1. Under what circumstances can a PCB circuit board be wave soldered without a carrier?
Recently, someone posed a question online: “When is it possible for a PCB to be wave soldered without a carrier or template?”
2. In fact, during the early days of PCBA assembly in electronics factories, the use of carriers was almost nonexistent. At that time, nearly all PCBs were directly subjected to wave soldering without any carriers, unless the circuit board was unable to support significant weight, such as power boards.
3. Based on my observations, the reliance on carrier systems has emerged alongside the rise of selective wave soldering, as well as the trend toward thinner, smaller circuit board designs. Consequently, not all wave soldering processes require a furnace carrier.
4. So, under what conditions can a PCB pass through the wave soldering furnace without a carrier? Here, I outline some of the essential requirements:
5. PCB design requirements:
1. At least 5mm or more of the PCB’s edge should be reserved for the wave soldering chain (gripper) and for the PCBA when it is positioned in the magazine.
2. The PCB thickness should be 1.6mm or greater to prevent issues like warpage and overflow during the reflow process.
3. It is advisable that the gap between all solder pads be maintained at over 1.0mm to prevent short-circuiting of the solder joints.
**Parts and Layout Requirements:**
**For the Wave Soldering Board:**
1. The type and orientation of SMD components must comply with wave soldering requirements. (Generally, SMD components should be oriented perpendicular to the board’s travel direction.)
2. The wave soldering area of the circuit board should only accommodate SMD components, SOT, SOP, QFP, and other components sized 0603 or larger. Components like BGA, PLCC, QFN, connectors, and transformers, as well as those sized 0402 or smaller, should not be placed on the wave soldering surface.
3. All through-hole components must be designed on the primary side, and their orientation must meet wave soldering requirements. (Pin rows should be parallel to the board’s travel direction.)
**Related Reading:** Design Specifications for Component Placement during Wave Soldering
4. Components on the PCB should not be excessively heavy to avoid bending the circuit board due to gravitational forces.
**Process Requirements:**
1. All SMD components on the wave soldering surface must be secured with red glue to prevent them from dislodging in the soldering furnace.
2. It is not recommended to include solder pads that cannot be wetted with solder (such as button contacts or gold fingers) on the wave solder contact surface (the second side).
3. A limited number of solder pads that cannot be wetted with solder may be included on the contact surface of the soldering furnace but must be covered with high-temperature tape that does not leave adhesive residue. The tape should be removed after the process is complete. This design should be avoided to reduce labor time.
4. It is recommended to use short-foot operations and wave soldering for all through-hole components to mitigate short-circuit issues, and it is advised that the component length does not exceed 2.54mm.
Recently, someone posed a question online: “When is it possible for a PCB to be wave soldered without a carrier or template?”
2. In fact, during the early days of PCBA assembly in electronics factories, the use of carriers was almost nonexistent. At that time, nearly all PCBs were directly subjected to wave soldering without any carriers, unless the circuit board was unable to support significant weight, such as power boards.
3. Based on my observations, the reliance on carrier systems has emerged alongside the rise of selective wave soldering, as well as the trend toward thinner, smaller circuit board designs. Consequently, not all wave soldering processes require a furnace carrier.
4. So, under what conditions can a PCB pass through the wave soldering furnace without a carrier? Here, I outline some of the essential requirements:
5. PCB design requirements:
1. At least 5mm or more of the PCB’s edge should be reserved for the wave soldering chain (gripper) and for the PCBA when it is positioned in the magazine.
2. The PCB thickness should be 1.6mm or greater to prevent issues like warpage and overflow during the reflow process.
3. It is advisable that the gap between all solder pads be maintained at over 1.0mm to prevent short-circuiting of the solder joints.
**Parts and Layout Requirements:**
**For the Wave Soldering Board:**
1. The type and orientation of SMD components must comply with wave soldering requirements. (Generally, SMD components should be oriented perpendicular to the board’s travel direction.)
2. The wave soldering area of the circuit board should only accommodate SMD components, SOT, SOP, QFP, and other components sized 0603 or larger. Components like BGA, PLCC, QFN, connectors, and transformers, as well as those sized 0402 or smaller, should not be placed on the wave soldering surface.
3. All through-hole components must be designed on the primary side, and their orientation must meet wave soldering requirements. (Pin rows should be parallel to the board’s travel direction.)
**Related Reading:** Design Specifications for Component Placement during Wave Soldering
4. Components on the PCB should not be excessively heavy to avoid bending the circuit board due to gravitational forces.
**Process Requirements:**
1. All SMD components on the wave soldering surface must be secured with red glue to prevent them from dislodging in the soldering furnace.
2. It is not recommended to include solder pads that cannot be wetted with solder (such as button contacts or gold fingers) on the wave solder contact surface (the second side).
3. A limited number of solder pads that cannot be wetted with solder may be included on the contact surface of the soldering furnace but must be covered with high-temperature tape that does not leave adhesive residue. The tape should be removed after the process is complete. This design should be avoided to reduce labor time.
4. It is recommended to use short-foot operations and wave soldering for all through-hole components to mitigate short-circuit issues, and it is advised that the component length does not exceed 2.54mm.
