In the previous article, we introduced to our readers what is SMT (surface mount technology). We also covered the advantages of SMT and the standard process of SMT assembly.

We also learned that the SMT chip process is often used during mass production in the PCBA chip processing industry. It is very convenient for use in various advanced electronic products and equipment, including notebook computers, etc …

In today’s world where electronic products are gradually becoming smaller, can SMT completely replace DIP? At the end of this article, you’ll be able to answer that question for yourself. But first, let’s explain what DIP stands for.

What is DIP?

The full name of DIP is Dual In-line Package, also called dual in-line package technology. DIP is one of the plug-in component packages and is also named Through-hole Technology or THT in short.

In simple terms, SMT uses “sticking” technology while DIP “plugged-in”. DIP electronic components have two rows of pins. Soldering those pins done by inserting the two rows of pins into the soldering positions according to the number of solder via holes in pcb.

DIP advantages

In our previous article, we listed the advantages of SMT processing in PCBA. And the advantages are obviously vast. If that’s the case, why use DIP processing technology? Here are some of the reasons:

• 1. Temperature problem. Some components are not resistant to high temperatures, such as electrolytic capacitors, metal oxide film resistors, and transistors. These components have a temperature resistance of 105-235 °C, and cannot be soldered by reflow soldering;
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• 2. Packaging issues. Sockets, terminals, and high-power components still haven’t been produced in SMT packaging. For that reason, we can only use such components in DIP packaging format;
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• 3. Cost issue. Although many common components already have SMT packages such as integrated chips, inductors, transformers, diodes, and transistors, DIP packages are much cheaper than SMT packages. In order to control the cost of circuit boards, SMT packages and DIP packages are both used when designing circuit boards.
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• 4. Other factors such as power consumption and size also create the need to use DIP components instead of SMT in specific designs.

 How does DIP plug-in processing work?

When assembling DIP components, the pump continuously sprays liquid tin waves to form solder wave crests. When the circuit board on the conveyor belt enters at a certain speed, the solder overflows to the surface of the circuit board in the form of wave peaks while welding the solder joints of the plug-in material. This technique is called wave soldering.

In PCBasic, the standard DIP assembly process is as follows:

• 1. Components checking, assembly, and processing.
• 2. Components are plugged into the PCB.
• 3. AOI before the furnace.
• 4. Wave soldering.
• 5. AOI after the furnace.
• 6. Component cutting.
• 7. repair welding maintenance.
• 8. Board washing.
• 9. FCT function test.
• 10. QA inspection.

For many reasons DIP still plays an important role in the PCBA electronic processing industry. Compared with the automation of SMT, the DIP plug-in requires a large-scale manual operation that needs a lot of human labor. In theory, because of the high proportion of labor, the defect rate of DIP will be relatively high. Therefore, while doing DIP processing it’s crucial to monitor and guarantee the quality of the PCBA.

Precautions for DIP processing

Like every project, DIP also has its own precautions that must be considered before the processing begins:

• 1. Use board components or PCBs with good solderability and no contamination.

• 2. During the plug-in process, pay attention to the strength of the plug-in to avoid damage to the PCB or surrounding components. At the same time, ensure the consistency of the component orientation, component position, and component height.

• 3. The operator adjusts the soldering temperature according to the circuit board to avoid false soldering and false soldering of the solder joints caused by too low temperature, deformation of the circuit board and accelerated solder oxidation due to excessive temperature.

• 4. The height of the crest should be adjusted to ½-⅓ of the board thickness. Avoid hanging and solder leakage caused by a low wave crest, and tin stacking and scalding of components due to a high wave crest.

• 5. Improve the activity of the soldering ridge, fully heat the PCB and components, and remove harmful impurities.

 Summary

After reading the comprehensive introduction and precautions of DIP processing above, we go back to the original question – can SMT completely replace DIP?

The answer is: that SMT patches cannot completely replace DIP processing.

SMT and DIP are both important parts of PCBA processing, but not all PCBA manufacturers have SMT placement capability and DIP post-soldering capability, and the processing quality is difficult to guarantee.

When choosing a PCBA partner, we recommend conducting an on-site inspection of the processing factory.

PCBasic also provides you with factory inspection services. If you cannot come in person, we can provide you with an online real-time factory inspection at any time. If you have a custom pcb assembly need or request, we have the power to fulfill it for you.