Archive for the ‘FAQ’ Category

What You Know About Counterbores in PCB Design and Manufacturing

Friday, August 18th, 2023

In the world of design and manufacturing, precision is paramount. Every detail, down to the placement of a single component, can impact the performance and appearance of a product. This is where the concept of counterbores comes into play, a technique employed in various industries to create recessed areas for components or fasteners.

But firstly, what is counterbore? Today we will show you the definition and applications of the countersink in a PCB design.

Definition and Applications:

A counterbore is a cylindrical, flat-bottomed hole that is strategically cut into a material to accommodate specific components or fasteners. It is commonly used in various industries, including woodworking, metalworking, and mechanical engineering. The purpose of a counterbore is to create a recessed area where a component, such as a bolt head, nut, or other hardware, can sit flush with or below the surface of the material. This technique ensures a smooth appearance, prevents interference with other components, and provides mechanical stability.

Counterbores in PCB Design and Manufacturing

In the realm of printed circuit boards (PCBs), counterbores play a crucial role in achieving efficient and functional designs. PCBs are essential components in electronic devices, and their design requires careful consideration of component placement, connectivity, and mechanical stability. Counterbores in PCBs serve several important functions:

Component Alignment and Clearance: Certain components on a PCB, such as connectors, switches, or specialized modules, require precise alignment and clearance for optimal functionality. A counterbore can be introduced to create a recessed area that accommodates these components, ensuring proper alignment with neighboring components and minimizing the risk of interference.

Flush Mounting: To maintain a sleek and compact design, some components need to be mounted flush with the surface of the PCB. A counterbore creates a flat-bottomed recess that allows the component to sit at the same level as the PCB surface, contributing to an aesthetically pleasing and functional layout.

Mechanical Support: Components that are susceptible to mechanical stress or impact may benefit from additional support. By incorporating a counterbore, the PCB design can provide a more secure location for these components, reducing the risk of damage.

Heat Dissipation Enhancement: In applications where certain components generate significant heat, such as power amplifiers or processors, heat sinks are often employed to dissipate the heat. A counterbore can facilitate proper alignment and contact between the heat sink and the component, optimizing heat transfer and overall thermal performance.

The production of counterbores in PCBs involves specialized manufacturing techniques. BEST Technology as a professional PCB manufacturer, we will use precision drilling and routing equipment to create accurately sized and positioned counterbores.

If you want to know more about the counterbores, welcome to follow our post or contact us.

Tags:counterbore, counterbores, holes, PCB holes
Posted in best pcb, bestpcb, Design Guide, FAQ, FR4 PCB, HDI PCB, PCB News, PCB Technology, PCBA, Special PCB | No Comments »

Heavy Copper PCB for Industrial Power Supply

Saturday, July 29th, 2023

All of us know the printed circuit board, but do you know what is the heavy copper PCB? Best Tech is a very experienced heavy copper PCB fabricator since year 2006. Heavy Copper PCB is a type of printed circuit board that features with thicker copper layers than standard FR4 PCBs. While conventional PCBs typically have copper thicknesses ranging from 1 to 3 ounces (per square foot), heavy copper PCBs have copper thicknesses exceeding 3 ounces and can go up to 20 or more ounces. These copper layers are typically found in the inner and outer layers of the PCB, heavy copper providing enhanced current-carrying capacity and improved heat dissipation capabilities.

The increased copper thickness in heavy copper PCBs allows them to handle higher currents without experiencing excessive heat buildup or voltage drops. This makes them well-suited for applications that require high power handling, such as industrial power supplies, power converters, motor drives, and automotive electronics. Heavy copper PCBs are designed to withstand harsh operating conditions and provide robust performance and reliability.

Today, we would like to talk about the heavy copper PCB used in Industrial Power Supply. In this blog post, we will explore the realm of Industrial Power Supply, delving into the design considerations, material selection, production challenges, exceptional heat dissipation, and unrivaled conductivity of Heavy Copper PCBs. Join us on this enthralling journey as we uncover the secrets behind their application in Industrial Power Supply scenarios, including the testing of inductance, capacitance, and resistance. Get ready to witness the power of Heavy Copper PCBs in the realm of Industrial Power Supply!

