Heat Sealers: Introduction and Overview

Table of Contents

A heat sealer (also called a bag sealer or heat sealing machine) is a device that uses heat and pressure to bond thermoplastic materials, creating an airtight, leak-proof seal on bags or pouches. Heat sealers are widely used in packaging to protect contents from moisture, dust, and contamination. They can seal plastic bags, foil or Mylar pouches, multi-layer barrier bags, and more, making them essential for food, medical, and industrial packaging. By understanding the different types of heat sealers, their features, and applications, you can choose the right bag sealer machine for your needs.

Types of Heat Sealers

Heat sealers come in several varieties, but the two main categories are impulse sealers and continuous (constant) heat sealers. Each type has its own mechanism and best-use scenarios.

Impulse Sealers

Impulse heat sealers use a short, high-current pulse to heat the sealing bar only when closing the bag. There is no warm-up time – the sealer stays cool until activated. Because power is applied only during the seal cycle, impulse sealers are energy-efficient and safer to operate (no part remains hot between seals). They are ideal for low- to medium-volume use. Handheld or tabletop impulse sealers typically handle thinner thermoplastics (common plastics like polyethylene (PE) or polypropylene (PP)) up to about 10–15 mil thick. For example, impulse sealers are perfect for everyday plastic bags, padded mailers, and even metalized or laminated films used in food packaging.

Impulse sealers come in various forms: simple manual clamshell sealers, bench units with foot pedals, or portable models. They often feature adjustable timers or temperature controls to match the seal to the material. (Many impulse machines include PTFE-covered bars so plastic doesn’t stick when heated.) Because they heat briefly, impulse sealers require little energy and burn off quickly after each seal, reducing the risk of overheating the package.

Heat sealers forming device
Heat sealers forming device

Continuous (Constant) Heat Sealers

Continuous (or direct heat) sealers maintain their jaws at a constant high temperature. The machine must be turned on and allowed to warm up to operating temperature before sealing. Once heated, products can be fed under the hot sealing bar on a conveyor or in cycles without pausing for temperature recovery. This makes continuous sealers ideal for high-volume, fast-paced production. They can seal a large number of bags rapidly and consistently – much faster than impulse models for long production runs.

Continuous sealers penetrate heat more deeply, allowing them to bond thicker or multi-layered materials. For example, they are commonly used to seal foil-lined coffee bags, Mylar pouches, cellophane, and other heavy-duty films. (One source notes that constant heat sealers are “perfect for coffee bags with metalized material” and “great for thicker Mylar”.) The trade-offs are that continuous sealers consume more power and typically cost more. They also require safety features (like guards or auto-shutoff) since the sealing bars stay hot.

Heat sealers

For quick comparison, the table below highlights key differences between impulse and continuous heat sealers:

Impulse vs Continuous Heat Sealers Comparison

Feature Impulse Sealer Continuous (Band) Sealer
Heat Mechanism Heats for a short burst when sealing (no warm-up needed) Maintains constant heat (warm-up required)
Warm-Up Time No warm-up; ready to seal immediately Requires warm-up to reach operating temp
Material Compatibility Best for thinner films (PE, PP, PVC, Mylar, Tyvek, etc.) Handles thicker or laminated films (foil, foil-laminates, heavy films)
Throughput Low to medium volume; manual or batch use Medium to high volume; continuous production
Energy Use Lower (only heats during seal) Higher (continuous heating)
Initial Cost Generally lower Generally higher
Operator Attention Requires pressing for each seal Less operator needed once running
Safety Safer for operators (bars cool except during seal) Requires caution (bars stay hot)

The above differences reflect industry sources: impulse sealers “use pulses of heat” and only heat when engaged, making them energy-efficient, whereas continuous sealers “are temperature controlled and have jaws that remain hot,” suited for high-speed sealing of durable packages.

Key Features to Consider When Buying a Heat Sealer Machine

When selecting a heat sealing machine for your business or project, evaluate the following features:

  • Sealing Width and Bag Size: Choose a sealer that accommodates the width (seal length) and size of bags you need. Common seal bar lengths range from 6–18 inches or more.

  • Material Thickness Capacity: Check the maximum bag thickness (in mils) the sealer can handle. For example, a basic handheld impulse sealer typically seals up to ~10 mil thickness, while heavy-duty foot or double-impulse sealers can handle 15–20 mil or thicker. Continuous band sealers often seal even thicker materials due to better heat penetration.

  • Heating Controls: Look for adjustable timer or temperature controls to match the material. Precisely setting the dwell time/temperature ensures a strong seal without burning through the plastic. Some models use digital displays or knobs. (For instance, one benchtop model has a timing knob so the user “turn[s] the knob to set the time… and remove[s the bag] when the light indicates that the cycle is complete”.)

  • Cutting Blade: Some sealers include a built-in cutter. An integrated cutter trims the bag immediately after sealing, creating a clean edge and eliminating the need for scissors. If you need to trim excess film, a sealer with cutter can greatly speed up packaging. (See “Benefits of Using a Heat Sealer With Cutter” below.)

