Design of Castellated Holes

Hole Shape, Size and Spacing: Castellated mounting holes typically have a round shape, but they can also be square or rectangular. The size of the holes should accommodate the screws or other fasteners being used for mounting. Spacing between the holes should be sufficient to prevent solder bridging and ensure proper electrical isolation between connections.

Castellation Depth and Width: The depth and width of the castellations depend on the thickness of the material being mounted and the size of the solder joint required. The castellations should be deep enough to ensure a strong solder joint but not so deep that they weaken the structural integrity of the mounting hole.

Spacing and Alignment: Ensure proper spacing and alignment between the castellations to facilitate soldering and assembly. The castellations should be evenly spaced around the perimeter of the mounting hole to provide uniform support.

Thermal and Mechanical Factors: Depending on the application, you may need to consider thermal and mechanical factors. For applications subjected to high temperatures or mechanical stress, may need to use thicker material, or increase the size of the castellations to ensure proper stability and reliability.

Benefits of Castellated Mounting Holes

Space-saving – Castellated holes eliminate the need for additional connectors or headers, allowing for more compact printed circuit board designs.

Simplified Assembly – Castellated mounting holes simplify the assembly process, reduce assembly time and labor costs by providing an easy way for soldering components directly onto another surface, such as a larger printed circuit board or another module.

Increase Stability and Reliability – Castellated mounting holes, with notches or gaps around the perimeter, provide strong mechanical connections between components. This guarantees stability and reliability in applications subjected to vibration or mechanical stress.

Improved Electrical Connection – Castellated holes provide robust electrical connection between components thus minimizing signal loss and ensuring consistent electrical performance.

Modular Design – Castellated mounting holes enable a modular design approach, which enhances flexibility, scalability, and ease of upgrades or repairs.

Lower Assembly Cost – By eliminating the need for additional connectors or mounting hardware between components.

Disadvantages of Castellated Mounting Holes

Complexity in PCB Design: Integrating castellated mounting holes into a printed circuit board design can add complexity. Proper placement and sizing of the holes are critical to ensure alignment and compatibility with other components.

Increase Manufacturing Costs: Fabricating printed circuit boards with castellated mounting holes require specialized equipment and technique to ensure precise cutting and plating of the holes.

Increase Risk of Solder Bridges: The design of castellated mounting holes may increase the risk of solder bridges forming between adjacent pads during the soldering process.

Limited Reusability: Once components are soldered onto a surface using castellated mounting holes, they may be difficult to remove or reuse without causing damage to the printed circuit board or the components themselves.

Assembly Complexity: While castellated mounting holes can introduce additional complexity, particularly in hand soldering operations or when working with automated assembly equipment.

Interference with Signal Traces: The presence of castellated mounting holes on a printed circuit board may interfere with nearby signal traces. Designers need to carefully consider the placement of these holes to avoid signal integrity issues.

Despite these disadvantages, castellated mounting holes remain a valuable option in many electronic hardware designs.

Applications of Castellated Mounting Holes

Castellated mounting holes offer versatility, reliability, and space-saving benefits, making them suitable for a wide range of applications such as:

Wireless Communication Modules: Castellated mounting holes are often used in radio frequency (RF) modules, such as Wi-Fi modules, Bluetooth modules, and RF transceivers.

Internet of Things (IoT) Devices: Castellated mounting holes facilitate the integration of multiple components, sensors, and communication modules onto a single printed circuit board, enabling compact and robust designs.
Embedded Systems: In embedded systems, where space is limited, castellated mounting holes are used to attach small modules to the main PCB.

Wearable Technology: Wearable devices benefit from the space-saving nature of castellated mounting holes.

Industrial Control Systems: Castellated mounting holes are used in devices like industrial controllers, data acquisition systems, and automation equipment. They provide secure connections and withstand harsh environmental conditions.

Consumer Electronics: Consumer electronic devices, such as gaming consoles, media players, and smart home devices, use castellated mounting holes for integrating additional features or expanding functionality.

Future Evolution

The future of castellated mounting holes in electronic hardware design is likely to be influenced by several factors:

• Miniaturization Trends
• Advanced Manufacturing Techniques
• Integration with Emerging Technologies
• Innovations in Assembly Processes
• Material Advancements

PCB Unlimited offers PCB fabrication services and PCB assembly services. You can get an online quote for USA Quickturn PCBs, Taiwan PCBs and China PCBs, request a custom quote by simply email your design files to support@pcbunlimited.com.