Firstly, before you are moving start for the design, it need to get to understand the Design guideline rules of heavy copper PCB.

From the guidelines of heavy copper PCB, it could get to know it encompass considerations such as trace width, trace spacing, and thermal relief patterns. The increased copper thickness necessitates wider traces to accommodate higher currents, while proper spacing is crucial to avoid thermal hotspots and ensure reliable operation. Additionally, selecting suitable materials with excellent mechanical strength and thermal properties is vital to ensure the robustness and longevity of Heavy Copper PCBs. Hope this will bring some ideas to you during your design.

Secondly, as a heavy cooper PCB manufacturing vendor, Best Tech would like to advise the Production Challenges for the heavy copper PCB.

During producing Heavy Copper PCBs presents manufacturers with a set of intricate challenges. Achieving uniform copper thickness across the board’s surface demands advanced plating techniques and precise control over process parameters. Careful attention must be given to the etching process to prevent over-etching, which can compromise the integrity of the copper layers. Moreover, the additional weight of copper requires a sturdy substrate to support the board’s structure. Manufacturers must navigate these challenges with expertise and precision to deliver high-quality Heavy Copper PCBs.

You may have a question in mind, why we need to use the heavy copper PCB for the Industrial Power Supply, because the heavy copper PCB have Exceptional Heat Dissipation and Conductivity: One of the standout features of Heavy Copper PCBs is their unrivaled heat dissipation capabilities. The increased copper thickness acts as a robust conductor, efficiently channeling heat away from power components. This exceptional heat dissipation prevents thermal stress and ensures the longevity and reliability of Industrial Power Supply systems. Additionally, the high conductivity of Heavy Copper PCBs enables efficient power transmission, reducing losses and improving overall system efficiency.

Furthermore, Heavy Copper PCBs undergo rigorous testing to ensure optimal performance in Industrial Power Supply applications. Inductance testing verifies the effectiveness of copper layers in reducing magnetic interference. Capacitance testing evaluates the ability of the PCB to store electrical energy, while resistance testing determines the conductivity and resistance of copper traces. These tests play a crucial role in validating the quality and performance of Heavy Copper PCBs in demanding power supply scenarios.

Heavy Copper PCBs find widespread applications in the field of Industrial Power Supply, particularly in the production of robust and efficient power control products. They are integral components in industrial power converters, motor drives, uninterruptible power supplies (UPS), and various automation systems. The exceptional heat dissipation and high current-carrying capacity of Heavy Copper PCBs make them ideal for handling the power demands of these applications, ensuring reliable and efficient power delivery.

Finally, in the world of Industrial Power Supply, Heavy Copper PCBs emerge as true powerhouses, combining meticulous design, advanced manufacturing processes, and exceptional heat dissipation capabilities. By adhering to design guidelines, overcoming production challenges, and conducting thorough testing, Heavy Copper PCBs prove their mettle in demanding power supply scenarios. As they continue to evolve, these powerhouses will shape the future of Industrial Power Supply, empowering systems with reliability, efficiency, and unrivaled performance. Prepare to witness the electrifying impact of Heavy Copper PCBs in the realm of Industrial Power Supply!

If you have more question heavy copper PCB for Industrial Power Supply, warmly welcomed to contact Best Tech for more get more information of heavy copper PCB which used in Industrial Power Supply. You can visit www.bestpcbs.com to know more about us.

Tags:heavy copper pcb, power supply PCB
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Can I Design Via Holes in Thick Film Ceramic Boards?

Tuesday, April 18th, 2023

May some engineers or designers who be interested in thick film ceramic circuit are curious about can thick film ceramic boards design with via holes like FR4 PCB? Herein, we will explore the feasibility of using thick film ceramic boards for via holes, including the materials and processes involved, as well as the advantages of this approach.

What is thick film ceramic board?

The “Thick Film” refers to the thickness of conductor layer on a Ceramic PCB. Normally the thickness will be at least 10um, around 10~13um, which is thicker than spurting technology in Thin Film Ceramic PCB. And of course thickness is less than DCB Ceramic board or FR4 board.

