What is Electroplating? How It Works?

Bobby Brown

Post 2023-12-19

Overview

Electroplating is a surface treatment technique widely used in various fields, mainly for metal surfaces. It aims to provide protective layers, aesthetic decoration, and improved conductivity, but may produce harmful chemicals during manufacturing.
Electroplating attaches metal ions to substrates via an electrolytic process, involving anodes, cathodes, and electrolytes. Different metals offer diverse characteristics for decorative, protective, or specialty needs.
Electroplating methods vary, including rack, barrel, and fluidized bed plating, each suited for different parts and requirements, playing a key role in product quality.
Flow meters and nozzles are crucial in the electroplating industry for precise control of chemical volume, distribution, and contact time, affecting layer quality. Applications include equipment rinsing, flow monitoring, and chemical agent monitoring.

Why Electroplate? Pros and Cons of Electroplating
The Principles and Types of Electroplating
- Electroplating Principles
- Types of Electroplating
Electroplating Processes
Applications of Flow Meters and Nozzles in Electroplating Industry

Why Electroplate? Pros and Cons of Electroplating

Electroplating, widely used in electronics, automotive, aerospace, and chemical industries, involves electrochemical reactions to deposit metal or alloy layers on objects for various purposes like enhancing aesthetic appeal, improving conductivity, hardness, and repairing surface imperfections. It employs methods like mass, rack, continuous, and in-line plating, suitable for different types of parts. The benefits include improved physical, mechanical, and chemical properties of the plated items. However, this complex process has potential defects such as pitting and adhesion loss. Environmental concerns also arise due to the hazardous chemicals produced.

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The Principles and Types of Electroplating

Electroplating Principles

Electroplating involves an electrolytic process where metal ions in an electrolyte solution are deposited onto a substrate's surface to form a coating. In this process, there are three key components: the anode (metal for coating), the cathode (the object to be plated), and the electrolyte (plating solution). The anode is a metal piece that supplies the metal for the coating, while the cathode is the object to be plated. The electrolyte typically consists of a solution with cations of the coating metal, non-metal ions, and other chemical components. When electricity is applied, the metal cations in the electrolyte move to the cathode, where they are reduced to metal by gaining electrons and adhering to the object's surface. Simultaneously, the metal at the anode dissolves (oxidizes), providing more metal ions to the electrolyte. Over time, a thin metal film develops on the surface of the object being plated.

Types of Electroplating

| Decorative electroplating layer commonly used for accessories (Photo - PhotoMIX Company)

Different metals used for electroplating offer varying levels of hardness, impacting wear resistance and corrosion resistance. The choice of metal for decorative coating depends on the desired appearance. For electronic components, conductivity is a key factor. The classification of electroplating by metal usage includes:

Decorative Electroplating: This type includes plating with bronze, nickel, chrome, etc., aimed at enhancing the smoothness and aesthetic appeal of the product surface. The metal layer usually has a high shine, giving products a more luxurious look. Common applications include decorative hardware for bags, shoes, apparel, and bathroom fittings.

Protective Electroplating: Used for parts like screws, canvas snaps, and building hardware, this type is mainly for improving corrosion resistance, wear resistance, and rust prevention. For example, screws often exposed to outdoor environments benefit significantly from rust-proofing treatments. Zinc, nickel, and tin are the most common materials used in protective electroplating.

Specialty Electroplating: Silver, copper, and gold, known for their excellent conductivity, are used not only for decorative purposes but also for plating circuit boards and other products to enhance conductivity. Besides, specialty electroplating can also be used to enhance weldability, increase impedance, and other specific requirements by coating the surface with special properties metal layers.

Electroplating Processes

Electroplating involves a variety of techniques, each suitable for specific needs, and plays a crucial role in manufacturing high-quality products. Here's a brief introduction to different electroplating processes and their applications:

Rack Plating: This process involves fixing items to be plated on a metal rack, suitable for small, complex precision objects like precision hardware parts, lithium battery connectors, and semiconductor components.

Barrel Plating: Small parts are placed in a rotating metal barrel for uniform coating, primarily used for mass production of small hardware parts like screws, nuts, bolts, and automotive components, effectively used in surface treatment for automotive parts.

Fluidized Bed Plating: Involves a bed of solid particles filled with electrolyte solution. Objects placed in this bed get evenly coated, suitable for small, complex-shaped items, particularly those needing intricate shape processing.

Continuous Strip Plating: Flat metal strips are continuously passed through an electrolytic bath, producing uniform coatings, commonly used in the production of electronic components like Printed Circuit Boards (PCBs) and connectors, as well as protective layers for metal strip hardware.

