When boards pass the reflow oven, it is most likely that the boards will get twist or warp.

How to prevent the issue? See following advise by Linked Electronics.

1.Reduce the temperature in the reflow oven.
High temperature is the main cause for the reason, so just reduce the temperature in the oven. Or the reduce the speed for heating and cooling, it will largely reduce

the chances for board warp or twist. But this might cause short circuit for soldering.

2. Use High TG Material.

For TG130 the standard TG material, the boards get soft much faster when passing the reflow oven. And the chances are very high that boards will get twist or warp.

By using higher TG material, this will change, but the cost is much higher.

3. Increase the Finished Thickness of PCB Board.

Nowadays, to achieve thinner electronics products, PCBs are also getting thinner. Linked Electronics receives more and more thinner boards, for example, 0.8mm, 1.0m, some even 0.6mm. It is really difficult to prevent twist and warp issue for such thickness. If possible, Linked Electronics advise that using 1.6mm thickness material or even thicker.

4. Reduce the panel size.

For bigger size printed circuit board, it will easily get twist and warp. Thus reduce the panel size by making fewer units per panel will solve the problem.

5. Use reflow carrier/template

If the above is hard to achieve, Linked Electronics advise using reflow carrier/template to prevent the issue. Whether it is heat expansion or contract with cold, the carrier can hold the PCB tightly without any issues.

If the carrier cannot reduce the chances for twist and warp, just add a lid for the carrier. This will solve the problem.

But the cost will be very high, and there will be manual work to put the PCBs on the carrier.

6. Use Routing instead of v-cut for panelization.

V-cut will reduce the holding force in the panel. Change the way to panel the PCBs by routing and stamp vias.

Or reduce the v-cut thickness depth.

When boards pass the reflow oven, it is most likely that the boards will get twist or warp.

How to prevent the issue? See following advise by Linked Electronics.