How Photo Etching Resolves Thermal Management ConcernsApril 2023
Excessive heat is a serious problem for a wide range of engineering applications. When heat isn’t properly controlled or minimized, it often results in deleterious effects on one or more parts of a system, including degraded performance and shorter operational lifespans. In some cases, thermal runaway can have literally deadly consequences, causing a fire or the abrupt failure of a device used to sustain life.
Fortunately, a variety of thermal-control strategies have been developed over the years to address this issue. And photochemical etching is at the heart of many solutions commonly used to combat the phenomenon of excessive heat. For many applications, photo etching enables the creation of the kinds of compact, precisely rendered parts necessary for effective management of heat. What follows is an overview of the issue of thermal management and the ways that photo etching can design solutions for reducing heat.
Industries That Require Thermally Controlled Parts
Given the ubiquity of heat-generating devices and systems, it comes as no surprise that thermal management is a standard problem across many manufacturing sectors. Industries that need strict thermal control solutions for their parts and systems include:
The electronics sector is particularly dependent on thermal management to avoid damage to extremely sensitive parts and components, like microprocessors. These kinds of devices are easily harmed by excessive heat and can suffer impaired performance or complete failure as a result. Even when this isn’t an issue, lack of good thermal control tends to diminish the energy efficiency of electronic systems, increasing their overall cost of ownership.
Many types of medical devices demand strict control of heat. Devices applied directly to or implanted inside a patient’s body can cause severe physical harm if heat levels are not properly controlled. In addition, measurement devices can generate inaccurate results due to physical distortions triggered by heat. Thermal management can also play a key role in the sterilization of sensitive medical devices that can be harmed by steam and similar anti-infection agents.
For gas- and diesel-powered vehicles, minimizing engine heat is essential to keep this equipment in top operating condition. Excessive heat causes vital components of the engine to warp, inflicting harm on the emission control system and other potentially serious consequences. Electric vehicles, although not reliant on combustion engines, are similarly vulnerable to thermal issues, as battery packs will prematurely age and wear down from exposure to uncontrolled levels of heat.
Note that this is not a complete listing of industries in which thermal management is an ongoing concern. Now let’s look at the ways that photo etching can provide effective thermal-control solutions.
Photochemical etching is customarily used in the making of heat sinks, which are thermal regulation devices that can be found in many types of machinery. The principle behind heat sinks is simple: They draw heat away from another component as a way of controlling temperature levels. Heat sinks, as passive heat exchangers, perform this action via natural conduction.
To aid conduction, heat sinks are designed to have as large a surface area as possible while accommodating space limitations of the equipment in which they are installed. The standard heat sink design consists of a base material from which a collection of long, tightly arranged pins, or fins, protrude. This design has the benefit of enabling easy installation in a wide variety of applications.
The heat sink is attached to the heat-generating component. When the heat sink is in use, their pins naturally draw heat from the component, thereby lowering the component’s temperature and, if all goes well, keeping it within an acceptable operating range.
Heat sinks are generally made of either copper or aluminum. Of the two options, copper is superior when it comes to thermal conductivity, but this material is also relatively heavy and expensive, factors that limit its usefulness in real-world applications. For that reason, aluminum is the more popular option for creating heat sinks. Aluminum alloys tend to work particularly well. Both copper and aluminum alloys can be machined with photochemical etching.
There are various types of heat sinks in use today, the most common of which include:
- Plate fin heat sinks – These have wall-like fins that protrude from the base and run in parallel from one end of the plate to the other. They are frequently used in applications with unidirectional airflow and a large heat source.
- Pin fin heat sinks – These feature a collection of square, cylindrical, or elliptically shaped pins protruding from the base. Good for all airflow conditions, they’re often used in conjunction with small heat sources.
- Flared heat sinks – These have pins or plates protruding in a flared (slanted outwards) arrangement. These types have superior cooling capabilities and are best suited for applications that can accommodate their space requirements.
- Radial heat sinks – These feature a circular base with parallel fins protruding around it in a 360-degree arrangement. They are useful for applications where heat should be dissipated in all directions from a central thermal source.
Heat sinks are used in many industries, but they are especially common in the electronics sector for protecting sensitive components. They benefit enormously from the precision and efficiency of the photo etching process.
Cold plates are another type of thermal management device that can be crafted with photochemical machining. Much like heat sinks, these are frequently used for thermal dissipation in sensitive electronic devices and are typically made from copper or aluminum.
The basic design of a cold plate is a metal block with internal channels—created with photo etching—that convey a liquid coolant (or sometimes forced air) in and out. The plate is attached directly to the heat-generating component whose temperature needs to be controlled. The cold plate is itself attached to a greater cooling system that normally includes a heat exchanger, liquid reservoir, and a pump; these components work together to circulate fluid continuously to ensure that heat levels remain always within an acceptable range.
Aside from electronics, cold plates can be found in a broad array of applications, from soda fountains to wind turbines.
Etched Resistive Heating Elements
Etched foil heating elements provide another striking example of the design flexibility possible with photo etching. These products are crafted by applying a thin metal foil onto an electrically insulating substrate material (typically polyimide or silicone rubber), and then using photochemical etching to create a conductive circuit design that complies with the client’s precise specifications for pattern and resistance qualities. Many types of metals can be used for the heating elements, including copper, nickel, and stainless steel.
Because they can be designed extremely thin (often <0.01 in.) without loss of functionality, these heating elements are especially useful for thermal control in areas with restricted space. They are found in applications as diverse as automotive defrosting systems, blood analysis apparatuses, food processing equipment, and industrial plating tanks.
Contact UWE, Inc., for Experienced Photo Etching Services
Since 1969, United Western Enterprises has been one of the most respected photo etching companies in the U.S., with a client list that includes major organizations from the aerospace, automotive, biomedical, and commercial electronics sectors. Our team is highly experienced in a broad spectrum of etching applications, including thermal management products for industrial use. For the best photo etching services available today, contact UWE, Inc.
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