Thick film ceramic circuit enables to put resistor, electric capacitor, conductor, semi-conductor, and interchangeable conductor on ceramic board, after manufacturing steps of printing and high temperature sintering. The more important thing is by using thick film technology, we can make all the resistors with the same value, or different value for different resistor on the same board.

Materials and processes for via holes

In general, thick film ceramic circuit is not suitable for designing via holes. Because the characteristics of thick film ceramic board mainly depends on the insulation properties of its ceramic substrate, rather than conductive properties. The conductivity of thick film ceramic plate is not good than Metal Core PCB, or even we can say it has a very poor conductivity, usually can’t meet the requirements of the via hole.

But, designing via holes in thick film ceramics is available in Best Technology. Generally speaking, the fabrication of via holes in thick film ceramic boards typically involves several key materials and processes.

From the designer’s perspective, a conductive material is used to create a continuous conductive path from one side of the ceramic board to the other. Common conductive materials include gold paste, silver paste, and copper paste. These materials are usually screen printed onto the ceramic board in the desired pattern, and then fired at high temperatures to achieve sintering and form a conductive layer.

Once the conductive layer is formed, the via holes are created by drilling or punching small holes through the ceramic board at the desired locations. These holes are then filled with a conductive material, such as silver paste or copper paste, to establish electrical connections between the different layers of the circuit.

Finally, the via holes are fired again at high temperatures to achieve sintering and ensure good adhesion and electrical performance.

Advantages of Via Holes in Thick Film Ceramic Boards

These via holes offer several advantages in the design and fabrication of thick film ceramic boards, including as following:

Electrical connectivity

Via holes provide electrical connectivity between different layers of a thick film ceramic board. They allow for the interconnection of different circuitry or conductive layers, enabling the flow of electrical signals or power between different parts of the board. This allows for complex and multi-layered circuit designs, which can be highly beneficial in applications that require intricate circuitry or high-density interconnects.

Space-saving

Via holes can provide a means of vertical interconnection, allowing for more efficient use of board real estate. Instead of routing traces or conductors on the surface of the board, which can take up valuable space, via holes can be used to route connections through the board, freeing up surface area for other components or functions. This is especially advantageous in compact or miniaturized electronic devices where space is limited.

Thermal management

Via holes can aid in thermal management in thick film ceramics. They can be used to transfer heat from one layer of the board to another, helping to dissipate heat generated by components or circuits. This can be particularly important in high-power or high-heat applications, where efficient thermal management is crucial for preventing overheating and ensuring reliable performance.

Mechanical stability

Via holes provide additional support and reinforcement to the board, reducing the risk of warping, bending, or cracking. Via holes can also help improve the overall mechanical integrity of the board by reducing stress concentration points and enhancing its structural rigidity.

Design flexibility

Via holes offer design flexibility in thick film ceramic boards. They can be designed and placed according to the specific requirements of the circuit or system, allowing for customized and optimized designs. Via holes can be used to route traces, create vias for component mounting, or provide grounding or shielding, among other functionalities. This flexibility in design allows for more efficient and effective circuit layouts, which can lead to improved performance and reliability.

As previously mentioned, designing via holes in thick film ceramic boards offers various benefits. However, when it comes to choosing the appropriate paste for via holes, silver paste is often recommended to our customers. But why is that? Can I use gold or copper? In our upcoming article, we will delve into the reasons behind this recommendation and provide you with valuable insights. Stay tuned to uncover the answers!

Tags:ceramic PCB
Posted in bestpcb, Ceramic PCB, Design Guide, FAQ | No Comments »

10 Tips to Reduce the manufacturing cost of Printed Circuit Board

Thursday, March 23rd, 2023

Many times, when PCB engineer or purchaser seek for a PCB manufacturer to make circuit boards, that always think the price is too high, but don’t know where makes the price is so high and how to optimize the cost on the premise of ensuring the quality of the circuit board. Herein, we share a very useful guideline about “Ten tips to reduce the PCB manufacturing cost”, welcome to read on!

