Electrical Function


        PCB is used for bearer and enable components, the components are connected to each other by the traces on the PCB and 

play a variety of functions, so the completeness and accuracy of the electrical function of a PCB is crucial.

       LocoPCB factory has sophisticated imported manufacturing equipment and inspection equipment from Germany, Japan and 

Taiwan and have built a mature quality inspection process to ensure the completeness and accuracy of the electrical function of 

the PCB.


1、Brief introduction of X-ray


A. Use of X-ray

The market demand of multilayer PCB and HDI PCB is increasing, so the requirement for the lamination accuracy become higher 

and higher.

The X-ray inspection machine is used for detect the lamination accuracy, it always use in lamination process and drilling process 

to check if each layer in the PCB have aligned with each other or not.

We can find out the production error and eliminate defective products in advance(when production) by use the X-ray inspection 

machine to ensure the yield rate and the build time of the production.


B. Principle of X-ray

The engineer control the X-ray tube and emits X-rays. The X-rays penetrate the PCB and received by the imaging system. The 

data will process by the computer and compare with the correct data to find out manufacturing defects.


C. The main problem of X-RAY inspection

Measurement function:point to point, line to line, diameter, radius, concentric circles,layer offset.

Process:Lamination and drilling



2、Brief introduction of AOI


A. Use of AOI

According to the structural development of PCB, multi-layer, high-precision circuit design is more and more extensive, and the 

manufacturing process/environment/equipment requirements for PCB are  becoming more and more demanding.

In order to ensure the yield rate of the production, we use AOI for checking completeness of  the traces in the outer and inner 

copper layer after etching process.


B. Principle of AOI

     AOI is inspection equipment which base on optical principle and used for checking the defect of the copper layers after etching. 

The machine autoscan the PCB via the camera and collect the imaging. And then compare with the standard data library to find out 

the defect on the copper layer and show the defect via the display. So that the repair personnel can follow it to fix the defect


C. The main problem of X-RAY inspection

Measurement function:Trace width/spacing, BGA, IC, PAD, open circuit, short circuit, scratch or others

Process:Outer and inner copper layer.


3、Brief introduction of Metalloscope


A. Use of Metalloscope

Metalloscope combine the traditional optical microscope with the computer via photoelectric conversion. Not only can observation 

via the eyepiece, but also can real-time observation the dynamic image via the monitor of the computer. And can edit, mark, save, 

and print the pictures if needed.

We make the cross section of the PCB into crystal slicing and use the Metalloscope to observe the

crystal slicing to ensure the quality of the cross section of the PCB.


B. The main problem of Metalloscope

Test items:stack-up, hole wall roughness, wicking、copper thickness on hole wall、copper thickness on

copper layer, the thickness of the solder mask, etching factor

Process:lamination, drilling, plating, solder mask


4、Brief introduction of CMI760


A. Use of CMI760

CMI760 designed to meet the needs of copper thickness measurement and quality control in the printed circuit board industry, 

the CMI760 can be used to measure surface copper and hole-wall copper thickness.


B. Principle of CMI760

The probe of the CMI760 in contact with the copper surface or deep into the holes. Measure the copper thickness on surface and

the copper thickness on hole-wall by micro-resistance and eddy current


C. The main problem of CMI760

Measurement function:copper thickness on surface、copper thickness on hole-wall、the thickness of solder mask

Process:plating、FQC、surface finish


5、Electric test


A. Use of Electric tester

Make sure the completeness of electrical function of the PCB before assembling is crucial. Electrical test machine will test the continuity 

of the PCB to ensure it has complete electrical function


B. Types of Electric tester

a. Flying Probe Tester

Flying probe test is mainly applied to prototype PCB, the data for flying probe test will export form the gerber file and import into 

the tester, and the probe of the tester will test the continuity of each traces on the PCB according to the data and generate a report, 

The engineer will handle the PCB according to the report. (fix or direct scrapping), As a professional manufacturer, LocoPCB have 

more than 80 flying probe tester.

b. Universal tester

Universal tester is mainly applied to small-medium volume PCB; we will custom a tool for universal test according to the gerber file. 

The tool is expensive, so that is not suitable for prototype PCB.

c. The main problem of tester

Measurement function:open circuit, short circuit

Measurement range: line pattern conduction, layer interconnection conduction, via holes conduction, installation holes conduction


6、Base Material

The processing basis of PCB is based on the base material; We use superior base material from KB/sy/Nouya/ITEQ


Still need help? Contact Us Contact Us

Office: 2F,Building E, Yuanfen Industrial Zone, Bulong Road, LongHua District, Shenzhen, Guangdong, China
Factory: Wushi Village, Qiaotou Town, YingDe City, Guangdong,China
Email:service@locopcb.com
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