What is a Shrink Wrapping Machine?
First, let’s talk about the Shrink Wrapping Machine, the most common type of shrink packaging machine. Its professional name is “L-shaped seal shrink packaging machine” or “L Bar Shrink Film Wrapping Packing Machine.”
Working Principle
Bag Forming: It uses a special L-shaped sealer and cutter to create a horizontal seal vertically and then a vertical seal horizontally. In a continuous motion, the plastic film forms a “pocket” or “wrap” around the back and bottom of the item (depending on the machine settings).
Shrinking: After sealing and cutting, the packaged item passes through a shrink tunnel (hot air tunnel). The hot air shrinks the film, conforming to the contours of the product, enhancing its appearance, while protecting it from dust, moisture, and moisture.
Main Features and Applications
Features: Suitable for packaging single or multiple products, with high packaging efficiency, making it ideal for automated production lines.
Applications: Widely used in food, beverages, daily chemicals, pharmaceuticals, stationery, electronics, and other fields. For example:
Packaging of mineral water and beverages.
Collective packaging of cosmetics and medicine boxes.
Transparent packaging of books and stationery.
Why does the blade get stuck in the plastic?
This is a very common problem with shrink wrapping machines, often caused by a combination of factors. Blade sticking can result in a weak seal, incomplete cuts, burrs, and even machine downtime.
The following are the main causes and solutions for this problem:
Film is positioned incorrectly
If there’s always a section of your plastic film that won’t cut, check your positioning! The shrink wrapping machine has a line. Your film needs to be positioned within it to be cut. Film outside this line won’t be cut.
Solution:
Move the film inside this line and let it be cut by the cutter
Temperature Issues (Most Common Cause)
Cause:
Too low a temperature: The blade isn’t hot enough to instantly melt the film, causing it to “tear” or “stick,” becoming entangled in the blade.
Too high a temperature: Excessively high temperatures can cause the film to over-melt, turning it into a viscous liquid. This also sticks to the blade, forming a hard, charred mass upon cooling, which can affect the next cut.
Solution:
Adjust to the optimal temperature: Reset the blade temperature based on the film material (e.g., POF, PE, PVC) and thickness. Finding the optimal temperature requires repeated testing. Suppliers typically provide a reference temperature range.
Problems with the Sealing and Cutting Blades
Causes:
Insufficient Blade Pressure: Insufficient pressure prevents cleanly pressing and cutting the film.
Worn or Damaged Blades: The blade edge becomes blunt, chipped, or the coating peels off, resulting in a less-than-sharp cut.
Misaligned Blades: The upper and lower (or L-shaped) blades are not perfectly aligned, resulting in uneven pressure and incomplete cutting in some areas.
Solutions:
Adjust the pressure: Appropriately increase the pressure on the sealing and cutting blades.
Check and Replace Blades: Regularly inspect the blades; replace or sharpen them if severely worn.
Recalibrate Blades: Ensure the blades are flat and aligned to ensure even pressure across the entire sealing surface.
Film Material Problems
Causes:
Material Mismatch: The film material used is not suitable for the edge sealer. For example, some PE films have strong self-adhesive properties and are more likely to stick to the blade.
Poor Quality or Moisture: Low-quality or damp film can produce more impurities and sticky substances when heated.
Solution:
Replace the film: Try using a film designed specifically for edge sealers with improved anti-stick properties (such as high-quality POF film).
Ensure film storage conditions: Store the film in a dry, cool place.
Machine Setup and Synchronization Issues
Cause:
Excessive sealing and cutting time: The blade remains in the downward pressure position for too long, causing the film to overheat and stick.
Out-of-sync film feed speed and sealing and cutting rhythm: The film tension is unstable, resulting in excessive slack or tension at the moment of sealing and cutting.
Solution:
Optimize sealing and cutting time: While ensuring a secure seal, minimize the contact time of the sealing and cutting blades.
Adjust film tension: Check and adjust the tension of the film feed roller to ensure that the film is flat and appropriately stretched during sealing and cutting.
Cleaning and Maintenance Issues
Cause:
Residue on the blade: Carbonization of previously adhered plastic creates a rough surface, which can exacerbate subsequent sticking.
Solution:
Clean the blade regularly: After the machine has cooled, spray the blade with a special high-temperature, anti-stick silicone oil or wipe it with a soft cloth. Never scratch the blade with hard objects to avoid damaging the Teflon coating. Cleaning is a key step in daily maintenance.
Machine Quality Issues
Some older machines may have a blunt blade, difficult to control the temperature, or require temperature readjustment after prolonged use, which can also cause plastic blade jams.
Solution: Choose EasternPack’s Shrink Wrapping Packing Machine to eliminate all your worries. Worried about blade jams? Send us your film samples in advance. Our team will conduct professional machine testing to verify your film type’s compatibility and adjust the temperature to the optimal level before delivery. Upon receipt, you can start using the machine immediately without any tedious adjustments.
Summarize the troubleshooting steps
If a blade jam occurs, we recommend the following steps:
Clean the blade.
Check and adjust the temperature (this is the most likely cause).
Check and adjust blade pressure and alignment.
Try replacing a roll of film with a known good one.
Finally, check the machine’s synchronization and timing settings.
A systematic troubleshooting approach can usually identify and resolve the problem, restoring stable and efficient machine operation.