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Things to look for in a PCB manufacturer

There are many manufacturers of printed circuit boards — so many that when you need to find one fast, it can be very easy to feel overwhelmed. How do you choose the right one for your project?

Believe it or not, not all PCB manufacturers are created equal. Before you place your printed circuit board order with a PCB manufacturer, make sure they have the following things going for them. This will help ensure you have a good experience and a successful project.

Several Years in Business

Experience counts for the most when it comes to manufacturing printed circuit boards. This isn’t to say newbies can’t do it well, but when you’re facing a critical project deadline or working on something important, you don’t want to take chances. Several years in business indicates that a manufacturer is competent and that they can consistently innovate and adapt over time. Try to find a manufacturer to partner with who’s been active in the industry for at least a few years.

The Appropriate Certifications

There are two different processes used in PCB construction: through the hole and surface mount. You should learn about a specific manufacturer’s processes and quality standards before doing business with them. Make sure they have the right credentials and certifications to demonstrate high-quality processes and materials. Tread carefully when investigating this aspect of a printed circuit board manufacturer. Some of them say that they’re compliant with industry quality standards, but they’re really just going through the motions. They don’t actually have the right procedures in place to become properly certified.

Know Where Customer Service is Located

Some PCB manufacturers don’t actually have a customer service team. Instead, they hand off customer service calls to their sales representatives (see PCB brokers below). This doesn’t have to be a bad thing if their sales reps are skilled at providing the information existing customers need, and most of them probably are. But it’s a good idea to find out where the customer service team is located. If they’re in a time zone on the other side of the world, it could be difficult for you to get the support you need. If there are language barriers because none of the support reps speak English as their first language, it may be hard for you to get the service you need. This probably wouldn’t be a dealbreaker in any case, but you should know what you’re getting yourself into.

Competitive Pricing

If you have the chance to speak with a representative of the printed circuit board manufacturer, you should ask if their pricing can compete with that of offshore manufacturers. If the company is based and operated in the United States, the answer will probably be no, but it doesn’t hurt to ask. More importantly, the manufacturer’s processes and materials should be of a quality that justifies the price they’re charging. Cheaper doesn’t always mean better. As long as it’s within your budget and they have the qualifications and services you require, you shouldn’t see their pricing as an issue.

Proof of the Above

As sad as it is, not all business representatives are honest when they provide information about the company they work for. If you’ve been on the phone asking a manufacturer’s rep about the things discussed so far, you should take it a step further and make sure it all checks out on their website. Look for seals from official organizations verifying their credentials and quality standards. Check their ratings with the Better Business Bureau. You should also look for reviews left by other customers who’ve used them in the past.

If everything checks out, you’ll have found a PCB manufacturer you can be comfortable doing business with, for both your current project and all of your projects to come.

PCB Brokers

The vast majority of the Chinese and Taiwanese PCB manufacturers do not have a customer service or sales team in North America. They rely completely on PCB brokers. PCB broker typically works with several offshore PCB manufacturers and some domestic ones as well. A good PCB broker will take the time to understand your project requirements and find the best PCB manufacturer for you project in terms of technology, lead time and pricing.

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Here’s how prototype PCBs are made with such accuracy.

Front-End Engineering Checks

Before a PCB prototype is built, there are countless aspects that go into planning the final result. First, the PCB manufacturer will look over the board design (Gerber files), and begin preparing the circuit board with a list of step-by-step instructions that are laid out for fabrication. After review, an engineer will then convert these plans into a data format that will help to engineer the PCB. This engineer also will check for any issues with format or clean up.

This data is used to create the final board, which is also given a unique tool number. This number keeps track of the printed circuit boards that go through the building process. Even the smallest of changes to a circuit board revision will result in a new tool number, which helps to ensure there is no confusion during the PCB manufacturing and fabrication processes of multiple orders.

Plotting

After the correct files are inspected, and a panel array is chosen for the best fit, photo plotting begins. This is the start of the production process. The photoplotter utilizes a laser to plot the patterns, silk screens, and other primary images that are required on the PCB.

Lamination and Drilling

One of the three primary types of printed circuit boards, multi-layered PCBs, require lamination to fuse the multiple layers together. This is typically done using heat and pressure.

Once the product is laminated, expert drilling systems are programmed to drill holes precisely and accurately into the boards. The drilling program ensures that there is no human error during the PCB manufacturing process.

