This article will explain how you can solder electronic components onto a PCB.
We’ll discuss SMT vs. Through-hole technology, SMD, and BGA ( Ball Grid Array ). We’ll also take some time to make a specific parenthesis on the best way to solder connectors onto a printed circuit board.
Let’s start with SMT; look at the following video, which shows the SMT process.
Table of Contents
COMPARISON TABLE SUMMARY BETWEEN SMT TECHNOLOGY AND THT TECHNOLOGY
| SMT (Surface Mount Technology) | THT (Through Hole Technology) | |
| Components | SOIC, SOT, LCCCP, LCC, QFP, BGA, CSR, Chip resistor/capacitor | DIP, PGA, Lead Resistor/Capacitor |
| Base Board | 1.27mm-grid base board, hole diameter 0.3-0.5mm | 2.54mm – grid base board, hole diameter 0.8-0.9 mm |
| Soldering Type | Reflow soldering / Wave Soldering | Reflow soldering / Wave Soldering |
| Area | Small | Big |
| Assembly Tech | Surface mounting | Through hole technology |
| Automation | Automatic Mounter | Automatic Mounter/Manual |
| Advantages | Allows for smaller PCB size | Provides stronger bonds |
| Higher component density | Ideal for components that will be under stress | |
| Fewer drilled holes are required, which makes it more affordable | Good for fast prototyping | |
| Faster production time | ||
| SMT components are placed at rates of 1000s/hour | ||
| The soldering is more reliable | ||
| SMT has proven to be more reliable when performing in conditions of vibration and shake | ||
| Disadvantages | For components that will be under mechanical stress (e.g., connectors) SMT can be unreliable when used as the only method to attach components on a PCB | It requires drilling holes on PCBs |
| Drilling holes on a PCB is expensive | ||
| Drilling holes on a PCB is time-consuming | ||
| It limits routing area on multi-layer boards | ||
| Through hole overall is more expensive | ||
| Through hole requires soldering on both sides of the PCB, making the process more lengthy |
SMT MEANING IN ELECTRONICS
SMT means Surface Mount Technology. This is a method used to mount electronic components directly onto the surface of printed circuit boards.
The SMT method uses pick and place machines to place all the SMD components on a PCB, a machine just like the one you saw in the video above.
SMD MEANING IN ELECTRONICS
The meaning of SMD in electronics is Surface Mount Device. In the picture below, you can see a clear example of a PCB with surface mount devices (Electronic components).
All of the components on this PCB have been mounted using surface mount technology.
All components on the board are made to be used in an SMD/SMT process. Here’s a picture of what SMD components look like.
The SMT (surface mounting technology) method has largely replaced the through-hole technology approach to mounting components on a PCB.
SMT QUOTES – PCB ASSEMBLY
Before you contact an SMT company for an SMT quote, you should already know a couple of things.
Knowing the following will get you a very realistic SMT quote, plus SMT companies will know that you mean business.
- For the SMT quote, tell the company whether you want them to supply all SMT components or whether you will supply them all or a part of them.
- The board type can be a single piece or panelized board.
- An SMT company will ask you about the assembly sides for the board. Will the SMT quote be for only the top side of the board, the bottom side, or both sides?
- Quantities of PCBs, of course.
- The number of component types on each board
- The number of Through-Hole components. A PCB, in many instances, will have both SMT and THT components; to get an SMT quote, a company will want to know how many THT components they’ll have to deal with.
If you’re interested in a quote for SMT assembly, please get in touch with us with all the information we just mentioned, and we’ll help you with it.
Please look at the following short video to have a very good visual of the through-hole technology process.
WHAT IS THROUGH HOLE TECHNOLOGY?
The Through Hole technology process is that of mounting electronic components with leads (tht components) through holes that have already been drilled on a printed circuit board.
You might be interested in reading How to Reduce Component Lead Times?
The name of the long wires on the electronic components in the picture above leads. These components are then placed on a PCB manually or using a machine, as shown in the following image.
SMD VS SMT – WHAT IS THE DIFFERENCE BETWEEN SMD AND SMT?
SMT, meaning = surface mount technology, refers to the technology of mounting and soldering surface mount components onto a PCB.
SMD or surface mount device refers to an electronic component that can only be placed on a PCB using an SMT machine; the component is soldered on the PCB with soldering paste.
WHICH ONE IS BETTER FOR MANUFACTURING, SMT, OR THROUGH HOLE TECHNOLOGY?
For manufacturing, SMT makes more sense as it is more cost-effective. Here’s a summary of the advantages and disadvantages of both methods.