  • Operation Mode: Decide between manual/semi-automatic or automatic. Manual or foot-pedal sealers require an operator to hold bags in place; automatic band sealers feed the bag along a conveyor. For high-volume work, a continuous band sealer with auto-feed is ideal.

  • Build Quality and Duty Cycle: Heavy-use machines are often metal and may be rated for continuous-duty use. For occasional or light use, a smaller plastic-bodied desktop sealer may suffice. Check manufacturer ratings (e.g. “duty cycle”) to ensure the machine fits your daily workload.

  • Safety Features: Look for features like a Teflon-coated sealing bar (prevents sticking), insulated handles, auto shutoff, or safety guards. Notably, impulse sealers are inherently safer because the heating element is only hot when sealing, but it’s still wise to use caution around any hot parts.

  • Voltage/Power and Vacuum Capability: Ensure the sealer matches your power supply (e.g. 110V vs 220V). Some heat sealers also offer optional vacuum or gas-flush attachments if you need to remove air from bags before sealing (common in food packaging).

  • Brand and Support: Consider reputable manufacturers that offer warranties and replacement parts (like sealing bars, PTFE covers, cutters). Quality support can be crucial for downtime mitigation.

By matching these features to your packaging needs, you can select a heat sealing machine that will seal effectively, safely, and reliably.

Shrink Wrap Machine Shrink Tunnel (Heat sealers)

Best Applications: What Can You Seal?

Heat sealers can be used on a wide variety of bag and pouch materials. Common applications include:

  • Plastic Bags (PE, PP, PVC): Standard plastic bags or pouches (polyethylene or polypropylene) are easily sealed by most impulse or continuous sealers. These cover grocery bags, padded mailers, garment bags, etc.

  • Mylar and Foil Bags: Mylar (a metallized polyester) bags and foil laminated pouches (e.g. coffee bags, spice pouches) require good heat penetration. Continuous heat sealers are often used here; they handle these thicker, reflective films well. Impulse sealers can also seal Mylar, but may need higher settings. As one packaging supplier notes, heat-sealing Mylar bags provides “reliable protection and airtight closure” for food items.

  • Multi-layer Barrier Bags: Vacuum-seal bags and oxygen-barrier pouches (often used for freeze-dried or medical products) are typically heat-sealed to preserve freshness and sterility. Heat sealers ensure a tight seal on multilayer nylon/PE laminates and stand-up pouches.

  • Food and Perishables: Many small food businesses use heat sealers for packaging snacks, nuts, coffee, herbs, or bulk foods. Sealing bags keeps products fresh by preventing air and moisture ingress. (For example, foil coffee bags are routinely sealed to retain aroma.)

  • Medical and Sterile Packaging: Hospitals and labs use medical grade bag sealers (often continuous or vacuum sealers) to seal instrument pouches or sterile packaging. Materials like sterilization wraps or Tyvek require precise sealing.

  • Retail and Consumer Items: Any product sold in plastic or film packages can use heat sealing – from hardware parts and toys to sample sachets and gift items. A heat sealer provides a quick way to securely close polyethylene merchandizing bags or blister backings.

  • Laboratory and Industrial: Glovebags, electrodeposited film, and other specialty plastic films can also be sealed. Heat sealers are common in labs for sealing reagent bags and polymer films.

In short, if a bag is heat-sealable (i.e. made of thermoplastic or has a heat-seal coating), a heat sealer can likely seal it. Always check the material specifications. For example, impulse sealers are recommended for many thermoplastics – they can seal items including Mylar or Tyvek—while continuous sealers excel with thicker foils and heavy-duty bags.

Benefits of Using a Heat Sealer With Cutter

Some heat sealing machines include a built-in cutter, often called a heat sealer with cutter. This feature brings several advantages:

  • One-Step Sealing and Cutting: A heat sealer with cutter seals the bag and then trims off the excess material in one action. For example, one model “slides a blade” after sealing that “removes any excess material 19 mm from the seal point”. This means you don’t need scissors or separate trimming steps – packaging is faster and more efficient.

  • Neat, Consistent Edges: The integrated cutter creates a straight, uniform cut on every bag, improving the appearance and reducing waste from uneven edges.

  • Convenience: Especially for continuous operations, the cutter saves operator time. After sealing, the bag emerges neatly trimmed and ready for labeling or shipping.

  • Safety and Cleanliness: A built-in cutter is designed for the machine’s operation, so it is often safer and more precise than using a hand-held blade. It also keeps the workspace tidier by immediately removing scrap trim.

Overall, a heat sealer with cutter is ideal if you frequently make custom-sized bags or need very clean edges. It combines two tools into one, boosting productivity in packaging tasks.

Tips for Choosing the Right Bag Sealer Machine

When shopping for a heat or bag sealing machine, keep these practical tips in mind:

  1. Assess Your Production Volume: If you only seal a few bags a day (e.g. small business, home use), a simple impulse sealer is usually sufficient. For large-scale packaging (hundreds to thousands of bags), consider a continuous band sealer. High-volume operations benefit from continuous sealers or automatic machines for speed.

  2. Match the Machine to Your Material: Know the type and thickness of your bags. Impulse sealers work well for most thin-to-medium plastics, while continuous sealers handle thicker, laminated, or foil bags. Always check the manufacturer’s specifications for material compatibility.

