Rotor Core Stack Molding Variation Detection by Position Normalization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing transfer molding processes for electric motor rotor core stacks face variations leading to defects such as resin leakage, missing magnets, and incomplete filling, which are exacerbated by cavity volume inconsistencies, affecting the volume of residual resin.
Innovation Solution
A method and system involving sensors and a controller to measure and analyze clamp press and plunger positions, calculate height offsets and normalized positions, and compare against upper and lower bounds to detect and reject defective rotor core stacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional transfer molding process is used without position normalization, then manufacturing simplicity is maintained, but manufacturing precision deteriorates due to cavity volume variations causing defective rotor core stacks
Solution Approach 1:
The patent transforms physical position measurements into normalized dimensionless parameters by dividing plunger position by clamp press position. This parameter transformation eliminates the influence of cavity volume variations and allows consistent detection of actual process anomalies without requiring complex calibration for each cavity configuration
Solution Approach 2:
The patent replaces complex mechanical measurement systems that would directly measure cavity fill volume with a simpler optical/sensor-based system that measures plunger and clamp press positions. The normalization calculation then substitutes for complex mechanical volumetric measurement, achieving high precision with simpler devices
2Manufacturing precision
If position normalization analysis is implemented, then manufacturing precision improves by detecting actual process variations, but device complexity increases due to additional sensors and controllers
Solution Approach 1:
The patent makes the existing plunger and clamp press position measurement systems serve a dual function: their original control function plus the new quality detection function. By normalizing these existing measurements, the system achieves multi-functionality without adding dedicated detection sensors, reducing the net increase in device complexity
Solution Approach 2:
The patent enables the molding process equipment itself to perform quality detection by using its own position measurement systems. The plunger and clamp press position sensors, originally intended for process control, now also serve as detection sensors through mathematical normalization, making the system self-diagnosing without external inspection equipment
3Productivity
If normalized position analysis is used to detect variations, then productivity improves by preventing defective products, but loss of time occurs due to additional measurement and calculation steps
Solution Approach 1:
The patent performs position measurements and normalization calculations during the molding process itself, before the cycle completes. By detecting anomalies early in the process, the system can immediately identify defective parts without waiting for post-manufacturing inspection, preventing defective products from entering production and improving overall productivity
Solution Approach 2:
The patent maintains continuous monitoring of plunger and clamp press positions throughout the molding cycle, with real-time normalization and anomaly detection. This continuous detection approach eliminates the need for intermittent sampling or post-process inspection, ensuring no defective products slip through while maintaining efficient production flow
Data Source
AI summary
A method to detect variations in a rotor core stack includes measuring a clamp press position of a clamp press and a plunger position of a plunger, determining a nominal position of the clamp press, calculating a height offset of the rotor core stack, calculating a normalized position of the plunger by adding the plunger position and the height offset of the rotor core stack, and analyzing the normalized plunger position to detect variations within the rotor core stack.