How to Optimize Conveyor Angle in Wave Soldering for Pcb Assembly Us

Optimize Conveyor Angle in Wave Soldering for Pcb Assembly Us

As technology advances, the demands placed on PCBs increase and components are more tightly positioned. Wave soldering has proved to be a very useful tool for manufacturing these increasingly complex boards but it is important to understand how the equipment works to ensure it performs at peak efficiency. Several factors affect the performance of the process including the conveyor angle, component placement and proper flux use. Using the wrong conveyor angle in wave soldering can lead to bridging, shorting, and other defects. Keeping the following tips in mind can help you optimize conveyor angle in your pcb assembly us and achieve the best results.

A common approach to reducing wave soldering related defects is to reduce the amount of solder held on the PCB surface. This can be accomplished by increasing the amount of soluble flux or modifying the composition of a liquid solder to improve its ability to separate from the lead and pad. In addition, increasing the lead and pad size can decrease the likelihood of a solder bridge and allow excess solder to flow away from the joint.

The first wave solder machines had plates that separated the molten solder into front and back waves that were then fed into a conveyor system. As the conveyor moved over the molten solder, it formed a narrow, flat wave (a “symmetrical wave”) that moved equally across the front and back of the plate. Dips in a pan of soluble flux followed the PCB through this process and, as the conveyor moved the assembly over the wave, solder flowed down all of its surfaces, connecting leads to pads. This configuration worked well and, with some exceptions, a high level of solder connections was achieved.

How to Optimize Conveyor Angle in Wave Soldering for Pcb Assembly Us

As component technology improved, the skinny symmetrical wave began to have problems. The smaller surface mount components were packed closely together and the resulting shadowing prevented the solder from reaching all of them. In addition, the flat crest of the wave made it easy for excess solder to cling to leads and create a bridging defect.

To minimize this, the inclination of the conveyor was changed (6deg was common) and high concentrations of rosin were added to the liquid flux. The rosin acted like an elastic membrane that stretched over the leads to slow down the movement of the solder and prevent the excess from clinging to the leads. This reduced the chances of bridging but also created messy assemblies that required expensive post-soldering cleaning.

In the end, hybrid assemblies that combine through-hole and SMD components require a selective wave pallet to allow the solder to reach all the components. In some cases, this will require a thicker pallet to provide adequate space for the components but, in general, this is an efficient way to maintain good soldering performance with both through-hole and SMD parts. However, for pure through-hole or SMD only assemblies, a more traditional method of hand or mini-wave selective soldering may be a better choice for minimizing defects.

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