What is PTH PCB, and Why is it Necessary

What is PTH PCB and why is it necessary

Table of Contents

In PCB manufacturing, copper sheets plated on a non-conductive substrate are drilled through holes and etched. Each of these holes connects a copper layer to another, such as on a board or an external component.

Nevertheless, the holes are not conducive without electroplating a thin layer of copper. This results in the establishment of a PTH PCB.

Here, we’ll examine this technology and compare it to NPTH.

What is PTH in PCB?


PTH PCB is a standard surface mount technology (SMT) used in the electronics industry. PTH is “plated through-hole,” a manufacturing process involving plating through holes in a printed circuit board (PCB) to create conductive pathways.

PTH is inserted through a hole. The metal is deposited through a spot on a non-conductive substrate by an autocatalytic oxidation-reduction mechanism. Plated-through holes undoubtedly aid the bonding between the layers in double layer PCB and multilayer PCB.

As well as through holes for ceramic copper plating, resin copper plating, diamond copper plating, etc. Multilayer or two-layer boards are plated through holes after they are drilled.

What is the purpose of PTH in PCB?

The purpose of PTH is to deposit a thinner electroless copper with a chemical process to serve as the later substrate of copper plating on a hole wall made of drilled and non-conductive material.

PTH components handling processes

PTH Components Handling Processes

The PTH PCB is a very complex system and its delicate components. The main features are:
●Axial insertion (resistors and diodes) – resistors and diodes are mounted directly on the line, usually in an area with no other components. This process is carried out manually or by automated equipment.
●Odd form insertion (connectors, transformers, etc.) – for this type of component, it is necessary to use special tools for disassembly and assembly into lines.
●Radial insertion (electrolytic capacitors) – the capacitor is inserted into the line and put into a holder, which can be moved along the length of the line. This process is carried out manually or by using automated equipment.

What are the differences between PTH and NPTH in PCB?

By visually looking for signs of plating on the borehole wall in the PCB, it is simplest to identify between plating-through-hole and non-plating-through-hole PCBs. There won’t be any copper traces on non-plating-through-hole PCBs’ borehole walls.

PCBs with plated-through holes cost more than PCBs without plated-through holes. Additionally, PTH-printed circuit boards are frequently smaller than NPTH ones.

PTH drilling occurs before the electroless copper process, whereas NPTH drilling occurs following it. This is another way to distinguish between the two. The two are easy to define, but designing them in a circuit board architecture can be challenging.

Advantages of PTH production

Advantages of PTH Production

PTH assembly creates mechanical bonds between components and the circuit board that are far stronger than those made using surface-mount techniques. A full circuit board does not need to be replaced; rather, faulty connections can be manually fixed one at a time. PTH PCBs are more expensive, though.

Some other advantages of PTH PCB production are:

●It is possible to manually fix defective connections as opposed to replacing the entire circuit.
●Stronger mechanical relationships compared to SMT assembly in the PTH PCB assembly.
●PTH assembly works well with large components.

What are the applications of PTH?

PTH PCB is a type of PCB material that can produce electronic devices, such as mobile phones, tablets, laptops, and other high-tech products. The key application areas for PTH PCB are:

1. Printed circuit board (PCB) manufacturing;
2. Electronic equipment assembly;
3. Industrial automation equipment;
4. Medical equipment;
5. Automobile electronics components;
6. Video game consoles, computers, and smartphones.

What factors will cause PTH PCB failure? What problems will happen?

What factors will cause PTH PCB failure

Some other common causes of PTH PCB failure include:

  • Foil cracks

Cracks in the dielectric are often caused by physical stresses, such as thermal expansion. Several factors can cause these cracks, but they are most likely to occur during high-temperature operations.

  • Corner cracks
    Cracks in the dielectric material may occur where the board edge is bent or when there is a large load on an area of the board (such as a connector).
  • Barrel cracking
    Barrel cracking is a common problem with printed circuit boards used for years, especially when exposed to heat and humidity. This type of failure usually occurs near connectors with continuous stress from current flow through them. Barrel cracking can also result from mechanical damage, such as bending and bending during hot or cold temperatures.
  • Thermal excursion stress
    Thermal excursion stress causes thermal expansion at specific points on PCBs that cause cracks or delamination of some types of materials used in PCB construction.

Solutions to these problems

Customers using PTH PCB assembly services should use a few solutions. These consist of the following:

●Repeated thermal shocks should be applied to high aspect ratio through-hole PCBs during the prototype phase. This will make it easier to determine the temperature range at which failure occurs. This will allow PCB designers to modify their plans and choose better materials.
●Select a resin material with a high decomposition temperature (Td). By doing so, the PCB can withstand heat stress and won’t lose resin material weight.
●Keep the plated copper interconnections’ electroless copper thickness constant. Additionally, make sure the copper structure’s grain deposit is sturdy. These two elements can lessen the likelihood of ICD.
●Observe correct copper plating procedures.

Manufacturers who offer PTH PCB assembly services can facilitate the creation of high-reliability PCBs.

How to lower PTH PCB cost?

How to lower PTH PCB cost

The main reason for high-density PTH PCBs is that they are manufactured using traditional, manual processes. The drilling process is time-consuming and requires a lot of human intervention, which increases the cost. However, implementing new technologies and techniques makes it possible to reduce the cost of PTH PCB manufacturing.

  • Using larger annular rings
    Many PCB manufacturers use annular rings when they drill holes in their boards. These rings ensure that the drill bit does not cut through the copper on the other side of the board. This prevents shorts between two circuits and helps keep the board from overheating during drilling.
  • Reducing the hole density per square meter
    drilling larger holes reduces your PCB costs because it reduces the amount of copper that needs to be removed from your board. You can do this by increasing the size of your annular ring or by using fewer components per square meter on your board.
  • Reducing hole density per square meter
    Another factor affecting pricing is how many holes per square meter are on your board. The more holes you have per square meter, the higher your price due to increased manufacturing costs.


So, in the bottom line, PTH technology provides better electrical performance, lower cost, and faster market time.

IBE offers a wide range of PCB and PCBA solutions. With a commitment to supplying the best service and helping a business grow, IBE looks after both the engineering side of the parts and the business side. For further questions or concerns, please don’t hesitate to contact IBE.

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