Lamination Stack Bonding With Activator-Cured Adhesive Coatings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for connecting sheet metal parts to form lamination stacks face challenges such as electrical short-circuits, disrupted magnetic fields, and limited design freedom due to mechanical connections, and the time-consuming nature of adhesive bonding processes.
Innovation Solution
A method involving a continuous transport of a sheet metal strip coated with a hardenable polymer adhesive layer, where a fluid activator is applied and dried before cutting and stacking, allowing for precise cutting and uniform adhesive bonding between sheet metal parts using a two-stage hardening epoxy resin system, eliminating the need for additional bonding agents and accelerating the bonding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mechanical connections (screws, clamps) are used to connect sheet metal laminations, then the stack can be disassembled and design freedom is maintained, but electrical short-circuits occur and magnetic fields are disrupted
Solution Approach 1:
The invention extracts and eliminates the mechanical connection means (screws, clamps, nubs) from the stacking process. Instead of using discrete connection elements, the adhesive layer itself provides the bonding function, removing the source of electrical short-circuits and magnetic field disruption while maintaining design freedom.
Solution Approach 2:
The invention introduces an adhesive layer as an intermediary substance between sheet metal laminations. This adhesive mediator provides both mechanical bonding and electrical insulation, replacing the dual-function system of mechanical connectors plus insulation, thereby eliminating short-circuits without compromising design flexibility.
2Strength
If welding is used to join sheet metal parts, then design freedom is barely limited and strong bonding is achieved, but the laminations and insulation layer are damaged resulting in increased eddy-current losses
Solution Approach 1:
The invention replaces the thermal/mechanical welding process with a chemical adhesive bonding system. The adhesive layer cures to provide strong bonding without the localized heat input that causes eddy-current losses, while maintaining the integrity of the insulation layer and metal structure.
Solution Approach 2:
The invention changes the bonding mechanism from thermal (welding) to chemical (adhesive curing). This parameter change allows achieving comparable bonding strength without the harmful thermal effects that increase eddy-current losses and damage the insulation layer.
3Ease of manufacture
If stamping and stacking with mechanical connections is used, then connections are formed between sheet metal parts, but the insulation coating is damaged and short-circuits cannot be ruled out
Solution Approach 1:
The invention applies the adhesive layer to the sheet metal laminations before stacking. This preliminary action ensures that the insulation coating remains intact during the stacking process, as no mechanical deformation or contact is needed to create connections. The adhesive provides bonding without damaging the insulation.
4Reliability
If hot-melt adhesive varnish is used for adhesive stacking, then durable connection over entire area is achieved without damaging metal structure or insulation layer, but clamping and cooling process is very time-consuming
Solution Approach 1:
The invention changes the adhesive system from thermoplastic hot-melt (requiring cooling) to chemically curing adhesive (two-stage hardening epoxy resin system). This parameter change eliminates the time-consuming cooling phase while maintaining durable connections, as the adhesive cures chemically at room temperature or with mild heating.
Solution Approach 2:
The invention utilizes chemical phase transition (curing reaction) instead of thermal phase transition (cooling). The two-stage hardening epoxy resin system transitions from liquid to solid through chemical reaction, eliminating the need for prolonged cooling time while achieving durable bonding.
5Manufacturing precision
If continuous transport through application device is used for activator application, then coating quality and uniformity are enhanced, but additional processing steps are added
Solution Approach 1:
The invention merges the activator application step with the existing adhesive coating process. The fluid activator is applied in the same continuous transport line where the adhesive layer is already present, combining two coating operations into one integrated process without adding significant device complexity.
Solution Approach 2:
The invention uses a fluid activator as an intermediary substance that enhances the adhesive layer properties. This activator is applied through the existing continuous transport system, improving coating uniformity without requiring a completely separate processing line.
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 method enhances the quality and uniformity of the adhesive layer, reducing production time and energy consumption while maintaining the integrity of the metal structure and insulation, achieving a durable and efficient connection without damaging the lamination stacks.
Implementation Method 1
a fluid that contains an activator for the polymer adhesive layer is applied to the adhesive layer
Implementation Method 2
the applied fluid is dried
Data Source
AI summary
A method and a device for connecting sheet metal parts to form lamination stacks, wherein a sheet metal strip whose top and/or bottom surface has a hardenable polymer adhesive layer is transported continuously through an application device in which a fluid that contains an activator is applied to the adhesive layer, the applied fluid is dried, the sheet metal strip that is coated with the dried activator is continuously fed to a strip accumulator, the sheet metal strip from the strip accumulator is fed to a cyclically operating cutting device in which sheet metal parts are cut from the sheet metal strip and stacked on one another, and the cut and stacked sheet metal parts are connected to one another to form lamination stacks by means of the adhesive layers that are coated with the activator. The invention also relates to the lamination stacks produced according to the method.