A Comparison of Reflow Soldering and Wave Soldering

Reflow Soldering

Overview of the Reflow Soldering Process

Reflow soldering is the most prevalent soldering method in the PCB industry. It is primarily used for surface mount technology (SMT) components. The process begins by applying solder paste—comprising a mix of powdered solder and flux—to the pads on the PCB. Components are then placed onto these pads, and the entire assembly is passed through a reflow oven.

The PCB is placed in a reflow oven and hot air melts the paste to form solder joints. This thermal process typically includes several zones: preheat, soak, reflow, and cooling. Preheating is implemented so that the PCB doesn't experience thermal shock during the acute soldering process.

For smaller jobs or specific components, hot air pencils can be used instead of full ovens to achieve localized reflow soldering.

Common Applications in PCB Assembly

Reflow soldering is widely used in consumer electronics, automotive electronics, telecommunications devices, and industrial control systems. Our Printed circuit boards are widely built into robotics, medical, automobile, communication, industry and consumer electronics.

It is especially suitable for high-density PCBs where SMT components dominate. In such assemblies, precision and minimal thermal stress are essential.

Equipment and Materials Used in Reflow Soldering

The key equipment includes:

· Solder paste printer

· Pick-and-place machine

· Reflow oven

· Inspection systems like AOI (Automated Optical Inspection)

Materials include:

· Solder paste (lead-free or leaded)

· Flux

· SMT components

· PCBs with surface mount pads

We have advanced capabilities for SMT assembly to enable us meet all customers' PCBA needs under one roof in an inexpensive way.

Pros of Reflow Soldering

Suitable for SMT assembly
Trusted by most manufacturers
Does not require a large amount of monitoring
Less thermal shock
Options for limited soldering
A less wasteful process that can be applied to specific parts of the PCB

Wave Soldering

Overview of the Wave Soldering Process

Wave soldering operates differently from reflow. The wave soldering process begins by applying flux to the components that need to be soldered. This removes oxidation and prepares metal surfaces.

After preheating to avoid thermal shock, the 'wave' of solder will move over the PCB and begin soldering the various components—electric connections form during this stage. A cooling zone then solidifies these connections.

This method uses a bath of molten solder that flows upward in a wave-like motion. The PCB passes over this wave so that exposed metal leads are instantly joined with molten solder.

Typical Use Cases in Through-Hole Technology (THT)

Wave soldering is ideal for THT assemblies where component leads pass through holes on the board. It is the best method for engineers who need to solder a large number of PCBs at the same time.

Applications include power supplies, transformers, connectors, relays, and other high-current components often found in industrial machinery and automotive systems.

Equipment and Materials Used in Wave Soldering

Essential equipment includes:

· Flux applicator

· Preheater

· Wave solder machine with molten tin-lead or lead-free alloy

· Conveyor system

· Cooling system

Materials involve:

· Bar or wire-format solder

· Flux (rosin-based or water-soluble)

· THT components

· PCBs with plated through-holes

We offer Surface Mount (SMT), Thru-Hole (THT) and hybrid of both.

Pros of Wave Soldering

Suitable for THT assembly
More time-saving
Initiates less warpage
More affordable
Can provide strong solder joint quality
Produces a large number of PCBs simultaneously

Reflow Soldering vs. Wave Soldering

The main difference lies in how heat is applied. Reflow soldering uses hot air, while wave soldering uses a 'wave' of solder to mass-produce PCBs.

Reflow offers precision but may be slower for large batches. Conversely, wave soldering tends to be quicker and cheaper.

Environmental sensitivity also varies: the internal environment in a wave solder oven is far more sensitive—a small change in temperature or conditions might result in catastrophic damage to the PCBs.

Another contrast lies in design constraints: Manufacturers using wave soldering must consider pad size, pad shape, board orientation, whereas reflow has fewer such limitations.

Both Soldering Methods are Effective for Different PCB Types

Each method has its niche. While wave soldering is designed for THT assembly and reflow soldering is used for SMT assembly, hybrid boards may use both techniques on different sections.

Manual methods exist but are impractical at scale. For commercial production involving mixed technologies like DIP and SMD components on one board, dual-process lines using both methods are common.

Engineers must weigh production volume, budget constraints, component types, and technical expertise before choosing between reflow or wave techniques.

FAQ

Q: Can I use both reflow and wave on one PCB?
A: Yes. Boards with both surface-mount and through-hole components often undergo both processes—reflow first for SMT parts followed by wave for THT elements.

Q: Which method provides stronger joints?
A: Wave generally creates stronger mechanical joints ideal for larger components; however, reflow offers better precision for fine-pitch parts.

Q: Is one method more environmentally friendly?
A: Reflow can be less wasteful due to its targeted application using stencils; however, modern wave systems with lead-free solders also meet environmental standards.

Q: What type of inspection follows these processes?
A: Various testing method will be applied to the assembled boards before final shipment including Visual inspection, AOI Testing, X-ray Inspection

Fast, Easy, and Reliable PCB Manufacturing & Assembly with PCBAStore

At PCBAStore — Your nearest Printed Circuit Board (PCB) Fabrication and Assembly Store, we specialize in delivering high-quality solutions whether you need reflow or wave processes.

With over 16 years of fabrication experience and 8 years dedicated to assembly services,we have been offering full spec electronic manufacturing solutions From PCB designto box-build assembly services.

Our advanced facilities support all forms of SMT & THT technologies,including Panasonic Modular High Speed Placement Machinesand 10 temperature re-flow ovens. Whether you’re building prototypes or scaling up production,we offer express delivery as fast as 24 hours on fabrication, ensuring your project stays on track.

Choose PCBAStore when quality matters—and let us help you decide whether reflow or wave suits your build best.