Through Hole (Thru-Hole) PCB Assembly Services

Thru-hole (or through-hole) technology involves drilling holes into a printed circuit board where leads can be attached. Compared to surface mounting, it is an older technology.

Despite the fact that it is an older process, there are benefits to thru-hole PCB assembly. The through-hole mounting process creates stronger bonds between a circuit board and its components, leading to products that are more durable and more resistant to shock and impacts.

Whether or not through-hole PCB assembly is the right choice — or the only choice — for your application will depend on a number of factors. EMSG can provide a thorough consultation that helps determine the best way to proceed, whether you are developing a prototype or manufacturing a product.

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Benefits of Through-Hole Assembly

Today, surface mounting is the more common form of assembly in many diverse industries. However, PCB through-hole assembly still plays a vital role when it comes to building circuits meant for certain types of equipment — especially those that must undergo high levels of stress or operate at high speeds and extreme temperatures. The reason manufacturers use thru-hole PCB assembly for these types of products is the variety of benefits it offers, including: 

  • Strength of Bonds. Through-hole assembly involves sticking required components through a circuit board and then attaching them with a metal solder, which makes the connection between the circuit and its components strong. It’s crucial for all the parts of the circuit to remain intact as you use an electrical piece of equipment. That’s why its strength makes through-hole assembly the better option for high-risk electrical equipment than other methods such as surface mounting.
  • Durability. Stronger bonds between the circuit and its components indicate better durability and the capacity to handle harsher conditions without substantial wear and tear or damage. If you’re looking for an assembly method suited to aerospace industries or the use of heavy machinery, thru-hole assembly is the ideal option and will hold up more easily than others. A durable electrical circuit will last a long time, perhaps even saving you more frequent replacement expenses.
  • Reliability. The last thing you need is to spend your time worrying about whether or not your circuit assembly will hold each time you use a piece of machinery. When you use through-hole PCB assembly solutions, you can eliminate this uncertainty thanks to the reliability of drilling and soldering technology. A reliable product can ease your concerns and help maintain a high level of efficiency for your operations, which is necessary for a harsh or fast-paced environment.
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Potential Applications

Because of its unique benefits, through-hole technology has multiple possible applications. The investment of additional time and money required to complete through-hole PCB assembly makes it best for large components such as transformers, semiconductors and electrolytic capacitors. The extra security it provides makes it a good option for any product that must withstand high levels of mechanical or environmental stress as well as high power and high voltage conditions.

Military and aerospace applications prefer thru-hole mounting for precisely these reasons. In situations where safety depends on properly functioning equipment, taking the extra steps to through-hole technology critical components is a necessity. As well, through-hole technology can be useful for product prototyping, where the testing process routinely subjects completed units to extreme conditions.


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Through-Hole Characteristics

When someone uses through-hole assembly, they start with a PCB and the PCB components. Then they drill holes into the board that are the ideal size to fit component leads. Once the leads are placed in the holes, they are attached to the board through the process of soldering, which holds them firmly in place and creates a strong, durable bond. This is the defining characteristic of through-hole assembly that makes the method so reliable and allows it to continue serving multiple types of industries.

A thru-hole assembled PCB may have many components attached to it, and there are two main kinds of components that engineers use during this process. These include:

  • Axial Leaded Components. Usually, the most noticeable characteristic of an axial leaded component is its symmetrical shape. This type of component often has a shape similar to that of a cylinder, with one lead or several leads protruding from both ends. When each wire ending is fitted through a hole, the axial component lies low on the circuit board and can occupy a wider or shorter space depending on how you position the leads. These pieces may include components such as resistors, inductors and capacitors.
  • Radial Leaded Components. Radial leaded components also typically come in the form of cylindrical or rectangular box-shaped figures and include different forms of capacitors, resistors and inductors. However, the main difference between these components and axial leaded components is that the former items have leads that protrude from one side rather than sticking out of both ends. Because of their overall appearance and make-up, attaching these pieces to your PCB board takes up less space than using axial leads, but also offers less placement flexibility.

Our Through-Hole PCB Assembly Services 

Different applications demand different through-hole technology equipment. To better serve our diverse group of clients, EMSG has invested in some of the most advanced soldering and assembly tools on the market today. We are fully qualified to manufacture printed circuit board assemblies to the IPC-A-610 requirement in both leaded and RoHS specifications.

Depending on your project needs, we can provide either fully automated through-hole assembly or semi-automated through-hole assembly services for runs of up to 50,000 units.

Thanks to our production capabilities, we are often brought in at the prototyping stages of a project. However, we also perform electronic contract manufacturing and testing as necessary. Our clients include government contractors and private manufacturers, all of whom count on EMSG for fast turnaround times, excellent customer service and industry-leading engineering expertise. We are happy to provide initial consultations by phone or email or to meet with you in person.

