Selective Soldering for PCB Assembly

A selective soldering approach offers PCB connectors the perfect instrument to overcome a few of the challenges. Selective soldering is a robotic device that pushes hot solder from a tank via a nozzle to cover the conduits running from the ground of a circuitry

What is Selective Soldering?

Selective soldering is indeed the method of soldering components selectively onto electronic components and formed modules, damaged in conventional printed circuit board assembly or through-holes technology mounting procedures by heat from the heat exchanger or wavelength soldering. This normally involves an SMT refill operation; selectively soldered components are generally surrounded by elements that have already been supplied in a soldering process and must be accurate enough to prevent damage to them.

Benefits over wave soldering such as no solder pallets are needed:

Wave Soldering is the routine method used for soldering pieces on circuitry for many years. Although originally developed for boards having completely thru-hole parts, some SMT bits will also be soldered.

For TH components to be mounted on circuit boards while PCB manufacturing, selective wave soldering pallets are employed. The pallets are built of an isolated epoxy composites substance. Wave Solder Pallets simplify the production process considerably, removing the need for heavy human work and manual work.

Some situations do not allow wave soldering, and manual soldering is not successful. The only alternative left is to employ the selective solder technique in these circumstances. A few of these requirements include:

• The high elevation of the component:

The solder wavelength has constraints, and certain components are large enough to obstruct the soldering of the wave.

• Unanimous heating:

Thick boards, particularly boards with extensive copper layers, might issue manual soldering for power and neutral aircraft. It’s hard to get one molten metal in the board to heat all the electrically coupled metal enough because the solder flows via the holes to make an excellent solder bond.

• The high-density accumulation of thru-hole connectors:

When big connections with tens of pins are utilized, a soldering iron may hardly be solder efficiently through each pin.

• Tight spacing of the component:

When thru-holes are too near to SMT components, there may be insufficient space to install a safety fixture around SMT modules to provide efficient wave soldering during smt assembly.

Soldering technology is becoming increasingly 3D, with connections to multiple levels. The maximum temperature is restricted for wave soldering through pallets, and the slurry reflow pin is just a 2D solution with space limits.

Selective soldering unit with Nitrogen assisted for clean, shiny solder joint:

Introduction

In these technologies, the major objective of using nitrogen is to avoid creating additional oxide on the solder interfaces of the SelectWave and the MultiWave. Furthermore, nitrogen inhibits the creation of extra dross while cleaning the MultiWave nozzles.

The nitrogen supply surrounding the soldering bottle avoids oxide layer development on the wave exterior and supports the flux action during the soldering operation. The cleaning of the nitrogen must rely on the support needed for the procedure.

Naturally, nitrogen with the greatest purity provides the finest support for the lowest use. But on the other side, less pure nitrogen may also complete the task with greater nitrogen utilization and mass flow. Everything relies on the commodity and the flows utilized.

At PNC, our pcb assembly services will include selective soldering as we have an in-house unit that is nitrogen-assisted for clean, shiny solder joints.

Faster than manual human soldering:

The positioning and soldering of electrical equipment onto circuit boards are also largely dependent on robotics in modern circuit board manufacturing factories. Does it suggest they have passed on to qualified manual assembly engineers? Not really.

As with other production processes, selective soldering is the ideal way for reducing costs and speed. Manual installation needs much-experienced personnel to perform what an electronic soldering line can accomplish more quickly.

Large, dense electronics beneath their pins, including Ball Grid Arrays (BGAs), need automatic solder reflow because of the difficulties of soldering the pins beneath them manually.

• Large quad flat packs featuring fine-width pins are planarity-sensitive when not all wires are on the surface exposed. This makes it hard to manually solder and prefers automated soldering devices.
• On the opposite end of the size range, tiny chip equipment, such as resistors and condensers, are too hard for hand positioning and soldering in 0201 containers (or smaller).

ERSA Eco Select 2:

ERSA adds a small ECO SELECT 2 to the renowned VERSAFLOW range as a global expert in selective soldering systems.

This system is particularly suited for modular manufacturing lines and is the perfect answer for small and medium enterprises production when flexibility is vital.

The ECO SELECT 2 is fitted with a programmed elevated flux for specific lines or row flux application, as are other ERSA selective soldering solutions. An incorporated spray sensor monitors the location of the flux stream.

Quick-wave IR emitters on the bottom side enable short preheating procedures. The segments of the heating cassette may be triggered depending on the product. The optional top-sided convection preheater allows even complicated components to be homogeneously warmed up.

The soldering process is indeed the backbone of the ECO SELECT 2. ERSA’s ‘pel off’ effect enables 0° soldering without span development and ensures the minimum DPM rates.

At PNC, we have this facility available and you can even get it at very economical rates.

Features autoload and unload:

At PNC, the process work using the Autoload and discharge system quicker. Our automated smt assembly load/unload decreases the human operation of the worksheet by 80% to enable punching processes more efficiently. The material loads & unloads from the same side of the device to save space. Higher manufacturing stability makes production unattended. There are certain important characteristics;

• Reduce handling periods by more than 80%
• Full brush board setup
• Grips of sensitive part nests.
• Includes the interaction autoload.

The capability of using leaded solder and lead-free (Unit has two different solder pots):

Lead-free solder has a detrimental effect on connection reliability. In terms of mechanical effect, plumbing solder is tougher than plumbing solder. In addition, plumbing-free soil generates surface compounds, flux impurities, and deposits of alloys that may produce poor surface energy. For these reasons, the change from leading to plumbing-free electronic manufacturing is not a comprehensive substitution of electric and hydraulic features:

• The lead is rather soft. You will discover that solder junctions without lead are tougher than solder junctions produced by lead. This increases the intensity and tiny changes, resulting in excellent dependability.
• Free lead soldering creates poor weathering, causing other difficulties, such as vacuum and burial.

Leaded solder offers many advantages for electronic production, but the tides of revolution are furious. All sectors using solder in considerable numbers will probably change to plumbing free shortly if they’ve not yet done so.

Engineers at PNC are experts in designing, pcb assembly, and fabricating customized PCB designs with efficient soldering techniques which are pocket-friendly at the same time.

Contact us at sales@pnconline.com to get the customized quote on your requirements.

Written by Sam Sangani

Sam Sangani is the President & CEO of PNC Inc., a Nutley, NJ based Printed Circuit Board manufacturer. Sam graduated from L. D. Engineering College with a BS Degree in Mechanical Engineering. He also continued his education and graduated from Steven’s Institute of Technology where he acquired a Master’s degree in Computer Science.

After completion of his BS, Sam worked as a QC Manager, for Xerox, Romania and London. He was responsible for the Quality Control of Cable and Wire Harness imports from Romania. After completing his Master’s Degree, he worked as a Senior Programmer with IBM, Tucson, Arizona. Sam was responsible for leading the Mainframe System Programming Team.

In 1997, Sam acquired PNC INC., a Nutley, NJ based PC Board fabrication Shop. From 1997-2013, Sam has made tremendous improvements and changes within PNC INC., as he added many new Products and Technologies in PNC’s portfolio. With his proven track record and leadership, PNC has never had an unprofitable year and has continued its growth yearly since 1997.

His current responsibilities are Strategic Planning, Corporate Management, New Business Ventures, Sales & Marketing, Trade Shows, Professional Services and leading productive teams to achieve peak potential. He has also utilized Lean Management techniques which have built a foundation for PNC’s high-paced growth. Sam also enjoys real-estate investing, web design & SEO, trading stocks, options, futures and Forex markets.