Unveiling the advantages and disadvantages of Surface ...

You can find more information on our web, so please take a look.

Introduction

Printed circuit board assembly, in particular, has significantly benefited from surface mount technology (SMT). SMT eliminates the requirement for drilled holes and manual insertion by mounting electronic components directly onto a PCB's surface. This technique offers several advantages, such as smaller and thinner PCBs, flexibility in design, reduced material costs, simplified automation, and high signal transmission capabilities.

Advantages of SMT in PCB Assembly

Ultra-Thin and Miniature PCBs

The size and weight of surface-mount components are significantly lower than their through-hole counterparts. Boards are smaller and thinner because their compactness makes better use of space on printed circuit boards. As a result, products can be designed to be more compact without compromising functionality or performance.

Flexibility

SMT provides great flexibility in terms of PCB materials and designs. It enables the use of flexible PCBs (flex PCBs) and rigid-flex PCBs that can bend or conform to specific shapes or spaces. This flexibility opens up opportunities for innovative designs while maintaining excellent electrical performance.

Lesser Expense on Materials and Cardboard

Unlike through-hole components that require manual insertion, SMD components can be automatically placed on the board using pick-and-place machines or automated assembly lines. This automation streamlines the production process, reduces labour costs, and improves efficiency.

Simplified Manufacturing Process

When compared to through-hole components, surface-mount devices (SMDs) can be automatically positioned on the board through the use of pick-and-place machines or automated assembly lines. Because of this automation, production is more streamlined, costs less to operate, and more efficient overall.

Frequency and High Signal Transmission

Fast signal transmission with less radio frequency interference is made possible using SMT components, which are compatible with high-density double-sided and multi-layer printed circuit board assembly. Additionally, SMT assemblies' lack of leads improves their resilience to vibration and guarantees dependable signal integrity.

Drawbacks of SMT for PCB Build-Up

High Initial Investment

Implementing SMT assembly requires investment in specialized equipment such as reflow ovens, solder paste screen printers, pick-and-place machines, and hot air rework stations. These machines can be costly but are essential for efficient and accurate assembly.

Difficult to Inspect

Due to the small sizes and numerous solder joints of most SMD components, inspection becomes challenging. Identifying defects or faults can be time-consuming, especially when dealing with complex packages like ball grid arrays (BGAs), where solder balls are located under the component.

With competitive price and timely delivery, KF-SMT sincerely hope to be your supplier and partner.

Fragility

Comparing surface-mount components to their through-hole counterparts, SMD parts are more delicate and fragile. They can be easily damaged if mishandled or dropped during the manufacturing process or while in use. Special care must be taken to handle and package these components using anti-static measures in clean room environments.

Expensive Small Batch Production

Technical complexity necessitates skilled operators and specialized equipment, making prototyping or small-batch manufacture of SMT PCBs an expensive ordeal. Due to the high initial setup expenses, SMT technology may not be cost-effective for small volumes.

Limited Power Capabilities

Surface mount technology isn't suitable for all electrical components, active or passive, because of power constraints. Components generating high heat may not be suitable for surface mounting as it can cause solder melting and compromise the integrity of the connection.

Despite these challenges, SMT remains a highly recommended practice in the manufacturing industry due to its numerous benefits. It enables manufacturing efficiency, design flexibility, better performance in harsh conditions or high-frequency applications, and more compact devices without compromising functionality or performance attributes. With ongoing advancements and innovations in SMT technology aimed at addressing existing limitations and improving production processes further, we can expect to see continued growth and impact on the industry.

Did you know that choosing which tires to use on a Formula 1 race car has a critical effect on the car&#;s performance? The tires normally used don&#;t have any treads on them. These give the car the best grip on the pavement, but they will hydroplane in the rain. The rain tires, on the other hand, have treads to conduct the water away from the tire to give it a better grip, but the heat and friction of dry pavement will rip these tires apart. Making the right tire decision for the track conditions can be a difficult job.

