Cascade Temperature Algorithm Demonstrates Thermal Testing Goals Reached

Cascade Temperature Algorithm Demonstrates Thermal Testing Goals Reached Faster with the Potential of Differential

Having a specific requirement to test a product to a given temperature profile, how does one show that the actual temperature requirements are being achieved?

Many times, there are parts of a device to be tested that have different heat capacities and also possible active load heat sources. A single-point temperature control algorithm can have trouble effectively dealing with these variables. Additionally, while it may be tempting to say that a temperature setpoint has been achieved when the numbers on the display panel reach the desired value. – Without diving into the mathematics, being aware of a couple of the basic aspects of heat transfer help understand the problems at hand and achieve the best results:

1) Heat transfers more effectively when the heat source has a greater difference from the point of interest.

2) Convection heat transfer works a lot better when there is plenty of airflows. Truth is, many inexpensive temperature chambers have very low airflow. Air achieves the needed temperature fairly quickly but devices in the airflow, especially if they have any substantial mass or are in the shadow so to speak of another part will take a long time to reach the required temperature.

3) Heat transfer by conduction will always be faster.

Many of the better modern temperature controllers now have the built-in capability to read two or more temperature probes. When you can identify a specific location in the part that is of special interest or proven to be a representative point that can be used to indicate that the temperature setpoint has been achieved, then Synergy Nano’s easy to use advanced temperature control algorithm can be used to improve the process as follows:

1) Allow temperature overshoot within specified limits to get the device to temperature more quickly (greater Temperature differential).

2) Verify when the temperature has been achieved removing unnecessary wait times.

3) Compensate for effects of active heat load, gradients, and latency in the device.

4) Provide recorded proof that proper testing has been done.

Advanced temperature control algorithms, now commonplace with better temperature controllers allow precise control of the Chamber or Thermal Platform temperature in order to get any specific location within the controlled zone to the required temperature. Active heat loads or areas that are somewhat thermally isolated from the heating/cooling source are also easily dealt with. Direct access to a network printer or PDF makes a record of the completion of the temperature test as required without tedious data formatting.

Parameter setting for DUT Temperature Control

As an additional step for improving thermal testing productivity, our dual-mode Hybrid Benchtop Temperature Chamber allows faster and more effective thermal testing of devices regardless of different heat capacity and active loads. It is simply a temperature chamber with both a thermal platform on the floor and a convection chamber. The Synergy Nano multi-zone temperature controller easily manages the temperature profile and reporting of results.

Hybrid Benchtop Temperature chambers

With this combination, customers report test times are actually cut in half.

Talk to the thermal experts at TotalTemp to find the best solution for your thermal testing needs.

June 5, 2023June 7, 2023

How and When to Use Thermal Chambers for Testing

Have you ever wondered what journey a piece of equipment or machinery took before ending up in space? Or what testing was done before the rocket’s blastoff? Or why does a piece of equipment fail prematurely? Well somewhere along the path to its final manufacturing, the components and sub-assemblies were developed and designed with the environmental conditions of where it would be operating in mind. Without this critical step in the manufacturing process, you would be far more likely to have some components fail prematurely (e.g. exposing a lithium-ion battery to extreme cold will reduce its longevity and storage capacity). By testing the component, you can ensure quality and reliability, and most importantly overall performance in the environment it is expected to work in. Quite frankly, that is just the way it is done. There are numerous ways to test a component for specific environmental conditions, one of them being the use of temperature or thermal chambers.

What is it?

A Temperature Chamber, also known as an environmental test chamber, performs thermal tests through the use of convection. They typically use a fan for the forced air convection, like a convection oven used in your house; however, instead of making cookies, you are testing products and equipment.

Not so fast

These “ovens” rely on the fans to move the air past the device under test for heat transfer. Therefore, if you want better performance you are going to need more airflow. Increasing the airflow comes at a cost since the unexpected heating from the air friction is significant. Also, more power is required for the test (e.g. operating costs go up) and then there will be increased noise and system wear as well.

