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4 Oz Copper PCB

Jarnistech > Heavy Copper PCB > 4 Oz Copper PCB
4 Oz Copper PCB

The 4 oz PCB, also known as a heavy copper PCB, holds a prominent position in the electronics industry. Its widespread demand can be attributed to its unique characteristics and its application versatility.

This write-up aims to offer exhaustive insights for those intrigued by the implications of a 4 oz PCB and the significance of 4 oz copper thickness. By delving into this topic, readers will gain a thorough understanding and expand their knowledge in this area.

What is a 4 oz Copper PCB?

The amount of copper on a PCB circuit board is usually stated in ounces per foot (oz/ft2) indicating the weight of the copper foil, per square foot of board area excluding the fiberglass substrate.

Typical copper thicknesses used in PCB are as follow:

1 ounce per foot is about 35 micrometers.
2 ounces per foot equals around 70 micrometers.
3 ounces per foot translates to approximately 105 micrometers.
4 ounces per square foot corresponds, to 140 micrometers.

Therefore, a 4 oz copper PCB contains approximately 4 ounces of copper foil weight per square foot on each conductive layer. In terms of thickness, 4 oz copper equates to approximately:

●140 μm (micrometers)
●5.5 mils
●0.14 mm (millimeters)

This heavy copper foil thickness offers exceptional performance and is well-suited for demanding electronics applications that require robust conductivity and power handling capabilities.

What is the Base Material of 4 Oz Copper PCB?

The selection of raw base materials are plays a pivotal role in PCB manufacturing because it influences their functionality and performance efficiency directly. The performance efficiency of a printed circuit board is closely tied to this crucial decision.

Regarding 4 oz copper PCB, the predominantly utilized base material is FR-4, a choice that complies with the standard operating threshold of 140 degrees Celsius. Moreover, High Transition Temperature (High Tg) material presents another viable selection, bearing the capacity to endure elevated temperatures roughly around 170 degrees Celsius. This crucial selection pivots on the project-specific criteria, contemplating considerations like the project genre and its complexity.

It is important to note that the choice of base material significantly influences the properties of the 4 oz copper PCB. Each base material possesses its own distinct characteristics and performance attributes. When comparing FR-4 and High Tg base materials, the resulting properties of the 4 oz copper PCB will exhibit notable differences based on the chosen base material.

In the end, the choice of a base material is primarily steered by client-specific needs and desirable preferences. Acquiring an intimate understanding of the distinct characteristics and properties inherent to various base materials empowers PCB manufacturers to engage deeply with their clientele. This effort the identification of the most fitting base material that to ensure provide PCB board of high quality.

What is the 4 Oz Copper Thickness?

For the assurance of peak performance of your printed circuit board, meticulous consideration must be given to its thickness. The thickness of a PCB assumes an indispensable position in its all-encompassing functionality and dependability.

When manufacturing 4 oz PCB, precision is paramount to ensure accurate thickness. The standard thickness for 4 oz PCB typically falls within the range of 0.6mm to 0.65mm. This standardized thickness helps maintain consistency and reliability across various applications.

Beyond thickness, the layout of the PCB entails provisions for annexing extra components according to particular project stipulations. Plus, the dimensions of the PCB can deviate predicated on the project’s demands. The orthodox measurements of the PCB can span from a minimal 6mm by 6mm to a substantial 467mm by 610mm.

The size and thickness of the PCB are determined by how complex your project’s. These aspects play a role in ensuring the PCB operates effectively so its essential to focus on them during both the design and production phases. Also there are options, for customizing the PCB thickness and size to meet your clients specific requirements.

By prioritizing precision and customization, you can ensure that the thickness and size of your PCB align with the project’s specifications, resulting in an optimized and reliable PCB solution.

How Many Layers Does 4 Oz Copper PCB Have?

The layer count in a 4 oz copper PCB plays a pivotal role in its configuration. The determination of the layer count hinges upon the particular requisites of the project in question.

Generally, a 4 oz copper PCB can be engineered with a dual layer or multi-layer design. Rudimentary configurations often employ two layers, whereas intricate designs necessitate multiple layers to house complex circuitry and components.

The generous dimensions of a 4 oz copper PCB facilitate the inclusion of an array of components. In particular instances, an extra layer may be incorporated to accommodate other components,and enable enhanced functionality.

For projects with simpler electronic applications, a double-layer 4 oz copper PCB may suffice. However, for projects involving high-tech electronics and complex functionality, multiple layers of 4 oz copper PCB are generally employed.

