Before you purchase any shrink wrap packaging machine, it is important to understand how these machines work.
As a matter of fact, these machines come in many configurations, and therefore, the working principle may vary slightly.
Today, we will start by exploring the main working mechanism of shrink wrap machine, then explore how each equipment works.
What is a Shrink Wrap Machine?
A shrink wrap machine is a distinct system that locks up goods in a tamper-evident and transparent film before sealing and shrinking it using heat. This creates an airtight seal, keeping your products safe from moisture, gas, and other foreign elements.
Shrink wrappers simply take the tedious task of wrapping goods off your plate, giving you time to focus on supervision and product quality.
Key Components of Shrink Wrap Machine
| Parts of a Shrink Wrap Machine | Function |
| Sealing system | ·      Cuts the shrink wrap into smaller pieces before wrapping them around your respective goods and sealing them up in preparation for shrinking. |
| Film unwind stand | ·      Unrolls the shrink wrap before conveying it to the sealing unit for packaging. |
| Product conveyor | ·      Relays the unwrapped goods from the loading station to the sealing unit.
·      Transports the wrapped products to the shrinking zone before ejecting the wrapped goods or delivering them to the next packaging station. |
| Heat tunnel/shrink tunnel | ·      Subjects the sealed or wrapped products to hot air, ultimately shrinking the loose film until it tightly grips the products. |
| Temperature control | ·      Allows you to adjust the temperature levels to avert overheating, which can melt the shrink wrap or even harm the wrapped goods. |
| Cooling tunnel | ·      Injects cool air, prompting the heated plastic film to solidify, thus providing your goods with stronger protection. |
| Heating Elements | ·      Generate and supply heat evenly to the shrink tunnel.
·      Often comprised of metal-sheathed heating rods. |
| Control Panel | ·      Consists of the HMI and PLC, which allow you to activate the machine, run it, and deactivate it when done packaging. |
| Machine Casing | ·      Protects the machine’s internal components, as well as you from heat and moving parts. |
How a Shrink Wrapping Machine Works
Step 1: Feeding the Film
Take a roll of plastic film, essentially one made from PVC, polyethylene, or any other heat-shrinkable material, and load it onto the shrink wrapper. Place it on the film unwind stand if you are using an automatic wrapper. However, if your system is manual, you might have to physically load the film and unroll it.
Step 2: Product Placement
Once the film has been loaded and cut into smaller sizes, your goods will be conveyed to the sealing station by the machine’s automatic product conveyor system. This will save you energy and time. Automatic shrink wrappers boast sensors, which will ensure that your product is positioned centrally on the shrink wrap. This will ensure that the entire product is evenly and sufficiently covered.
Step 3: Wrapping the Film Around the Product
Once your product is positioned at the center of the shrink wrap, for instance, a centerfold shrink wrap, the rollers present in the sealing unit will proceed to enclose the product with the film evenly. Subsequently, the sealing unit’s sealing bar is lowered, and it begins by trimming off the extra shrink wrap material. After this, the sealing bar encloses all the edges, leaving your product fully covered in a befitting plastic film.
Step 4: Applying Heat to Shrink the Film
With the product fully wrapped and sealed in plastic film, it is then conveyed to the shrink tunnel by the machine’s product conveyor belt. Here, controlled heat is applied evenly, leading to the contraction of the shrink wrap without risking ruining the film or your products.
Once the right amount of heat is applied, the film loses its looseness, consequently fitting your products like a glove on a hand. The table below shows the temperature settings you should adhere to when shrinking your wrap film.
| Shrink Wrap Film Type | Recommended Temperature Range (°C) |
| Polyethylene | 150-180 |
| Polyolefin | 160-175 |
| PVC | 120-150 |
Step 5: Cooling and Ejecting the Product
To conclude the wrapping process, cool air is blown onto the shrunken wrap film. This solidifies the film, making its grip on the products stronger and tighter. The solid film is also stronger and much harder to tamper with. If you are reliant on a manual shrink wrap, you can bath the wraps with cold water or let them cool down naturally.
Types of Shrink Wrapping Machine & How They Work
· L-bar Sealers
These shrink wrapping machines typically work with centerfold shrink wraps mainly because they comprise a sealing bar whose shape resembles the letter ‘L’. This bar comprises a micro knife, which cuts the film covering your item before sealing it using a hot wire.
· Sleeve Wrappers
Sleeve wrapping machines primarily serve as secondary packaging units, allowing you to bundle together and neatly package products like beverage cans and jars. They simply place your products at the center of polyethene film sleeves before sealing both sides. This leaves the top and bottom unsealed.
· Shrink Tunnels
These chambers come connected to sealers, and they are primarily tasked with shrinking the plastic film wrapping your items. Shrink tunnels comprise a heating zone and, in some instances, multiple heating zones, which apply the right amount of heat on the wrapper, leading to uniform film shrinking.
· Fully Automatic Shrink Wrapping Machine
These shrink wrap machines hardly necessitate your input in either wrapping, sealing, or shrinking. They feature components such as conveyor systems, sensors, and computerized interfaces, which undertake these tasks automatically. With an automatic shrink wrapper, you can shrink-wrap up to 20,000 items a day, thus broadening your profit margins.
FAQs
Which is the best shrink wrap film?
Polyolefin is often singled out as one of the most outstanding shrink wrap films, and this is primarily because of its strength and food-safe classification. However, other films, particularly PVC and polyethylene, are equally good.
What are the disadvantages of shrink wrapping?
Shrink wrapping, as beneficial as it is, comes with some shortcomings, including easy puncturing when exposed to sharp objects. This packaging method is also unsuitable for items that necessitate airflow, such as certain cosmetics.
How long does shrink wrap last?
The general expectation is that your shrink wrap should remain effective for 6-12 months. However, this is not always the case since exposing shrink wrap to sharp objects or unfavorable elements like heat can significantly shorten its lifespan.
How much does a shrink-wrapping machine cost?
Shrink wrapping machines do not come with standard specifications, and this makes estimating their cost quite difficult. Their price is heavily informed by their capacity, automation level, and design, among other factors. However, to lay your hands on a fully automatic shrink wrapper, you should be prepared to part with at least $30,000.
Which is the safest shrink wrap film for food products?
POF thrives in packaging foods, both fresh and baked, and this is a testament to its unrivalled food-safety rating. It is essentially non-poisonous even when it comes into direct contact with your food.
What is the difference between shrink wrapping and stretch wrapping?
Stretch wrapping encloses your items using an elastic yet strong film, consequently protecting them and grouping them. Shrink wrapping, in contrast, secures your items by enveloping them in a transparent and shrunken plastic film, thus providing greater protection.
What are the advantages of shrink wrapping?
Unlike other wrapping methods, shrink wrapping promises superior protection since the shrunken film is sturdier and less prone to wear and tear. It also gives you a clear glimpse of the wrapped items, making it easier for you to keep track of your inventory.
Flexshrink; Your Trusted Shrink Wrap Machine Manufacturer in China
At Flexshrink, we specialize in designing and manufacturing a wide range of shrink packaging machines. From manual shrink wrapping machines to fully automatic shrink wrapping machines, we offer a wide range of packaging solutions.
If you are looking for custom-made shrink packaging solution, Flexshrink is your trusted partner in China – Get our machine catalogues now.