Suspension Plating: Objects are suspended in the electrolyte rather than fixed on a rack, applied to micro-components needing high-precision surface treatment, such as micro-sensors, micro-lenses in MEMS devices, or implantable medical devices in medical equipment.

Vapor Deposition Plating: Utilizes electrochemical deposition to create fine plating layers, suitable for complex thin films and coatings like optical coatings and thin film processes in the semiconductor industry for Integrated Circuit (IC) manufacturing.

Rolling Plating: Involves passing the substrate continuously through an electrolytic bath for uniform plating, used for creating protective layers on metal strips and decorative materials in construction.

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Applications of Flow Meters and Nozzles in Electroplating Industry

In the electroplating industry, the quality of electroplated layers is significantly influenced by various factors including the amount and distribution of electroplating solutions sprayed, the contact time between the liquid and materials, and the force with which the solution impacts the panels. This makes the quality and performance of nozzles critical in electroplating processes. Additionally, the pre-treatment processes such as surface cleaning of the objects to be plated, as well as washing during the process, are conducted using nozzle spraying. Barrel plating tanks also require nozzles for cleaning purposes. Both flow meters and nozzles play pivotal roles in the electroplating industry; nozzles are extensively used in pre-treatment processes to enhance the quality of electroplating layers, while flow meters are utilized to measure the volume of electroplating solutions used, aiding in controlling the efficiency of the manufacturing process

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Application 1: Electroplating Equipment Rinse Process － Low-Pressure Wide-Angle Nozzle

| Low-Pressure Wide-Angle Nozzles are Wildly Used in Rinse Process

Case: A renowned Taiwanese PCB equipment manufacturer

specializes in the research and development of automated equipment for circuit boards. This includes vertical electroplating equipment, horizontal circuit board machinery, and photoelectric devices. In their electroplating equipment, the rinsing process is critical to avoid damaging the circuit substrates, necessitating the use of low-pressure water flow for cleaning. The company sought a nozzle capable of wide-area spraying even under low pressure.

The solution: LORRIC's D Clamp series nozzles

These low-pressure wide-angle fan-shaped nozzles utilize a reflective surface outside the spray orifice to achieve a spray design effective even in low-pressure environments. They can create a cleaning area wider than 145 degrees, offering efficient rinsing performance. Additionally, the D Clamp series features a pipe-clamp style for easy installation and a multi-piece structure, simplifying maintenance and replacement for users

Application 2: Flow Monitoring & Central Control Communication in Electroplating Equipment

| The flow meter serves as a communication bridge between various equipment and the central console

Case: A prominent Taiwanese automation equipment manufacturer

specializes in DES line processes for printed circuit boards, deburring machines, and electroplating equipment for circuit boards and metal hardware, faced a challenge. Precise measurement of liquids and gases was crucial for their gold and tin electroplating equipment. Additionally, their electroplating machines required flow meters to transmit signals for communication with the central control console.

The solution: LORRIC's variable area-type flow meters and paddle wheel flow meters

For measuring water and gas usage in electroplating equipment, LORRIC's area-type float flow meters were recommended, ensuring accuracy within ±5% F.S. The flow scale of the main body is laser-engraved for easy on-site identification and durability. For communication with the central control console, LORRIC's FP-AS510 AxleSense paddle wheel flow meter was suggested. This meter comes with three communication formats: 4-20mA analog output, Modbus RTU RS485 control signal, and optocoupler switch signal (Pulse signal), offering comprehensive communication options for users

Application 3: Monitoring Flow of Electroplating Chemical Agents

| Flow Monitoring in Vertical Continuous Plating Line

Case: A notable Taiwanese manufacturer specializing in PCB

The company utilizes a Vertical Continuous Plating Line in their production. This system enhances the distribution efficiency in electroplating and maintains consistent quality across all boards. The vertical continuous plating equipment employs various chemical agents, necessitating flow meters that can efficiently monitor chemical usage and possess corrosion resistance.

The solution: LORRIC's variable area-type flow meters and paddle wheel flow meters

LORRIC's area-type flow meters are made of high-quality plastics, offering strong resistance to aggressive chemical solutions, thereby reducing the frequency of maintenance and lowering costs. Furthermore, for efficient monitoring of chemical usage in electroplating equipment, flow meters with communication capabilities are essential. To meet the customer's communication output requirements, LORRIC's FP-AS510 paddle wheel flow meter emerged as the optimal solution. This product features three communication outputs (4-20mA analog output, Modbus RTU RS485 control signal, and optocoupler switch signal (Pulse signal)), compatible with the communication formats of in-house control equipment.