Frequently asked questions

HF welding (High Frequency welding, also called RF welding) uses high-frequency electromagnetic energy to excite the molecular structure of thermoplastics, heating them rapidly from within. A die under press pressure determines the final shape of the welded part. The result: strong, durable, airtight or watertight seals between plastic components and PVC or PU substrates. For the full explainer + how Carmo applies HF welding in practice, see What is High Frequency welding.

The most common HF-weldable materials are polyvinylchloride (PVC) and polyurethane (PU). EVA, PET-G, and several PET-family formulations also weld successfully via HF. HF-activated adhesives can join materials not normally considered compatible, for example sealing thermoformed blisters to cardboard for packaging applications.

PVC remains the right material for a large class of medical and technical components: it HF-welds cleanly, holds up under demanding service conditions, and has a long, well-understood track record in medical devices. The sustainability question is real, and Carmo addresses it directly: Carmo works proactively toward sustainable use of PVC, is working to completely phase out DEHP plasticisers, and actively trials new and even organic plasticisers. Many Carmo PVC products are already DEHP-free, and the list is growing. Where a non-PVC material is the better fit for a project, material choice is part of the design and development engagement rather than a fixed default.

Plasticisers are needed when working in PVC, which is inherently a stiff material. Carmo works actively to introduce new and more sustainable plasticisers, and many Carmo PVC products are already DEHP-free, with the list growing. For medical components, material and additive selection is matched to your device’s regulatory requirements (REACH, RoHS, and your device-file specifics) during the design engagement, not treated as a one-size-fits-all recipe.

Yes. Weldable PVC and plastic eyelets and clip grommets are one of Carmo’s core technical-component families: round, oval and square eyelets, clip grommets, ready-to-go borders and corners, and the patented Carmo Metal Reinforced Eyelet (3–4× the pull strength of a traditionally mounted metal grommet, plus the wear resistance of metal). They mount via Carmo’s own HF welding machine line (CP9, CP8 and others) into tarpaulins, banners, marine covers, and harsh-environment applications. Full range and detail: /en/technical-components/grommets-and-eyelets/.

Yes. Carmo’s HF-weldable PVC inflation valves serve grey-zone premium and safety applications: rescue equipment (life rafts, life jackets), pressure-relief medical mattresses, premium sleep systems, and industrial inflatables. The range covers free-flow and non-return types across several sizes and profiles, engineered to weld cleanly on your own production line. Detail: /en/technical-components/valves/inflation-valves/.

Yes. Carmo provides samples and advice to help you evaluate components for your project. Request samples here, or contact [email protected] / +45 4912 2100 to discuss your specific need.

Carmo generally ships in standard pack sizes and accommodates requested quantities wherever possible. Minimum order quantities vary by product type; where a product needs extensive manual handling, an administration fee may apply. For development and prototype work there is no rigid MOQ; see rapid prototyping. Contact [email protected] for the minimum order quantity on a specific product.

Carmo ships to most parts of the world. Specific delivery routes and Incoterms are settled during scoping; contact [email protected] to confirm delivery to a specific country.

Bank transfers. Specific terms and currency settled during scoping.

Yes. Carmo encourages potential customers to visit Carmo in Espergærde. The visit lets you meet the engineering team that would handle your project and see the production environment first-hand. Contact [email protected] to arrange.

Carmo’s sales and engineering team carry over 100 years of combined HF welding experience and routinely consult on equipment selection. The right HF welding equipment depends on your component geometry, production volume, and integration with your existing production line. Carmo’s own machine line (the EP3 manual, CP9 automated single-side, and CP8 automated double-side) paired with a CE-marked turnkey HF generator solution from Carmo’s strategic partner Forsstrom forms a coordinated system; sales and engineering work together to scope what fits your application.

For prototype components in production material, see /en/services/rapid-prototyping/; Carmo Print Moulding is the development engagement model. For prototype HF welding equipment for special projects, scoping happens case-by-case with the engineering team. Contact [email protected] to discuss.