Laminated Core Heating Adhesion for Low-Temperature Curing
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Solution Overview
Problem
Existing methods for manufacturing laminated cores using self-bonding electrical steel sheets face challenges in easy separation and prevention of overheating, leading to inefficiencies and material loss due to high temperature processing.
Innovation Solution
An apparatus comprising a lower die with piercing dies, an adhesive applying unit, a laminating unit, and a second heating unit with an induction heater, allowing for controlled low-temperature curing and easy separation of laminated cores, using a back pressure unit and a heating jig to prevent overheating and ensure uniform heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high temperature heating (180-250°C) is applied to cure the adhesive layer in the die, then the adhesive bonding strength is improved, but thermal expansion occurs making die design difficult and parts of the product may be burnt
Solution Approach 1:
The heating process is segmented into two distinct stages: first, low-temperature curing of the adhesive layer (40-80°C) to achieve bonding without thermal damage; second, high-temperature post-heating (180-250°C) after ejection to complete the curing process. This segmentation allows the adhesive to cure at low temperature avoiding thermal expansion and burning, then achieve full bonding strength through controlled post-heating outside the die
Solution Approach 2:
The adhesive layer is preliminarily cured at low temperature (40-80°C) within the die during the laminating process, establishing initial bonding strength before ejection. This preliminary action prevents the need for high-temperature curing within the die, avoiding thermal expansion and burning issues, while still achieving adequate initial adhesion for handling and stacking
2Use of energy by moving object
If high frequency induction heating is used to heat the laminated core, then heating efficiency is improved, but heat is concentrated in specific areas such as magnet insertion areas or teeth causing burning
Solution Approach 1:
The heating process applies different temperature conditions to different stages: low-temperature uniform heating (40-80°C) is applied during laminating to cure the adhesive without localized overheating, while high-temperature post-heating (180-250°C) is applied after ejection to complete curing. This local quality control in the heating process prevents concentrated heat in specific areas like magnet insertion zones or teeth that would cause burning
3Ease of operation
If a laminar member with protrusions for separation is interposed between products, then separation of laminated cores is enabled, but an additional separation process is required which lowers productivity and causes material loss
Solution Approach 1:
The laminated core structure itself provides separation capability through the adhesive bonding mechanism. By controlling the adhesive application and curing process, adjacent laminated cores naturally separate after ejection without requiring additional separation components or processes. The cores are self-sufficient for separation, eliminating the need for extra laminar members with protrusions and their associated handling steps
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
Facilitates easy separation of laminated cores, reduces manufacturing time and cost, and prevents overheating, thereby improving product quality and reducing defects.
Implementation Method 1
When employing high frequency induction heating as a heating method
Implementation Method 2
The adhesion method applies an adhesive to a strip fed to a press die to bond laminar members with each other using the adhesive
Implementation Method 3
Laminar members are sequentially stacked in a squeeze ring installed in a blanking die
Data Source
AI summary
The apparatus for manufacturing a laminated core with heating adhesion according to the present invention is characterized by comprising a lower die 10 comprising a plurality of piercing dies 11, an adhesive applying unit 12 installed on one side of the piercing dies 11, and a laminating unit 13 installed on one side of the adhesive applying unit 12; an upper die 20 comprising piercing punches 21 arranged above the piercing dies 11 and a blanking punch 22 arranged above the laminating unit 13; and an SB steel strip 102 continuously fed to an upper part of the lower die 10, for being formed into a laminar member 101 by operation of the piercing punch 21 and the blanking punch 22, wherein the laminating unit 13 comprises a blanking die 131, a squeeze ring 132 installed at a lower part of the blanking die 131, and a first heating unit 135 installed at a lower part of the squeeze ring 132, and laminates the laminar member 101 in the inner diameter surface of the squeeze ring 132 to manufacture a laminated core 100.