SmartHeat^®

Introduction

Savvy electronic production engineers define success by how they maximize their productivity, yield, and product reliability. All of these factors depend directly upon process control. To achieve success, OK International has developed SmartHeat^® conduction soldering systems which uniquely sense the exact thermal requirement for each solder joint and respond by delivering the precise amount of thermal energy at the rate required to create a reliable connection. The result is a high degree of control without resorting to higher tip idle temperatures required by conventional ceramic heater technologies. Consequently the risk of component / board damage is minimized, especially important with the greater thermal demands required by lead-free applications.

As you'll see below, SmartHeat^® provides unique benefits in the delivery of high reliability low risk conduction soldering solutions, especially with lead-free alloys. All of these add up to provide a highly consistent level of process control.

SmartHeat^® Delivers Direct Power

First and foremost, the success of conduction soldering depends upon the availability and controlled flow of thermal energy into the connection during the two critical phases - flux activation and intermetallic bond formation. Lead-free alloys, with higher thermal demands, further heighten these requirements. Conventional ceramic heaters attempt to control this process by managing indirect parameters, such as the tip idle temperature. In contrast, SmartHeat^® technology senses the specific thermal demand directly at the solder pad and delivers the precise quantity and flow of thermal energy during both phases to ensure a reliable connection.

Stored Thermal Energy Transfer

Within the handpiece of a typical hand soldering system are two thermal energy supplies - the heater (source) and the tip mass (storage). At the moment the tip meets the pad, the tip stored energy is uncontrollably released into the pad, with the risk of flux boil off and component damage. Conventional ceramic heater soldering systems address increased thermal demands by raising tip idle temperature (stored energy is directly related to the tip mass and tip idle temperature) resulting in a high risk of component damage and reduced tip life. Since SmartHeat^® based systems respond directly to varying pad thermal demands, they are able to deliver the precise thermal energy at lower temperatures thereby eliminating the risk of damage.

Reduced Risk of Overshoot

Conventional soldering stations strive to control the process with tip temperature using thermocouple sensors and ceramic heaters. Inherent with this technology will be significant temperature variances throughout the tip body and consequently thermal overshoot/undershoot. The risk is unreliable solder connections or damaged components. Smartheat^® technology, on the other hand, detects and controls the energy requirement of the pad, avoiding thermal delivery variances thereby eliminating the risk of component damage.

Provide Temperature Stability - No Need for Calibration

Nearly all industry standards associated with conduction soldering performance cite temperature stability as a key requirement. To meet the demands of temperature stability, conventional ceramic heater systems depend on the sensor, heater and operator set point controls. Each of these elements is subject to drift and instability requiring frequent calibration and certification to ensure compliance. By contrast, the repeatability of SmartHeat^® technology is inherently determined by the molecular properties of the heater material and does not shift over time, ensuring long term stability without the need for calibration.

Precision Tip Selection - The Conductivity Factor

During the execution of a successful soldering connection, the tip is the thermal energy "highway" from the heater to the pad and, therefore, the choice of tip geometry is critical to prevent power losses. In addition to providing the most thermally efficient tip designs, OK International has pioneered the tip "Conductivity Factor" rating system providing operators with quantifiable guidance in the selection of the optimum tip geometry. Additionally, our proprietary Power Meter can quantify exact pad energy requirements, further refining the tip selection process. Lead-free alloys, with tighter thermal demands, make these tools mandatory.

Perfect for Lead-Free

The steps required for reliable lead-free connections parallel those for traditional alloys except that the thermal demands are greater. The typical operator response to the higher thermal demand is to increase tip idle temperature - unfortunately at higher temperatures the contribution to thermal performance is negligible. More importantly, the increase in tip idle temperature comes dangerously close to component and substrate damage levels making process control critical. Compared to conventional technology, Smartheat^® delivers precise process control assuring consistently reliable connections at low operating temperatures which provide the thermal performance necessary for lead-free.

Increase Tip Life and Value

The useful life of a tip is dependent upon many factors including flux corrosion, oxidation and tin dissolution. With higher tip idle temperatures, the contribution from these factors is dramatically increased. The resultant de-wetting from these chemical surface interactions causes many operators to increase tip force, which significantly accelerates tip life deterioration. With the advantages of Smartheat^® technology operators can solder at lower temperatures and, combined with proper tip selection and care, dramatically extend tip life and value.