Prototyping Techniques for Etched-Foil Heaters Etched-foil heaters provide excellent temperature control and uniformity in a broad range of applications. Their thin profile and foil elements contribute to fast warm-up, consistent heat distribution, and extended heater life. To achieve ideal performance, however, the heater must be properly configured to the thermal demands of the application. The complex physics of heat transfer makes it difficult to predict all aspects of system performance in the early design stages. Therefore, applications requiring tightly regulated temperature may require extensive prototype work. This white paper presents some tools and techniques to assist in
thermal prototyping, which seeks to optimize the heater for desired: - Initial warm-up and cycle recovery time
- Temperature uniformity or distribution
- Control accuracy
Factors influencing performance may include: - Total heater wattage
- Heater and sensor positioning
- Profiled and multiple heater elements
- Insulation
- Controller type
Analytical Methods Numerical analysis can eliminate part of the cost and lead time of repeated bench trials with actual equipment. Two analytical methods are: Thermal Transfer Estimation Programs Thermal estimation programs use simplified heat transfer equations to provide initial estimates of total wattage requirements. They consider warm-up and process heat requirements, plus losses due to convection, and radiation. Thermal estimation programs can yield a good starting value for heater wattage but usually fall short of an exhaustive analysis. They necessarily oversimplify both the description of the heater/heat sink and the heat loss formulas. However, wattage estimation programs should often be your first design step as they are not time consuming and relatively inexpensive to get a benchmark for prototyping. Finite Elements Analysis (FEA) Computerized FEA more accurately simulates thermal systems. It subdivides the heater and hardware into discrete elements and calculates the thermal profile of each element. It can model both steady state and transient conditions, in two or three dimensions. Click Here to Download the Full PDF | 
