THE 3 MOST CONCERNING EXTREME CONDITIONS FOR PLASTICS

THE 3 MOST CONCERNING EXTREME CONDITIONS FOR PLASTICS

WHAT TO KNOW ABOUT ENVIRONMENTAL EXTREMES WHEN SELECTING PLASTIC MATERIALS

You can find plastic machined parts and manifolds as critical parts of devices in almost any environment: from cell counters  in a climate-controlled lab to components on the International Space Station. When machining components that must perform under extreme operating conditions, a good engineer understands that selecting the right material is a critical step.

*Updated July 11, 2024

While making products from metal or glass does have its own advantages, sometimes it's not the most practical or best suited option. One of the major advantages of choosing plastic is that many different polymers can meet the environmental requirements of any project. Thanks to advances in their creation, engineers can find a material  that will work in extreme operating conditions. A few of the more common environments our engineers find themselves considering are extreme heat, chemical exposure, and water exposure.

A common temperature condition our team faces is extreme heat. Before making any decisions, engineers need to define what “extreme heat” means for your specific project. Consider these 4 important details:

1. What's the most extreme temperature the component will face?
2. At what frequency will those temperatures spike?
3. Will your component stay at that extreme temperature for long?
4. What's the potential/frequency of dips below the constant operating temperature?

Specifically, understanding the relationship between the continuous operating temperature and temperature spikes will impact material choice and the material properties required to meet the needs of the project. Some materials might be able to handle short spikes outside their continuous operating range without overloading, giving a wider range of materials to consider when making your selection.

However, engineers need to understand all operating environment conditions to selecting suitable material for their project regarding thermal protection. For example, rocket engines get extremely hot and sustain that heat, while other machinery may experience intermittent bursts of heat followed by a cooling-off period. Many plastics can only take these short periods of extreme heat before compromising their structure. We cannot stress enough how imperative it is to have a handle on where the component will operate most often.

Some materials that operate reliably in extreme heat are:

• PPS
• PEEK
• Torlon

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Chemical exposure qualifies as a common harsh environment when designing products in the life science and medical industries. As chemicals used within these industries can be abrasive and corrosive, choosing the wrong material can result in stress cracks and non-functional components.

Before moving forward with your project, determine the type of chemical the component will be exposed to and the frequency and duration of the exposure. Then work with an engineer (and a reference guide) to determine the best material for your project.

When projects require contamination-level chemical resistance, we suggest:

• CTFE
• Teflon
• Acetal/Delrin

The need for moisture resistance spans industries. Weather, sterilization techniques, and overall operating environments all require components that can operate despite some degree of exposure to moisture. Choosing the wrong material without a proper barrier coating can cause moisture absorption that will lead to decreased dimensional stability. The result will be a component that doesn’t operate consistently – or at all.

To select the right material with consistent reliability, engineers need to verify the operating environment's type of moisture (water, steam, lubricant, etc.) and how often that moisture will be present. A component destined to operate underwater needs a very different material than one that will experience occasional bursts of steam.

Some materials that have great and reliable moisture resistance are:

• PPS
• Ultem
• Radel

While these 3 factors need the most consideration, engineers and designers need to think holistically. They need to consider also the mechanical factors (e.g. strength, pressure) among other project requirements to pick the best material. Read our Design Guide for further information about those factors and how to choose wisely.

All in all, the bottom line is that a component destined to be used in extreme operating conditions must be machined well and use the best material possible. The experienced engineers at Controlled Fluidics can help on both fronts. Contact us today!