Despite how easy (or complicated) it may be to bake a cake or grandma’s cookie recipe in a convection oven, the performance of a test within a Thermal Chamber is not that simple. In fact, there are at least three types of thermal testing that can be performed within a thermal chamber: Thermal cycling tests burn-in tests, and thermal shock tests. All three tests evaluate a component at different temperature extremes in a different way:

Thermal cycling is often a more controlled rate, alternating between the two temperature extremes. The speed of the transition can be adjusted to limit thermal stresses and allow guarantee of parts achieving the temperature. There are hold times called soaks at specified temperatures to make sure the parts achieve the expected temperature. Faster ramp rates are usually better in production but on the other side, care must be taken to not stress the parts beyond what they are able to withstand.

Burn-in test is typically a sustained hold at a given temperature (usually hot) to verify operational parameters of a device in a specific environment over time, Thermal shock, on the other hand, is taking the component from one temperature extreme and another and “shocking” it with very rapid transitions. This is completed with testing chambers or thermal platforms that either automatically transfer the component being tested from one hot chamber to another nearby cold chamber or simply by using high-performance heaters and cooling in a single chamber zone. As you can see there is a little more to it than a convection cooking oven.

Another important thing that should be considered is meeting industry standards of testing. A lot has been written over time regarding appropriate environmental testing and most choices will depend on the intended destination for the product. There are some industry standards that are used as rules or guidelines for testing that can be adapted to other needs. The environmental chamber or thermal platform will allow you need to ensure it meets the standards of the application it will be used for.

For example, MIL-STD-810, Environmental Engineering Considerations and Laboratory Tests, was designed originally for products entering the defense industry; however, this standard is routinely used for commercial products too. This standard covers a wide range of environmental conditions such as thermal shock testing, exposure to high and low-temperature extremes, and humidity. Thus, depending on what environment your product will operate in there is a good chance you will be using MIL-STD-810 for environmental simulation in the design phase to ensure quality and reliability.

But that standard is just the tip of the iceberg. There are countless other standards (e.g. ASTM) whether or not they are related to the defense industry that require additional design specifications and testing. Therefore, if you want to ensure quality and reliability through an environmental simulation consider the best choice to be a temperature chamber to ensure first-time quality work of your product.

June 5, 2023June 26, 2023

Benefits of a Small Thermal Vacuum Chamber for Space Simulation

What is a small thermal vacuum chamber?

Thermal vacuum testing is a critical step in the design and qualification of space and flight components that are operating at high altitudes such as the mission-critical or sub-assembly components. It enables the component to be subject to space and upper atmospheric conditions – simultaneous altitude and temperature extremes. In a vacuum environment, heat is transferred through radiation or conduction since convection (transfer by air currents) is not possible without air. Thus, a thermal vacuum is a vacuum chamber that controls the temperature of the parts by conductive or radiant heat. This is easily accomplished with thermal platforms in smaller, portable systems.

Why Portable Space Simulation?

If you are testing or designing any high-altitude aircraft (e.g. spacecraft or aircraft) or anything leaving Earth’s atmosphere it’s important to consider thermal vacuum chamber testing to ensure your materials behave as designed. Unfortunately, space simulation systems are often sized remarkably larger than required due to a lack of foresight on what future requirements will be, This results in various inefficiencies. Thus, there are several cost-effective space simulation options; one of them being small thermal vacuum chambers.

A small portable space simulation chamber will meet the needs for testing many smaller components. The small size makes it more affordable and not something so expensive that you would need to take the devices to be tested to another facility at an hourly rate to perform testing. Pull downtimes for achieving vacuum are typically minutes instead of hours when using a small portable system. Likewise, temperature change rates are much faster. Using the conductive nature of a thermal platform will always be faster than radiant methods typically used in larger chambers

Why use a TotalTemp Thermal Vacuum System?

If the above is enough to convince you that small thermal vacuum chambers are necessary, perhaps a couple more reasons:

Logging to file and direct Network printing/logging of test results
Easy Automation with the Synergy Nano controller
Quality and reliability from years of experience in the field
TotalTemp customer support is the best in the industry
Better temperature control with a thermal platform instead of by radiant temperature control methods.

If you are testing spacecraft or aircraft components or anything that operates at high altitudes or in space, it is highly recommended that you use Total Temp Technologies’ small thermal vacuum chamber for testing.