Substrate

Different brands of substrate have different price. For a simple example, if you require a multi-layer PCB, Tg should greater than 150^o, and PP need to over 0.20mm, then use GDM will cheaper than KB or SL. But GDM is usually used for making single or double-sided PCB, it is not recommended to make multi-layer circuit board. If you need to fabricate an 8 layers of multi-layer PCB, KB Tg170 is ideal for your choice since it has good performance and relatively cost-efficient.

Solder mask oil

In generally, what we should consider about the solder mask (S/M) are color and brand.

For the solder mask color, the most commonly used are green, white and black, if you would like to choose other special colors such as blue, yellow, gray, the price will be a little more costly.

From the brand aspect, currently the best brand is Taiyo solder mask, because it has high viscosity, stable dielectric constant, good insulation and oxidation resistance properties, but it is more expensive than others. Other brands of solder mask oil will be relatively cheap, but the quality is not particularly stable and can’t be guaranteed. So if the circuit boards need to used on bulk products, we recommend to use Taiyo to get a stable quality.

Printing film

If it is a bulk order with simple design and trace width/space >= 5/5mil, almost manufacturers will use printing film to generate traces. But please remember: the larger the board size, the higher cost of film. (Generally speaking, Prototypes or small orders are use LDI exposure machine to generate the trace, but for mass production, manufacturer will priority choose film and then use LDI.)

Line width/space

The thinner traces, the higher manufacturing price. Because the line is thinner, the accuracy of the equipment and the quality of the chemical solution are required to be relatively high, and the yield will be relatively low, resulting in higher costs. Each manufacturer has its capability, so choose a suitable supplier is most important, view Best’s website to check our capability.

Drill holes

The smaller the hole, the higher the price, the diameter of less than 0.3mm will increase the price. The more holes there are, the higher the price will be. Other special holes will also increase the cost, such as half holes, blind holes, PTH holes larger than 6.0mm, etc. Because the hole is small, only one board can be drilled at a time when drilling the hole on PCB material, which is low efficiency and the possibility of drilling a broken drill bitter is also large, resulting in higher cost.

Finished copper thickness

Finished copper thickness ≥2oz, and hole copper >25μm board will increase the cost. Because the price of copper itself is relatively expensive, the thicker the copper, the higher the price, coupled with the cost of additional electric copper, leads to the overall price rise.

Finished board thickness

There is little difference in the price of PCB with board thickness of 1.2mm and 1.6mm, but if the board thickness is 2.0mm or even thicker, its cost will increase correspondingly. The thicker the board, the more sheets of fiberglass, so the cost will increase accordingly.

Outline

If there are more slots, and the slots are less than 1.0mm, the cost will increase. This is because the gong groove of the board is more shaped, resulting in the processing time is elongated. In addition, if the width of the groove is small, processing can not be too fast, easy to break the milling cutter, so the processing efficiency is low, the natural production cost increases.

Surface treatment

Our common surface treatment processes are: OSP(antioxidant), lead HASL, lead-free HASL (environmental protection), gold plating, immersion gold, ENEPIG and some combination processes. The price of the above process is more expensive in turns, that is, OSP (antioxidant) < lead HASL < lead free HASL < gold plating < immersion gold < ENEPIG.

Tooling fee and testing fee

Tooling fee: in generally most of manufacturers use milling cutter to punch outline if this is a prototype order or small order. But if bulk order, it is needed to use a tooling jig, so there is a tooling fee need to pay.

Testing fee: flying probe tester is usually for small order, mass production need to use testing jig, and there is a different testing fee for both.

Above elements can affect the cost of making a board, you can try to follow those guidelines if you have a limited budget. Or if you want to know a exactly cost, please send RFQ to Best Technology, our sales will give you a best price.

Posted in best pcb, bestpcb, FAQ, FR4 PCB, PCB News | No Comments »

3M Epoxy Adhesive DP190-Gray & 3M Epoxy Adhesive DP190-Translucent

Friday, April 22nd, 2022

Both 3M Epoxy Adhesive DP190-Gray and 3M Epoxy Adhesive DP190-Translucent are a two-part epoxy adhesive that delivers exceptional performance with high shear and peel strength.

They can bond to a wide range of materials, such as metals, ceramics, wood, fiberboard, glass, rubber and many plastics. So, PCB is no exception. But what are the similarities and differences between them?

