SMT Reflow Ovens: Manufacturers, Cost and Temperature ...

Reflow ovens have become indispensable tools in the field of electronics manufacturing, particularly with the adoption of surface mount technology (SMT). These ovens operate on meticulously designed heating profiles that facilitate the melting of solder paste, crucial for securely attaching components such as resistors, capacitors, and integrated circuits onto printed circuit boards (PCBs).

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This article outlines prominent SMT reflow oven manufacturers, typical cost ranges based on various features and production capacities, and essential temperature parameters that define an effective reflow profile. This guidance will assist electronics manufacturers in choosing reflow ovens that fit their production requirements.

Leading Manufacturers of Reflow Ovens

The electronics assembly industry is served by a select group of prominent reflow oven manufacturers globally:

Ersas

Based in Germany and part of the Kurtz Ersa group, Ersas provides several options in convection and vapor phase reflow ovens through its ERSAS Rework and ERSAS Production product lines. Their advanced convection ovens include features such as smart nitrogen control, designed to minimize soldering defects.

Heller

Heller Industries, under GM Nameplate, manufactures both convection and vapor phase reflow ovens in the United States. The MK5 series features an 11-zone conveyorized tunnel oven that can be configured for various thermal profiles, while the PowerHeat series emphasizes rapid thermal response and efficiency.

Electrovert

Headquartered in Ireland and part of Stow Automation, Electrovert produces the Eria brand of reflow ovens. Their Eria Voyager convection ovens come in both standard and high-performance models, equipped with features such as vacuum transport. Meanwhile, the Eria Mistral offers economical air or nitrogen oven options.

Rehm Thermal Systems

Rehm, a German manufacturer, specializes in producing convection, condensation, and vapor phase ovens suitable for applications involving lead-free and semiconductor packaging. Their Vision XP+ series showcases high-end convection ovens with innovative features like the VacuMotion transport system.

Vitronics Soltec

Also based in Germany, Vitronics Soltec produces the Centurion and XPM2 series of convection reflow ovens. These product lines are designed for optimal thermal performance specifically for lead-free solder profiles. Notably, the XPM2 series includes models capable of handling larger boards up to 850 x 1,050 mm.

Price Ranges for Reflow Ovens

The cost of reflow ovens varies significantly depending on features, configurations, and production capabilities:

Economical Models: $15,000 to $30,000

• Compact convection ovens
• Manual loading/unloading mechanisms
• Basic profiling/tracking capabilities

Mid-range Models: $30,000 to $60,000

• Ample-sized ovens with conveyor systems
• Advanced profiling and optimized temperature control
• Nitrogen atmosphere options available
• Ideal for small to medium production volumes

High-end Models: $60,000 to $250,000+

• High throughput and large PCB capabilities
• Pinless handling and vacuum transport systems
• Smart multi-zone convection technology
• High flexibility for large batches and complex mixes

Typically, reflow ovens are sized and priced based on the size of PCBs, peak temperature capabilities, and throughput measured in boards per hour (BPH). Incorporating advanced features, such as sophisticated profiling software or additional transport systems, also increases the overall cost.

Understanding Reflow Profiles

The primary function of a reflow oven is to generate thermal profiles that melt solder paste correctly and create strong solder joints without compromising the integrity of sensitive electronic components. Each PCB design, component type, and solder alloy often dictates a unique profiling approach, but several vital characteristics are common in typical reflow profiles:

Stages of Reflow

Reflow profiles are comprised of four critical thermal stages:

1. Preheat: A gradual increase in temperature, typically between 150°C to 200°C, that activates the flux and helps reduce thermal stress on the assembly.
2. Soak: A short dwell time at around 150°C to 200°C to allow for temperature equalization across the board.
3. Reflow: A rapid rise in temperature above 200°C, where the solder melts and adheres to pads. The peak temperature varies based on the solder alloy, with common profiles achieving 230°C to 260°C.
4. Cooling Down: A controlled reduction in temperature to solidify solder joints without generating excessive thermal stress. Cooling rates should not exceed 4°C per second.

Peak Temperature Considerations

The maximum temperature reached during reflow depends on the solder alloy utilized:

• Tin-lead alloys typically peak around 215°C
• Lead-free alloys necessitate higher peak temperatures between 230°C to 260°C

Surpassing peak temperature parameters risks damaging components, while lower peak temperatures can lead to inadequate wetting attributes and cold solder joints.

Essential Thermal Performance Metrics

Key specifications that contribute to oven profiling performance include:

• Heating and cooling rates
• Range of adjustable peak temperatures
• Configurations for soak zones
• Number of independently controlled heating zones

Having more zones, with enhanced ramp control and elevated peak temperatures, permits refined custom profiling.