June 5, 2023June 7, 2023

What is the Best Way to Accomplish Appropriate Thermal Test on an Electronic Device?

Why are Thermal Platforms a good alternative to traditional convection temperature chambers?

There are many reasons thermal testing on products is required.

Primarily to verify that the product will work properly in the environment (thermal and otherwise) that it is intended to perform. Sometimes, also to discover end-of-life issues for products, maximize performance or to weed out early failures that might result in product failures

For reasons primarily of simplicity and ease of use, the most widely employed method of forcing products to temperatures for thermal testing is a (convection based) temperature chamber.

According to laws of Thermodynamics, heat transfer (in and out of a product) is accomplished through one or more of the three following methods. Conduction, convection and radiation.

Convection, as in a standard temperature chamber, while considerably less effective is often used exclusively for the testing of thermal environmental testing. Technically speaking the heat transfer method is described as forced-convection or Advection (see equations there) where heat is transferred by circulating air past the source of heat and subsequently past the device under test. Employing a temperature controller sensing the air temperature with a setpoint of the desired temperature, temperature stability at various points can be achieved.

For completeness, Radiation should be mentioned as well. For most environmental testing applications other than thermal vacuum where convection or physical contact is not possible radiation is not the best choice. Temperature control by radiation is not as easily managed.

The typical scheme of thermal test by convection works well enough for many applications but some of the limitations of chambers are as follows:

Additional instrumentation is required to sense the product temperature if you really want to be sure if-and-when the device reached the required temperature.
Heat transfer via convection is much slower than heat transfer by conduction (see equations there) resulting in extended test times to assure actual device temperature.
Active loads are less readily managed with convection, again resulting in uncertainty of actual device temperatures
Benchtop chambers are often larger than needed for the specific application resulting in cascading inefficiencies of time, lab space, and utilities.

Thermal Platforms as an alternative to chambers brings fast test times and efficiency of lab provisions (space, HVAC load, maintenance, electricity, cryogenic fluids when required). Platforms with advanced temperature algorithms can achieve temperatures quickly and efficiently by monitoring both the platform and device temperatures.

Thermal platforms have issues to be considered as well. First of all, for the promised great improvement in heat transfer, good thermal contact is required. Many electronic devices either already have a flat conductive surface or can be readily fixtured to provide a good thermal path to the device. If that is not the case, a traditional convection temperature chamber or Hybrid Benchtop Chamber; that is one that combines the benefits of convection and convection to achieve greater performance may be in order.

Significant additional improvements of the processes of thermal test are achieved through proper application of easy to use automation features. Advanced features such as control algorithms that can directly read the device temperature have been available for many years but are now made easier to implement with modern temperature controllers like the Synergy Nano controller.

Ease of use from a high quality instrument such as this allows numerous advantages including:

Logging to internal files, with multipoint sensors available
Log files can be exported to office software or printed directly to a network connected printer
Remote control via serial, Ethernet, FTP or optional GPIB with industry standard LabVIEW and other drivers included
Easy to use local programmability to make flexible ramp and dwell profiles that can be saved and copied.
Flexible alarms and notifications can be easily established to flag events, out of bounds condition or completion of test. Email, text messages or local alarm notifications or actions
Selectable display can show multiple readouts, basic graphing and even control of two separate thermal zones

TotalTemp is happy help you find the best solution for your thermal testing requirements with helpful knowledgeable support staff.

June 5, 2023June 11, 2025

Temperature Testing Practices

Many items require thermal environmental testing. Items going through product development, requiring validation for high-reliability applications, and products exposed to extreme environments among others require specific thermal testing.

Diligent adherence to requirements results in performing a meaningful test and ultimately higher quality products as opposed to simply taking the easiest route to put a testing checkmark in the box.

A few important aspects of the testing can help ensure that best practices in thermal testing are followed to get real results from testing efforts.

1. Testing can be time-consuming. Properly applied automation will increase repeatability and can produce consistent results. Test results can be automatically stored on the test equipment, in the cloud, or automatically printed to a network printer.
2. Automation also reduces some unexpected uncertainties in the testing such as reducing the temptation to open the door/lid of the chamber during the test.
  