Copper Deposition and Plating

The conductive copper layer, which is deposited through electrolysis, is essential to the functionality of all prototype printed circuit boards. PCBs officially become conductive surfaces after electroplating, which is where the copper is plated via a plating bath. These copper tracks are a type of conductive path that connect two points within the PCB.

After the prototype printed circuit boards are tested for quality assurance, they are then fabricated into cross sections and lastly, inspected for cleanliness.

For more information on PCB manufacturing, contact PCB Unlimited today!

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Printed Circuit Boards typically include mechanical layers, solder mask layers, silkscreen layers, solder paste layers and one or more copper layers depending on the complexity of the boards.

The outer layer contain the boundaries (shape and physical dimensions) of the PCB. Additional mechanical layers may contain tooling specification and other mechanical information.

The copper layers contain the routing layers as well as the ground and power planes.

The solder mask is a solder resist coat that is usually applied to the outer layers of the PCB for protection against oxidation and to prevent solder bridges from forming between closely spaced solder pads. Solder mask is usually green but is also available in many colors.

The silkscreen layers contains the reference designators, among other things, for the electronic components located on the top and bottom sides of the board. The text is usually printed with a permanent non-conductive ink. Silkscreen is usually white but is also available in other colors.

The solder paste layers contain the location, the size and the shape of the SMD pads on the board. This information is then used to make the apertures in the SMT stencil.

Reasons For Using Multiple Layers In Printed Circuit Boards.

Miniaturization
Multilayer PCBs enable designers to reduce the board size by adding layers. This is very important as miniaturization of electronic products continue to drive the industry.

Reduced complexity
Multiple layers make PCB routing easy because copper traces in one layer can connect to traces in other layers to complete the path.

Supply and ground isolation
Multi-layer PCBs (4 or more layers) have their own supply and ground layers. This provides isolation between supply and ground pins preventing short circuit.

Simplify Construction & Reduce Weight
Eliminate or reduce the need of connectors for multiple separate PCBs.

Higher density of assembly

Single Layer Versus Multiple Layer Printed Circuit Boards.

Single Layer PCBs have the electronic components on one side of the board and the conductor pattern on the other side. Multilayer PCBs can have the electronic components on the top side, the bottom side or both sides of boards and have one or more conductor patterns.

Single-layer or single-sided PCBs are typically used in simple electronics. They are cheap to manufacture and are often used in applications that demand high volumes such as calculators, radios, and printers.

Double-layer boards are necessary for moderately advanced technology including HVAC systems, power supplies, LED lighting, and automotive dashboard lighting.

Multi-layered boards delve into the territory of complex data storage, GPS technology, medical equipment, and satellites.

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Similarities between the two

Though these PCB options have major differences, they still utilize many of the same components. Both single and double-sided prototype PCBs serve as electrical catalysts in order to transmit power and make connections between different components.

They are also made of the same FR4 material, a type of fiberglass that is mixed with epoxy and formed into multiple layers. For example, a four-layer board has internal layers that improve the distribution of power on your PCB layout. It does this by decreasing the loop area and improving EMI performance.

Single-Sided PCBs

Single-sided PCBs have one layer of conductive material and are best suited for low density designs. A series of leads pass among the through-holes of the component-side before they are soldered to the copper tracks.

Single-sided PCB assembly was the original way to fabricate prototype circuit boards. As technology advanced and more power was needed for surface mount components, double-sided PCBs were manufactured.

• Ideal for simple low-density designs
• Lower cost than double sided PCBs, especially for large orders
• Easier to manufacture

Double-Sided PCBs

Double-sided PCBs became a convenient way to double the conducting power of the substrate core without sacrificing surface area, the key problem with single-sided PCBs. In a double-sided PCB, through-holes components are mounted on the top and surface mounts are present on the bottom. They are connected through “vias,” or holes that connect the two sides.

• Reduce board size by increasing circuit
• Provide greater flexibility for designers
• Reduce cost of for high density circuits

The main differences

Simply put, double-sided PCBs have more power. As the world’s need for technology advances, double-sided PCBs have become the most popular option for prototype printed circuit boards on the market today. Regardless, this is still the more expensive option for your printed circuit board prototype. Many small electronics are still able to benefit from single-sided uses and the cost is much cheaper. If you’re stuck trying to choose between the two options, the intended use for your prototype PCBs will be the determining factor.

