Induction Solder Joint Heating for Uniform Power Electronics Assembly
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Solution Overview
Problem
Existing soldering methods in power electronics result in varying quality of soldered connections due to uneven heating and cooling, leading to potential defects.
Innovation Solution
A method using induced eddy currents from a magnetic field generated by a winding to uniformly heat and cool solder joints, with temperature control via pyrometers, ensuring precise alignment and termination of heating based on temperature thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional heating methods (oven or induction) are used to melt solder, then the soldering process can be completed, but the soldered connections exhibit varying quality due to locally uneven heating and cooling
Solution Approach 1:
The patent replaces conventional thermal conduction heating (mechanical/thermal system) with electromagnetic induction heating. A magnetic field is applied to the substrate to induce eddy currents that generate heat directly within the substrate material, enabling uniform and localized temperature control at each soldering position without the temperature gradients caused by conventional heating methods.
Solution Approach 2:
The patent changes the heating mechanism from external thermal conduction to internal electromagnetic heating. By controlling the magnetic field parameters (strength, frequency, duration) and the relative movement between the magnetic field source and substrate, precise temperature control is achieved at each soldering location, eliminating the uneven heating problem.
2Productivity
If the substrate is moved relative to the magnetic field source to position different components under the heating zone, then multiple components can be soldered, but the relative movement may cause components to collide with the magnetic field source
Solution Approach 1:
The patent introduces a third spatial dimension (vertical offset) between the substrate and the magnetic field source. The substrate is positioned at a controlled distance from the magnetic field source, allowing the substrate to move horizontally to position different components under the heating zone while the vertical spacing prevents any collision between components and the magnetic field source.
Solution Approach 2:
The patent introduces a non-conductive support structure as an intermediary between the substrate and the magnetic field source. This support structure maintains the required spacing, prevents collision, and allows free movement of the substrate relative to the magnetic field source while providing mechanical support for the components during the soldering process.
3Measurement precision
If temperature measurement is performed in the region of each component, then precise temperature control is achieved, but the measurement device may interfere with the soldering process or collide with components
Solution Approach 1:
The patent replaces contact-based temperature measurement (which would require physical probes near components) with contactless optical measurement using a pyrometer. The pyrometer measures temperature by detecting thermal radiation from the substrate surface, eliminating the need for physical measurement devices that could interfere with components or require complex positioning mechanisms.
Solution Approach 2:
The patent uses optical measurement to create a remote copy of the temperature information from the soldering region. The pyrometer detects thermal radiation and converts it into temperature data, allowing accurate temperature monitoring without physical contact with the components or substrate, thus avoiding interference with the soldering process.
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
Ensures high-quality solder joints with uniform heating and cooling, reducing defects and enabling efficient, high-repeatability soldering processes.
Implementation Method 1
heating the solder arranged between the respective component and the metal layer by inducing eddy currents in the region of the respective component by means of a magnetic field generated by the winding
Implementation Method 2
heating the solder arranged between the respective component and the metal layer by inducing eddy currents in the region of the respective component by means of a magnetic field generated by the winding
Implementation Method 3
The temperature in the region of the respective component is measured by measuring the temperature of a surface region of the substrate arranged in the normal direction of the substrate and aligned with the region of the respective component, in particular aligned with the respective component, on a side of the substrate facing away from the respective component
Data Source
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AI summary
The invention relates to a method for forming soldered joints between components to be soldered and a substrate comprising an electrically non-conductive insulating layer and a metal layer structured into conductor tracks arranged on the insulating layer, wherein the components are arranged on the metal layer and a solder is arranged between the components and the metal layer, wherein in the method a relative movement of the substrate to an energizable winding is carried out such that, after the relative movement, a central region of a winding surface enclosed by the winding is aligned in the normal direction of the substrate with a first component to be soldered, subsequently the solder arranged between the first component and the metal layer is heated by induction of eddy currents, and subsequently a further relative movement of the substrate to the winding is carried out such thatthat, after the relative movement has been carried out, the central area of the winding surface is aligned in the normal direction of the substrate with a second component to be soldered, and the second component is then soldered. The invention further relates to a soldering device designed for carrying out the method.