Similarities

Provide tough, strong bonds through high shear and peel strength.
Capable of bonding to a wide variety of different materials.
Deliver extended work-life, providing additional time for adjustment.
Exhibit good environmental aging properties, delivering long-term durability.

Differences

3M Epoxy Adhesive DP190-Gray has a moderately high modulus. With a 90-minute work-life, it reaches handling strength in approximately 10 hours and full cure in 7 days at room temperature.

Additionally, this epoxy adhesive has medium viscosity and self-leveling with a 1:1 mix ratio by volume. But its flexibility and elongation are moderate.

3M Epoxy Adhesive DP190-Translucent has a moderately low modulus. With an 80-minute work-life, it reaches handling strength in approximately 10 hours and full cure in 14 days at room temperature.

It has low viscosity and self-leveling with a 1:1 mix ratio by volume. Additionally, it features high flexibility and elongation.

This is all about the similarities and differences between the 3M Epoxy Adhesive DP190-Gray and 3M Epoxy Adhesive DP190-Translucent. It is supposed that you have known about them.

But if you still have any questions about them or PCB, please feel free to contact us. Because at Best Technology, we are fully equipped to handle your PCB manufacturing requirements.

Tags:PCB, printed circuit board
Posted in best pcb, bestpcb, FAQ, PCB News, PCB Technology | No Comments »

Notes for cleaning PCBA

Monday, October 18th, 2021

PCBA includes components assembly and DIP plug-in, in the whole process, there will be reflow soldering, wave soldering, manual soldering, due to the current Electronic products are getting smaller and smaller, and the size requirements of PCBA are getting smaller and smaller, but the requirements for quality (including product reliability and stability, etc.) are getting higher and higher. Many customers require PCBA boards with conformal coating to increase stability and reliability and ensure product quality and performance. But the PCBA board must be cleaned before with conformal coating.

Because there will be a variety of flux residues on the soldered MCPCB board, some of which are acidic, soluble and corrosive, etc., if these residues are not cleaned, the coating will also cause very great damage to the product. In this blog I’d like to share some notes for cleaning PCBA.

PCBA board after soldering, should be cleaned as soon as possible (flux residue will produce corrosion over time), cleaning residual flux and other pollutants on PCBA board.

When cleaning the PCBA board, prevent the cleaning agent from intruding into the unsealed components to avoid damage to the components. After cleaning, it should be placed in the oven at about 30-50 degrees, baked for about half an hour, and then removed after drying PCBA board.

When cleaning the PCBA board, protect the components and labels on the board. Otherwise, the mounted and welded PCBA board will be wasted.

Cleaning PCBA board affects the life and reliability of electronic products. Some of PCBA boards are not cleaned, which may lead to short circuit and leakage, leading to unqualified products and many failures, increasing the cost of recovery and maintenance, so it is not worth the loss to clean PCBA boards.

Best Technology has our own SMT factory and can help our customers to buy the components at the same time. If you have any new inquiry of PCBA, welcome to send it to me then I can send you the quotation for comparison with your other suppliers.

Posted in best pcb, bestpcb, FAQ, PCBA | No Comments »

Aluminum vs Copper Core PCB

Wednesday, May 19th, 2021

In Best Technology, currently the most common metal used forÂ Metal Core PCB manufacturer are Aluminum, Copper. Today letâ€™s talk about the main differences between aluminum substrate and copper substrate, hoping to help you choose the right substrate in future design projects.

Although they both share similar properties and functions, there are still a few variations between the two kinds of metals. Some of the key differences between aluminium and copper core PCBs are explained in the points below.

1. Thermal Conductivity

The thermal conductivity of copper substrate is up to about 400(W/mK) and the thermal conductivity of aluminum substrate is generally about 200W(W/mK). The thermal conductivity is higher, the transfer efficiency will be better, and the heat dissipation will be better, then the working life will be longer.

2. Electrical Conductivity

Both aluminum and copper, being metals, are electrical conductors of electricity, although the exact degree of this varies between the two metals. When it comes to electrical conductivity, copper has a clear advantage over aluminum. In other words, in applications where there is a need for efficient electrical conductivity, copper makes for an ideal pick.

