Old and New Technologies Align in Today's Modern Circuit Assembly


SMT Reflow Soldering

The process of soldering is the key component of printed circuit board assembly. It continues to evolve to meet the needs of today’s modern electronic markets.

Today’s modern electronics manufacturer has an arsenal that includes both traditional and cutting-edge technologies to get the job done.

Circuit board assembly includes several steps during manufacturing, but none quite as crucial as component soldering. When it comes time to apply solder, there are several options your manufacturer can use to find the most reliable solution at the most comfortable price.

Some soldering processes, like SMT reflow soldering and through-hole wave soldering, have been around for decades, and are still used today by most contract electronics manufacturers. Others, like jet printing, are newcomers that have entered the market in the last five to ten years, bringing additional flexibility, speed, and accuracy with them.

The Challenge of Diversity

Today’s manufacturing challenges stem in large part from the diversity of components that go into production; ensuring soldering includes processes that can get the right amount of solder paste on each component is a must.

In this article, we’ll review the various types of soldering used by EMS contract manufacturers to help you better understand which is the right choice for your products.

SMT Reflow Soldering

SMT reflow soldering is used for surface mount applications where the board component is firmly attached to the surface of the circuit board. Solder paste is stenciled or screened on before board parts are placed into the paste. The circuit boards are then run through a conveyorized oven using a controlled thermal profile which solidifies the solder to the board and turns the solder into a solid, uniform joint.

Wave Soldering

Wave solder is used for through-hole manufacturing, where board components are pushed through the circuit board via plated holes in the board. The circuit boards are run through a conveyorized oven with a controlled thermal profile. This preheats the circuit board, preventing thermal shock while activating the flux before it goes over a molten solder wave, soldering the components from the bottom of the board. 

Selective Soldering

A more modern soldering process that reduces the necessity for hand soldering and even wave solder in some applications is selective soldering. Selective soldering is used for through-hole components where wave soldering cannot be used, allowing a solder nozzle to run over the board soldering individual joints from the bottom of the board.  

When selective soldering is most beneficial:

Selective soldering is often used  in cases where the circuit board design will not allow wave soldering.

Hand Soldering

Last but not least of the traditional soldering methods is hand soldering. Hand soldering may be used for point to point soldering, and is most often utilized if there are physical constraints that make washing the board following soldering impractical.

New Jet Soldering Technology

While any of the processes above can get the job done, ever newer technology has arrived on the EMS scene that makes the PCB assembly process faster, more affordable, and a whole lot more flexible.

Using traditional soldering methods like reflow soldering means applying solder paste using a custom stencil. This requires additional work in the form of setting the stencil, setting up the stencil printer and adding the paste.

Using a jet printer, solder deposition accuracy is improved, allowing manufacturers to achieve accurate solder paste placement of any shape and size while reducing the time required for circuit assembly. New jet printing also negates the necessity for the traditional stencils needed to apply solder paste for reflow soldering. At several hundred dollars a stencil, these costs can add up for customers with higher complexity assemblies that may require several stencil revisions until the target assembly yield is achieved. Multiple versions of the stencils are often required, and can add costs and lead time for product developers as they prepare products for market.

With jet printing, however, programming can be changed and adjustments easily made; the new MYDATA 600 jet printer can even compensate for minor irregularities in circuit board topography if the board is slightly warped or twisted.

When jet printing technology was initially introduced onto the market, there were concerns that the process could not be done as quickly as more traditional methods. These fears have largely been dismissed as the technology matures; by reducing changeover times and providing on-the-fly programming adjustments when necessary, the majority of projects will actually be done more quickly and at lower cost for OEMs.

What type of soldering will your products require?

The knowledgeable manufacturing team at ControlTek ensures every ControlTek customer gets the soldering that’s right for their products. Call us today to find out how you can gain efficiencies and save costs while producing quality products.

Contact ControlTek to speak with a manufacturing engineer today.


Return To Our Blog