Rotating Contact Wheel for Electroplating Demetallization
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Solution Overview
Problem
Existing continuous electroplating systems face high maintenance costs and inefficiencies due to the metallization of contact means, which leads to increased maintenance efforts and difficulties in demetallization, especially when dealing with anodically resistant and oxidizing materials.
Innovation Solution
The use of rotating contact wheels with a single curved arc contact and an electrically isolated circumference, where the arc contact is cathodically metallized and anodically demetallized with each revolution, and a phase-shifted second contact wheel ensures uninterrupted cathodic power supply without the need for auxiliary cathodes or membranes, utilizing an electrically conductive diamond coating for improved demetallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If contact wheels are used for electrical contacting in continuous electroplating systems, then electrical contact and transport of goods is achieved, but the contact wheels become metallized which increases maintenance costs and maintenance effort
Solution Approach 1:
The contact wheel is divided into multiple contact sectors around its circumference. Each contact sector can be independently polarized (cathodically or anodically) by the control means. This segmentation allows only the required portion of the contact wheel to be metallized during contact with the goods, while other sectors remain non-metallized or are demetallized, thereby reducing overall maintenance effort and costs.
Solution Approach 2:
The polarity of the contact wheel sectors is dynamically changed during rotation through control means that can switch between cathodic and anodic polarization. This dynamic control ensures that contact sectors are cathodically polarized only when needed for electrical contact and goods transport, and can be anodically polarized subsequently to remove metallization, thus reducing maintenance requirements.
2Ease of operation
If multiple contact sectors are used on contact wheels, then electrical contacting capability is improved, but manufacturing costs and device complexity increase
Solution Approach 1:
The contact wheel serves multiple functions: it provides electrical contact to the goods, transports the goods through the electrolyte, and its segmented structure with controllable polarity allows it to function both as a cathodic contact means and as an anodic demetallization means. This multi-functionality reduces the need for separate auxiliary cathodes and complex membrane systems, simplifying the overall device despite the segmented structure.
3Ease of repair
If auxiliary cathodes and semipermeable membranes are used for demetallization, then contact wheel demetallization is achieved, but the system requires frequent replacement of auxiliary cathodes which increases maintenance
Solution Approach 1:
The contact wheel itself serves as both the cathodic contact means during goods treatment and as the anodic demetallization means when needed. By reversing the polarity of the same contact wheel sectors, the system achieves self-service demetallization without requiring separate auxiliary cathodes or semipermeable membranes, thereby reducing maintenance and simplifying the device structure.
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 solution reduces maintenance costs by eliminating the need for auxiliary cathodes and membranes, prevents mutual metallization of contact wheels, and ensures complete demetallization of anodically resistant materials, while maintaining efficient electroplating with reduced voltage drop and increased wear resistance.
Implementation Method 1
The arc contact is connected cathodically to at least one anode of the continuous electroplating system. During this time, not only the surface of the goods is electrolytically metallized, but also the surface of the arc contact. As the contact wheel continues to rotate, the electrically insulating part of the contact wheel reaches the surface of the goods at an angle of 360° - α. During this time, in which the arc contact is currently not in contact with the material, the arc contact is anodically connected to the electrically conductive surface of the material, which during this time acts as a cathodic counter-electrode to the arc contact. The arc contact is electrolytically demetallized and freed from the previously metallized layer.
Implementation Method 2
utilizing an electrically conductive diamond coating for improved demetallization
Data Source
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AI summary
The invention relates to the electric contacting of flat products to be treated electrolytically in flow-through systems. The products are particularly solar cells and printed circuit boards that are to be galvanized. The necessary electric contacting is carried out in the electrolyte by rotating contact wheels (1), which at the same time can be used as transport means. Each contact wheel has a curved contact (3) on the circumference, said contact having a central angle of for example α=190° and an insulation region for the remaining angle. With each rotation of the contact wheel (1), each curved contact (3) is switched consecutively one after the other cathodically for metalizing the product against an anode and then anodically against the surface of the product as a counter electrode for demetallizing the curved contact (3) by a control unit C. In order to prevent current interruptions of the electrolytic process, another spaced contact wheel (1) is used in the same way, comprising a curved contact (3) that electrically contacts the product offset from the first contact wheel by an angle of 180°.