3. Electrical Resistance

Resistance is very important when it comes to PCB design, as it can have an effect on the overall function and stability of the component. Given that copper has a higher density than aluminum, it tends to have a lower resistance than aluminum, so copper isÂ an betterÂ choice where thereâ€™s a requirement for thinner circuits and faster electricity transfer.

4. Weight

Since copper has the higher density for per unit area, the weight of copper PCB is much heavier than aluminum PCB for the same design.

In applications where light-weight construction is required more than anything else, aluminum is the preferred material of choice. On the other hand, applications where weight is not much of an issue, tends to be the ones where copper is widely used.

5. Application

Copper core PCBÂ isÂ the best heat dissipation among all MCPCB, soÂ itâ€™sÂ mostly used in automobile headlights, taillights and some high-tech electronic products (unmanned aircraft, mining machine) high-power lighting equipment. The aluminum core PCB is mostly used in indoor lighting, energy saving lighting, street lightingÂ and other energy-saving lighting electronic products.

In conclusion, due to the above different parameters and performance, the cost of copper is generally more expensive thanÂ aluminum. If you have other questions about MCPCB, welcome to contact us .

Posted in FAQ, mcpcb, Metal Core PCB, Our News, PCB News, PCB Technology | No Comments »

What’s fiducial marks on the PCB?

Saturday, April 24th, 2021

You may ever be recommended by some PCB manufacturers to add the fiducial holes on the board edge. Do you know what is fiducial marks and whatâ€™s the purpose for this kind of holes in a PCB?

Now, let me to show you something for what is the fiducial holes.

Fiducial holes, we also call it fiducials mark, while we assemble a PCB, it will need to locate the positions for each component, and it is positioned based on the fiducial mark as the reference point.

There are 3 types fiducial marks, first type is fiducial marks on a single board, second type is the fiducial marks on a PCB panel, third one is the fiducial marks for some single component on the board.

Here are the pictures for you to understand the types of the fiducials.

Fiducial mark on a single board is designed for positioned all circuits features on a single board. It is necessary to have a fiducial mark on a single board.

And fiducial marks on a PCB panel is used to assist positioning the circuits.

For the fiducial mark of a single component, it is designed to position the fiducial mark of a single component, which can improve the placement progress (For QFP, CSP, BGA and other important components must have the fiducial marks).

So, it is important to add the fiducial holes on a PCB board.

Also, while we make the panel for the PCB board, on the diagonal of the four corners, it is required to have 2 fiducial points at least on 2 diagonal corners. you can also place 4 marks on the four corners, but generally, assembly plant will only need 2 marks for recognize.

See below a PCB panel for reference:

In the other hand, while you design the PCB, please try not to put the silk screens, pads, traces etc. within 2mm of the optical fiducial marks. Otherwise, the SMT machine will not be able to recognize the optical fiducial on the PCB boards.

And if you add the fiducial holes on the area which without any circuits, to avoid the holes being etching while the process, so generally we suggest to add a metal circles around the fiducial holes, to make it more obviously on the boards.

If you have any new PCB design which you also want to add the fiducial marks.

You are welcome to contact Best Technology for a help and we will show our best help for you.

Posted in FAQ, FR4 PCB, PCB Technology, PCBA | 1 Comment »

Main types surface finish of FR4 Printed wiring board

Wednesday, November 4th, 2020

Printed Circuit Board surface finish is a coating between bare FR4 board and components. The main function for surface finish is to protect the exposed copper circuitry and provide a solderable surface when assemblingï¼ˆsoldering) the components to a copper clad PCB board.

Most of the Rigid Circuit board company can make several different types of surface finish. Best Technology as a leading custom FR4 printed circuit board manufacturer since year 2006, it could provide following different finish.
HASL
Lead-free HASL
Immersion Tin/Immersion Silver
OSP (organic Solderability Preservative)
Gold
ENIG (Electroless Nickel Immersion)
Hard Gold
Wire bonding Gold

As the surface mounts assembly service became more complex and needs to conform to new regulations like RoHS and WEEE. People maybe face the question how to choose a suitable surface finish for your FR4 Copper board?

