When your packaging line is running smoothly, it’s a beautiful thing. But once problems arise, it can quickly turn into a costly nightmare.

Every minute your automated packaging machine jams, or every batch of drip coffee bags that fails a leak test, means you are wasting labor costs, premium roasted coffee beans, and packaging materials.

Over the years, Tonchant has accumulated extensive experience in producing both packaging materials (filter rolls and outer films) and fully automated packaging machinery. We have witnessed almost every possible malfunction on the production line. The good news is: almost all of these malfunctions are completely preventable.

Here are the four most common problems with drip coffee packaging, their root causes, and specific solutions to fix them.

Problem 1: The Outer Packaging Bag Leaks or Bursts Open

You package the coffee, flush it with nitrogen, and it looks great. But a few days later in the warehouse, the bags look deflated, or worse, they burst open during shipping.

• The Cause: This is almost always due to sealing temperature issues or a mismatch between the machine’s heating jaws and the film material. If the temperature is too low, the inner sealant layer (PE or CPP) will not melt sufficiently and will not bond. If the temperature is too high, the jaws will cause the plastic to “boil,” resulting in microscopic pinholes at the seam.

• The Solution: You need to find the exact “sealing window” for your specific roll of film.

  • The Test: Lower the temperature by 5°C and run a test. Slowly increase the temperature incrementally until a seal is formed that cannot be pulled apart by hand (the film itself should stretch or tear before the seal breaks).

• The Tonchant Advantage: If you use Tonchant roll film on a Tonchant machine, we provide the precise temperature and dwell time parameters in advance. No guesswork required.

Problem 2: The Inner Drip Filter Tears During Brewing

For consumers, the worst-case scenario is pouring hot water into a premium drip coffee bag, only to have the bottom suddenly burst open, spilling a clump of muddy coffee grounds directly into their cup.

• The Cause: There are two possible reasons for this. First, the tensile strength of the filter material is simply insufficient. Second, the heat-sealing process was too aggressive, degrading the edge strength of the filter material. This is especially common if you attempt to heat-seal biodegradable PLA (Corn Fiber) mesh.

• The Solution:

  • Material Upgrade: Use a high-strength nonwoven fabric or premium mesh specifically engineered to withstand the weight of wet coffee grounds.

  • Equipment Upgrade: If you are using eco-friendly PLA filter rolls, you must stop using heat-sealing machines and switch to Ultrasonic Sealing Technology. Tonchant machines use high-frequency sound waves to instantly fuse the filter edges, avoiding thermal damage and ensuring a strong, clean seam that will never break.

Problem 3: The Coffee Spoils Too Quickly (Staling)

Three months later, a customer opens the package only to find that the coffee smells like cardboard and the fresh roasted aroma has completely disappeared.

• The Cause: Oxygen infiltration. This usually means your nitrogen flushing system is out of sync, or the Oxygen Transmission Rate (OTR) of the outer packaging film is too high. Cheap, thin plastic bags allow oxygen to slowly permeate over time, regardless of how much nitrogen you flushed into the bag on day one.

• The Solution:

  • Check the calibration of your nitrogen generator. The flush must be completed within milliseconds right before the final seal is closed.

  • Upgrade your roll film. You must use a high-barrier composite structure. Tonchant recommends using Pure Aluminum Foil (AL) or high-quality Metallized PET (VMPET) structures for any coffee expected to sit on a retail shelf for more than 3 months.

Problem 4: Film Jams and “Eye Mark” Tracking Errors

Your Vertical Form Fill Seal (VFFS) machine keeps stopping. The cut line is misaligned, slicing straight through the middle of your printed logo instead of cleanly cutting at the top edge.

• The Cause: The photoelectric sensor is losing track of the “Eye Marks” (the small black rectangles printed on the edge of the film). This typically occurs if the film is too thin and stretches under the machine’s pulling tension, or if the film surface is too glossy, causing the sensor’s light to reflect incorrectly.

• The Solution: * Ensure the film thickness of the drip coffee outer bag is strictly controlled between 70 and 90 microns. A film that is too thin will stretch and deform under mechanical stress.

• The Tonchant Advantage: Our prepress design team ensures that the eye mark contrast is perfectly calibrated to standard optical sensors. Furthermore, Tonchant machines use active tension control motors to keep the film taut consistently, eliminating stretching and cutting misalignment from the first bag to the last.

Conclusion: Stop Fighting Your Equipment

Packaging should be the most efficient part of your coffee business, not the most difficult. When roasters try to cobble together a production line using packaging film from one supplier, filter paper from another, and machines from a third, troubleshooting inevitably becomes a game of finger-pointing.

At Tonchant, we are committed to eliminating that friction. Because we engineer our own filter meshes, print our own roll films, and manufacture the automated equipment, we ensure that every single component works seamlessly together.

Are you experiencing specific packaging defects on your production line? Contact our engineering team today for a free consultation. Tell us about the problem you are encountering, and we will help you engineer the perfect solution.