如何有效避免在陶瓷電容器焊接到電路板上的工序中發生彎曲引起電容器斷裂的問題?為避免這種情況發生,將電容器安裝在電路板彎曲部位的反方向上,會有比較好的效果。安裝方法如下:
How to effectively avoid the problem of capacitor fracture caused by bending in the process of capacitor welding to circuit board? In order to avoid this kind of situation, it will be better to install the capacitor in the opposite direction of the bending part of the circuit board. The installation method is as follows:
1)電路板施壓方向與零件安裝方向
Pressure direction of circuit board and installation direction of parts
圖1分別是針對電路板施壓方向縱向和橫向裝配零件的例子。面對壓力的方向,將零件進行橫向安裝,可減緩來自電路板的壓力。
Figure 1 is an example of assembling parts vertically and horizontally in the direction of applying pressure to a circuit board. Facing the direction of pressure, install the parts horizontally to reduce the pressure from the circuit board.
圖1 電路板施壓方向與零件裝配朝向
通過抗電路板彎曲試驗,將圖1中①、②的評價結果如圖2所示。可知通過裝配在②方向上,電路板彎曲耐性增高,不易對零件施加壓力。
Through the bending resistance test, the evaluation results of ① and ② in Fig. 1 are shown in Fig. 2. It can be seen that through assembly in the direction of ②, the bending resistance of the circuit board is increased, and it is not easy to exert pressure on the parts.
零件安裝方向與殘留率之間的關系
Relationship between installation direction and residual rate of parts
圖2 零件安裝方向與殘留率之間的關系
2)電路板裂口附近的電容器安裝
Capacitor installation near circuit board crack
電路板裂口或電路板切口處,是生產工序中最容易導致電路板施壓的環節。例如,電路板裂口附近如圖3裝配零件時,如果以B、D<C<A的順序裝配則容易受到壓力。
Circuit board crack or circuit board cut is the most easy to cause circuit board pressure in the production process. For example, when assembling parts near the crack of the circuit board as shown in Figure 3, if the parts are assembled in the order of B, d < C < A, they are easy to be stressed.
圖3 電路板裂口附近的零件安裝實例
那么,我們看一下有無缺口時電路板的變形程度。
Well, let's look at the deformation of the circuit board with or without a notch.
有無缺口時,電路板彎曲有何不同呢?FEM解析結果如圖4、圖5所示。
What is the difference between the bending of the circuit board with and without a notch? The results of FEM analysis are shown in Fig. 4 and Fig. 5.
設想在模型圖中所示位置裝配零件的情況。(電路板1.6mm厚的FR4)
Imagine assembling parts in the position shown in the model drawing. (circuit board 1.6mm thick FR4)
圖4為沒有缺口的情況。電路板的壓力大,在電路板裝配位置會產生紅色~黃色拉伸應力,電容器存在發生開裂的危險。
Figure 4 shows the case without gap. Due to the high pressure of the circuit board, the red to yellow tensile stress will be produced at the assembly position of the circuit board, and the capacitor may crack.
另一方面,圖5是有缺口的情況,可知裝配零件的位置為綠色,電路板幾乎沒有產生彎曲。施加在零件上的壓力能夠控制在相當小的范圍,所以是避免電容器開裂的有效方法。
On the other hand, it can be seen that there are almost no bending parts in the circuit board 5. The pressure applied on the parts can be controlled in a relatively small range, so it is an effective method to avoid capacitor cracking.
圖4 無缺口模型與彎曲分布
圖5 有缺口模型與彎曲分布
綜上所述,通過電路板缺口緩解壓力,為此與缺口邊線平行配置零件朝向(圖3中D)最有效。此外,無法改變零件朝向時,為使電路板不易發生變形,建議設置缺口為好(圖3中B)。
To sum up, it is most effective to relieve the pressure through the circuit board notch, so it is most effective to configure the part orientation (D in Fig. 3) parallel to the notch edge line. In addition, when the orientation of the parts cannot be changed, it is recommended to set the notch (B in Fig. 3) in order to prevent the circuit board from deformation.