Before decide to choose suitable surface of copper conductors circuit board, you may need to take the cost, RoHS, your components type, PCB assembly method, factory circuit fabrication capability, and rigid board circuit testability into consideration.
Basis on above information of copper foil PCB, we would like to make a explain PCB finish in detail, wish this may help when you make decision at circuit board design and manufacturing.

HASL/Lead Free HASL
It is a most popular surface finish, and the cost is low and easy to repairable, it is acceptable for simple SMT. But the surface is uneven, it is not suitable for fine pitch components and not good for plated through-hole(PTH). In other way, it is poor wetting.
Material different with same finish
HASL(standard):Typically Tin-Lead
HASL(Lead Free):Typically Tin-copper, Tin-Nickel, without lead
The thickness will conform to IPC 6012 class 2 standard

Advantages of HASL-LF
Excellent solderability
Inexpensive / Low cost
Widely Available and used
Easy reworkable
Allows large processing window
Long industry experience / well known finish

Disadvantages of HASL-LF
Uneven surfaces for printed circuit board
No good for fine pitch components from Samtec/Hirose/Molex
Thermal shock
Solder Bride for circuit board assembly
Plugged or reduced PTHâ€™s
Not suited for < 20mil pitch SMD & BGA
Bridging on fine pitch
Not ideal for HDI products

Immersion Tin

Advantages
Flat surface
No Pb
Good for fine pitch / BGA / smaller components
Mid range cost for lead free finish
Press fit suitable finish
Good solderability after multiple thermal excursions
Easy reworkable

Disadvantages
Very sensitive to handling â€“ gloves must be used
Tin whisker concerns
Aggressive to solder mask â€“ solder mask dam shall be â‰¥ 5 mil
Not recommended to use peelable masks
Exposed tin on final assembly can corrode
Not good for multiple reflow/assembly process
Difficult to measure thickness

OSP (organic Solderability Preservative)
OSP(organic Solderability Preservative) same with HASL, lower cost but the OSP have flat surface, and it is not good for PTH components, sensitive and short shelf life, it is very easy come to oxidation.

Advantages
Flat surface
No Pb
Good for fine pitch / BGA / smaller components
Inexpensive / Low cost
Easy reworkable
Simple Process
Disadvantages
Not easy to measure thickness
Not good for circuit copper board plated through-hole(PTH)
Short Shelf Life
Maybe cause ICT issue
Exposed Cu on Final assembly
Handling sensitiveâ€“ gloves must be used and scratches avoided

The above surface finish of Printed Wiring Board compared with Gold finish, the cost is corresponding cheaper, but in my coming blog, I would like mainly to explain Gold finish for printed circuit board fabricator with 13 years rich-experienced in FR4 PCB custom contract manufacturer.

If you have any question about the printed circuit boards (PCBs). Warmly welcome to send mail or call Best Tech.

Posted in FAQ, FR4 PCB, SMT Technology | No Comments »

Why don’t use BeO as substrate to make DBC ceramic PCB?

Wednesday, September 9th, 2020

It is widely known that BeO with high thermal conductivity (200-250W/m.k).

High dielectric constant 6-7 (0.1MHz) and dielectric loss tangent is 10-4 (0.1GHz).

It is ideal material for ceramic PCB, lots of engineers want to use it as DBC ceramic PCB substrate.

But it is unfeasible, the powder of BeO is extremely poisonous.

The poison gas is produced by the reaction between oxygen, Cu and BeO under

1065-1085 degrees Celsius, so it is limited to make cooper on BeO substrate,

it has caused AlN (Aluminium Nitride) is becoming more and more popular.

Though BeO is unfeasible for DBC technology, but it is feasible for thick film technology.

Because when doing the conductor (Au or AgPd) on BeO substrate, we use silk-screen printing, no need to under high temperature environment, there is no chemical reactions.

Below the manufacturing process for your reference.

Here is the photo of BeO with AgPd conductor.

Tags:Beo, DBC ceramic PCB
Posted in Ceramic PCB, FAQ, Our News, PCB News, PCB Technology | No Comments »