EDITOR ’ S CHOICE THERMAL SOLUTIONS
WATLOW
Solving thermal system complexity
Thermal solutions are a part of almost every industry , from chip manufacturing and medical devices to oil and gas operations . What these diverse industries have in common is a need to design simple , yet responsive systems that can monitor and maintain the precise application of heat . However , this need means that engineers must contend with various complexities . Here , Brandy Phillips , engineering manager at industrial electric heating element manufacturer Watlow , explains how adaptive thermal solutions ( ATS ) can provide an answer to common heat processing challenges .
Any device or process with a heater needs some degree of thermal control , with some devices or processes needing more precise control than others . That precision is traditionally achieved by adding sensors and controllers to heaters . The more precision needed , the more complex the control apparatus and the wiring becomes .
ATS , which combines sensing , heating and control technologies , represent a different and more innovative approach to controlling thermal performance for complex systems . However , adding the complexity is not always an option , which is where challenges present themselves .
COMPLEX SYSTEMS IN SMALL SPACES
A surface that needs to be heated to within a certain temperature range requires not only several heating elements , but also sensors that can detect the temperature of the surface at various points . Those sensors then deliver that feedback to a controller that then responds by adjusting the power sent to the heaters . If the temperature of the surface fluctuates , the sensors and controller should be able to respond in tandem to maintain the desirable temperature range .
Traditionally , the approach to getting such fine control of the heating surface has been to increase the zone count , which requires the addition of independent sensors , wires and controllers . As the system scales , the complexity grows , but the overall space in which this needs to happen does not . In many manufacturing scenarios , precise control is needed in a confined space , and additional wiring and equipment is not feasible .
CONTROL SYSTEM CHALLENGES
Manufacturers may experience disconnection between their control systems . Different banks of sensors at different points in a process are often connected to separate controllers , which might not be networked in such a way that their activity can be coordinated easily , which results in unresponsive systems .
The above challenge often results in adding an element of unpredictability to the system . The added complexity of additional sensors and controllers will , for some applications , either compromise adaptability or prevent the system from achieving desired thermal uniformity . These , in turn , lead to excess waste and variable material quality .
UNLOCKING THESE CHALLENGES
Precision and tunability of a thermal system is traditionally achieved by adding sensors and controllers to the system . But there are plenty of applications where this is not a viable option , including semiconductor manufacturing , analytical devices and home medical devices . ATS makes possible a greater degree of control in systems where piling on more components is simply not an option .
Every application is unique , and some can take advantage of many ATS technologies at once while others might use just one . In semiconductor manufacturing , deposition pedestal heaters must reach certain temperatures during the chipmaking process , and temperature uniformity is critical to quality control . The pedestal itself allows little room for extra wires . With high TCR materials and multi-loop control and sensing , individual heaters can be made into sensors , and the number of heating zones can be more than doubled . These zones can be independently controlled , in real time , adjusting heater output to achieve a more uniform surface temperature .
Furthermore , existing medical and analytical equipment often have to meet new agency requirements , like safety specifications for allowed temperatures . Having heaters that can sense their own temperature , when then adjusts power levels via power conversion , helps to keep temperatures within safe limits .
Watlow , which manufactures industrial heating technology , has decades of experience with thermal systems to help engineers and designers to incorporate ATS technology into a variety of industrial processes and products .
The beauty of ATS is that it is not one solution , but a suite of solutions that can be tailored to specific engineering challenges . Unlocking the benefits of this technology requires a deep understanding of the product or process in question , including the thermal and power requirements of the system .
For more information about ATS , visit watlow . com
18 PECM Issue 57