PCB Surface Finishes & Coatings

Surface Finishes & Coating

PCBs Gold Fingers - Why It Matters ?

What is PCB Gold Finger? PCB gold fingers refer to the metal contact points on a printed circuit board, typically located at the board's edge. They are commonly made of metallic materials such as gold or upgraded gold alloys . Since the surface of the pads is gold-plated and the conductive contacts are arranged like fingers, they are called "gold fingers". Gold is extremely resistant to oxidation and has strong conductivity in comparison with other PCB surface finishes like HASL. Although it looks nic......

Dec 18, 2023

Surface Finishes & Coating

Technical Guidance: Five Via Finishes: Exposed, Tented, Plugged, Epoxy and Copper Paste Filled

Definition and Universal Inspection Standards In response to customer requests, we have added the processes of "plugged vias," "epoxy-filled vias," and "copper paste filled vias," which can be selected in the ordering interface. Refer to the rules for via-in-pad filled vias (click here to view). When ordering a PCB there are generally five via covering options available: Untented (Exposed), Tented, Plugged, Epoxy-Filled & Capped, and Copper-Paste-Filled & Capped. Finish Type Appearance Key Advantages ......

Oct 23, 2023

Surface Finishes & Coating

How to Waterproof a PCB: A Step-by-Step Potting Guide

PCBs are everywhere, they are an integral part of nowadays essential things. We can not imagine a world without them. Almost all the things which have power or that can take power have at least a PCB. Because they are used so often the circuit needs to operate in challenging environments. Mostly we are talking about outdoors, under the hood or in humid industrial settings. The term potting becomes a crucial solution for all this. Potting a printed circuit board (PCB) helps protect it from moisture, du......

Sep 16, 2025

Surface Finishes & Coating

HASL Surface Finish : Proven Reliability and Cost Efficiency in High-Quality PCB Manufacturing

In case you have ever been confused by seeing the acronym HASL on the PCB spec sheet and wondered what it means, here is the brief description: HASL is the abbreviation of Hot Air Solder Leveling, and it is one of the oldest, and still most dependable, surface finishes in the printed circuit board. You simply put the board into a pot of molten solder, typically a tin-lead or lead-free blend, and blow hot air over the solder to remove the excess and leaving a thin coat of solder on each exposed copper ......

Feb 24, 2026

Surface Finishes & Coating

Design and Surface Finish of Coil Boards

Circular coils are a wiring method sometimes used in PCB layout. They serve primarily as inductors, transformers, antennas, and more. Considering the production of PCBs containing coiled traces, please take note of the following points: 1. Compared to conventional circuits, it might not be possible to detect short circuits between windings of circular coils if the coil is a closed circuit. Therefore, the requirement for trace width and spacing is 0.254 mm (with a limit of 0.15 mm, but only when the co......

Sep 05, 2023

Surface Finishes & Coating

Conformal Coating in PCB Technology: Benefits, Challenges, and Future Developments

If you're searching for conformal coating, you're likely looking for a reliable way to protect your PCB from moisture, dust, chemicals, or harsh environments. Choosing the right coating directly affects product reliability, performance, and lifespan. In this guide, you'll learn what conformal coating is, the main types available, and how to select the best option for your application. We'll also cover key benefits, application methods (manual, automated, and selective), as well as inspection, rework, ......

Jul 25, 2023

Surface Finishes & Coating

All you need to know about PCB Gold Fingers

In today's highly connected, tech-driven world, seamless communication between devices is essential, and it all starts at the circuit board level. A critical element in enabling this communication is the use of gold fingers, the gold-plated connectors that link circuit boards to motherboards, making the flow of signals possible. Although it looks nice, gold plating is not merely for aesthetic purposes, it serves a practical function critical to the connector performance. Without gold fingers, critical......

