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HF welding of PVC and other plastic eyelets

What is HF welding or High Frequency welding?



HF welding is an abbreviation for high frequency welding (also often known as Radio frequency welding (RF welding) or electrical heat sealing) is a manufacturing process where two plastic parts are welded together using an electromagnetic field. You can read more on the actual process here.

Plastic eyelets made of PVC (Vinyl) and a number og other materials are ideal candidates for mounting with HF welding.

Plastic and PVC eyelets that are HF welded will partially melt and fuse together with the foil and create a strong flexible bond. This is especially true when working with mesh materials - e.g. in advertising banners, sun screens or building wraps.

Common products manufactured with high frequency welding are tarpaulins, tents, ceilings, advertising banners, waterbeds, inflatable boats, medical and especially blod and urine-bags, tensile structures, conveyor belts, rain clothing etc.



How to weld plastic eyelets with HF welding

Three main options exists for welding of PVC and plastic eyelets: Using a standalone tools, a manuel eyelet setter / punch, or using a fully automated machine:


Welding tool

Eyelet setter

Eyelet machine


The three main parts involved in High frequency welding are:


Parts needed for HF welding of plastic and PVC eyelets


Carmo supplies electrodes for each of our weldable componenents and a series of machines for automatic welding of eyelets.



Advantage of HF welding PVC and plastic eyelets

The great advantage of HF welding is the speed of welding: The material is heated from the inside and fuses quickly, within few seconds.

Compared to high frequency welding, a lot of other methods (hot air, infrared radiation, laser) the energy /heat is supplied from the outside. This means that the heat must first penetrate the material in order to heat the contact-surfaces, thus risking to burn the top layer of the welded material.

You could compare this to heating your food in the microwave oven vs in a traditional oven.



Why use PVC and plastic eyelets?

Carmos HF weldable plastic eyelets are strong, flexible and do not rupture. We blend the right composition of raw materials to meet your specific demands for performance, weather conditions, UV radiation exposure, etc.

Compared to metal grommets, welded plastic eyelets will fuse together with the foil and result in a joint that is significantly stronger and can withstand significantly higher pull forces. This is especially true when working in mesh materials.

They offer offer more advantages for the outdoor vinyl banner producer, e.g.:

  • Outperforms metal grommets in flexibility and strength
  • Durable in harsh environments. Will not rust and leave stains
  • No hemming required,
  • the only solution for single layer vinyl.
  • "Invisible" placement of eyelets on the back of the banner is possible.
Weldable eyelets could tripple the your banner strength

(click for larger images)


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Carmo has a 60 year track record of delivering highly specialized technical and medical components.

We design, produce and sell quality injection moulded plastic components globally. We service industries as diverse as Medico, Maritime, Mining, Agriculture and Automotive.

Quality, Service and Flexibility are the key words of our production and in all aspects of our interaction with our customers. We are focused on minimizing hassle and maximizing service, while helping our customers turning ideas into products.

We are based in Denmark and run a highly automated production. By leveraging robotics and vision technology, we are able to deliver components with very high quality, well-defined properties and functionality at competitive prices.

We put all our knowhow and experience in ensuring our customers an easy integration and stability in their products and production.

From our sales offices and inventories in Denmark, France and the UK we are able to supply our core markets and customers within days.

Our core competency is components for High Frequency welding, with a special focus on valves, eyelets and components for medical bags. We maintain PVC as a special focus, however deliver 50% of our turnover in other plastic materials.

Our four main business areas are:

Technical Components Medical Components Modular storage boxes Product Development Services

Weldable eyelets and fittings

Valves for inflating, over pressure and vacuum

Threaded nozzles and caps

HF/RF welding machines

Market leader in drainage valves, connectors and fittings for medical bags

Customization and OEM production

Modular, high quality transparent boxes

Approved for storage of food and fragile objects

Sold under the brand UltraPlast

Product design and realisation

Pilot production, test and documentation

Ramp-up and production

In addition to above, our main manufacturing strength is quality injection moulding in all technical
plastics - including PVC. Carmo PVC products are made in a number of different PVC grades - all special and protected Carmo recipes.

We can manufacture in cleanroom down to class 10.000.
2K moulding

We have chosen quality to be the keyword for our production and
distribution. Since 1993 Carmo has been holding an ISO certification and we are today ISO certified according to ISO 9001:2008.