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Quality Standards for Through-Hole Assembly

When we provide our through-hole PCB assembly services to clients, we strive to adhere to IPC quality standards every time because we know how important it is to keep electrical components as safe and efficient as possible. It’s crucial to understand common defects in through-hole assembly PCBs, as well as how to avoid them and build strong, durable products.

Solder joint quality makes a huge difference in the overall quality of the through-hole assembled PCB structure. The soldering is what makes the product because it is the process that holds everything together — specifically, the board and its components. Defects of the solder joint include issues such as:

  • Inaccurate placement of components
  • Fractures
  • Nonwetting
  • Short Circuits
  • Lead Protrusion
  • Corrosion


Meanwhile, it is possible to prevent and protect against these types of issues and more by practicing diligence and committing to accuracy when placing components and soldering the leads. The proper soldering technique includes inserting the wire into the hole, and then using heat on the lead, the pads and the hole. When you apply the solder, it should melt into a liquid and fill up the hole until the solder spills out and covers both ends of the board surrounding the hole.

As a member of IPC, we endeavor to hold up their standards and values when it comes to this complex, delicate process so that we can continue to offer reliable services. IPC’s aspiration goals on standards read, “IPC will be the most respected organization known for its leadership and global footprint in providing standards and quality programs supporting the electronics industry,” a statement we stand behind as supporters of high-quality electrical products.

Our Equipment

We perform most automated through-hole assemblies using the Universal 6287A axial insertion machine, which places components in their proper place on your circuit board with speed and accuracy. We use the Contact Systems CS400C to construct high mix through-hole production, of which EMSG currently has eight machines operating over two shifts. Whether our clients need quick turnover, small or high-volume assemblies, we can meet the necessary requirements.

After component assembly, EMSG uses automated machines to remove the need for manual soldering. These include the Hollis Future I machine, which has the capacity to work with circuit boards up to 18″ square, and Ace KISS-103 machines that offer programmable soldering options.


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Automated Through-Hole PCB Assembly

Why assemble your PCBs using manual through-hole technology when you can have a through-hole PCB assembly company automate and streamline the process? More and more industries use automated technology in manufacturing industries today than ever before. Automated through-hole PCB assembly allows machines to place and solder PCB components faster than employees could do the job manually, which is why the practice of combining manual and machine assembly has become so widespread.

We have a variety of machines that make assembly faster and more efficient. We automate processes using equipment such as the Universal 6287A axial insertion machine, the Hollis Future I SMT and the Ace KISS-103. We are constantly working to integrate new ways to maximize safety, productivity and effectiveness at our company so that we can deliver you high-grade equipment components.

In addition to our machines, we have over 50 individual workstations with ESD protection to maximize safety. We use both technology and human hands to help ensure that the soldering process runs smoothly and that the PCBs we develop and their components will create a strong, durable bond.

Partially automated through-hole assembly saves time and finances while lowering the risk of errors in production. This leads to the use of more reliable equipment and machinery in industries on a global level, which has a positive impact on security and efficiency. As a result, automation has fundamentally changed PCB manufacturing and will continue to influence it for years to come.

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Testing Through-Hole PCBs

A large part of manufacturing and assembling PCBs involves the process of testing the products once they have been completed. Living up to quality expectations is important to our company, which is why we have implemented a thorough, accurate testing and inspection method into our business operations.

Assembling electrical components and delivering them to customers without first running them through careful inspection leaves room for error and increases the risk of equipment malfunctions, which slows down operations for businesses. Our automated testing and inspection system catches defects before PCBs go out the door and prevents these types of issues.

At EMSG, we use a 2 Mirtec MV-3L optical inspection system that searches for mechanical and manufacturing issues in new PCBs.

Using all these tools, we can accurately detect many types of defects in the design and construction of the PCB through-hole assembly board, such as damage or cracks, inaccurate component placement, incorrect polarity and other potential issues. We only allow our customers to purchase our through-hole assembled PCB services after we have completed the inspection process.


With EMSG’s PCB thru-hole assembly services, you can focus on other elements of your industry or company by trusting us to build and test critical electrical components for your equipment. Our thorough testing process protects your investments and helps ensure that the PCBs we offer will act as long-term solutions for your industry.

Working With EMSG

Based in York, we are available to provide thru-hole assembly services for clients in Pennsylvania and beyond, including all major East Coast cities and the D.C. Metro area. Our 20,000-square-foot facility is ISO 9001-certified.

Let us work with you to turn your vision into a marketable product. Since 1995, we have been a partner to demanding commercial and industrial clients requiring reliable PCB assembly services. To learn more about how we can help, contact our head office at 717-764-0002complete our contact form or book an appointment at your convenience.

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