Heller Industries 1809 MK5 Voidless / Vacuum Reflow Soldering Oven (1911 Mk5)

The 1809 MK5 is an in-line high-throughput reflow oven designed for SMT and PCB assembly that incorporates a vacuum or voidless reflow option. Unlike standard reflow ovens which operate in air or nitrogen, the vacuum variant includes a dedicated vacuum chamber (or vacuum zone) where the PCB is exposed to sub-atmospheric pressures during or after peak reflow. This vacuum cycle helps remove gas entrapment and voids in solder joints and interfaces—leading to higher joint integrity and less solder voiding.
Additionally, the 1809 MK5 features a high number of heating zones (9 top + 9 bottom) and dual cooling zones, enabling high speed (up to ~80 cm/min) throughput while maintaining tight thermal control.

The vacuum system integrated into the 1809 MK5 works by pumping down the chamber (often in multiple steps) to reduce ambient pressure around the PCB during reflow. This allows trapped gases (flux volatiles, encapsulated air) to expand and escape before final solidification of solder joints. According to Heller, this leads to void rates below 1% in many applications.
Benefits include:

• Improved solder joint reliability and strength (especially under vibration or thermal cycling)
• Better BGA/CSP/flip-chip performance with fewer voids underneath pads
• Enhanced cosmetic appearance and fewer rework events.

The 1809 MK5 supports high-mix, high-volume production. It can achieve belt speeds of up to 32 inches (≈80 cm) per minute in production use.
It also supports comprehensive process control: advanced heater module response (<1 sec to <0.1 °C change), wide process windows for universal profiling, and capability to store up to 500 recipes and 500 profile graphs.

The tunnel opening supports a maximum board width of about 22 inches (≈ 55.9 cm) in standard configuration.
The oven’s overall length is ~183″ (≈4.65 m) in one spec sheet, giving it a large footprint but enabling long heated zones and high throughput.
It supports both air and nitrogen atmospheres, and when configured for vacuum/voidless operation, features the vacuum chamber option for enhanced soldering performance.

The 1809 MK5 supports standard convection reflow in air or nitrogen, but the “Voidless / Vacuum” variant specifically integrates a vacuum chamber for void reduction. The vacuum option also often includes nitrogen-inert environment with oxygen levels down to 10 ppm.
Moreover, Heller’s balanced-flow heater modules and uniform gas management reduce nitrogen consumption by up to ~40%.

• Significant reduction in solder joint voiding (common cause of reliability failures).
• Enhanced process control and repeatability via closed-loop oxygen monitoring, Cpk reporting software, and advanced profiling.
• Fast cooling options (e.g., blow-thru cooling) reduce time above liquidus and optimise intermetallic growth.
• Lower total cost of ownership through reduced nitrogen and electricity consumption versus older models.

1. Key considerations include:

• Ensuring the vacuum option is specified (some 1809 MK5 units may be convection only).
• Matching solder alloy and component types to the profile capabilities (voidless reflow is especially beneficial for BGAs, large pads, CSPs).
• Accounting for footprint and utilities: for example, the machine requires sufficient conveyor length, nitrogen (if used), a vacuum pump system, and possibly water cooling options.
• Training and process validation: vacuum reflow requires careful profiling, monitoring of vacuum pump performance, and understanding of solder joint inspection for voiding.
• Integration with data / SPC systems: the 1809 MK5 offers advanced process logging (500 recipes, 500 graphs) and Cpk reporting to support quality assurance in high-reliability manufacturing.

Compared to standard reflow ovens, the 1809 MK5 with vacuum/voidless capability offers a step-change in solder joint quality, especially where voiding or joint integrity is critical (e.g., aerospace, automotive, medical electronics). The vacuum chamber ensures minimal trapped gases, better heat transfer, and stronger joints.
In terms of throughput and process control, it remains competitive (up to ~80 cm/min belt speed) while adding advanced features like advanced flux separation, high zone count (9 top + 9 bottom zones) and dual cooling zones—in many cases giving better process flexibility with lower operating cost (nitrogen, electricity) than older generation ovens.
For manufacturers needing the highest reliability and minimal voiding, selecting a vacuum/voidless oven like this offers clear ROI through reduced rework, fewer reliability failures, and improved yield.