  In addition to disturbing the temperature uniformity of the test, if cool air is introduced when the system is at extreme hot or cold temperatures, moist air can result in unwanted condensation or corrosion on the devices being tested.
3. Best heat transfer will get the job done most effectively. When possible conductive heat transfer will achieve the setpoint in less time with less energy. When heat transfer by conduction is not possible or practical a convection chamber or a hybrid combining conduction and convection is a good idea.
4. When using a temperature chamber, for best heat transfer, be sure that airflow across the device is as great as possible to transfer heat effectively as possible.
5. Use of a secondary sensor in a Temperature Chamber or Thermal Platform can be applied to either verify that critical zones in the product to be tested actually achieve the specified or with a controller that employs smarter temperature control algorithms which can consider both the system temperature and individual device under test (DUT) temperature.
6. Prior to purchase, always give plenty of consideration to the most preferred cooling method given the testing requirements and facilities available.
TotalTemp Technologies can guide you through all the trade-offs, including cooling methods. We not only design, manufacture and sell some of the best equipment out there but also offer free dedicated consulting to get you to the best thermal testing equipment that meet your unique requirements.

Call us (888) 712-2228 or contact us if you have any questions.

Different Ways to Use Environmental Chambers

Environmental chambers are used by many industries to help design the perfect products or confirm safety and compliance for ones that are slated to be mass-produced. For almost seven decades now, these chambers have been used to test all types of products from massive aerospace components to everyday consumer packaged goods.

Environmental chambers are an investment both monetarily and time-wise. Sometimes, companies may look to invest in a used chamber rather than a new one for cost savings. If you are going to move forward with any type of used equipment, do so with caution. You would definitely want to have it thoroughly inspected as your customers will be counting on you. The control systems the most quickly.

Consider the time savings of having a modern reliable controller

1) Reducing the chances of a runaway condition

2) Reducing time investment required using a temperature controller with modern automation

Features such as:

Ramp/dwell profiling
Advanced device temperature monitoring/control
Logging
Remote computer access to controller
Networking features such as email/text alerts and cloud storage of profiles/test data

So, why are using these so necessary for a lot of organizations? It can be very expensive, and dangerous for that matter if products are not rigorously tested in realistic environmental conditions. The reactions to various types of conditions provide key data for further development, tweaks, and finalization before these products hit the market.

Though a multitude of products is tested in environmental chambers daily, there are three main ways in which these chambers are used:

Reliability Evaluation
Disintegration Timing
Material Reactions

Reliability Evaluation

Chambers are often designed to have a variety of conditions they can emulate in a realistic manner to test how reliable the product will be. This testing can expose flaws in how the product is manufactured. Identifying weaknesses right out of the gate can save a great deal of capital in the end. As each tweak is made, the product can be re-tested until any flaws are eliminated.

Disintegration Timing

Environmental chambers can be used not only to test how strong a product is but also how long it takes to be destroyed. By raising the intensity of certain conditions like humidity or temperature, researchers can determine what the lifespan of the product is before it begins to deteriorate. These extreme conditions are certainly ones in which you would not want to try out a new product for the first time in real life.

Material Reactions

Understanding how not only your product reacts to various environmental factors, but also how its individual material components react may be key to its success. The chamber does not only have to test a completed project. It can test products in merely the design phase, or can even be used singularly for research purposes. Finding the sturdiest materials to build it from the ground up can help create a consistent and trustworthy product.

Environmental chambers come in a variety of shapes, sizes, and prices – from ones that are put a large vehicle in down to small table-top devices. There are even hand-held devices that can be transported easily for those who need to do testing on the go. They all are constructed to have different real-world environmental factors that they test. These can include temperature, humidity levels, vibration, photo-stability, and more. These chambers simulate virtually any condition you currently think exists in the real world. Plus, as technology has advanced, so have the testing units. Many now include digital data interfaces and touch screens.

If you’re considering creating a new product, it is important to really do your research and understand what protocols you will need to follow. Use environmental chambers to understand how reliable a product is, how long it will last and how well its individual materials hold up. Once you are armed with this information, you can feel confident in moving forward with your product and taking it into mass production (and the general comfortable will be confident in using it).

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