It worth noting that the standard layer count for 4 oz copper PCB commonly spans from 2 to 24 layers. Nonetheless, we can be tailored to align with the unique necessities and predilections of our clientele.

Where to Use for 4 Oz PCB?

4 oz PCB are highly valuable and versatile components that play a crucial role in the realm of electronics. Their unique characteristics make them applicable in various domains.

In the modern landscape of the BARE PCB industry, 4 oz copper thickness is employed in electronic devices that demand cutting-edge technology. Additionally, these PCB find utility in welding equipment, where their capabilities are effectively harnessed.

Power converters rely on the configurations provided by 4 oz PCB. Moreover, these PCBs are instrumental in high-tech space systems and radar systems, showcasing their significance in such advanced applications.

Furthermore, the automotive sector and solar panel systems benefit from the utilization of 4 oz copper PCB. These PCB serve vital roles in electric and general power supply systems, enhancing their performance and efficiency.

Control panels are integral in various industries, and 4 oz PCB play a pivotal role in the manufacturing of industrial panels. Additionally, these PCB can be found in vending machines, car dashboards, amplifier systems, and lighting systems, further exemplifying their wide-ranging applications.

How Does Manufacturing and Assembling for 4 Oz Copper PCB?

The process of Manufacturing and assembling a 4 oz copper PCB entails a series of meticulous steps that encompass both the fabrication of the PCB itself and the subsequent component assembly.. Here’s a detailed look at the procedure:

PCB Manufacturing:

a. Design and Layout: Create the PCB design using computer-aided design (CAD) software, defining the circuitry, component placement and layer configuration.

b. Material Selection: Choose the appropriate base material, typically FR-4 or High Tg material and copper foil with a thickness of 4 oz per square foot.

c. Substrate Preparation: Clean and prepare the substrate material, such as fiberglass-reinforced epoxy laminate sheets, by cutting them to the desired size and shape for the PCB.

d. Copper Foil Bonding: Apply heat and adhesive to bond the copper foil to the substrate, ensuring a strong and uniform bond.

e. Imaging and Etching: Apply a photoresist layer, expose it using a photomask with the desired circuit pattern, and then etch away the unwanted copper using an etchant solution, leaving behind the circuit traces.

f. Drilling: Precisely drill holes, known as vias, for component mounting and interconnection. These vias are typically plated with copper for electrical conductivity between layers.

g. Plating: Electroplate the PCB to deposit a thin layer of copper over the exposed circuitry and vias, enhancing conductivity and protecting the traces.

h. Solder Mask and Legend Printing: Apply a solder mask over the PCB surface, leaving only the desired soldering areas exposed. Print component designators, labels, and other markings using ink.

i. Surface Finish: Apply a surface finish, such as HASL, ENIG, or OSP, to protect exposed copper surfaces from oxidation and facilitate soldering.

j. Testing and Inspection: Thoroughly test and inspect the manufactured PCBs using electrical testing, visual inspection, and functional testing to ensure quality and adherence to specifications.

Component Assembly:

a. Bill of Materials (BOM): Prepare a comprehensive BOM listing all the required components for the PCB assembly.

b. Component Procurement: Source and procure the necessary electronic components from reliable suppliers.

c. SMT (Surface Mount Technology) Assembly: Utilize automated assembly equipment to mount surface-mounted components (SMDs) onto the PCB, using solder paste and reflow soldering techniques.

d. Through-Hole Component Assembly: Mount through-hole components onto the PCB using manual or automated processes, such as wave soldering or selective soldering.

e. Inspection: Conduct visual inspection and automated optical inspection (AOI) to verify the correct placement and soldering quality of components.

f. Testing: Perform functional testing, electrical testing, and any required programming or firmware loading to ensure the assembled PCB meets performance and functional requirements.

g. Final Quality Check: Conduct a final inspection to ensure the PCB assembly is free from defects and meets all quality standards.

h. Packaging and Delivery: Clean, package, and prepare the assembled PCB for shipment to customers, ensuring proper protection during transportation.

Throughout the manufacturing and assembly process, quality control measures are implemented to detect and rectify any defects, ensuring the production of high-quality 4 oz copper PCB and reliable PCB assemblies.

What Are Key Indicators of 4 oz PCB Fabrication Quality?

To ensure the reliable production of high-quality 4 oz copper boards, there are several critical metrics and process capability markers that indicate the technical competence of a PCB manufacturer:

Tight Laminate Thickness Variation (<5%): The manufacturer should maintain a narrow range of laminate thickness deviation, ensuring consistent board thickness across the PCB.

