Understanding High-Frequency (HF) Welding

March 21, 2023

High-Frequency (HF) welding is a method of joining thermoplastic materials using high-frequency electromagnetic waves. Known in the United States as Radio Frequency welding, this welding method is an efficient, and precise alternative to other welding techniques such as Hot Air and Hot Welding.  As HF welding gains momentum in the United States, it is important to understand the benefits and how it may work for your business!


How does HF welding work?

High-Frequency welding works by passing high-frequency electromagnetic waves through the thermoplastic material to be joined. The material is then heated to its melting point and pressure is applied to fuse the two pieces together. The frequency of the waves determines the speed, heat, and depth of the welding process, and the pressure applied controls the strength of the bond.

The high-frequency waves are generated by an electrode and are transmitted to the material through a die. The die focuses the energy and concentrates it onto the joint area, ensuring a precise and consistent weld every time.


What is high-frequency welding used for?

High-frequency welding has become a widely accepted technology for bonding polyvinyl chloride and other materials. Welding produces outstanding results with impressive durability.  High-frequency welding is used in the production of a wide variety of products.  Ranging from small medical bags and inflatable toys to large tarps, covers, and banners. HF Welding is also used in the manufacturing of custom dies and shapes.  Using the bar and customer dies and tooling, the RFlex machine offers the customer to create unique shapes and logos. 

This method of welding creates strong, airtight seams in these materials, which is especially important for applications that require a high degree of durability and resistance to tearing and puncturing. The process can also be used to weld together multiple layers of the same material, which can be useful for creating thicker, more robust products. Overall, high-frequency thermoplastic welding is a versatile and effective technique for joining a wide range of materials used in various industries.


Image: truck siding has long straight seams that are created using High-Freqency  welding

Applications of HF Welding

High-Frequency welding is used in multiple industries that create straight and uniquely shaped products. From consistent straight welds like tarpaulins, high-speed rolling doors, and billboards to unique shapes such as oil booms, tent peaks, water tanks, and more. Many companies require multiple technologies for different seams in their process.

Here are some industries and other technologies that use Radio Frequency or High-Frequecy today:

  • Tarps

  • Tents

  • Billboards

  • Inflatables

  • Water Tanks

  • Oil Booms

If you have a question on your industry and if HF will work for you, reach out to our team of experts today!  

Disaster-Oil BoomsImage: Oil boom used to create dams and stop contamination


Advantages of HF Welding

From precision to versatility, there are countless advantages to RF or High-Frequency Welding.  

  • Consistent: The precise nature of the process ensures that the weld is consistent and accurate, leading to a high-quality final product.  With the movement of the bar or dies versus the material, you do not need to worry about issues with the seam or weld.  

  • Flexibility: The process can be easily adapted to different materials and thicknesses, making it suitable for a wide range of applications.  With a large variety of weldable materials, the applications are endless that can be welded on an RF machine.  If you are curious if your material is weldable, check out our Weldability Chart!

  • Airtight and WaterProof Seams: with HF welding, the chemical makeup of the material changes and bonds together in a more secure way.  Creating an airtight seam that is perfect for inflatables, tents, and countless other applications. 

  • Energy Efficiency: HF welding uses less energy compared to other welding methods, reducing both energy costs and the carbon footprint of the manufacturing process.

  • Versatility in Shapes: With the dies and bars, you have more options when it comes to unique shapes.  Opening up the applications that can be done on RF versus other methods of welding.  


What materials can be HF welded?

While high-frequency welds are strong and reliable, not all material can be welded successfully on the RFlex or RFlex travel machine.  High-frequency thermoplastic welding is suitable for a wide range of thermoplastic materials such as polyethylene, polypropylene, polyurethane, PVC, and many others. The welding process involves the use of high-frequency electromagnetic waves to create heat, which melts the plastic materials to form a bond. To get the best results, you will want both sides of the product to be the same.  You cannot weld 2 different types of material together as the bond will not be created due to the variation in their makeup.  Trying to weld two different types of material will not create a durable bond and will fail to hold.  

There are upwards of 30 different types of material that can be welded using the High-Frequency method. Or check out our weldability chart to quickly check if high-frequency welding is right for you!  You can also send material in to have it tested on the actual machine!  While high-frequency welds are strong and reliable, not all material can be welded successfully on the RFlex or RFlex travel machine.  Miller Weldmaster will work with you, the customer, to test all material and product on the RFlex machine.  If you are interested in learning more, or, having Miller Weldmaster test your material, contact us today!


Image: Dies used to produce High-Frequency welds


HF welding is a versatile, efficient, and cost-effective method for joining thermoplastic materials. With its many advantages, including speed, precision, flexibility, and energy efficiency, it is no wonder that HF welding has become such a popular choice in a wide range of industries. Whether you're in packaging, medical, automotive, or textiles, HF welding is a reliable and effective solution for your welding needs.

Miller Weldmaster Solutions

Miller Weldmaster has multiple solutions for those customers interested in High Frequency or Radio Frequency welding! For the most versatile RF welder in the industry, Miller has the RFlex.  The RFlex was designed for the production of PVC or PU products.  With enhanced features such as a foldable trough for better material handling and autotuning for consistent welds, your production will be even more efficient and reliable.

If your application requires long runs where a straight seem with more automation, the RFlex Travel would be the perfect welding machine for you!  With the traveling head, the RFlex travel allows you to line up your material with the lasers on the track, press a button, and let the travel head do the welding for you. Producing a reliable and effortless production.


If you are interested in learning more about High Frequency, please reach out to our Team of Experts today!  

Topics: Radio Frequency

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