PTC Ceramic Resistor Electrode Trimming for Resistance Precision
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Solution Overview
Problem
Existing PTC ceramic resistors exhibit significant variation in electrical resistance within and between production batches, leading to increased manufacturing costs and inefficiencies in heating devices due to the need to discard resistors outside the desired resistance range.
Innovation Solution
A method involving measuring the electrical resistance of PTC ceramic resistors and selectively removing sections of the metallic electrode layers to adjust the resistance to a target value, thereby reducing electrode coverage and increasing resistance, using techniques like laser ablation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If resistors are manufactured using conventional PTC ceramic processes, then production efficiency is maintained, but electrical resistance varies significantly between production batches and within batches
Solution Approach 1:
The patent applies preliminary action by measuring the electrical resistance of each individual resistor during the production process and identifying which resistors require electrode material removal. This allows for selective post-processing of only those resistors that fall outside the target resistance range, rather than processing all resistors uniformly. The measurement and classification step is performed in advance to guide the subsequent selective removal process.
Solution Approach 2:
The patent changes the electrical resistance parameter of resistors by selectively removing electrode material. By controlling the amount of electrode material removed from specific regions of the resistor, the electrical resistance is adjusted to fall within the desired range. This parameter change is achieved through controlled ablation or removal of conductive material, directly modifying the resistance characteristic of individual resistors.
2Reliability
If resistors with resistance outside the target range are discarded, then heating device performance is maintained, but manufacturing costs increase significantly
Solution Approach 1:
The patent applies discarding and recovering by rescuing resistors that would otherwise be discarded. Instead of throwing away resistors with resistance outside the target range, the process recovers them by selectively removing electrode material to adjust their resistance into the acceptable range. This transforms waste material into usable products, reducing both waste and manufacturing costs.
Solution Approach 2:
The patent converts the harm of having resistors with incorrect resistance into a benefit. Resistors that initially fail to meet specifications are not discarded but instead undergo selective electrode removal to correct their resistance values. This turns defective products into acceptable products, improving overall yield and reducing waste while maintaining heating device performance consistency.
3Manufacturing precision
If sections of electrode layers are removed to increase resistance, then more resistors meet specifications, but additional processing steps are required
Solution Approach 1:
The patent applies local quality by selectively removing electrode material from specific regions of the resistor rather than uniformly processing the entire resistor. The electrode removal is localized to areas where it will most effectively adjust the resistance while minimizing unnecessary processing. This localized approach achieves the desired resistance adjustment with more efficient processing.
Solution Approach 2:
The patent applies segmentation by dividing the electrode layer into distinct regions, some of which are removed and others retained. The electrode layer is segmented such that specific portions are ablated or removed to adjust resistance, while other portions remain intact to maintain electrical connectivity. This segmented removal pattern allows for precise resistance control.
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 reduces the variation in resistor resistance, minimizes waste, and lowers production costs by ensuring more resistors meet the desired specifications, resulting in more homogeneous heat production in heating devices.
Implementation Method 1
measuring the electrical resistance for an electric current flowing from one metallic electrode layer through the ceramic plate to the opposite metallic electrode layer
Implementation Method 2
using techniques like laser ablation
Data Source
AI summary
This disclosure refers to a method for confectioning resistors that each comprise a PTC ceramic plate and metallic electrode layers covering opposite faces of the ceramic plate, said method comprising the following steps: measuring an electrical resistance of a resistor to be confectioned by applying an electrical potential to one of electrode layers such that an electric current flows from one of the electrode layers through the ceramic plate to the electrode layer on the opposite face of the ceramic plate, comparing the measured resistance to a target resistance, and removing, if the measured resistance is lower than the target resistance, a section of at least one of the electrode layers. This disclosure also refers to such a resistor and a heating device comprising such resistors.