Induction Sealing of Metallized Film With High-Frequency Position Tolerance
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Solution Overview
Problem
Existing induction heating sealing systems for packaging materials are sensitive to the precise positioning of the inductor and workpiece, leading to inconsistent sealing quality due to misalignment and motion of the packaging material during processing.
Innovation Solution
Reduce the thickness of the metallized film workpiece to below 0.5 µm and increase the frequency of the AC power source to between 1 MHz and 30 MHz, preferably 6,78 MHz or 13,56 MHz, to induce eddy currents effectively without increasing inductor current, thereby reducing sensitivity to positioning errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inductor is powered by an AC power source generating a frequency of around 535 kHz, then efficient and robust seals are achieved, but the system becomes sensitive to relative positions between the inductor and the workpiece
Solution Approach 1:
The patent changes the operating frequency parameter from the conventional 535 kHz to a higher frequency range of 1-30 MHz. This parameter change fundamentally alters the electromagnetic interaction characteristics, reducing the skin depth and improving the coupling between the inductor and the metallized film. The higher frequency enables effective heating even when the workpiece position varies, thereby reducing positioning sensitivity while maintaining sealing reliability.
2Manufacturing precision
If the thickness of the metallized film is reduced to below 0.5 µm, then the system becomes less sensitive to positioning errors, but the power density in the sealing area may be insufficient
Solution Approach 1:
The patent simultaneously changes two parameters: reducing the metallized film thickness to below 0.5 µm (improving positioning tolerance) and increasing the operating frequency to 1-30 MHz (maintaining power density). The higher frequency compensates for the reduced thickness by increasing the induced eddy currents, ensuring sufficient power is delivered to the sealing area even with thinner film.
3Manufacturing precision
If the frequency of the AC power source is increased to between 1 MHz and 30 MHz, then the sensitivity to positioning errors is reduced, but the inductor current would need to be increased to maintain power
Solution Approach 1:
The patent changes the frequency parameter to 1-30 MHz, which improves positioning sensitivity. The thinner metallized film (below 0.5 µm) is specifically optimized for this higher frequency range, creating an efficient electromagnetic coupling that reduces the inductor current requirement compared to using thicker film at lower frequencies. The combination of high frequency and thin film thickness achieves both positioning robustness and power efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides robust and efficient seals with reduced sensitivity to positioning, ensuring consistent sealing quality and reliability in packaging machines.
Implementation Method 1
an inductor is arranged close to the laminate containing the aluminum foil, and the laminate is pressed together with the material to which it is to be joined; the aluminum foil is heated by means of induction
Implementation Method 2
induce eddy currents in a metallized film for inductive heating of the packaging material
Implementation Method 3
Heat is then generated in the workpiece due to Joule effect
Data Source
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AI summary
An induction heating sealing device (50, 50') for induction welding of a packaging material (20) for producing sealed packages (30) of pourable food products in a package producing machine (10) is provided. The packaging material (20) has at least one layer of metallized film (20d). The induction heating sealing device (50, 50') comprises an AC power source (54) and an inductor coil (52) connected to the AC power source (54) and configured to induce eddy currents in the metallized film (20d) for inductive heating of the packaging material (20), wherein the AC power source (54) is configured to generate a variable-voltage or current signal (S) of a frequency higher than 1 MHz.