Guide to SMT Assembly for Businesses


SMT stands for surface mount technology, an area of electronic assembly that has become increasingly popular over the last three to four decades.

In fact, this technology was first introduced in the 1960s, but back then it was referred to as planar mounting. It wasn’t until 1986 that this technique really took off, replacing the through-hole technology (THT) that had been the norm up until that point.

In this guide, we’re going to take a look at what SMT is and the assembly process, along with the benefits of this technology and how this has been adopted and applied by businesses. Read on to find out more.

What is SMT Assembly?

Surface mount technology (SMT) refers to an assembly method that is used to strategically apply electronic components directly to the surface of a printed circuit board (PCB). These components are placed and soldered to PCBs using automated processes.

As devices and electronics have become smaller and smaller, this assembly method has become extremely popular. Arguably, it is now the norm in most products. 

That being said, if your business relies on PCB assembly processes at any stage, it’s vital that you choose the right method for you. Opt for the wrong one and this will have a big impact on efficiency, cost, and your overall manufacturing process.

So, to help you determine whether SMT assembly is right for you, we’re now going to dive a little deeper into the benefits and uses of this assembly method and how it is achieved.

What is SMT Most Commonly Used For?

SMT assembly is used in lots of applications across a wide variety of industries, covering everything from consumer devices to aerospace systems.

To give you a better idea of how this method is used and by which businesses, we’ve put together some of the most common uses for surface mount technology right now. These include:

  • Consumer electronics like laptops and USB flash drives
  • Telecommunications, including smartphones
  • Medical devices like pacemakers and MRIs
  • Marine technology, particularly portable navigation systems
  • Industrial control systems
  • Aerospace and defense systems

So, as you can see, SMT has a lot of applications and spans many industries. That is why it is so important to consider whether this is the right method for your business.

The Benefits of SMT for Businesses

There are lots of advantages to choosing SMT assembly and understanding how this can benefit your business can help you to make the most informed decision. With that in mind, here are some of the top reasons to choose SMT assembly:

Flexibility in construction

SMT assembly allows for greater flexibility as components can be placed on both sides of the PCB, which means designs can be more complex where required.

Improved reliability and performance

As SMT components are smaller than THT components, they allow for better heat dissipation and improved signal integrity. This means they are more reliable and they perform better.

The process can be automated

SMT is a simpler assembly process, therefore, it can be almost entirely automated. Because of this, it is far less risky, and more reliable as we’ve said and it reduces the chance of an error. Not to mention it can help to cut costs, but we’ll look at this in more detail next.

Cutting costs and increasing efficiency

SMT assembly is a more efficient process, largely because it is automated, which can help to drive down electronic manufacturing costs. Not only that, but it is capable of producing a higher volume of boards at a faster rate. This can increase the output, leading to a better cost per unit.

Producing smaller, lighter boards

As this assembly method does not require holes to be drilled and the materials are lighter, they are perfect for more compact devices. This is critical in today’s world where everything from TVs and smartphones to medical devices and navigation systems are always shrinking; with many expected to be small and portable.

Increasing density and opportunities

The space on PCBs is used more effectively with SMT, which means smaller and more sensitive components can be mounted to them. Plus, more components in general can be added to the same space, getting more from the smaller frame and SMT can co-exist with THT components on the same board.

The SMT Assembly Process

In this final section, we’re going to take a look at the steps required for the SMT assembly process. For the most part, it looks something like this:

1. Solder paste printing – The first step is printing the PCB with solder paste. This is done through the openings in a stencil and requires the use of a solder paste printer at the start of the SMT manufacturing line

2. Pick and place – At the next stage, a machine will pick and place each of the components onto the board, making sure they go in the corresponding positions. This is done using a compatible design file

3. Reflow soldering – Now the PCB goes through the reflow oven and the solder paste is melted to ensure all components adhere to the board. This is then left to cool to ensure they are fixed in place

4. Cleaning the board – The PCB must now go through a cleaning process. This stage is designed to remove any dirt or excess solder, as well as any hazardous residues left on board. A cleaning machine is typically used to do this, although this stage can happen on or off the assembly line

5. Inspection and reworking – The final stage of the process is to inspect the PCBs for any defects or issues. The quality of the solder will be checked, as well as ensuring that the boards meet manufacturing standards and regulations. If there are any problems or defects, the board must go through a process called reworking, in which these issues are fixed or the board is remanufactured

So, there you have it, the SMT assembly process explained in greater detail. That, in combination with the list of uses and benefits for this assembly method, can help you determine if this is right for your business or not.

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