Sandwich Solder Assembly Using Flux-Free Preform Fixing
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Solution Overview
Problem
The existing methods for producing sandwich arrangements using solder connections face issues with positional changes and instability during transport, leading to potential misalignment, tilting, or detachment of components due to vibrations or acceleration, which results in unsatisfactory mechanical, electrical, and thermal connections.
Innovation Solution
A method that uses a non-flux fixing agent to temporarily fix a solder preform to a component, allowing for the formation of a solder deposit, which is then used to create a sandwich arrangement without the need for flux, thereby reducing void defects and the use of complex mechanical fixing devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solder preform or component with solder depot is transported into the oven, then the solder connection can be formed, but positional changes, tilting, or detachment of components occur due to vibrations or acceleration during transport
Solution Approach 1:
A flux-free fixing agent is introduced as an intermediary substance between the solder preform/contact surface and the component. This fixing agent temporarily secures the solder preform to the component during transport and assembly, preventing positional changes, tilting, or detachment without requiring complex mechanical fixing devices. The fixing agent serves as a mediator that provides stabilization during critical phases before soldering occurs.
Solution Approach 2:
The patent replaces complex mechanical fixing devices with a chemical/adhesive-based fixing agent. Instead of using mechanical clamps, holders, or positioning mechanisms to prevent component movement during transport, a flux-free fixing agent is applied to provide temporary adhesion. This substitution eliminates the need for complicated mechanical systems while achieving the same stabilization goal.
2Reliability
If flux is used to create a solder deposit, then the solder connection can be formed, but void defects occur at the interface between the component and solder
Solution Approach 1:
The patent extracts and eliminates flux from the soldering process. By removing flux entirely from the system, the source of void defects at the component-solder interface is eliminated. The flux-free fixing agent performs the necessary adhesive function without producing the harmful byproducts and gas emissions that flux generates during soldering, thereby preventing void formation.
Solution Approach 2:
The patent converts the potential harm of using flux (which causes void defects) into a benefit by developing a flux-free alternative. The fixing agent provides the necessary adhesive and protective functions that flux traditionally performed, but without the harmful side effects. This transforms the problem of flux-induced voids into an opportunity to achieve cleaner, void-free solder connections.
3Manufacturing precision
If mechanical fixing devices are used to secure the solder preform, then positional stability is achieved, but the production process becomes more complex and time-consuming
Solution Approach 1:
The patent replaces mechanical fixing devices with a flux-free fixing agent that provides temporary adhesion through chemical/adhesive bonding. This substitution eliminates the need for mechanical clamps, holders, or positioning mechanisms, simplifying the production process and enabling faster assembly. The fixing agent can be applied quickly and allows for natural handling and transport without mechanical intervention.
Solution Approach 2:
The patent changes the physical-chemical parameters of the interface between solder preform and component by introducing a fixing agent with specific adhesive properties. This fixing agent provides sufficient holding strength during transport and assembly but can be easily removed or decomposed during the soldering process, allowing for efficient production without compromising positioning accuracy.
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
This approach significantly reduces production rejects, maintains the mechanical, thermal, and electrical performance of the components, and allows for the production of sandwich arrangements with minimal void defects, ensuring a stable and effective solder connection.
Implementation Method 1
a) providing a first component with a contact surface A, a second component with a contact surface D, a fixing agent composition and a solder preform with discrete contact surfaces B and C
Implementation Method 2
b) fixing the solder preform to the contact surface A or D by means of the fixing agent, wherein the fixed solder preform is then melted and the molten solder thus formed is cooled below its solidification temperature
Implementation Method 3
the molten solder thus formed is cooled below its solidification temperature
Implementation Method 4
a) providing a first component with a contact surface A, a second component with a contact surface D, a fixing agent composition and a solder preform
Data Source
AI summary
The invention relates to a method for producing a sandwich arrangement consisting of a first component having a contact surface A, a second component having a contact surface D, and solder between the contact surfaces A and D, the solder being produced by melting a solder deposit arranged between the two components and connected to one of the components, on the contact surface A or D, and subsequent cooling of the molten solder at the solidification temperature thereof, the solder deposit being previously produced by melting a solder preform fixed to the relevant contact surface by means of an applied fixing agent consisting of a fixing agent composition and subsequent cooling of the molten solder at the solidification temperature thereof, the solder deposit being arranged with the free contact surface thereof facing the corresponding contact surface D or A of the as yet unconnected component. Said fixing agent composition consists of between 0 and 97 wt. % of at least one solvent selected from the group consisting of water and organic solvents boiling at ≤ 285°C, between 3 and 100 wt. % of at least one material M1 selected from the group consisting of (i) thermoplastic organic polymers that are meltable between 30 and 180°C and (ii) non-polymer organic compounds without acid groups, which are meltable between 30 and 180°C, between 0 and 20 wt. % of at least one material M2 selected from the group consisting of (iii) organic polymers that are not meltable between 30 and 180°C and (iv) non-polymer organic compounds without acid groups, which are not meltable between 30 and 180°C and do not have a boiling point or have a boiling of above 285°C, and between 0 and 30 wt. % of at least one inorganic solid filler. In the absence of at least one constituent (i) in the at least one material M1 1500 µm2, the sum of the surface portions, provided with the fixing agent, of the contact surfaces A and B or C and D forming a common overlapping surface when the solder preform is put in place, amounts to 50 surface % of the common overlapping surface, while in the sole absence of at least one constituent (ii) in the at least one material M1 1500 µm2, said sum amounts to 100 surface % of the common overlapping surface.