Aluminum foil bag feeding machine anti double bag solution | Magnetic induction double sheet detector solves stacking defects

1、 The dual bag problem of aluminum foil bag feeding machine

Why are aluminum foil bags particularly prone to double bags

When aluminum foil composite packaging bags (aluminum foil+PE/PET multi-layer composite structure) are operated on the bag feeding machine, the problem of double bags is more prominent than that of ordinary transition bags, for three reasons:

Serious electrostatic adsorption. During the process of bag making, transportation, and storage, aluminum foil bags generate a large amount of static charges due to surface friction. When two bags are stacked together, the electrostatic force makes them firmly adhere, making it difficult for the suction cup to separate only one piece when taking out the bag.

Partial adhesion after lamination. Aluminum foil bags are stacked in the bag compartment, and the weight of the upper bag presses the lower bag tightly. In addition, the aluminum foil layer itself has good flexibility, and the edges and central areas between bags are prone to local vacuum adsorption, like two pieces of glass stacked together and not easily separated.

The bag surface is smooth and the friction coefficient is low. The outer surface of the aluminum foil is smooth, and the sliding friction coefficient between the two aluminum foil bags is small. When the suction cup pulls up one piece, it drives the adjacent piece to move together, which is more prone to double tearing than rough materials.

1.2 Chain loss caused by double bags

The double bag problem is not just about wasting one packaging bag, but also dragging down every subsequent process

Bag opening failure: After the double bag enters the bag opening station, the bag opening suction cup cannot correctly open the bag opening and directly jumps or gets stuck

Abnormal filling: Even if the bag is reluctantly opened, the filling nozzle is inserted between two layers of bags, and the material is scattered in the interlayer, resulting in inaccurate weighing and material waste

Poor heat sealing: Two layers of bag openings are stacked together for heat sealing, and the sealing strength is insufficient, resulting in leakage and false sealing, and the entire bag is scrapped

Equipment jamming: Double bag thickness doubles on the conveyor gripper, making it easy to get stuck on the guide rail or turntable station. Stop and clean for at least 10-15 minutes once

Terminal accident: Double bag products that missed inspection enter the market, consumers receive "bag in bag", complaints, returns, brand damage

A bag feeding machine has a normal production capacity of 80-120 bags per minute, and even with only a 1% double bag rate, 48-72 defective products can be produced in one hour. Calculated at a cost of 5-10 yuan per bag of materials, the daily material loss is several thousand yuan.

2、 Why choose magnetic induction detection solution

2.1 Specialty of Aluminum Foil Bags - Metal Layer

The biggest difference between aluminum foil bags and ordinary transparent PE bags and woven bags is that the bag body contains an aluminum foil metal layer. This layer of aluminum foil (usually 6-9 μ m thick) is a conductive metal material.

The working principle of the magnetic induction dual detector is to use this layer of metal:

Detection principle: The probe of the detector generates an alternating magnetic field. When the bag containing the aluminum foil layer passes through the detection area, the aluminum foil metal layer generates eddy currents in the magnetic field. The total thickness of aluminum foil for single and double bags is different, and the intensity of eddy currents generated is also different - the eddy current signal for double bags is about twice that of single bags. The detector determines whether a single bag or a double bag has passed by comparing the real-time signal with the calibration reference value.

This principle is naturally suitable for aluminum foil bag scenarios:

Aluminum foil layer is a definite metal conductor, with stable and repeatable signals

The signal difference between single bag and double bag is large (nearly twice), with high discrimination

Not affected by bag color, printing pattern, transparency

2.2 Comparison with other testing schemes

The core advantage of the magnetic induction solution is that the aluminum foil bag comes with its own detection conditions. No additional modifications are required for the bag, no labeling is needed, and no changes to the packaging material are needed - the aluminum foil layer of the bag itself is the source of the detection signal.

3、 Detailed solution explanation

3.1 System composition

Core components:

Detection probe: Targeting sensor SE-1000BS-F5.0, installed on the upper and lower sides of the conveying path of the bag taking machine to form a detection area

Detection controller: processes probe signals, real-time determines single bag/double bag, outputs switch signal to bag machine PLC

Signal connection line: shielded cable, resistant to workshop electromagnetic interference

3.2 Installation location

Best installation point: after the suction cup takes out the bag and before the bag opening station.

At this stage, the bag has just been sucked out of the bag compartment and is in a single-layer unfolded or stacked state, and has not yet entered the bag opening process. At this point, double bags have been detected and can be directly returned to retrieve the bags without affecting subsequent processes.

Installation requirements:

The probe spacing is set according to the thickness of the bag (usually 10-30mm)

Aim the probe at the center area where the bag passes, avoiding the folded edges and sealing positions of the bag

The bag feeding machine has a speed of 80-120 bags per minute, and the detector response time should be ≤ 50ms to meet the high-speed rhythm

3.3 Workflow

Calibration: Use a normal aluminum foil bag to pass through the detection area, record the single bag reference signal value, and set the judgment threshold

Online detection: After each bag is taken, the bag passes through the probe detection area, and the detector measures the signal in real time

Judgment:

Signal within reference range → single bag, release

Signal exceeds threshold → Double bag, immediately output signal to bag machine PLC

Action execution:

After receiving the double bag signal, the bag machine automatically puts the double bags back into the bag compartment or removes them to the waste channel

Suction cups can be removed from the bag without stopping the entire process

3.4 Adapt to different specifications of aluminum foil bags

The bag machine production line often needs to switch between packaging bags of different specifications. Magnetic induction detector replacement operation:

Same material but different size: generally does not require recalibration, the thickness of the aluminum foil layer is the same, and the signal difference is not significant (small materials need to be recalibrated, depending on the working conditions, communicate with the engineer)

Different composite structures (such as pure aluminum foil vs aluminum plated film): The thickness of the metal layer is different and needs to be recalibrated

Switching bags from different suppliers: It is recommended to calibrate and confirm 3-5 bags after each switch

4、 Summary of program advantages

5、 Typical application scenarios

Snack food: packed in aluminum foil bags with spicy strips, dried tofu, Soy egg and nuts

Prefabricated dishes: aluminum foil self standing bag packaging for cooking bags and soup products

Seasoning: Aluminum foil composite bag packaging for sauce packaging and hot pot base

Pet food: packaged in aluminum foil fresh-keeping bags

Healthcare: Aluminum foil bagged powders and tablets

As long as your packaging bag contains an aluminum foil layer (pure aluminum foil or aluminum plating is acceptable) and uses a bag packaging machine, this solution can be directly applied. You can contact the official phone number of Atong at 13342814291, and we will provide you with a solution.