some of friends always ask me that what is SMT? and what is SMD? What is the different about them?

so today i share with you all this article with you all:

SMT and SMD.

These two little acronyms get mixed up a lot in the electronics manufacturing service world. On paper, they only vary by a single letter, but in practice, there’s a lot more separating SMTs and SMDs. Chiefly, one is a process and the other is a device.

An SMD, or surface mounted device, is an electronic component that you would find on a board.

An SMT, or surface mount technology, is the method of placing components (like an SMD) on the board. In electronic manufacturing services, the SMT process often works with SMDs, perhaps adding to the confusion. And while it is important to know the difference between the two, the value of either is amplified when they are used in concert.

What is the difference between SMT and SMD?

SMT stands for Surface Mount Technology, the entire technology of mounting and soldering surface mount components onto a printed circuit board or PCB. The actual process is summarised below:

Firstly, a PCB(Printed Circuit Board) stencil is aligned on the surface of the boards and solder paste is applied using a squeegee to ensure the pads are coated with a uniform and controlled amount of solder paste. the machine use is called solder paste printer(named screen printer, smt printer, smd printer, pcb printer also)

Secondly, via a pick and place machine or hand placement(also called chip mounter, smd placement machine, smt machine,chip shooter machine), the components are mounted onto the boards in their respective locations. The wet solder paste will act as a temporary adhesive but it is still important to ensure that the boards are moved gently to prevent misalignment.

Thirdly, the boards are passed through a reflow oven(also call reflow soldering machine, soldering machine, reflow solder, welding machine, lead free reflow oven, non-lead free reflow oven, smt reflow oven, smt oven, smd reflow oven) which subjects the boards to infrared radiation, melting the solder paste and forming solder joints.

Then the boards are passed through an AOI machine, or Automatic Optic Inspection machine which runs a number of quality checks on the boards visually, such as component alignment and checking for solder bridges. The boards then proceed to further testing.

In the 1980s, SMT production technology became increasingly more refined and as a result, is widely used in mass production. As costs were reduced and technical performance enhanced, more advanced but economical equipment became available. Surface mount technology has numerous advantages, not limited to reducing the volume of devices, such as improved performance, greater functionality and lower costs. As such, SMT brought with it a new generation of electronic assembly technology, which is widely applied in applications from aviation, communications, automotive and medical electronics, down to household appliances and other fields.

SMD is an abbreviation for surface mount devices, a device assembled using surface mount components and technology. In the early stages, SMD were soldered manually by hand. Then the first batch of pick and place machines could only handle a few simple components. The more complex and smaller components still needed to be placed manually.

Not long before the introduction of surface mount components over 20 years ago, a new era was born. From simple resistors to complex ICs, almost every through hole component now has an SMT equivalent.

Where SMT and SMD combine

In the early years of SMDs, smaller and more complex components had to be placed and soldered by hand. Machines could do some of the pieces, limited to size and type. Today, manufacturing boards using SMT is somewhat similar, but much faster and far more accurate.

Back then, small bits of silver or lead were placed on the board to attach the component. These elements are still used, but in a solder paste, which is a mixture of flux and small bits of solder. SMT machines can attach thousands of SMDs per hour, compared to maybe a few hundred by hand. Consequently, nearly every through-hole process now has an SMT equivalent.

The popularity of SMDs came in response to how much more efficiently SMT could produce boards. The smaller component meant that both time and space could be maximized when both were used together. The SMD meant that more could be done with a smaller, more precise devise. And SMT could get them assembled more quickly and accurately than any process before. The cost savings combined has resulted in more and more electronics manufacturing services putting SMDs on an SMT.

SMT and SMD at SMTHELP Enterprises

SMT is a process that Smthelp Enterprises has embraced, mostly for the value it brings to our partners. We offer this process to bring the highest-quality products and the most efficient and lowest cost possible. We have an eight-stage oven that brings even more accuracy and control to this highly-sensitive process.

You’ll also find many SMDs at Smthelp Enterprises. We aren’t only about being efficient with production time. We are also interested in making the most of every board and component we product on your behalf. If we can cut down on the materials needed for your project by using an SMD, then that is what we want to do. So really the argument of SMD vs SMT isn't really valid, both have their place in PCB assembly.

Smthelp Enterprises always aims for the best quality and efficiency, which makes the use of SMT and SMDs a no-brainer. Let’s talk about how we can work together, using these tools, to bring a high-quality product to you.