Next author ： Mr. Yibo hi tech, member of we media Wang Huidong

3:30 p.m , The sun is warm , The spring breeze blows on my face .

Lili designed a PCB, After many days of struggle, I finally invested in the plate factory to make plates .

Take off the burden , Lighten the burden , Make an appointment with a male ticket and the mouse goes to the cinema in the evening , To see the latest blockbuster 《 Hug you through the cold winter 》.

Why is his boyfriend called a mouse ,

It's not that this man is not good-looking , But because he got up in the middle of the night and ate instant noodles , Found by Lili , So he gave it the nickname mouse , Since then, he has replaced his own name , The debut .

It's said that women are the ones who please themselves .

The first time after work , She has to take care of herself first , Show the most beautiful side to men's tickets .

Suddenly the telephone rang .

yes PCB From the board factory ,

say gerber There is a short circuit in the file comparison .

If this cannot be confirmed , Will be a fatal problem .

PCB In the first stage of engineering production , Do it first IPC356 The inspection of .

It turns out that IPC356 When analyzing , There is a short circuit in the following network .

If this cannot be confirmed , Will be a fatal problem .

PCB In the first stage of engineering production , Do it first IPC356 The inspection of .

It turns out that IPC356 When analyzing , There is a short circuit in the following network .

The screenshot of the report sent by the factory is as follows , Altogether 7 Short circuit at , As shown below .

Lily stopped what she was doing , Open notebook , Began the arduous process of finding the short circuit , Except for two places, she has the requirement of forced short circuit in the design , Can confirm that there is no abnormality , The other five short circuit positions , If you want to die, you can't find where it is .

Later, after many communications with the factory , The factory gives a screenshot of the location of the short circuit , Do you see anything unusual , All virtual test points are in the center of the mark . Red is the location of the virtual test point .

All virtual test points are in the center area of the mark .

As shown in the figure below ：

Lead free marking 、 Anti static marking 、 Recyclable mark 、 Label area, etc .

IPC356 Introduction of documents

• A specific format developed by American printed circuit science , A network collection file that records the logical relationships of design documents .

• Ensure that we PCB File output gerber A logical network consistent with the schematic diagram of the document .

• And CAM Compare the physical network established by the software . You can check our output gerber Documents and drilling documents , Whether or not PCB The schematic diagram is consistent , Especially the safety of network open and short circuit .

• Known as the “ The patron saint of design engineers ,PCB Safety station for processing .” Known as the .

We can see from the picture above ,PCB The original document 、gerber file 、 And the working draft of the factory has the following relationship :

GERBER The document is from PCB Generated in the original file .

Working paper produced by the factory , Yes, it is GERBER Made from the original document .

Usually PCB When the electrical test is done by the manufacturing factory , Just ensure that the physical and logical relationship between the working draft and the original is consistent .

If the original GERBER File output exception , All subsequent tests must be broken .

So you need a file to appear , To simulate the principle of factory electrical test equipment , Generate virtual test points , Compare the open and short circuits , This ensures the output of the original GERBER The correctness of the ,IPC356 Documents came into being .

Why do it IPC The inspection of

because GERBER The document is from PCB Exported from the original design document , In the export of GERBER In the process of , Because of differences in software versions or abnormal file settings , Resulting in output GERBER File with the PCB There is an exception in the physical and logical relationship of the original design file , That is usually called open short circuit . You know very well PCB What are the consequences of opening a short circuit .

Lili made board PCB The factory did IPC356 Abnormal after comparison , She couldn't understand , Later, she consulted her old friend Lin Ruyan , That's what makes me look good .

It turned out that when creating tag encapsulation , There are two options , As shown in the figure below .

When the database was built , Some engineers will put Package symbol and Mechaniclsymbol Wait to confuse

1. If the new package type is selected incorrectly as Package symbol, You have to add... To the package pad, If not pad, After the package is built , Saving will report an error （ But actually in the package PAD It's unnecessary , Usually many engineers have an idea , Will add a set to 0 Of pad）

2. The normal machining auxiliary type mark should be built Mechanical symbol type , This type does not need to add... In the package pad, It will not be there. IPC356 In case of open short circuit , False positives .

The setting when the package is created

After listening to the smoke explanation , Lily understood , You chose the first option when you created the package （Package symbol） And added a plus pad, It turns out that the root causes of all problems are brought by themselves , Learn from , To sum up your experience , go to the battle-front without any burden .

After confirming that the network is normal , Lili replied to the factory's email , Her mood is very beautiful , She hummed a tune to the cinema .

In order to make it easier for her boyfriend to find herself , She went to her seat in advance to wait for him .

At the beginning of the film , He called her with a male ticket and asked where she was , Can't find her , Lili stood up at once , I saw the male tickets looking around , So he waved his hand excitedly , Shout out ：“ The mouse , The mouse , here …….”

Next to a group of beautiful women , As soon as I hear the word mouse , Just a sound , Run around .

Leave a blank face of Lili …….

That's exactly what it is. ：

Mark establishment is not standardized ,

Anonymous network on the board .

Work hard to find more ,

A false alarm, a cold sweat .