PCB Technical - PCBA patch process Synthetic stone furnace tray

The main reason for PCB deformation is due to the high temperature softening the FR4 sheet, so I found a material to be used as a furnace tray

With the advancement of science and technology, electronic products are becoming thinner, thinner and shorter, and electronic parts are becoming thinner and thinner. Even the thickness of PCB circuit boards (PCB) is becoming thinner and thinner. Thin PCB circuit board thickness, such a thin PCB circuit board is very prone to board deformation due to high temperature when it passes through the high temperature of SMT Reflow (reflow furnace), and even the parts fall into the furnace.

In order to overcome such problems, smart engineers came up with the use of Reflow Carrier (pass furnace tray) to support the PCB circuit board to reduce the deformation of the PCB circuit board. A large part of the deformation of the PCB circuit board is due to the high temperature softening the FR4 board, so as long as you find a material with the following characteristics, it can be used as a furnace tray:

Its softening and denaturing temperature should be higher than 300 degree Celsius, it can be used repeatedly without deformation.

The material should be as cheap as possible and can be mass-produced.

The material must be processable.

The material is best to be light.

The material is better not to absorb heat easily.

Less heat shrinkage.

In the past, almost all of us have used aluminum alloy materials (in addition, high-carbon steel, magnesium alloy) to make furnace trays. Although aluminum alloy is lighter than ordinary iron metal, it is still a bit heavier to pick up the girl on the production line, and aluminum The alloy material is easy to absorb heat. After the furnace, you need to wear heat-resistant gloves or wait for a period of cooling time before you can pick it up. It is a bit inconvenient to operate.

In recent years, a new material has gradually been widely used in SMT's Reflow Carrier to replace aluminum alloy trays. This material is called synthetic stone. It is basically a compound made of high-temperature resistant glass fiber. It can withstand temperature up to 340 degree Celsius above, and can be machined by CNC. It has certain hardness, is not easy to deform, and does not absorb heat compared to aluminum alloy. It can be touched by hand immediately after the reflow furnace is completed; there are other benefits of not absorbing heat, engineers It is easier to control the temperature in the reflow furnace to achieve the best tin-eating quality of the parts.

The price of this kind of synthetic stone is also cheaper than the current rising aluminum alloy, but this kind of synthetic stone is less resistant to repeated use than aluminum alloy. Generally, it can be reused for about 10,000 reflow furnace cycles.

Benefits of using oven trays:

It can reduce the deformation of PCB caused by the high temperature softening caused by the reflow furnace.

It can be used to carry thin PCB or FPCB (soft board) parts and through reflow furnace.

Can be used to carry irregular-shaped PCB parts and reflow furnace

It can carry multiple PCBs through the furnace at the same time to increase output.