Everyone knows how to prevent PCB bending and board warping from going through the reflow furnace. The following is an explanation for everyone:

1. Reduce the influence of temperature on PCB board stress

Karena “suhu” adalah sumber utama tegangan papan, selama suhu oven reflow diturunkan atau laju pemanasan dan pendinginan papan dalam oven reflow diperlambat, terjadinya pelengkungan dan lengkungan pelat bisa sangat berkurang. Namun, efek samping lain dapat terjadi, seperti korsleting solder.

2. Menggunakan lembar Tg tinggi

Tg adalah suhu transisi gelas, yaitu suhu di mana bahan berubah dari keadaan kaca ke keadaan karet. Semakin rendah nilai Tg bahan, semakin cepat papan mulai melunak setelah memasuki oven reflow, dan waktu yang dibutuhkan untuk menjadi karet lunak juga akan menjadi lebih lama, dan deformasi papan tentu saja akan lebih serius . Menggunakan pelat Tg yang lebih tinggi dapat meningkatkan kemampuannya untuk menahan tegangan dan deformasi, tetapi harga materialnya relatif tinggi.

3. Tingkatkan ketebalan papan sirkuit

In order to achieve the purpose of lighter and thinner for many electronic products, the thickness of the board has left 1.0mm, 0.8mm, and even a thickness of 0.6mm. It is really difficult for such a thickness to keep the board from deforming after the reflow furnace. It is recommended that if there is no requirement for lightness and thinness, the board* can use a thickness of 1.6mm, which can greatly reduce the risk of bending and deformation of the board.

4. Reduce the size of the circuit board and reduce the number of puzzles

Since most of the reflow furnaces use chains to drive the circuit board forward, the larger the size of the circuit board will be due to its own weight, dent and deformation in the reflow furnace, so try to put the long side of the circuit board as the edge of the board. On the chain of the reflow furnace, the depression and deformation caused by the weight of the circuit board can be reduced. The reduction in the number of panels is also based on this reason. Low dent deformation.

5. Perlengkapan baki tungku bekas

If the above methods are difficult to achieve, *reflow carrier/template is used to reduce the amount of deformation. The reason why the reflow carrier/template can reduce the bending of the plate is because it is hoped whether it is thermal expansion or cold contraction. The tray can hold the circuit board and wait until the temperature of the circuit board is lower than the Tg value and start to harden again, and can also maintain the size of the garden.

Jika palet satu lapis tidak dapat mengurangi deformasi papan sirkuit, penutup harus ditambahkan untuk menjepit papan sirkuit dengan palet atas dan bawah. Ini dapat sangat mengurangi masalah deformasi papan sirkuit melalui tungku reflow. Namun, nampan oven ini cukup mahal, dan harus ditempatkan dan didaur ulang secara manual.

6. Gunakan Router alih-alih V-Cut untuk menggunakan sub-board
Karena V-Cut akan merusak kekuatan struktural panel di antara papan sirkuit, cobalah untuk tidak menggunakan sub-board V-Cut atau mengurangi kedalaman V-Cut.