When you want to get involved in printed circuit board manufacturing, each option has pros and cons when building prototype PCBs. To find out which option is best for you, don’t hesitate to contact PCB Unlimited, the best PCB assembly, design and layout, and fabrication company around. Visit our website at pcbunlimited.com for more information today.

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Printed circuit boards hit the scene and changed the game. Taking away the physical wires, copper tracks were printed into circuit boards, building conductive tracks that connected two points. Removing wires and using these tracks saved space and made conductive speed exponentially faster. Now they’re in everything.

Here we are now, tangled in printed circuit boards that are supporting our technologically dependent existences. How?

Whatever you’re reading this from

You’re here reading this and you’re not doing it from a newspaper. Computers, tablets, mobile phones, and anything able to connect to the internet are able to do so from the hardware under the shiny shell we so desire to have. It’s always fun to realize that when people stand in line to pay more than $1,000 for the newest iPhone release, they’re paying for a bunch of printed circuit boards in a pretty shell.

Television

One of the other electronic devices being utilized more often than not, even the older generations of televisions had printed circuit boards inside of them. Now, as televisions are becoming smarter and an increasingly accessible device in the Internet of Things, their complexity is burgeoning. We know you can connect the aforementioned devices to your TV. Your flawless 4K picture streamed from a tablet isn’t magic, it’s printed circuit boards and company.

Microwaves

We like tossing this one into the mix because, at this point, you get that printed circuit boards are synonymous with technology. When people think of technology, it’s usually computers, mobile phones, tablets, etc. It’s not the convenient thing you use to heat up your leftovers, tell time, thaw frozen food, and be an all-around kitchen hero. Credit needs to be given where it’s due and, in the name of food, the microwave is an essential technological part of your life-long culinary team.

This is the smallest list of devices that wouldn’t exist without printed circuit board technologies. What’s even cooler is that as technology develops over time, we could see things that blow our minds as much as the iPhone blew our grandparents’.

The post In Case You Didn’t Know, Printed Circuit Boards Are In Almost Everything appeared first on Blog PCB Unlimited.

Usually, the base is made of a type of fiberglass material. In fact, rigid and flexible printed circuit boards have been commonplace since the Auto-Sembly process was developed by the United States Army in the mid-1950s, and nearly all rigid boards were made from fiberglass until very recently. However, there have been some new developments within the world of circuit board prototyping. In some cases, the core base material is made from metal.

Also known as aluminum PCBs, these circuit boards are quite interesting. Here’s an intro guide to working with these metal core PCBs.

Structure of Metal Core Printed Circuit Boards

These PCBs don’t vary that much in their structure from traditional printed PCBs, and the metal is comprised of a combination of aluminum, magnesium, and silumin. A typical metal core PCB layout includes:

The top layer: Soldermask
The second layer: Circuit layer, which is copper foil
The third layer: Dielectric layer
The base layer: The aluminum combination described above

Benefits of Aluminum PCBs

There are plenty of advantages of choosing this specific type of PCB and PCB assembly. They include:

1. The heat dissipation is much more advanced than with the typical FR-4 PCBs. This means you don’t have to worry about high temperatures ruining your board, while not compromising the LED output.
2. They are up to 10 times as thermally conductive as PCBs made with epoxy glass and incredibly thinner.
3. They don’t require a lot of copper, so you can save money on costs while boosting their effectiveness. This can be especially helpful during the circuit board prototyping phase.
4. They’re ideal for optimum thermal transfer.
5. They have an increased dimensional stability because the metal, even though it is very thin, is quite strong.

Metal core PCBs are becoming more common in the world of PCBs, and they are quite complex. Interested in using a metal core base in your next circuit board prototype? Feel free to get in touch with our professional PCB assembly experts today. Because when it comes to new PCB assembly innovations, we always want our customers to be in the know.

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The stencil thickness and the geometry of the stencil apertures determine the precise volume of solder paste deposited onto the printed circuit boards. The aperture size is also relevant since the relation (aspect ratio) between this and the material thickness will determine if the release of solder paste is optimal. For more information read our article on standard SMT apertures modifications. Controlling these two parameters is crucial to achieve sufficient solder joints. Material thicknesses like 0.004”, 0.005” and 0.006” are the most used for the majority of SMT applications.

Once the solder paste is deposited and the SMT Stencil lifted away from the PCB, the board will be ready for the placement of the SMT components. Read our SMT Stencil step-by-step tutorial

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