjust the speed for the film and bag type. For a new bag, start at a lower speed and check the seal before increasing speed.

Raise the temperature step by step. Making a large adjustment at once can burn the film, so small changes are safer.

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

Always check the seal on real bags by pulling it apart by hand and squeezing a full bag. A good seal is even along its length, with no wrinkles or burnt spots. Each film type and thickness needs its own settings, so write down the temperature and speed for every bag you pack. On the AS600F, the seal is set 10–20 mm from the edge of the bag by adjusting the table height.

The seal depends on three main settings: temperature, speed and pressure. The pressure is set at the factory for most bags and usually does not need adjustment. If you cannot get a good seal by changing temperature and speed, increase the pressure in small steps.

The fan cools the seal after it leaves the heated block. Whether the fan runs depends on the film material and its thickness. For common single-layer polyethylene film, the FS150 manual recommends switching the fan on. Polypropylene film requires 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, well below the top speed of the machines. At first use or after a long standstill, warm the heater at a low temperature for a few minutes to remove any moisture from the heating element. While the blocks heat up, run the belts at low speed to avoid damage.

Band sealer, pedal sealer or vacuum packer

A band sealer seals bags one after another on a conveyor, so production does not stop between bags. This suits 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 places the bag on the conveyor.

Pedal heat sealers close one bag per press of the pedal and suit fewer bags. Vacuum packing machines remove air from the bag before sealing, which is needed for products that must be packed without air. Band sealers do not remove air: they close the bag with the air inside.

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

A pedal heat sealer is different. The bag mouth 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 pull a bag mouth of any length through its belts.

A band sealer and a constant heat pedal sealer, such as the ZONE300D, both keep their heated blocks at the set temperature throughout the shift. A band sealer therefore needs 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 heats only when its jaws are closed, so it does not need a warm-up or cool-down period.

At 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. At a band sealer, your hands are free to prepare the next bag. If the bag mouth is wider than the pedal sealer’s bar, you must seal it in two presses, and the overlap can be a weak spot. A band sealer closes the whole mouth in one continuous seal, which avoids this problem.

A chamber vacuum packing machine only takes bags that fit lying flat inside its chamber and works in cycles: the lid closes, air is drawn out, 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 because a wide seal supports more weight. The AS600F makes a 13 mm embossed seal, which is wider than the narrow seal made by impulse pedal sealers.

Vertical band sealers for powders and liquids

On a vertical band sealer, the bag stands upright on the conveyor. This keeps powders, granulate and liquids at the bottom of the bag and out of 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 lay flat.

A vertical model is chosen when the product must stay below the seal. Horizontal models are used for dry solids that do not shift or spill.

Keeping the product below the seal matters because any product in the seal area weakens the seal and can cause leaks.

When filling the bag, make sure the product stays well below the seal line. Let powder settle before the bag reaches the belts to avoid 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 entry to the machine, line up the open end of the bag with the guide plate so it goes into the belts straight. A crooked or wrinkled entry can cause the seal to leak. Check that each bag mouth is flat and straight before it enters the belts.

On the F150PM and AS600F, the center 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 straight under the belts. On the FS150 and F150PM, adjust the table in height and move it forward or back to match the bag size. Powders and liquids are often filled in areas that can get dusty or wet, but the manuals for the F150PM and AS600F require a place without corrosive or humid air.

What affects the price of a band sealer

The price of a band sealer depends on features such as a printer, conveyor load, bag height adjustment and film thickness range. The running cost comes from wear parts like sealing belts and motor brushes. The price for each model is shown on its product card.

The price is affected 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 can handle.

Running costs are mainly from electricity and wear parts, such as the sealing belts and guide belts. On the F150PM, the printer’s ink is an additional cost. The product cards have a Get offer button for a quote and an Add to inquiry button that collects several products into one request.

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

Most of the electricity used by these machines goes into the heating elements. The motors use much less power: 50 W on the FS150 and F150PM, and 120 W on the AS600F.

Care and safe shutdown

Band sealers need daily cleaning of the sealing belts to keep the seal strong. Every month, check the sealing belts and the toothed guide belts for wear. Check the motor carbon brushes and replace them when worn to avoid downtime.

The sealing head is hot during operation. Keep hands away from the belts while the machine runs. For the AS600F, switch off the heating first, let the cooling fan run to cool the blocks, then switch off the power.

Every day, clean any film residue from the sealing belts and wipe down the conveyor.

If a belt is torn, it will leave marks on the seal and must be replaced immediately. On the AS600F, the product page also lists checks of the heating tubes, the rubber wheels and the temperature controller.

The sealing head is hot, so always switch off 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 make sure no water gets into the control panel. The exposed gears need grease every six months to keep them running smoothly. If film sticks to the sealing belt or the heated block, stop the machine and remove the film only when the block is cool.

The F150PM and AS600F manuals call for a new heating tube when the block takes more than ten minutes to reach the set temperature. The FS150 and F150PM are shut down in the same order as the AS600F, and on all three the belts keep running until the blocks have cooled. On the FS150, wait until the temperature drops below 100 °C to protect the sealing belt. On the F150PM and AS600F, wait until it drops below 50 °C. A sealing belt that breaks early is often stretched too tight, runs on its edge, is creased, or has film or dirt stuck to it. Too small a gap at the heated blocks or too high a temperature also makes it break early. Never wear gloves or jewelry near the belts, and always switch off the power when leaving the machine.

Checklist before you order

Before ordering, check the film type and thickness, the weight and height of your bags, how many bags you seal a day, whether you need to print a code or date, the space at your filling station and your power supply. The comparison table above shows the figures for each band sealer model.

Know the film material and thickness of your bags and compare them with the film thickness row of the table above. Weigh your heaviest filled bag and measure the tallest one to make sure they fit the model you choose.

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, allowing room for the bag to come out after sealing. Check the socket: 220 V, or 110 V for the FS150 and the F150PM.

Plan the location for the machine so it stands level, with at least 10 cm of free space around it for ventilation. Keep it away from heat sources and steam, and make sure there is enough room to change the belts when needed.

The F150PM and AS600F manuals specify a room temperature of 5–30 °C for proper 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 stopping. The conveyor moves each filled bag through the sealing area, so production is steady.

How heavy a bag can a band sealer handle?

FS150 and F150PM can seal bags up to 3 kg. The AS600F can seal bags up to 5 kg each, with a total conveyor load 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 on the bag while sealing it. The printer settings are adjusted separately from the sealer.