  3. Choose Appropriate Seal Strength: For valuable or sensitive products, you may need the strongest seal (constant heat at higher temp). For inexpensive plastics or short-term use, impulse seals are often adequate. If uncertain, many suppliers can recommend a model for your bag material and contents.

  4. Decide on Manual vs. Automated: A handheld or foot-pedal sealer requires operator involvement for each bag, which is fine for low quantities. For medium runs, a table-top semi-automatic (foot switch actuated) may be ideal. For high throughput, an automatic belt or conveyor sealer reduces labor.

  5. Check Features: Consider if you need a cutter, vacuum capability, adjustable temperature, or digital controls. While these add cost, they can improve efficiency or seal quality for specific applications.

  6. Consider Budget and ROI: Entry-level impulse sealers can be very affordable (often under a few hundred dollars), making them great for startups. Industrial band sealers cost more upfront, but may pay off if you regularly process large volumes. Think about long-term durability and maintenance too.

  7. Read Reviews and Ask for Demonstrations: If possible, see the machine in action on a similar bag. Quality and ease of use vary by model. Also ensure spare parts (sealing strips, cutters, etc.) are available.

By carefully matching the sealer’s capabilities to your bags and workflow, you’ll get the best performance and value from your investment.

Conclusion and Call to Action

Choosing the right heat sealing machine (or bag sealer machine) ensures your products stay fresh, safe, and well-packaged. Whether you need a compact plastic bag sealer for a small shop or an industrial impulse heat sealer / continuous sealer for large-scale production, understanding the types and features is key. We hope this guide has helped clarify how heat sealers work, what to look for, and where each type excels. For expert advice or to explore high-quality heat sealer machines (with optional cutters, vacuum capability, etc.), consider contacting Yundu Filling Machine. Our team can help you find the perfect sealing solution for your application. Feel free to reach out for a quote or more information on bag sealing equipment that meets your needs.

Heat Sealer FAQ

Transparency is the cornerstone of our Yundu team. That’s why below, you can find the most common questions and answers we receive surrounding our Heat Sealer.

Impulse and continuous heat sealers both use heat to seal bags, but they operate differently. An impulse sealer heats its sealing bar only momentarily when sealing, requiring no warm-up time. It’s energy-efficient and well-suited for thinner plastics. A continuous (constant) heat sealer keeps its jaws at a set temperature continuously, which means you must wait for the machine to warm up. Continuous sealers handle thicker or multilayer materials and high-speed production, but they consume more power. (In short, use impulse for quick, low-volume jobs and thin films; use continuous for heavy-duty, high-volume sealing.)

Yes, many heat sealers can seal Mylar and foil pouches. Thicker foil bags often require the thorough heat of a continuous sealer. In practice, continuous sealers are ideal for Mylar or foil bags (like coffee or freeze-dried food pouches) because they penetrate heat better. Some heavy-duty impulse sealers can also seal Mylar if set to a high temperature. When sealing such materials, always use the correct temperature/time and consider a Teflon cover to prevent sticking.

This depends on the model. As a rule of thumb: a basic hand impulse sealer handles up to about 10 mil thickness, a foot or bench impulse sealer up to ~15 mil, and a heavy-duty/double-impulse sealer up to ~20 mil. Continuous band sealers may handle even thicker laminates. Always check the machine’s specs for maximum seal thickness (in mils or gauge) to ensure it meets your bag’s requirements.

A heat sealer with cutter is a machine that not only seals the bag but also has an integrated blade to trim the excess film. After sealing, the built-in cutter slides along the bag edge and removes the extra material. This leaves a neat, uniform edge on each bag. The benefit is that you get a sealed, finished bag in one step – no separate cutting needed.

Yes, modern heat sealers are generally safe if used correctly. Impulse sealers are designed so that the heating element is only hot during the seal cycle, reducing burn risk. Many models also have insulating handles and automatic shut-off once the seal is complete. Still, never touch the heating bars during operation and be cautious of hot surfaces. Always follow the manufacturer’s safety guidelines (e.g. wear gloves if needed) and keep the machine clean. Routine maintenance (replacing worn PTFE strips or silicone pads) also helps ensure safe operation.

Regular maintenance keeps seals strong and machine life long. Common tasks include:

  • Cleaning: Remove plastic residue or dust from the sealing bars and trim area after use.

  • Inspecting parts: Check the condition of the PTFE (Teflon) cover and the rubber/silicone sealing pad (if present). Replace them when worn or damaged.

  • Heating element: For impulse sealers, the nichrome wire heater may eventually need replacement (these are sold as spare parts).

  • Calibration: Ensure the timer or temperature settings still produce good seals; recalibrate if the seal seems weak.
    Manufacturers often advise regular checks. One packaging equipment guide recommends “cleaning the machine, checking for wear and tear, and replacing any worn-out parts” per the manufacturer’s guidelines.

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Hey there, I’m Daisy

I’m the Sales manager of Yundu. We have been helping manufacturing industries increase their productivity and capacity with our advanced filling machines for over 20 years.

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