Have you really done the right way to add stamp holes on PCB

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

October 8th , In winter , Yin , No warm sun ,
The wind is blowing , cold , Cold and frozen .
workshop , PCBA workshop .
When Rao Xiaoxiao meets Ye Qingxian , He is not idle .
The spirit of extermination pervaded the workshop , I feel like I'm at war .
Will the board come out ？
It will be .

Ye Qingxian is a calm and calm Sketchpad man .
Rao Xiaoxiao is a passionate and passionate PCBA people .
How are you sure .
Not that I'm too confident .
Because the board has come .

I vaguely heard his running voice .
Look at him , Rao Xiaoxiao raised his little hand and pointed to the front .
Ye Qingxian saw his disciple a Mao running towards him with the board in his arms .

Running and shouting ：“ Master, this model will be shipped soon , The factory said that the board cannot be divided by the board dividing machine , Still trying to find a way .”
“ Find a way , There's no need for the board splitting machine , As a teacher, my supreme skill .”
Ye Qingxian is exercising in the dark. It's true Qi , He felt he was ready .
No one saw how he got the board .

Ah Mao only felt a light in his arms , The board is in Ye Qingxian's hands .
The veins on Ye Qingxian's forehead burst , The surrounding is full of cold murderous gas .
The wind rises strongly, flies with clouds .

Suddenly, ye Qingxian saw a face , A face full of country and city .
When a woman looks best , It's when she can't help laughing even though she wants to be serious .
Ye Qingxian suddenly calmed down , Girl, what are you laughing at .
I didn't laugh , I just want to remind master Xia ye , It's not too late for you to look at the situation of the board before you work .”
Ye Qingxian thought so , So he looked down with a smile to see the situation of the board .
Suddenly his smile stiffened on his face .
this ……

I saw that the stamp hole on the board was well added under the device , Exactly USB Below the package .
Ye Qingxian's face instantly turned pig liver color .
Mao also said nervously ：“ Shifu, don't use Qi to separate the board , The last one 10 Laminate , You just use the supreme magic skill , As a result, the board was broken and scrapped by hand , You'd better listen to miss Rao this time ”

The air stagnates at this moment , It feels like ten thousand years .
Ye Qingxian slowly exhaled a breath , Whispered :“ Then listen to miss ye .”
Rao Xiaoxiao walked forward slowly , A smile , Standing in front of leisure , Tell me , Then came the following heartfelt words .

The stamp hole is our PCB One of the common ways of splitting , It is highly praised by the industry for its quickness and efficiency .
When using, ensure that ：

1. When processing , It's strong enough .
 2. Split time , Easy to split .

Therefore, the design of stamp holes needs to meet the following requirements ：

a) The commonly used hole size of stamp hole is 0.4-1.0mm, The number of stamp holes is 3-6 star , It is usually adjusted according to the actual situation of the board . Stamp holes are usually made NPTH hole （ Nonmetallic pores ）

b) Stamp hole position requirements ： When a board edge exists 2 When assembling the above stamp holes , It should be ensured that the outermost set of stamp holes is within the distance from the edge of the plate 15mm within , And try to ensure symmetry .

c) The position of the stamp hole , Avoid devices protruding out of the board and devices too close to the board edge .

d) Veneer, veneer and process edge , Regular spacing 2.0mm, Plate thickness >2.0 The spacing shall be appropriately increased to 2.5-3.0mm, It is convenient to use a large Gong knife to form .

The design of stamp holes should consider after splicing , Whether the edge of the board is neat , Minimum burr , Whether the partition is convenient , Whether the strength during production is sufficient . After dividing the board, in order to make its edges neat , Generally, the stamp hole is designed on the center line or completely added in the board , But it is not recommended to completely add it outside the board , The burr is relatively large , The edge of the Board shall be deburred by hand .

This is a E A picture shared within the company , You can use it for reference . 

Stamp holes are usually designed in three ways , One is that there is space in the board , Then the stamp hole 2/3 Above or completely added into the board .
The stamp holes completely inserted into the board are designed as follows ：

The following figure shows the burr effect of the plate edge after the stamp hole plate is divided , Although there are burrs , But it does not affect the overall size of the board , The edge burr is relatively small , So we prefer this way to add . But this way of adding stamp holes , The requirements for the space in the board are relatively strict , If the object in the board is too close to the edge of the board , Do not consider this way .

  The second way , Is added to the center of the shape , That is, half of the stamp hole is in the plate , Half outside the board , In this case, the factory CAM Engineers prefer . however PCB There are some connection positions after the board is divided, and half of them may be on the board , The other half is on the edge of the craft , If the inside is left on the board, find a way to remove the burrs . As shown in the figure below ：

The effect after splitting ：

The third is the least recommended way , Is to put the stamp hole completely outside the board , Tangent to the plate edge , Usually because the space in the board is limited , The device or wiring is too close to the board edge .

The following figure shows the effect after splitting , The burr is very big , Use hand or special tools to remove burrs twice .

In addition, the stamp hole should not be too close to the line in the board , To maintain 20mil The distance above , Because in actual production , Stamp holes need to be surrounded by 10mil Above the dead space . As shown in the figure below , The distance from the stamp hole to the routing line is too close , The wiring will be broken during plate splitting .

The effect of line shifting modification ：

There is space in the board, and the number of stamp holes should not be too small , Otherwise, the board will be broken , It is suggested that 5-6 star , According to the PCB Adjust flexibly according to the actual situation of .

Rao Xiaoxiao said so much in one breath , Ye Qing nodded restlessly , Mouth praise way ：“ Professional, professional , Listen to the girl , Take fewer detours . But I dare ask the girl , I put stamp holes on this board USB Below , The installation is now complete , How to divide the board ”

Rao Xiaoxiao stared at a pair of beautiful eyes , Smiled and said to Ye Qingxian ：“ saw , First stick the saw to the edge of the device , Divide it , Then polish it by hand , Make sure that USB It can be inserted normally , Of course, it also takes time , In addition, some burrs may remain on the edge of the plate . If it is mass production, we must first PCB After splitting the board , Then open the fixture for welding , But time is tight this time , You can only do special things .”

Ye Qingxian meditates for a moment , Whispered ：“ Then do as Miss Rao said , Ah Mao , You designed this PCB The board , The molding method is also determined by you . Then it's up to you to do it , You should have a long memory in the future , Stamp holes can't be added randomly . Okay , You go to the board , The customer is in a hurry , Miss ye and I will visit their production line first , Learn again PCBA Skills ”

After that , Ye Qingxian went to visit the production line with Rao Xiaoxiao with a smile , Leave a Mao alone in the wind .
Everyone has a time to avoid others , But no one can ever escape himself .

Ye Qingxian is no exception .