The importance of using X-ray inspection machines in the production process of PCB

With the fast development of high-level and high-precision PCB boards, the accuracy of the alignment between layers has become more and more stringent, and the problem of layer deviation has become more and more serious. Caused layer deviation with many reasons . Now, based on some common problems that I encountered in the work and personal experience, I have analyzed the main factors that cause layer deviations in the inner layer and the lamination process. Please correct my deficiencies if something wrong.

 

The general definition of layer deviation:

The layer deviation mean the difference in concentration between PCB layers that originally alignment. The range of requirements is regulated according to the design requirements of different PCB types. The smaller the hole-to-copper spacing, the stricter the control, to ensure its ability of conduct and over-current.

 

The methods of testing layer deviations in the production process:

The current method commonly used in the industry is to add a group of concentric circles at each corner of the circuit board, and adjust the spacing between concentric circles according to the requirements of the production board layers deviation, in the production process,we usually use the X-Ray inspection machine or X-drill to check the Degree of deviation ,then we can know the situation of the layer deviation.

 

Layer deviation classification:

Based on the layer level of causing deviation and the process of causing layer deviation, the layer deviation can be mainly divided into inner layer deviation and pressure layer deviation ;

 

Analysis of causes of layer deviation:

First, the reason of inner layer deviation

The inner layer is a mainly the process of transferring the graphics of the film to the inner core board, so the layer deviation will only be caused by the process of graphics transfer to produce. The main reasons for the layer deviation are: the inner layer film is not Inconsistency and the Exposure machine position shifting, improper handling of personnel during the position exposure process, and other factors.

Second, the reason of pressure layer deviation

The main reasons: inconsistency in the rise and shrinkage of the core plates in each layer, poor positioning of the punching holes, misalignment of the welding positions, misalignment of the rivets, and sliding of the press plate during the press-fitting process.

 

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XD is a professional OEM Manufacturer, specializing in electronics manufacturing service including electronic design and engineering, PCB fabrication, SMT and PCB assembly, components sourcing, prototyping, box build, turnkey solution and other value-added services for industries including energy, metering/measurements, medical care, consumer electronics, game devices, telecom, security, signs/display and security industries.