THROUGH HOLE TECHNOLOGY ADVANTAGES
- Provides stronger bonds
- Ideal for components that will be under stress
- Good for fast prototyping
THROUGH HOLE TECHNOLOGY DISADVANTAGES
- It requires drilling holes on PCBs
- Drilling holes on a PCB is expensive
- Drilling holes on a PCB is time-consuming
- It limits routing area on multi-layer boards
- Through-hole overall is more expensive
- Through-hole requires soldering on both sides of the PCB, making the process more lengthy
SURFACE MOUNT TECHNOLOGY ADVANTAGES
- Allows for smaller PCB size
- Higher component density
- Fewer drilled holes are required, which makes it more affordable
- Faster production time
- SMT components are placed at rates of 1000s/hour
- The soldering is more reliable
- SMT has proven to be more reliable when performing in conditions of vibration and shake
SURFACE MOUNT TECHNOLOGY DISADVANTAGE
- For components that will be under mechanical stress (e.g., connectors), SMT can be unreliable when used as the only method to attach components to a PCB
SHOULD CONNECTORS BE SMD/SMT OR THROUGH HOLE?
Connectors are meant to be under a lot of stress as users will constantly plug in and out a USB cable or any other type of power cable; the last thing you want is for the connector to detach from the PCB and leave the user with a dead electronic device.
The best approach to soldering connectors onto a PCB is to use a through-hole method for the front and SMT for the back.
Some designers might even decide to attach the connectors onto the PCB using screws; this adds more security to the connector’s attachment and would make the removal of the connector more straightforward in case it needs to be replaced.
WHY IS SMT USED?
As electronic products become smaller and more advanced, the need to allocate more electronic components onto smaller PCBS gave way to SMT.
SMT is also more cost-effective as it doesn’t require holes to be drilled in the PCB boards, which is costly and time-consuming.
WHAT IS BGA SOLDERING TECHNOLOGY?
BGA stands for Ball Grid Array; this is a type of surface-mount packaging used to solder integrated circuits onto PCBs.
Please note that this method permanently mounts components onto a PCB.
This process uses the whole bottom surface of the device as the soldering area, using a grid of, say 8 by 8 bolls of solder.
On the other hand, with Through Hole and standard SMT technology, we only solder the perimeter of the components.
To properly solder (and desolder!) a BGA microprocessor onto a PCB, expensive equipment is required. This is often cited as one of the main disadvantages of this technology.
CONCLUSION
SMT (Surface Mount Technology) means that electronic components are placed on a PCB by a fully automated pick and place machine.
Most electronics factories now use SMT as it is much more cost and time-efficient than THM (Through Hole Mounting) which was the common way to build a PCBA (Printed Circuit Board Assembly) until the eighties.
As the market demands a lot of products, such as cell phones, to become smaller and smaller, the industry has made the electronic components smaller as well, such that the smallest size is the 0201 package which measures only 0.6mm x 0.30mm.
Components this tiny are almost impossible to be soldered on by hand.
Through-hole technology (THT components) remains popular among hardware electronics hobbyists and is also suitable for quick prototypes.
SMT VS THROUGH HOLE – FAQ
WHY USE THROUGH HOLE TECHNOLOGY IN PCB DESIGN?
It would be best to use Through Hole technology when designing a PCB if you know your electronic device will be under much stress.
Through Hole offers secure physical connections, heat tolerance, and power handling capabilities. This makes the PCB boards very durable.
Many of the boards for industrial machines and equipment use almost exclusively through-hole components.
WHAT IS THE SMT PROCESS?
It’s when an automated machine places SMT components (electronic components) on a PCB; unlike the through-hole process, the SMT components are directly placed on the surface of the printed circuit board.
WHAT IS SMT USED FOR?
SMT (Surface Mount Technology) is used to mount SMT components on a printed circuit board in a more cost-effective way than doing it by through-hole technology.
Through-hole technology requires holes to be previously punctured in the PCB. Also, small electronic components no longer allow for the use of through-hole technology.
WHAT IS THE DIFFERENCE BETWEEN SMD AND SMT?
The difference between SMD and SMT is that SMD (surface mount device) refers to an electronic component mounted on a PCB.
In contrast, SMT (surface mount technology) relates to the method used to place electronic components on a printed circuit board.
WHAT IS SMT IN PCB?
SMT in PCB refers to Surface Mount Technology, a method for placing electronic components on a printed circuit board.
WHAT IS AN SMT OPERATOR?
An SMT operator is someone whose job is to monitor, maintain, and adjust the equipment used to create PCBs using the SMT approach.
