Forced Convection Surface Mount Reflow System

The fastest response times, the most precise control

Minimizing the thermal inertia of heating elements has always been a major objective of Heller oven design. For instant heat source reaction to varying loads, Heller uses low-mass heaters with highly sensitive, individual controls to scan and adjust power levels ten times a second. This assures uniform temperature, from leading to trailing edge, and board-to-board, regardless of component density or board loading.

As a result, even boards loaded with QFPs, BGAs, PLCCs and heavy connectors inter-mixed with small chips and MELFs produce consistent results. In addition, reflow challenges-heavy multi-layer boards, copper-invar-copper boards, even mixed technology boards-can be processed as successfully as conventional PCBs.

Excellent zone-to-zone temperature separation, plus powerful controlled cooling, yields reflow spikes that achieve liquidus times of 30-60 seconds easily, for proper solder joint metallurgy. Sophisticated temperature and air flow controls also provide optimal top-to-bottom thermal gradients. The proprietary design of Heller's extra high volume, high velocity (EHV2) heating module combines many engineering concepts to deliver superior performance.

Controlling the velocity of the air at board level ensures the stability of all components, from low-profile chips to relay packages. Specially engineered high-volume, high-temperature blowers installed in each module develop a turbulent flow of gas around the components and board to attain temperature equilibrium rapidly. The thermal capacity of each heater is extremely high, resulting in fast warm up. Even under heavy loads, Heller's heaters have more than 60% reserve capacity.

The most advanced, easy-to-use system controller

The brain of Heller's reflow system is a sophisticated, closed-loop PID controller that interfaces through a high-powered PC. Its custom software is easy for operators to use, while providing engineers with a vast array of powerful process development tools.

For most of these tools is the three thermocouple board profiling system. This system provides multicolor time vs board temperature graphics as well as instantaneous temperature and slope data and time above threshold. Up to 500 profiles can be stored and recalled for process control and historical studies.

Data logging and password protection are also integral parts of the software system. In the rare event that a failure occurs in any part of the system, the software performs a self-diagnostic function, simplifying repair and correction. With the addition of a modem to the PC, Heller's RMATS (Remote Maintenance and Technical Support) can be contacted to help diagnose and correct any operating situation or assist in profile development. Another convenient optional feature, Autostart, turns the system on or off automatically to maximize system run time.

The most rugged design and reliable performance

Heller reflow systems are durable and robust, to fulfill the requirements for continuous 24-hour operation with minimal maintenance. They are designed to meet the needs of customers with rigorous demands, such as those found at the world's highest volume board assembly facilities.

Heller features include stainless steel mesh belt conveyors and optional edge hold conveyor chains requiring virtually no lubrication, blower motors rated for years of constant use at high temperature, plus self-cleaning heating and cooling modules to prevent flux accumulation. To assure maximum reliability, all major electrical and electronic system components meet appropriate standards worldwide.

And when a Heller system does need attention, our highly trained and mobile service organization supplies spare parts, retrofits, upgrades, assistance and remote diagnostics around the world.