Atmospheric Conditions

Many modern reflow ovens allow for a switch between air and nitrogen atmospheres:

• Air reflow is straightforward and cost-effective but necessitates proper ventilation.
• Nitrogen atmospheres help reduce oxidation and minimize defects, producing superior solder joints and improved wetting properties.

Comparison of Reflow Oven Features

Common Reflow Soldering Issues

Certain defects are frequently encountered in reflow soldering:

Cold Solder Joints

These joints exhibit poor wetting and leave dull, convex appearances, resulting in weak adhesion. Insufficient heating during the reflow process can cause this issue.

Solder Balling

Solder balls are small globs of solder left on assemblies after reflow, typically stemming from problems during solder paste printing.

Maintaining careful oven profiling is essential to mitigate these and other thermal defects.

Common Inquiries

Convection vs. Vapor Phase Ovens

Convection ovens utilize heating elements and fans to circulate warm air, offering efficient heat transfer and flexible profiling options. In contrast, vapor phase ovens operate by immersing assemblies in an inert liquid that boils at a fixed temperature, providing even heating but reduced profiling flexibility.

Ease of Manual Loading/Unloading

Most ovens above entry-level models incorporate automated transport systems. For those operating manually:

• Wide pass-through doors facilitate easy access for inserting and retrieving assemblies.
• Product detectors help prevent errors when handling heated boards.
• Ergonomically designed workflows minimize strain through proper working heights.

Choosing Between Air and Nitrogen Reflow

When selecting the ideal atmosphere, consider the following:

• Nitrogen minimizes oxidation defects and can enhance wetting on complex alloys. However, it incurs additional costs.
• Air reflow serves as a viable economical choice if the necessary infrastructure is in place and atmosphere-related defects aren't present.
• Switchable atmospheres provide flexibility for potential future adaptations.

Key Real-Time Data to Monitor

Monitoring vital process parameters ensures optimal functionality:

• Heating zone temperatures
• Total thermal loads
• Conveyor speeds/dwell time tracking
• Oxygen levels in the atmosphere (for nitrogen ovens)
• Cooling temperature variations

Tracking these metrics guarantees that conditions remain within acceptable thresholds throughout the manufacturing process.

Maintenance Schedule for Reflow Ovens

Conducting an annual preventative maintenance check from the manufacturer is crucial for reliable oven performance:

• Inspect essential components, including fans, heating elements, and atmosphere sensors.
• Check for thermal uniformity across multiple zones.
• Evaluate the condition of transport mechanisms.
• Update software and calibration firmware as necessary.

Final Thoughts

With surface mount assembly becoming increasingly predominant in modern electronics, investing in a high-performance reflow oven tailored to production specifications is critical. This overview of notable manufacturers, cost ranges, influential features affecting profiling, and common defects offers valuable insights for electronics manufacturers seeking the ideal soldering solution. Aligning oven specifications with board size, complexity, solder composition, and quality standards lays the groundwork for efficient and reliable reflow soldering.

Checklist for Reflow Oven Purchase

• Determine production volume (boards/hour)
• Identify supported board sizes
• Select handling type (conveyor, rail, robotic)
• Assess heating configurations (zones, rates, and uniformity)
• Decide on atmosphere preference (air or nitrogen)
• Evaluate temperature range and profiling capabilities
• Consider software features (traceability, data logging)
• Establish a budget balancing cost against capabilities

Finding the Best Reflow Oven for SMT in Your Field

Guidance for Selecting the Ideal PCB Reflow Oven

When seeking the optimal reflow soldering oven suited for SMT, consider the following aspects:

• Effective Temperature Regulation: The reflow oven must uniformly heat the PCBA to avoid damage, particularly to LEDs. Adequate cooling systems are essential for heat management.
• Capability for Large PCBs: Opt for a soldering oven designed with a wide track layout suitable for large LED PCB handling.
• Nitrogen Compatibility: Certain LED PCBs may necessitate nitrogen environments to enhance solder quality; thus, select a reflow oven equipped for nitrogen use.
• Rapid Cooling Features: For mass production scenarios, the oven must cool quickly to minimize defects, with dual cooling systems (air and water) being optimal.

Recommended Reflow Ovens

• Large PCB Compatible Models: Consider I.C.T SMT reflow ovens designed for effective handling of large boards, featuring wide tracks and multiple temperature zones.
• Nitrogen Ready Soldering Ovens: To ensure superior soldering quality, opt for SMT ovens that include nitrogen functionality.
• Efficient Cooling SMT Ovens: Models with dual cooling capabilities provide quick cooling alongside high-performance standards.

Recommended Model: The Lyra622 reflow oven stands out as a viable option. For more demanding applications, the Lyra622N nitrogen-enhanced oven with dual cooling capabilities proves even more effective.

For additional information regarding Surface Mount Reflow Ovens, do not hesitate to reach out to us.