Oct 20, 2025

Surface Finishes & Coating

Considerations for Gold Finger Bevel Design

In our daily lives, we often come across products with a row of contacts on the PCB edge used for connections, which are known as PCB gold fingers. They are also referred to as "edge connectors", typically serving as the external connection interface for a PCB board when inserted into a slot. Technical Guidance So, what should you keep in mind when designing PCBs with gold fingers? Excessive beveling of PCB gold fingers can result in the fingers not making proper contact with the mating equipment duri......

Oct 08, 2023

Surface Finishes & Coating

Hard Gold PCB Finish: Achieving Exceptional Wear Resistance and Contact Performance

Surface finishes are not all the same thing, and this is obvious beyond mention when you are dealing with parts that are beaten against one another over and over. Hard gold. The most common finish used when PCBs must complete hundreds or even thousands of insert-and-remove operations before going out of service is essentially a hard alloy of gold electroplated over a nickel barrier coating. The prototypical piece of evidence that demonstrates why this is important is the edge connector, otherwise know......

Feb 28, 2026

Surface Finishes & Coating

Avoid PCB Assembly Failures: Mastering Solder Mask Expansion Rules and Best Practices

Solder mask protects copper traces and pads from oxidation, bridges, and contamination during assembly. Incorrect solder mask expansion—the clearance around features where mask is pulled back—leads to defects like shorts or exposed copper. Engineers must set expansion values precisely to ensure reliable soldering and long-term performance. Introduction: Why Solder Mask Expansion is Critical for PCB Reliability Understanding Solder Mask and Expansion Basics Solder mask is a polymer layer applied over t......

Feb 11, 2026

Surface Finishes & Coating

Solder Mask on PCBs : Protecting Traces, Guiding Assembly, and Boosting Long-Term Reliability

As we wear masks to save us from pollution, in the same way, the ones used by PCB to avoid contamination and oxidation. It became a very important step in PCB manufacturing over the years. In the early days, the manufacturers were more focused on one type of color, but today we have multicolor PCBs. That’s how the soldermask process evolved over the years. From protecting delicate copper traces to ensuring precise soldering during assembly. The solder masks directly influence yield and long-term field......

Jan 26, 2026

Surface Finishes & Coating

PCB Silkscreen Explained : From Design Intent to Professional Application and Manufacturing Precision

Let’s come to the topmost layer of a PCB, which is about annotations. We all need some reference material to work on, and the same applies to the assembler, from component assembly to referencing different section legends and silkscreen plates; it plays an important role. In a finished printed circuit board, the silkscreen layer is the least technically appreciated element. It is the most helpful layer for the end user because we can not look into the layout, datasheets, and schematics. That’s how som......

Jan 24, 2026

Surface Finishes & Coating

PCB Coating Spray: Conformal Layers for Bulletproof Circuit Protection

Conformal coating is like giving your printed circuit board an invisible raincoat or even a bulletproof vest. It’s a thin polymer film applied over the PCB and its parts to protect against moisture, dust and vibration. This shield is lightweight and flexible, which means it conforms closely to every contour of the board. The goal is to extend the board’s life and reduce failure rates in harsh conditions. Spray application is one popular method to lay down this protective coat. In this article, we will......

Dec 30, 2025

Surface Finishes & Coating

Choosing the Right Surface Finish for Your PCB: An Overview of HASL, ENIG, OSP, Immersion Tin and Immersion Silver

Printed Circuit Boards (PCBs) are essential components in the manufacturing of electronic devices ranging from smartphones to industrial machinery. A PCB comprises a substrate material, copper traces, soldermask, and a surface finish. The surface finish is a thin layer of metal applied to the copper traces of the PCB, which serves as a protective coating and facilitates the soldering of electronic components. Choosing the right surface finish is crucial for the functionality and reliability of a PCB. ......

Aug 01, 2023

Surface Finishes & Coating

What is ENEPIG and How Does it Compare to ENIG in PCB Finishing?

ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold) is a type of surface plating applied on a Printed Circuit Board to protect it from environmental factors during storage and operation. ENEPIG is prepared by depositing electroless Nickel (Ni 3-5 μm), followed by electroless Palladium (Pd 0.05-0.1μm), and an immersion Gold layer (Au 0.03-0.05 μm). It is good for solder joint strength, gold wire bonding, aluminium wire bonding, and provides low contact resistance. It can easily be deposite......

Sep 27, 2024

Surface Finishes & Coating

Understanding the Role of Solder Resist Materials in PCB Fabrication

Solder resist, also known as solder mask, Yes they are the same. Again two different names for the same thing but the solder mask one is adapted globally. The protective coating used on PCBs to stop solder from bridging undesired places is referred to by both designations. Although the term "solder mask" is frequently used, "solder resist" is more technically correct since the resist material opposes the solder as it is being assembled. Nonetheless, in the business, both phrases are frequently used in......

Jul 17, 2025

Surface Finishes & Coating

Comparing OSP Plating with Other PCB Surface Finishes

Once a PCB passes through the fabrication process, one of the final steps is to apply a surface plating to the exposed copper on the surface layers. The exposed copper will oxidize over time if it is not treated with a surface finish, and the various surface finishes used in PCBs are used to both prevent copper degradation and provide a solderable surface. One of these more specialized options is organic solderability preservative (OSP), which is the only organic compound-based copper surface treatmen......

Surface Finishes & Coating

Comparing HASL and ENIG Surface Finishes for PCBs

Selecting the right surface finish for a printed circuit board (PCB) is crucial to ensuring its performance, reliability, and longevity. Two of the most commonly used finishes are Hot Air Solder Leveling (HASL) and Electroless Nickel Immersion Gold (ENIG). Each of these surface finishes offers distinct advantages and disadvantages, making them suitable for different applications. In this article, we will compare HASL and ENIG to help you determine which finish is best suited for your PCB project. What......

Jun 28, 2024

Surface Finishes & Coating

How to Choose the Right Surface Finish for Your PCB

When it comes to designing and manufacturing of printed circuit boards (PCBs), considering the element of your surface finish is a critical decision. In addition to influencing the PCB's aesthetics, surface finish is essential to the functionality, dependability, solderability and longevity of the electronic equipment it powers. The surface finish serves as a protective layer on the exposed copper traces of a PCB. It prevents oxidation, promotes solderability, enhances conductivity, and provides a lev......

Feb 27, 2024

Surface Finishes & Coating

Comprehensive Guide to Exploring PCB Surface Finish

The PCB surface treatment process is a crucial step in PCB manufacturing. Its purpose is to protect the copper surface from oxidation and ensure that it can bond well with the solder during the soldering process. The following are some common PCB surface treatment processes and their advantages and disadvantages: HASL (Hot Air Solder Leveling) Hot air leveling (HASL) is a traditional method for treating the surface of PCBs. The process involves immersing the PCB in molten tin and then using hot air to......

Jan 31, 2024

Surface Finishes & Coating

Protective Measures for PCBs: Safeguarding Electronics from Environmental Factors and Electrical Hazards

Printed Circuit Boards (PCB’s) serve as crucial parts of electronic devices providing the framework for connecting various electrical components. Put in place strong protection measures to guarantee the dependable and durable operation of PCBs. PCB protection means preventing external influences, electrical problems, mechanical stress, and excessive temperatures from harming the board and it’s components. In the subsequent sections, we will delve into nine methods, which are summarized into five major......

Dec 07, 2023

Surface Finishes & Coating

Demystifying Conformal Coating

Welcome to JLCPCB's blog, your ultimate resource for all things related to conformal coating for printed circuit boards (PCBs). In this article, we will explore the significance of conformal coating, the different types of coating materials available, the application process, and the importance of quality assurance and testing. Whether you're a seasoned PCB designer or a beginner in the field, this article will provide valuable insights to help you understand and utilize conformal coatings effectively......

Oct 20, 2023