When preparing to design a printed circuit board, you may need to decide between surface mount and thru-hole packages for some components. Surface mount technology components, or SMTs, have a lot of advantages over traditional thru-hole components. There are, however, some disadvantages that you should be aware of too. Let&#;s take a closer look at some of these surface mount technology advantages and disadvantages.

Surface Mount Technology Advantages that You Should be Aware of

SMT parts have been around now for a long time now, and have become the standard when it comes to components used on printed circuit boards over plated thru-hole parts (PTH). Here are some of the reasons for the popularity of the SMT package style:

 

• Automated assembly: Most SMT parts can be easily installed on circuit boards using automated pick & place equipment. High volume parts, such as passive components, are loaded into the pick and place machine from reels while other parts are loaded from tube feeders or trays. This is a very important difference over PTH parts which often have to be manually assembled.
• Commonality of parts over PTH: SMT parts are usually less expensive than their PTH counterparts due to their size and volume. SMT parts are also more available than PTH parts because of how much they are in demand.
• Size: SMT parts are typically smaller than their PTH counterparts since they don&#;t have long leads that need to be inserted and soldered into holes. This allows the PCB designer to fit more components in less space on the board then can be done with PTH parts.
• Electrical performance: With more SMT parts being able to fit on the board than PTH parts due to their size, you also end up with shorter signal paths on the board. This will give your PCB better signal integrity, and less generated heat than with PTH parts.

You can see why surface mount parts are used so much, but there are some circumstances where thru-hole parts have the advantage.

High volume components are loaded into pick & place machines from reels like this

Some of the Disadvantages of Surface Mount Technology

Even though most printed circuit boards will benefit from being designed with SMT parts, there are some reasons why PTH parts may be more desirable:

• Easy to work with: Although rework technicians are very skilled with tweezers and magnifiers in order to rework small SMT parts, the larger PTH parts are easier to work with. Some SMT parts are so small that they present quite a challenge to find, de-solder, replace, and then re-solder. There is also the concern that there could be collateral damage by handheld soldering irons to nearby parts with the STM parts being so small and close together.
• Electrical performance: Although the SMT parts will give better signal performance due to their small size, the larger PTH parts are still needed for high-power applications. There often isn&#;t an SMT equivalent part, and in cases like this, you will need to use a PTH package instead.
• Mechanical strength: Connectors for single-use, such as I/O devices on a motherboard, are often an SMT part. A more robust connector, however, should be used in applications where they will constantly be connected and disconnected. Here is where a PTH part can be the best choice as its soldered thru-hole leads will give much better mechanical strength over a surface mount soldered part. The same goes for switches or any interface device that will be getting regular use.

Now that you know some of the advantages and disadvantages, let&#;s take a quick look at how best to decide.

How to Decide which Technology is Best for Your Design

The best time to decide between an SMT or PTH part is when you are choosing the components that you will use in your schematic. By incorporating these parts early in the design, you will make sure that the PCB Layout is created with the correct component package footprints. Here are some questions to consider when making your decision:

• Use: Will this component get &#;touched&#; much or be subjected to other stress?
• Power: Will this component be conducting a lot of power and heat?
• Performance: Which package style will give your circuit the best performance?
• Price: Is there a price benefit by choosing one package style over the other?
• Availability: How quickly will the part be available for prototypes?
• Rework: Are you expecting a lot of rework of the circuit, especially during prototyping?
• Assembly: Which package style will give you the highest quality assembly for the lowest cost?

For the most part, a surface mount part will be the best way to go, but don&#;t be afraid to choose a thru-hole part if it is really called for. Here is where your PCB contract manufacturer can really help with your decision. They will have the experience of working with all kinds of PCB component package styles in order to give you the best recommendations.

At VSE, we have been doing this now for over 30 years. We have a team of component engineers that keep their pulse on the component supply chain so that they know which parts are available now and in the future, and for what price. Meanwhile, our manufacturing engineers will be able to advise you on which parts will work best for the manufacturing process that will be used for your board.

For more information, please visit Smt Feeder Parts.

If you are looking for a CM that understands the engineering requirements of PCB component packages to ensure that each PCB assembly is built to the highest standards, look no further than VSE. Contact us today to learn more about partnering with us for your next project.