Excellent Foil-to-Foil Registration (<0.10mm): Precise alignment of copper foils during lamination is crucial for accurate circuitry and signal integrity. Void-Free Hole Fill

Down to 0.15mm Vias: The manufacturer must achieve complete hole fill during the plating process, ensuring reliable conductivity and interconnection within the PCB. Fine Line

Resolution Down to 1 mil Line/Space: The ability to produce fine features with high precision is necessary for intricate circuitry and dense PCB designs. High Peel Strengths Between Layers (>9 N/mm) with 0% Delamination: Adequate adhesion between PCB layers is vital to prevent delamination and ensure the structural integrity of the board.

Minimal Surface Roughness (<2 μm Ra): A smooth surface finish is essential for consistent solderability, component mounting, and reliable electrical performance.

Very Low Impedance Power/Ground Planes (<5 mΩ): Maintaining low impedance in power and ground planes is critical for minimizing signal noise and ensuring stable power distribution.

Well-Controlled Gold Plating Thickness (+/- 5%): Gold plating thickness should be tightly controlled to meet specific requirements for corrosion resistance and reliable electrical contacts.

Rigorous Incoming Material QC and Lot Traceability: Thorough quality control of incoming materials, along with comprehensive lot traceability, ensures consistency and reliability throughout the manufacturing process.

Extensive Inspection and Reliability Testing Capabilities: The manufacturer should have robust inspection and testing procedures in place to identify and address any potential defects or reliability issues.

Stringent Process Controls and Change Management: Well-defined and controlled processes, along with effective change management protocols, are necessary to maintain consistency and prevent deviations during production.

Zero-Defect Quality Culture at All Organizational Levels: A strong quality-oriented culture, supported by staff training and adherence to strict quality standards, ensures a focus on delivering defect-free products.

By evaluating a PCB manufacturer against these metrics and capabilities, you can assess their technical competence and determine their ability to reliably produce high-quality 4 oz copper boards.

Benefits of Partnering with a High Quality Manufacturer

Choosing a PCB manufacturer capable of flawless volume production with 4 oz copper offers significant advantages for electronics companies:

●Accelerated Time-to-Market
●Smooth Introduction with Reduced Risks
●Enhanced Performance
●Robust Quality
●Reliable Long-Term Supply
●Cost Savings
●On-Demand Flexibility

Why Choose JarnisTech?

If you are seeking a reliable supplier for 4 oz copper (140um or 56mil) PCB, JarnisTech is the optimal choice. With over 12 years of experience in PCB manufacturing, JarnisTech possesses extensive expertise in producing 4 oz copper PCB.

Our 4 oz copper PCB, commonly known as heavy copper or thick copper PCB, are particularly suitable for power supply products. At JarnisTech, we offer customized options, allowing you to specify the size, number of layers, surface finishes, and appropriate solder mask for your PCB requirements.

We offer a wide range of 4 oz copper PCB types, which include single-sided circuit boards, double-sided PCB, multilayer PCB, rigid printed circuit boards, flexible circuit boards and rigid-flex PCB. Our ample holdings encompass a complete spectrum of raw laminates, ensuring brisk production and punctual delivery. Additionally, the utilization of top-tier materials throughout the manufacturing protocol remains our key focus, ensure the dependability and functionality of our 4 oz copper PCB.

As a leading manufacturer and factory of 4 oz copper PCB in China, JarnisTech is committed to meeting all of our customers’ requirements. Our dedicated team of over 1000 skilled workers operates in two shifts, enabling us to accommodate orders for prototypes, small volumes, and large volumes of 4 oz copper PCB.

When designing your 4 oz copper PCB, we recommend a minimum trace width/space of 8 mil/8 mil. This ensures optimal performance and manufacturability.

Should you require more information or have queries, please make sure to contact with us. We stand ready to assist with you any challenges or concerns, rendering the necessary support you require.


To fully leverage the capabilities of advanced thick copper technology, it is essential for electronics product designers to establish a collaborative partnership with a skilled and dependable PCB manufacturer like JarnisTech. Our manufacturing expertise enables us to deliver flawless quality multilayer boards with 4 oz copper, offering numerous advantages such as low loss, high current capacity, improved thermal performance, and enhanced layout density.

By choosing JarnisTech as their partner, engineers can effectively mitigate risks, elevate the overall performance of their end products, and seamlessly embrace the cutting-edge 4 oz PCB technology. Our commitment to precision and reliability ensures that designers can confidently rely on us to meet their specific requirements and achieve successful outcomes.

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