After the PCB board is reflowed or wave soldered, there may be deformation problems such as board bending and warping. In severe cases, problems such as bursting and delamination may even occur. However, problems such as bursting and delamination are relatively rare, while the board bending Deformation problems such as board warping are more common, and often lead to abnormalities such as empty welding, virtual welding, tombstone, offset, etc. So, how to judge whether the PCB board is deformed? What are the hazards of PCB board deformation?
Determination criteria, causes and measurement methods of PCB board deformation

Flatness is usually used in the industry to measure the deformation of PCB boards, and flatness is mainly determined by two characteristics, namely: bowing and twisting.

Bowing means that when the four corners of the PCB are on the same plane, it is roughly cylindrical or spherically curved, while twisting means that one corner of the PCB is not on the same plane as the other three corners, And the board parallel to the diagonal of the board is warped. If the PCB board is circular or oval, it must be measured from the highest point in the vertical displacement direction.

The flatness of the PCB board may be affected by the board design.

Because different wiring or the layer structure of the multilayer board will lead to different stress or stress relief conditions. The thickness and material properties of the PCB are also important factors affecting the flatness.

For example, when choosing copper cladding, if a large PCB is designed to be full copper, when the actual PCB is subjected to external force, it will maintain the warpage, but if it is designed as a grid, it will not maintain, and It will return to the original flat state. In general, when designing, copper is also left on the process side, the purpose is to ensure the flatness of the PCB board.

According to the IPC standard, if the PCB board needs to be punched, the deformation range should be ≤ 0.75%, and if the PCB board only needs plug-ins, the deformation range should be ≤ 1.5%. (Note: In the IPC standard, it is called warpage)

So, if according to the IPC standard, how to measure and judge whether the deformation of the PCB board is qualified?

First, put the PCB board on a marble platform or a glass board with a thickness of more than 5cm, use a plug gauge to measure the largest size of the corner, and then use a ruler to measure the length of the PCB diagonal, if the drop / 2 times the value of the diagonal >0.75%, it is unqualified (Note: only plug-in, then relax to 1.5%).

The harm of PCB board deformation

In an automated surface mount or plug-in line, if the PCB board is not flat, it may cause inaccurate positioning, resulting in the failure of components to be mounted or plugged into the board, and may even cause equipment failure and damage to the equipment.

If the soldered PCB board is deformed, the feet of the plug-in will be difficult to cut flat, and the operation difficulty of the tinning process will be increased. Greatly increase the workload of subsequent panel repairs.

Finally, in the assembly process, the deformed PCB board may cause serious problems to production. For example, the PCB board does not fit well with the housing. When individual PCB boards are assembled, the efficiency may only be one tenth of other boards, and the subsequent The probability of failure has risen several times, which further exacerbated the after-sales problem.

Therefore, with the development of the industry, the deformation of PCB boards has attracted more and more attention, and higher requirements have been continuously started.

Some customers who have high requirements for product reliability have begun to formulate their own more stringent standards on the basis of IPC standards to ensure that their products are more competitive. In our PCB production process in Huaqiu, we are committed to In order to achieve high reliability and high standard product delivery for customers.

However, the PCB board is composed of copper foil, resin, glass fiber cloth and other materials. There are differences between the physical and chemical properties of various materials. During the processing process, it will undergo chemical potions, cold and heat changes, etc., and deformation is inevitable. The problem of deformation improvement is an industry-wide problem, and it cannot be solved overnight, but improvement can be made step by step.

As a manufacturer of high-reliability multilayer boards, Huaqiu is well aware of the danger of deformation, and is committed to achieving "cost reduction and efficiency increase" through technological innovation, so that high-reliability products can bring customers a better experience.

Huaqiu has deployed intelligent and automated equipment in each manufacturing link. The whole process adopts the MES system to automatically collect, analyze, and warn of data, break through the information gap between the decision-making end and the production end, and timely discover and process from order generation to production. Unqualified items in the process of goods, etc., reduce product defect rate, reduce costs, and achieve standardization and effectiveness in the production process.

For Huaqiu, the high reliability of PCB boards is by no means an empty slogan, but a solemn promise that must be done. Huaqiu will adhere to the pursuit of military-grade quality, continue to go deep into the details of product delivery, continuously temper, polish and optimize, and increase investment in high-precision intelligent factories.
For more information, please contact:
5F, Building 1, Shenzhen New Generation Industrial Park, No.136, Zhongkang Road, Meilin Street, Futian District, Shenzhen, China
Telephone:(+86) 755 83643663. Email: [email protected]
Website: https://www.nextpcb.net