Auto Molding PTFE Seals and Seats
by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Auto Molding for PTFE Components: High-Volume, High-Precision Solutions

Auto molding for PTFE components is a highly effective way to manufacture high-quality, high-volume runs of parts, including seals, seats, and valves. This blog post provides an overview of auto molding, then discusses when it is appropriate to use for PTFE parts as well as the benefits of using it.

What Is Auto Molding?

Auto molding, also known as compression molding, manufactures components by forcing heated plastic into a heated, open mold and then compressing it with an upper mold. It supports automated press cycling, and several parts can be made at once using multi-cavity molds. It is an efficient, high-precision method of manufacturing parts in an efficient, cost-effective manner without sacrificing quality and precision. 

Auto Molding Process

Here is a summary of the auto molding process.

  • Create Molds: Tool and die makers fabricate the molds through various methods such as precision machining, die casting, or advanced techniques like 3D printing. The mold design must support tight tolerances and repeatability to ensure accurate and consistent product quality.
  • Set Up the Machine: The molding equipment is prepared by cleaning the molds, preheating as necessary, and configuring the press settings according to the material and part geometry.
  • Prepare the Charge: The appropriate PTFE material (can be virgin or filled) is selected and measured to the correct amount. 
  • Insert the Charge: The material charge is placed at the center of the bottom mold cavity to ensure uniform compression.
  • Compress the Part: The mold is closed, and a combination of pressure and heat is applied to shape the component. 
  • Release the Part: Once the part is fully formed and cooled, the mold is opened, and the part is removed.
  • Clean and Finish: Any excess flash is trimmed, and additional finishing steps are performed. Then the part is ready for quality inspection. 

When Auto Molding Makes Sense

Auto molding is cost-effective with low to medium production runs of straightforward, simple geometries (rings, cylinders, discs). It supports the manufacturing of thick-walled parts as well as those with large cross-sections. Auto molding is often preferred to prototyping and early-stage development, but is equally applicable to final parts. In addition, tooling for compression molding is typically less complex and less expensive than other manufacturing options, including injection molding and machining.

Auto molding allows for better control over PTFE composition and orientation, which can be beneficial in specialty applications like medical or aerospace components. In addition, some fillers are more easily processed due to lower shear forces and better filler retention in the final part.

Advantages of Auto Molding for PTFE Components

Auto molding supports high-volume production runs with shorter lead times for large batches. Another key benefit is consistent mechanical properties across parts and scalable tooling. It leads to reduced scrap rates. Lower tooling costs and efficient production contribute to auto molding as a cost-efficient option for the manufacturing of many PTFE parts. 

Applications That Rely on Auto Molding

Numerous industries depend on auto molded PTFE parts, including semiconductor manufacturing, aerospace, medicine, and chemical processing. Parts include bearings, bushings, sleeves, piston rings, gaskets, seals, valve seats, diaphragms, and bellows.

Conclusion

Auto molding offers a reliable, efficient method for producing precision PTFE components at scale. Its suitability for high-volume runs, straightforward part geometries, and tight tolerances makes it an optimal solution for applications where consistency, repeatability, and cost-efficiency are critical. From aerospace to semiconductor manufacturing, auto molding continues to deliver proven value across industries that depend on high-performance polymer parts.

If you are looking at manufacturing options for PTFE components, contact us at Advanced EMC today. Our team will work with you from material section through manufacturing to ensure you get the parts you need.

PTFE Spring Energized Seals for Cryogenic Applications
by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Extreme Sealing: How Spring-Energized Seals Outperform in Harsh Environments

Extreme conditions such as cryogenic temperatures, aggressive chemicals, pressure cycling, and vacuum pressures pose significant challenges for traditional sealing methods. However, spring-energized seals, with their unique ability to maintain consistent contact forces even under severe thermal and mechanical stress, stand out as a superior solution in these harsh environments.

Combining high-performance polymers, such as PTFE, PEEK, and UHMW-PE, with a precision-engineered spring element ensures that these seals maintain consistent contact forces even under severe thermal and mechanical stress. The result is a reliable, long-lasting sealing solution capable of withstanding everything from dimensional changes to media that would degrade or deform conventional elastomeric seals, providing a sense of security in your investment.

In this post, we will explore how spring-energized seals enable extreme sealing performance across a range of demanding applications.

The Spring-Energized Seal Architecture: A Foundation for Extreme Sealing

Spring-energized seals make use of a mechanical energizer (the spring) encased within a polymeric seal jacket. Because they are energized, these springs maintain an effective seal force even when faced with extremes in temperature, pressure, and dimensional variations. Various spring-energizer sizes and geometries allow engineers to customize them to specific applications, if needed. There are also options available with the jack material, including fillers to enhance seal performance.

Challenges of Sealing in Extreme Environments

Cryogenic and Vacuum Conditions

Cryogenic temperatures and vacuum conditions create interesting challenges for reliable sealing solutions, including potential issues with outgassing, brittle behavior, significant dimensional changes, and issues with lubrication. 

Aggressive Media

Harsh environments can also include potential chemical incompatibility with the media as well as extremely aggressive chemicals such as acids, solvents, reactive gases, and sterilizers. Such issues can lead to excessive permeation and dimensional instability.

Pressure Cycling and Dynamic Loads

Pressure fluctuations and mechanical cycling have a heavy impact on seal performance, especially over time. Loss of contact with the sealing surface, extrusion, and fatigue, all of which can lead to seal failure and loss of consistent contact with the sealing surface. These challenges pose a significant problem for rotating equipment and actuators in particular.

Materials for Extreme Sealing

Material selection plays a crucial role in achieving extreme sealing. High-performance polymers such as PTFE, PEEK, and UHMW-PE, known for their unique properties and resilience in harsh conditions, are commonly utilized in extreme sealing applications.

Three high-performance polymers commonly utilized in extreme sealing applications include PTFE, PEEK, and UHMW-PE. 

PTFE is known for being chemically inert, self-lubricating, and possessing an ultra-low coefficient of friction. It also exhibits a wide operating temperature range of -250°C to +260°C. It is proven to perform reliably in harsh environments. PTFE also has minimal outgassing in a vacuum and is a good choice for cryogenic aerospace systems, medical sterilization equipment, and semiconductor processing. 

PEEK exhibits high strength, temperature resistance up to 260°C, and resistance to both radiation and hydrolysis. It maintains its dimensions very well under extreme pressures and can handle dynamic loads and cycling. PEEK spring-energized seals are often found in pumps, chemical reactors, aerospace fuel and hydraulic systems, as well as in both medical diagnostics and implants. 

UHMW-PE has excellent abrasion resistance and impact strength, as well as toughness even at extremely low temperatures. It also exhibits low moisture absorption and is both lightweight and durable. UHMW-PE spring-energized seals are often used in LNG (Liquid Natural Gas) transfer systems and cold storage equipment.

Conclusion

Extreme sealing demands more than conventional solutions can offer. With applications involving cryogenic temperatures, aggressive media, pressure swings, and vacuum, spring energizers outperform more traditional approaches. 

By combining engineered polymers like PTFE, PEEK, and UHMW-PE with a resilient spring element, spring-energized seals demonstrate their reliability even when everything else is under stress. They flex, adapt, and hold their seal even when conditions shift fast, instilling confidence in their adaptability under changing conditions.

If you need sealing performance you can count on in the harshest environments, Advanced EMC can help. Contact us today to discover the ideal sealing solution for your application.